Extrusion: Second Edition                                                      Copyright © 2006 ASM International®M. Bause...
10 / Extrusion, Second EditionThey are produced on horizontal presses and                          The high density makes ...
Chapter 2: Extruded Products / 11                                                                     pendent because of t...
12 / Extrusion, Second Edition                                                                  truded products were used ...
Chapter 2: Extruded Products / 13minum extrusion tools. This has played a                           same round container b...
14 / Extrusion, Second Editionlarge profiles the length of the rolling stock that                       a higher alloy cont...
Chapter 2: Extruded Products / 15signs offer significant advantages. Aluminum al-                 one of the largest North ...
16 / Extrusion, Second EditionFig. 2.11   Diesel power car of the Trans Europa Express (TEE) on the Rhine section   The de...
Chapter 2: Extruded Products / 17which set a world record of 515 km/h (320 mph)        Ing 91]. Further development result...
18 / Extrusion, Second EditionFig. 2.13   High-speed ICE1 of the Deutsche Bahn AG framed by the large sections of the carr...
Chapter 2: Extruded Products / 19Fig. 2.14   Passenger carrier design on the high-speed train ICE1 of the Deutsche Bahn AG...
20 / Extrusion, Second Edition   Silo wagons of this design were designed and                      load is approximately 1...
Chapter 2: Extruded Products / 21Fig. 2.17   Tilting trailer walls of an open goods wagon finished in extruded hollow secti...
22 / Extrusion, Second EditionFig. 2.19   Design and construction of the coal silo wagon shown in Fig. 2.18Fig. 2.20   Old...
Chapter 2: Extruded Products / 23window frames in extruded and age-hardened                    years, high demands were pl...
24 / Extrusion, Second Editionnumerous extruded profiles are used in car bod-                  cross-sectional geometry and...
Chapter 2: Extruded Products / 25side air bag is increasing because the good                          However, in cars thi...
26 / Extrusion, Second Editionday is the Audi A8 and the Audi A2 with the                     the age-hardening alloys AlM...
Chapter 2: Extruded Products / 27Fig. 2.29         Space frame of the Audi A2 in extruded sections, sheet and castings. So...
28 / Extrusion, Second Editiongions never lost sight of this basic principle; it                 this system are in operat...
Chapter 2: Extruded Products / 29                                                                    The increase in the t...
30 / Extrusion, Second Edition   The use of aluminum alloys for truck and                             Planked superstructu...
Chapter 2: Extruded Products / 31pacity. Aluminum is well suited for this. Finally,                in the future the domin...
32 / Extrusion, Second Editionreinforced plastic materials do have a lower den-                     fuselage in the form o...
Chapter 2: Extruded Products / 33   The fraction of extruded profiles within the                     aluminum industry has ...
34 / Extrusion, Second Editionerties, but also largely meet the corrosion re-quirements of the aerospace industry. In con-...
Chapter 2: Extruded Products / 35                                                                 ● The draft of the ship ...
36 / Extrusion, Second Editionmetric tons of aluminum. Modern large aircraft                     porting structures within...
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
ASM - Extruded Products
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ASM - Extruded Products

  1. 1. Extrusion: Second Edition Copyright © 2006 ASM International®M. Bauser, G. Sauer, K. Siegert, editors, p 9-58 All rights reserved.DOI:10.1361/exse2006p009 www.asminternational.orgCHAPTER 2Extruded ProductsGunther Sauer* ¨ THE HOT-WORKING PROCESS extrusion main applications of extrusion. This process canis used to produce semifinished products in the also be used for certain copper alloys; however,form of bar, strip, and solid sections as well as the materials used for the extrusion tooling can-tubes and hollow sections. The high mean com- not withstand the thermo-mechanical stresses.pressive stresses in the deformation zone of the Billet-on-billet extrusion enables coiled tubes ofcontainer enable materials to be worked that long length to be produced, for example, alu-cannot be processed into semifinished products minum alloy heat exchanger tubes and tin andby other hot-working processes, for example lead alloy multicore solders.rolling, because of their limited workability. The The extrusion process generally produces aextrusion process also enables semifinished semifinished product close to the finished sizeproducts to be produced from powder metal- with materials with working temperatures up tolurgy-based materials, composite materials, and 600 ЊC. This occurs in one production step inthe production of semifinished products from contrast to other processes used to form semifin-clad composites with material combinations in- ished products. Therefore, the design of thecluding aluminum/copper and aluminum/steel cross section of the semifinished product canusing the cladding process. Finally, the sheath- practically ignore any limitations associateding of electrical cables with lead or aluminum with subsequent processing operations. Thealloys using the transverse extrusion process has most suitable cross-sectional geometry can bebeen a standard process for a long time, as has freely selected for the specific application. Sim-the production of multicore solders with inte- ple matching of the cross-sectional geometry ofgrated flux cores using the same process. the extrusion to the static, dynamic, and geo- The pushing of the material being extruded metric requirements combined with the widethrough the shape-forming aperture of the extru- range of joining methods in assembly character-sion die enables cross-sectional shapes to be pro- ize the high functionality of the products pro-duced that cannot be manufactured by any other duced by this working process.hot-working process. The favorable deformationconditions with nonferrous metals such as tinand lead alloys as well as magnesium and alu- 2.1 Tin and Lead Extrudedminum alloys with good welding properties and Products with a Deformationworking temperatures that can be withstood by Temperature Range of 0 to 300 ЊCthe tool materials also enable the billet to be di-vided into several metal streams, and then re- Tin alloy extruded products are mainly softwelded in the shape-forming region of the ex- solders with or without flux cores for use in elec-trusion die to form tubes and hollow sections. trical engineering and electronics. Tin alloys areThe production of hollow sections is one of the significantly more common than are lead alloys.*Extruded Products from Materials with a Working Temperature Range of 600 to 1300 ЊC, Martin Bauser
  2. 2. 10 / Extrusion, Second EditionThey are produced on horizontal presses and The high density makes lead alloys particularlydrawn, coiled, or wound to the customers’ de- suitable for radiation and noise protection. Goodsired finished sizes on multispindle wire draw- workability combined with low melting pointsing machines as shown in Fig. 2.1. The produc- means that lead alloys are also used for the man-tion processes are described in section 5.3. Other ufacture of soft solder, which is described in sec-extruded products are anodes used for electro- tion 5.3. Lead alloys, similar to tin alloys, arechemical plating with tin, for example, tin plat- also suitable for the production of customing for corrosion protection. Tin alloy extruded shaped anodes as shown in Fig. 2.2 for electro-products are also used in the manufacture of chemical plating. An example is the approxi-chemical equipment. mately 20 lm thick and soft running surface in Lead alloy products have lost a large part of plain bearings such as bearing shells and bushes.their market since World War II because of the Although the use of specific lead alloys for thetoxic properties of these alloys. Even in the production of cable sheaths cannot be classified1950s, extruded lead alloys were still used for as environmentally harmful, the cable industrywater supply pipes up to the fittings on sinks. prefers alternative plastic and aluminum-baseThese materials were also used for extruded wa- materials. High-voltage cables are still sheathedter waste pipes. This has changed completely. in lead. Spacers for double glazing (Fig. 2.3) areLead alloys may no longer come into contact also extruded from lead alloys. Fishing nets andwith food products because they can form very curtains are usually weighted with lead linespoisonous lead salts. Drinking water counts as a produced by horizontal extrusion. Some exam-food and, therefore, lead drinking water pipes ples are shown in Fig. 2.3.are no longer permitted. Nevertheless, lead al- Lead alloys can be made relatively resistantloys offer a range of advantages that make al- to corrosion by the addition of tin. They can alsoternative materials difficult or even impossible be recycled relatively easily. However, the en-to find. Lead alloys have good resistance to vironmental political pressure will affect the cur-fluoric and sulfuric acids as well as phosphoric rent applications because of the toxic propertiesacid, ammonia, chlorine, and soda. They are of this material.therefore useful alloys for the chemical industry. Fig. 2.2 Extruded sections and tubes in lead base and tin al-Fig. 2.1 Soft solder with one or more flux cores (tube solder), loys for use as anodes for the electrochemical coat- extruded and drawn to the finished dimensions and ing, supply tubes for aggressive media, materials for seals andcoiled on plastic spools. Source: Collin radiation protection, etc. Source: Collin
  3. 3. Chapter 2: Extruded Products / 11 pendent because of the hexagonal lattice struc- ture. In addition, any partial cold working of magnesium components, as is necessary, for ex- ample, for the aluminum alloy side door beam in Fig. 2.24, in the section “Passenger Cars,” is practically impossible because of this hexagonal lattice structure. Magnesium alloys naturally have good machining characteristics. Unlike aluminum alloys, they do not need any chip- breaking alloying additions such as lead and bis- muth. Consequently, extruded semifinished products are eminently suited to the production of turned components including ones in daily use, for example, pencil sharpeners. A typical profile can be seen in Fig. 2.4 [Fuc 96]. In the past, the market for extruded magnesium alloy products was limited in spite of the products’ good properties, in particular, their low density. The reason for this is both the lattice-related poor cold-working properties, and the hot-work- ing properties that are very alloy dependent. TheFig. 2.3 Extruded solder with several flux cores, lead main application for magnesium alloys is, there- sheathed cable, and window spacer sections in leadalloys for double glazed windows, as well as lead lines for fishing fore, still cast components. The most well-nets and curtain weights. Source: Collin known application is the engine and gearbox housing used after World War II in the air-cooled flat twin engine in the Volkswagen Beetle.2.2 Magnesium and Aluminum Basically, magnesium products are used Extruded Products with a Working where the weight saving, e.g., components with Temperature Range of a low mass, has high priority. The main areas of 300 to 600 ЊC application are automobile and machine manu- facture. The extruded products shown in Fig. 2.5 and 2.6 are suited primarily for machine com-2.2.1 Magnesium Alloy Extruded Products ponents subjected to high acceleration and brak- Magnesium alloys are light materials with ing, for example, in textile machine componentsuseful mechanical properties. Their density of [Fuc 96]. These products are also used in theapproximately 0.0018 kg/m3 is about 36% less aerospace industry and in military applications.than that of the aluminum alloys. The Young’smodulus (E) is approximately 45 GPa and,therefore, about 65% of the E-modulus of alu-minum alloys. For this reason, they are, in prin-ciple, more interesting than aluminum alloys asa construction material for light components.However, the corrosion resistance of magnesiumcomponents is not usually as good as that of alu-minum components. They, therefore, have to begiven more surface protection. The corrosionsensitivity of magnesium alloys can be loweredsignificantly by reducing the trace element con-tent of copper, iron, manganese, and nickel intothe ppm region. The corrosion behavior of high-purity magnesium alloys approaches that of alu-minum alloys. This has considerably increasedthe interest in magnesium alloys as construction Fig. 2.4 From left to right: Section in MgAl2Zn for the pro- duction of pencil sharpeners, two sections inmaterials. However, the mechanical behavior of MgAl3Zn for warp knitting machine, and test arm sections formagnesium components is very directional de- disc magazines. Source: Fuchs-Metallwerke
  4. 4. 12 / Extrusion, Second Edition truded products were used to a significant degree in the period before World War II. Complete fu- selages in hot-rolled and section-reinforced magnesium sheets were produced for small air- craft [Bec 39]. Bus trailers were manufactured almost entirely from hot-worked magnesium al- loys, including a welded frame of extruded mag- nesium tubes clad with magnesium sheet [Bec 39]. Welded seat frames for passenger aircraft were made from extruded magnesium tubes. The increasing interest by the automobile in- dustry in light extruded products in order to save energy by reducing vehicle weight has resulted in increasing examination of extruded semifin- ished products in magnesium alloys. This will gain in importance if the further development of the magnesium alloys results in higher values of static and dynamic strength and improved work- ing and corrosion properties. It can, therefore, be assumed that magnesium alloys will also be used to an increasing extent for load-carrying components as well as safety components, which require a good proof stress and elonga-Fig. 2.5 Extruded section in MgAl3Zn for textile machines. tion. Magnesium alloys are, moreover, as easily Source: Fuchs-Metallwerke recycled as aluminum alloys. The extrusion of magnesium alloys is de- scribed in section 5.5. 2.2.2 Aluminum Alloy Extruded Products The main application of the hot-working pro- cess extrusion is in the general production of bars, tubes, and wire in aluminum alloys and, in particular, the manufacture of aluminum sec- tions. No other material is used as a semifinished product to the same extent in practically all areas of technology. Acceptable materials properties and modulus of elasticity, weight saving from the low-density, good surface quality, good di- mensional accuracy and minimum subsequent machining, and ease of recycling make alumi-Fig. 2.6 Hollow section in MgAl3Zn for the external rotor of a turbocharger for automobile engines. Source: num alloys both economically and environmen-Fuchs-Metallwerke tally interesting. These properties, as well as the largely unrestricted shape of the cross-section geometry, are the basis for the trend to the de- Magnesium alloys are being developed fur- velopment of ever more functional componentsther because of their suitability for light com- with good appearance and corrosion resistance.ponents with the intention of achieving higher The reason for the predominance of alumi-static and dynamic mechanical properties as well num profiles in extrusion is due to the moderateas improving the working properties [Tec 96/97/ working temperatures of the aluminum alloys.98, Gar 93]. Interest in magnesium alloy com- The extrusion tooling can then withstand theponents is increasing, particularly in the auto- thermo-mechanical stresses. In general, themobile industry. working temperature of aluminum alloys is be- In the past, hot-worked semifinished products low the annealing temperature of the hot-work-in the form of magnesium alloy sheet and ex- ing tool steels normally used to manufacture alu-
  5. 5. Chapter 2: Extruded Products / 13minum extrusion tools. This has played a same round container by using spreader tech-decisive role in the development of the design niques. West European aluminum extrusionof extrusion tooling for aluminum profiles. Very plants today can produce extruded sections rang-demanding aluminum profiles can now be pro- ing from 10 g/m to 130 kg/m. The section “Ex-duced. In recent years, the development of ex- trusion of Semifinished Products in Aluminumtrusion tools for the production of large profiles Alloys” describes the extrusion processes usedhas been particularly successful. today for aluminum alloys. Large profiles are used today in almost all ar- The large profile technology was first devel-eas of industry. In Europe alone there are four oped in the second half of the 1970s for the con-large extrusion presses with press powers of struction of railway rolling stock. Until then, the72,000 to 100,000 kN used to produce them. technical advantages of aluminum aroused someStandard solid and standard hollow sections interest in its use as a construction material, butwith a circumscribing circle diameter of approx- the classic method of construction of railcarimately 600 mm can be produced from 650 mm body shells using sheet and small extruded pro-round containers on the 98,000 kN direct extru- files could not compete with the proven con-sion press operated by Alusuisse in Singen (Ger- struction material steel. A light steel design ofmany) (Fig. 2.7). Solid flat sections with maxi- the body shells was about 50% cheaper than amum dimensions of 800 by 100 mm (width by comparable one made from aluminum alloys.height) and flat hollow sections with a maximum The light steel construction was, therefore, pre-size of 800 by 60 mm can be produced from the ferred. This changed with the introduction ofFig. 2.7 Large sections produced from containers with a circular bore on the 98,000 kN direct extrusion press in Singen. Adapted from Alusuisse
  6. 6. 14 / Extrusion, Second Editionlarge profiles the length of the rolling stock that a higher alloy content) do not offer the samecould be automatically welded to each other. profile geometry options as the low alloyedThe assembly cost of the railcar body shells and easily welded aluminum alloys such ascould be reduced to an extent that not only com- AlMgSi0.5 and AlMgSi0.7.pensated for the higher material cost of the alu- Figure 2.9 shows a body shell of the Parisminum but also reduced the total cost of the alu- Metro type MF 77 utilizing welded large profileminum wagon by approximately 30% of that of technology. The carriage cross section is shownthe steel wagon [Wis 92, Cor 95]. in Fig. 2.8, together with some of the large pro- Aluminum designs using large profiles that files necessary for its construction. Figure 2.10simplified assembly then started to compete with shows the right longitudinal rib needed to stiffensteel. Today, aluminum large profile technology the floor frame of the carriage of the San Fran-has become the economic solution in many cisco Metro in the alloy AlMgSi0.7 on the run-branches of technology. Large profiles enable out table of the 98,000 kN direct press in Singen,several fabricated classic components to be re- Germany.placed. Extruded profiles can be supplied as in- Since the introduction of the integral con-tegral components ready for installation. Large struction utilizing large section technology, alu-profiles not only can replace several classic com- minum designs can increasingly compete withponents but also, in addition to their static and steel designs in spite of the higher material costdynamic functions, take on additional functions of the aluminum. The specific properties of alu-in addition to the overall function with the min- minum alloys play a role here including the lowimum of additional material as shown in Fig 2.8, E-modulus of the various alloys and their lowwhich depicts cross-sectional views of a carriage density. Whereas the E-modulus of aluminumof the Paris Metro [Alz 85]. alloys can be assumed to be approximately 70 The mechanical properties of the aluminum GPa, that of steel is approximately 210 GPa,alloys used for the production of large aluminum three times as high. At the same time, the alu-profiles are adequate for most applications minum designs can be given the same stiffnesswhere good design enables the profile geometry as steel designs to avoid unacceptable bendingto be adequately dimensioned. Nevertheless, dif- or vibrations with significantly lower weightsficult to extrude and, to some extent, moderately because of the low density of 2.7 g/cm3. In ad-difficult to extrude aluminum alloys (those with dition, the elastic properties of aluminum de-Fig. 2.8 Shell of a type MF77 carriage of the Paris Metro, self-supporting in welded large section technology (Alsthom Atlantique/ Alusuisse, 1977/1981) manufactured in sections from the age-hardened material AlMgSi0.7. a, Multifunctional longitudinalstringer; b, construction of the carriage body in the roof longitudinal stringer region; c, weld joint geometry between the individualextruded sections; 1, multifunctional longitudinal stringer; 2, section in roof region with extruded weld preparations; 3, longitudinalstringer to ensure adequate stiffness of the floor group; 4, door mechanism; 5, rainwater gutter extruded on section 1; 6, door seallocation extruded on section 1; 7, roof closure section; 8, roof internal cladding; 9, floor section with extruded legs for the welded jointsas well as extruded center locations; 10, floor group sections with extruded slip seating for tolerance equalization; 11, section view ofthe floor sections with extruded locations for bolt heads. Source: Aluminium Zentrale
  7. 7. Chapter 2: Extruded Products / 15signs offer significant advantages. Aluminum al- one of the largest North American Railway com-loys have significantly higher elastic or energy panies, had built for them, excluding the con-absorption capacity relative to steel because of ventional locomotive design, an aluminum ex-their low E-modulus. This is an advantage that ample of the semistreamlined steam-poweredshould not be undervalued for aluminum designs “Royal Blue,” traveling between Chicago andsubjected to impact loads, for example, in rail or St. Louis [Hug 44]. Only the wheel trucks, cou-road transport vehicles. plings, and buffers of the eight passenger cars were made in steel, all other components from alloys of the alloy group AlCuMg. Long ex- Transport Construction truded profiles were used for the load-carrying Rolling Stock. Efficient low-weight rolling components of the car underframe. Even the col-stock has always been of interest to railway op- umns of the side walls were made of extrudederators. Low weights provide higher load capac- profiles, which were also used for the necessaryities with lower energy consumption and enable stiffening in other places in the carriage. Formedhigher vehicle accelerations when starting and sheets in the same aluminum alloy were used forhigher vehicle deceleration on braking, as well the cladding of the carriage walls, for the trainas a reduction in rail wear. These advantages are car roof as well as for the floor.mainly utilized by local traffic with its many Sections and sheet were joined together withstops, e.g., underground trains, but also by long rivets and arc welding. In addition, the internaldistance traffic, in particular, high speed rail fittings of the carriage, for example, the tablestraffic. and seats in the dining car, also were made from Toward the end of the 1920s, the transfor- aluminum alloys. The eight carriages built com- pletely from aluminum had a total weight of 350mation of weight reduction in rolling stock re- metric tons in contrast to the identically con-sulted in the replacement of steel internal fittings structed steel carriages with 650 metric tons, i.e.,by fittings made in aluminum alloys, initially in 54% of the weight of the steel carriages.passenger carriages. However, in 1934, the Bal-timore and Ohio Railroad Company, at that time Fig. 2.10 Large section in the aluminum alloy AlMgSi0.7 forFig. 2.9 Assembly of an aluminum MF77 type shell for the aluminum carriages for the San Francisco Metro Paris Metro using welded large section technology using large section welded technology on the runout table of thetogether with some large sections ready for assembly. Source: 98,000 kN direct extrusion press at Alusuisse Singen. Source:Alusuisse Alusuisse
  8. 8. 16 / Extrusion, Second EditionFig. 2.11 Diesel power car of the Trans Europa Express (TEE) on the Rhine section The desire to reduce the weight of rollingstock by using aluminum alloys continued to de-velop after World War II. In the second half ofthe 1950s, the German Rail Company operatedseveral of the advanced for the time fast diesellocomotives designated VT 11.5 with a maxi-mum speed of 160 km/h for the lucrative long-distance service. The carriages were made from riveted andspot-welded AlMgSi1 sheets with longitudinaland transverse stiffeners in extruded solidAlMgSi1 sections. Both types of semifinishedproducts were used in the age-hardened temper.Only the main transoms in the under frame ofthe carriage as well as the wheel trucks and cou-pling carriers were made in St52 steel as well asthe coupling system. Figure 2.11 shows this Fig. 2.12 Carriage body of the Trans Europa Express (TEE) indiesel train on the Rhine section, and Fig. 2.12 riveted and spot-welded ALMgSi sheets with lon- gitudinal and transverse stiffeners in extruded sections of theshows a cross section of the conventionally built same alloy in the heat treated temperand thus correspondingly expensive carriage. The multiunit railcar train shown in the pho-tographs with its design that is still modern bytoday’s standards traveled as the Trans EuropaExpress (TEE) in Inter-European long-distance for train speeds up to 200 km/h, speeds thattravel. It consisted of five carriages as well as could be achieved using electric locomotives. Inthe two power cars, each with a diesel engine, the context of the further technical developmentat the front and the back. The basic concept of of the wheel/rail system, the tracks have beenthis diesel multiunit railcar, two external power prepared in the past 10–15 years for significantlycars with the carriages in between, is practically higher speeds. In the near future, the Europeanthe basis of the German InterCity Express trains railways are targeting future high-speed rail traf-ICE1 and ICE2 used today. fic with speeds of 350 km/h (220 mph). Large During the postwar decades, the European na- advances along this path have been made by thetional railways built their rail networks initially French national railway SNCF with its TGV,
  9. 9. Chapter 2: Extruded Products / 17which set a world record of 515 km/h (320 mph) Ing 91]. Further development resulted in intereston test runs. In the next 20 years in Europe, a in the aluminum large profile technology for thecertified rail network for high-speed trains with multiunit railcars for the high-speed rail traffic.multiple current systems and corresponding sig- In this period, the percentage of rolling stocknal and control systems will develop in Europe produced using large aluminum alloy profileto allow inter-European long-distance trains to technology increased out of proportion. At thetravel the national rail networks. These stretches start of the 1970s, it was approximately 5% butare operated for inter-European long-distance has now increased to over 60% [Ing 91].train travel with train concepts that do not follow Whereas the French high-speed train TGV ofthe previously conventional train system of “a the SNCF with its respectable power and provenlocomotive with carriages.” One example is the ability over several years was manufactured inEurostar, a special design of the TGV with a steel, the German Railway decided to build itsmultiple current system that can travel between 280 km/h (175 mph) high-speed trains InterCityParis and London in three hours through the Express 1 (ICE1) and InterCity Express 2 (ICE2),Channel Tunnel. The ICE3 of the DB follows a as well as the 330 km/h InterCity Express 3similar concept. (ICE3), and the 230 km/h InterCity Express T From this perspective, the European railway (ICET), basically using self-supporting weldedoperators have a vital interest in trains with the large aluminum profile technology. The only ex-lowest possible weight for the high-speed rail ception was the power cars of the trains ICE1network as described previously. Low weights and ICE2, which were manufactured in steel tominimize the energy requirements for powering ensure that the driven four axles per power carthese trains as well as the wear of the tracks and could apply sufficient normal force onto thepermit high accelerations when starting and de- track to obtain the torque needed to achieve highcelerations on braking. acceleration and deceleration. The big breakthrough for the economical ap- This, however, results in high track loadingplication of aluminum alloys in carriage con- because each wheel truck of these power carsstruction was the development of the large pro- places a load of 40 metric tons onto the rails.file technology in the 1970s by Alusuisse. This Throughout Europe, however, the track can onlyenabled rolling stock to be entirely and eco- be loaded to a maximum of 34 metric tons pernomically produced from aluminum at a signifi- wheel truck. For this reason, the two high-speedcantly lower cost than comparable rolling stock trains ICE1 and ICE2 cannot use the inter-Eu-in steel lightweight construction. This involves ropean rail network. This, however, changedthe use of easily extruded, relatively corrosion with the introduction of the high-speed traininsensitive, and easily age-hardened aluminum ICE3, which in contrast to the power car train isalloys such as AlMgSi0.5 and AlMgSi0.7, with- designed as a multiunit train; i.e., the drivenout which the very demanding cross-sectional axles are spread along the entire train with everygeometries of the large profiles could not be pro- second axis being driven. These trains apply aduced. These extrusion alloys also provided sig- load less than 34 metric tons weight on the tracknificant freedom in the design of the cross sec- per wheel truck and are therefore suitable fortion to match the strength needed in the participation as multisystem trains for the Inter-component. Until now, this could not be European traffic [Tas 93]. The InterCity Expressachieved with moderate to difficult to extrude T (ICET) is in certain ways a special design ofalloys used previously in the manufacture of the ICE3 fitted with tilting technology devel-rolling stock. Modern concepts were also devel- oped in Italy. With this design, the multiunitoped for the steel lightweight designs of rolling train can travel around curved rails with highstock, but these could not significantly reduce speed. Figure 2.13 shows an example of thethe price advantage of the aluminum large pro- ICE1 framed with a schematic diagram of thefile technology [Aug 77, Wis 92]. The rolling extruded profiles for the floor group, the longi-stock produced from welded large profile tech- tudinal member of the floor group, and the con-nology also offers weight advantages over those necting edge wall profile of the left side of theproduced from the high-strength steels. Both passenger carriage. The joint aids visible on thethese factors resulted in the extensive applica- section corners in Fig. 2.13 for the longitudinaltion of the aluminum lightweight construction joining of the extruded sections are of interest.incorporating the large profile technology in Eu- Finally, Fig. 2.14 describes the design of therope and the United States in the 1980s [Dav 79, passenger carriage with all the large profiles for
  10. 10. 18 / Extrusion, Second EditionFig. 2.13 High-speed ICE1 of the Deutsche Bahn AG framed by the large sections of the carriage cross section shown in Fig. 2.14. Source: Alusuissethe left half of the carriage. In addition, Fig. 2.15 the aim of reducing transport energy costs. Forshows a view of the design of the passenger car- a long time, there has been increasingly rigorousriage of the high-speed trains ICE2 and ICE3. competition with other methods of transport, in- Other European national railways, for exam- cluding road transport. Initially, this involved in-ple, Denmark, England, Italy, and Norway, as creasing the load capacity of the freight wagonwell as Spain and Sweden, have learned the by using individual, usually movable, aluminumvalue of the self-supporting aluminum large pro- alloy components for the same wagon axle load.file technology in welded designs for high-speed Consideration was then given to significantlytrains as well as intercity passenger carriages improving the handling of the construction ele-and intercity rail cars. This technology has, for ments. Sliding roofs, folding roofs, as well asexample, been used for building the 250 km/h sliding doors and shutters, were manufactured(155 mph) high-speed Advanced Passenger from aluminum sheet and reinforced with ex-Train of British Rail and the 300 km/h (185 truded sections by the German railway, DB, asmph) ERT 500 of the Italien Ferrovie dello Stato well as the Swiss Federal Railway, SBB. With(FS). The French TGV Duplex, a double decker, time, complete wagon bodies also were builtnew high-speed train of the SNCF, will be man- from aluminum alloys. The structure of theseufactured using welded aluminum large profile wagons consisted of roll formed 1.5 to 2.0 mmtechnology to control the track loading. thick AlMg3 sheets reinforced with AlMgSi0.5 Self-supporting large profile aluminum tech- extruded sections, apart from the under framenology is used not only for high-speed trains and the vertical end wall columns, which wererunning on rails. The carriages of the track made in steel. In addition, the aluminum con-guided fast magnetic levitation Transrapid, with struction offers not only the advantage of weighta maximum speed of 500 km/h (310 mph) are reduction but is also maintenance friendly, i.e.,built using the self-supporting aluminum large in contrast to steel designs, no painting is neededprofile technology in a bolted design [Mil 88]. because of the corrosion resistance of the alu-The prototype is shown in Fig. 2.16. This assem- minum alloys used.bly method is described in the section “Bus Tilting sidewalls on open goods wagons forManufacture” later in this chapter. specific transport applications are manufactured Naturally, thought has been given to reducing from AlMgSi0.5 and AlMgSi0.7 extruded pro-the wagon weight in rail freight transport with files, as shown in Fig. 2.17. These sidewalls can
  11. 11. Chapter 2: Extruded Products / 19Fig. 2.14 Passenger carrier design on the high-speed train ICE1 of the Deutsche Bahn AG with the large sections of the left carriage section. Source: Alusuissebe highly loaded and do not require any surface large distances. This process is usually carriedprotection because of the corrosion resistance of out using rolling stock with the optimum loadthe aluminum alloys. capacity. The optimum storage capacity of these The focal point of European rail transport is wagons can be achieved by using self-support-mixed cargo transport where the loading space ing welded aluminum large profile technology,of a wagon is more important than the load- which makes them particularly economicalcarrying capacity. Consequently, the application compared with wagon designs in steel. Figuresof aluminum alloys is usually limited to movable 2.18 and 2.19 show an example of a coal silocomponents as described previously. Bulk goods wagon built with aluminum large profile tech-transport by rail has only a limited role in Eu- nology. The sidewalls as well as the chassis ofrope. this coal silo wagon consist mainly of large This differs in other countries, including extruded profiles in the aluminum alloyAustralia, Canada, South Africa, and the United AlMgSi0.7 with large format sheets ofStates, with, for example, rich surface reserves AlMg2.7Mn in the floor area. The assembly ofof coal and minerals. The extraction site is usu- the silo wagon involves the use of the sameally a long distance from the processing plant automatic welding systems that are used forso that bulk goods have to be transported over personnel carriages.
  12. 12. 20 / Extrusion, Second Edition Silo wagons of this design were designed and load is approximately 10% less than that of abuilt by Alusuisse to U.S. standards. In spite of steel wagon.the high material costs of the aluminum silo Road Vehicles. The development of auto-wagons, their manufacturing cost per ton pay- mobile manufacture including both cars andFig. 2.15 (a) Carriage shell cross section ICE2 and (b) carriage shell cross section ICE3, self-supporting using welded large section technology. Source: ADtranzFig. 2.16 Prototype of the magnetic levitation Transrapid manufactured with bolted aluminium large profile technology using aluminium AlMgSi0.7 extruded sections. Source: Alusuisse
  13. 13. Chapter 2: Extruded Products / 21Fig. 2.17 Tilting trailer walls of an open goods wagon finished in extruded hollow sections in the alloys AlMgSi0.5 and AlMgSi0.7. Source: AlusuisseFig. 2.18 Coal silo wagon produced in welded self-supporting large extrusion technology to U.S. standard. Source: Alusuissefreight vehicles has been associated with the use After World War II, this development in-of aluminum alloys from the beginning. Alu- creased rapidly. The use of aluminum alloys inminum gearbox and motor housings were al- road vehicles increased continuously. Today, af-ready being reported in the latter years of the ter steel, aluminum alloys are the most importantnineteenth century. In 1924, the Swabische Hut-¨ material in the manufacture of automobiles. Intenwerk developed a car with a self-supporting 1993, in Germany alone 315,000 metric tons ofaluminum design. In 1937, BMW fitted the well- aluminum were used in the manufacture of carsknown two-seater sports car 328 with an alu- and 58,000 metric tons in freight vehicles [Gorminum alloy body. In racing car manufacture, 94]. The main applications of aluminum arethe well-known Silver Arrow manufacturer castings for engine and gearbox housings, pis-Auto Union, BMW, and Mercedes Benz used tons, and cylinder heads, as well as car wheels.aluminum alloys to produce the lightest chassis It is also used as a semifinished product in thepossible. Toward the end of 1920s, the first form of sheets or strip for the manufacture ofbuses with aluminum bodies were built, particu- bonnets and boot lids, water and oil coolers, andlarly in Switzerland (Fig. 2.20). also sometimes for complete sports cars bodies
  14. 14. 22 / Extrusion, Second EditionFig. 2.19 Design and construction of the coal silo wagon shown in Fig. 2.18Fig. 2.20 Older bus body manufactured from aluminum alloys in Switzerland with a frame in extruded sections. Source: Alusuisseas well as extruded semifinished profiles for the consumption by about 0.6 to 0.8 l/km (in-production of trim and widow frames, and for creases mileage 3.5 to 4.7 mpg).safety components such as side-impact beams in ● Lower environmental pollution from exhaustcar doors. Car superstructures and bus bodies, gases as a result of the reduced fuel con-goods vehicle superstructures, and sidewalls, in sumption.addition to forgings for the manufacture of ● Reduction in maintenance costs due to thewheels and engine components, are also made better corrosion resistance of the aluminumfrom aluminum. This increasing use of alumi- alloysnum alloys provides these well-known advan- ● Simple recycling of the aluminum alloystages to the automobile industry: used as secondary aluminum● Lower vehicle mass and thus savings in mo- Passenger Cars. In 1958, Opel in Germany tive energy, i.e., fuel. According to [Her 90], introduced the Rekord shown in Fig. 2.21 as a the replacement of 200 kg of steel by 100 kg new design to the market. The car had as a new of aluminum in a car reduces the gasoline feature for the European automobile industry
  15. 15. Chapter 2: Extruded Products / 23window frames in extruded and age-hardened years, high demands were placed on the deco-aluminum alloy for the front and rear wind- rative appearance, in particular, on the optimumscreens, as well as the side windows in the doors. polish. Good mechanical properties were alsoThe aluminum frames were attached in such a required. The top of the door consisted only ofway to the steel sheet that the top of the door an aluminum frame, and this frame should notconsisted only of the window frames with the bend when the door was closed. Aluminum ex-window glass, as shown in Fig. 2.21. The ex- truded profile window frames appeared in manytruded profiles that formed the frames were de- car models for over a decade. During this period,signed in such a way that the rubber sections that between 150,000 and 200,000 metric tons alu-sealed against the body could be easily located minum sections flowed into this project. Carin the aluminum window frames. The extruded manufacturers finally stopped using this deco-profiles were formed to the window frames on rative aluminum window frame construction onstretch bending machines, welded together, the doors mainly because of the wind noise be-ground, and polished and anodized to a thick- tween the window frame and the body associ-ness of 4 to 6 lm. The section material used by ated with the rapidly increasing speeds. TheOpel was initially Al99.8ZnMg and, later, cause of the wind noise was the speed-relatedAl99.8MgSi. suction forces acting externally on the window Opel introduced this design within Germany surfaces and also the pressure forces from thefollowing pressure from the United States. The operation of internal fans on the inside of thedesign was quickly adopted by Audi, BMW, and window surfaces. This revealed a weakness inFord. The aluminum alloy solution heat treated the aluminum window frame design. As a con-during the billet heating was extruded into water sequence of the E-modulus of the aluminum al-(standing wave). The sections had a weight per loys used for the window frames being one-thirdmeter of only 0.150 to 0.850 kg. In the early that of a suitable steel, the aluminum window frames deformed elastically three times as much as a steel frame of the same design. Profile cross sections with higher moments of inertia could not easily be incorporated into the door design. This did not exclude, however, the further use of extruded profiles as frames for the front and rear car windscreens, as shown, for example, in the E class Mercedes in Fig. 2.22. In addition, Fig. 2.22 Rear window frame of the Mercedes W124 man-Fig. 2.21 Automobile window frame in extruded, age-hard- ufactured from extruded aluminum sections. The ened, and anodized aluminum sections on an front windshield of the vehicle had a similar frame. Source: Erbs-Opel Rekord manufactured in 1958. Source: Opel loh ¨
  16. 16. 24 / Extrusion, Second Editionnumerous extruded profiles are used in car bod- cross-sectional geometry and sufficient proofies for a wide range of applications, including stress and elongation are particularly suitable forsteering wheel adjustment, seat rails, sliding roof this application [Fra 89]. A correctly designedguides, and also for water and wind deflectors impact beam in an extruded aluminum alloyin the roof area of the body and side window with materials properties comparable to a geo-guides. Figure 2.23 depicts the metal frame for metrically similar steel impact beam can possessthe folding top cover of the SL class made from approximately three times the elastic deforma-an extruded profile. tion capability before plastic deformation oc- Aluminum extruded profiles are particularly curs.suited in special cases for the manufacture of Interest in the extruded age-hardened alumi-safety components for the automobile because num alloy side-impact beam combined with athe cross-sectional shape can be exactly matchedto the loading. They also offer favorable me-chanical properties and density and the low E-modulus as well. A typical example is the sidedoor beam that can fulfill its role in a very func-tional way. Side impact causes 30% of all roaddeaths in 25% of all car accidents in Germany.The car sides cannot be protected for space rea-sons by crumple zones as, for example, used inthe front and rear. Therefore, the car manufac-turers have over the years made great efforts toprotect the sides of cars using effective side-impact beams as well as air bags. Figures 2.24,2.25, and 2.28 show this technology in Audi ve-hicles. The impact beam must be able to absorb thetransmitted impact energy from an impact on theside door over a defined deformation displace-ment without breaking, buckling, or even dis-placement in order to protect the passengers. Re-search results have shown that extrudedaluminum alloy profiles with a symmetrical Fig. 2.24 Side door of the Audi 100 with built-in chroma- tized for corrosion protection, extruded section in the aluminum alloy AlMgSi1, F 31 with RP0.2 ‫ 062 ס‬N/mm2 and A5 ‫ .%01 ס‬Source: Alusuisse Fig. 2.25 Side-impact beam from the Audi 8 consisting ofFig. 2.23 Hood container cover of the Mercedes 300 SL and two extruded sections. Alloy AlMgSil, F 31. The 500 SL class with extruded aluminum section side-impact beam can be seen installed in Fig. 2.27. Source: Alu-frames. Source: Erbsloh ¨ suisse
  17. 17. Chapter 2: Extruded Products / 25side air bag is increasing because the good However, in cars this did lead to weight reduc-physical and mechanical properties, in particu- tions of about 60 kg in Europe and about 80 kglar, the elastic behavior, enable the safety re- in the United States. The desire for larger weightquirements to be fulfilled. Many automobile savings now has resulted in greater use of lightmanufacturers are now installing them. materials. In the future, engine and gearbox Naturally, there are numerous safety compo- housings will be made primarily from aluminumnents that are manufactured from extruded alu- alloys. Car manufacturers are also replacingminum profiles. Figure 2.26 shows a steering load-carrying steel automobile components withlinkage in which the left-hand link consists of aluminum. This gives an additional weight sav-sections of extruded profiles, whereas the flexi- ings of 60 to 70 kg and a definite improvementble right-hand part is manufactured from impact in the ride because of the significantly lower un-extruded tube sections with formed bellows. In damped weights.an accident, the bellows deform so that the im- Meanwhile, the automobile driver has be-pact on the steering column is reduced. The come increasingly more demanding. The stabil-good experience obtained with the deformation ity of the body, the airbag, and the side-impactbehavior of side-impact beams made from ex- beams, ABS and effective crumple zones pro-truded age-hardened aluminum hollow sections vide passenger protection. In addition, air con-has now been used in automobile plastic bumper ditioning, CD systems, navigation systems, andbeams with integrated aluminum hollow sec- other luxurious fittings should make traveling intions in the alloy AlMgSi0.5 or AlMgSi0.7. a car as pleasant as possible. Simultaneously, theThese sections naturally have to match the pro- fuel consumption should decrease and the ma-file of the bumper beam, i.e., they have to be terials from old vehicles be easily recycled.bent. Whereas this bending operation is carried In the future, these conflicting demands willout today on a large scale on stretched extruded be met by the use of light body designs in steel,profiles with significant cost for the bending, de- aluminum alloys, improved magnesium alloys,pending on the section geometry, possibly fol- and to a limited extent by fiber-reinforced plas-lowed by a sizing operation, these deformation tic, if necessary, up to self-supporting structures.processes can be carried out in the United States As early as 1950, Pakiney built the DYNAduring the extrusion process. The low hot flow PANHARD car with extensive use of AlMg3stress of the aluminum alloy aids the bending sheet and, later, AlMgCu. The car weighed onlyprocess. The introduction of defined and legally re- 650 kg and was extremely economical. In 1990,quired targets of weight saving, energy saving, Honda developed the sports car NSX withand simple recycling of the materials used has AlMgSi1 sheet, and Rover has used for manyinitiated significant innovations in recent years years in the Land Rover aluminum sheets for thein the automobile industry. Previously, alumi- body; initially, AlMgCu and, today, AlMgSi1num alloys were generally used for simple parts. [Alp 94]. The decisive step was made by AUDI AG with the production of the AUDI A8 shown in Fig 2.27. The body is made entirely of alu- minum. This breakthrough of aluminum into the steel domain has both shocked and challenged the wide strip manufacturers (body sheet). They are trying to counter this development with intelli- gent solutions for complete steel chassis, for ex- ample, with the use of prefinished body parts, tailored blanks. Tailored blanks are cut to size, designed for the load, body panels laser welded together from steel sheets of different thickness, strength, and surface quality. These prefinishedFig. 2.26 Steering link in the alloy AlMgSi1, F 31. The con- body parts, for example, complete wheel hous- nection on the left-hand side is from an extrudedsection, whereas the round, easily deformed in the event of a ings, enable assembly costs and also weight tocrash, corrugated section with the transition to the steering col- be reduced. This is the start of a process thatumn was manufactured from an extruded tube. The corrugatedregion is heat treated to a strength of F 22 to F 25. Source: Alu- should finish with the ultralight steel car body.suisse However, the high point of this development to-
  18. 18. 26 / Extrusion, Second Editionday is the Audi A8 and the Audi A2 with the the age-hardening alloys AlMgSi0.5 andspace frame construction of Alcoa. This con- AlMgSi0.7. Supporting floor panels consist ofstruction principle can be seen in Fig. 2.27 to the age-hardening alloy AlMgSi1Cu, small2.29. Audi uses for the production of the alu- sheet parts from the non-heat-treatable alloyminum body aluminum alloys containing the AlMg5Mn. The die cast nodes necessary forsame alloying elements, a basic requirement for joining the preformed and age-hardened ex-ease of recycling. The extruded sections needed truded profiles to balance out the tolerances forto assemble the space frame are produced in the space frame of the Audi A8 were manufac-Fig. 2.27 Audi A8 Quatro with a body of age-hardened aluminum alloys using the Alcoa space frame concept. Source: AudiFig. 2.28 Space frame of the Audi A8 shown in Fig. 2.27
  19. 19. Chapter 2: Extruded Products / 27Fig. 2.29 Space frame of the Audi A2 in extruded sections, sheet and castings. Source: Auditured with the vacuum casting process in the els that harden during this heat treatment. Theheat-treatable alloy AlSi10Mg. Other cast com- sections of the space frame heat more slowlyponents consisted of AlSi7. Die cast components because these are shielded by the body outerfor tolerance compensation were not used for the skin during the heat treatment. For this reason,space frame of the A2. the bent profile sections for the space frame have Finally, cold-worked strip sections in the flow to be supplied age-hardened in such a way thatline free (Luders lines) and heat-treatable alu- ¨ they harden only slightly during the age-hard-minum alloy AlMg0.4Si1.2 were used as exte- ening process described and do not over age. Inrior body panels. Table 2.1 provides an overview particular, the softened peripheral zones of theof the materials used to build the aluminum body section welded from the MIG welding should asof the Audi A8. far as possible reharden. The complete alumi- The automobile manufacturer joins the deliv- num body of the Audi A8 is approximately 200ered prefinished and age-hardened profile sec- kg lighter than a conventional steel body of thetions to assemblies by MIG welding with the aid same size.of jigs. The complete space frame is then built Bus Manufacture. The manufacture of busesusing the same joining technique. The floor pan- from aluminum alloys has a tradition in Swit-els and, in particular, the 1.0 to 1.15 mm thick zerland, as shown in Fig. 2.20. The Alpine coun-sheets for the body exterior skin were fixed us- try started to consider the reduction in weight ofing other joining techniques including, among goods vehicles in the 1920s. The engine powersothers, self-piercing rivets. Finally, the finished available at this time were still very limited andbody in white is age-hardened at a temperature could therefore be better utilized with a lowerof 230 ЊC for 30 min. It is mainly the body pan- weight. The Swiss with their mountainous re-Table 2.1 Aluminum alloys used for the aluminum body of the Audi A8 Material AA(a) Temper Rp0.2 (N/mm2)(b) Rm N/mm2(c) A5 %(d)Sheet AlMg0.4Si1.2 6016 T6 200 250 14 AlMgSi1Cu 6009 T6 230 280 10 AlMg5Mn 5182 ... 135 270 25Vacuum die casting AlSi10Mg ... T6 120–150 180 15Permanent mold casting AlSi7 ... T6 200 230–250 15Extruded section AlMgSi0.5/0.7 ... T6 210–245 1.08 Rp0.2 11(a) Aluminum Association designation. (b) Rp0.2 is 0.2% proof stress. (c) Rm is tensile strength. (d) A5 is elongation after fracture. Source: Audi
  20. 20. 28 / Extrusion, Second Editiongions never lost sight of this basic principle; it this system are in operation today in Switzer-increased in importance after World War II. land, Denmark, and Norway. System-built busOther countries, including Germany, also be- superstructures are also common in the Unitedcame interested in these solutions. States with sidewalls in extruded sections simi- Extruded profiles in aluminum alloys were the lar to those used today in Europe for railwaynatural solution for the economical lightweight rolling stock [Alp 94].construction of buses. Their low density and More than a decade ago, Alusuisse developedgood mechanical properties, as well as the op- a bolted bus superstructure with good results.timum shape-forming capability combined with The nucleus of this aluminum bus superstructurethe use of modern joining techniques, provided is the bolted corner elements as shown in Fig.not only the prerequisite for economic designs 2.32, which, combined with the system sections,of bus superstructures but also for a rational provide for simple assembly. After successfultransport of the passengers. trials in their own country, other European coun- The bus construction concept is based in prin- tries became interested in the process. The twociple on a lattice frame design of extruded alu- companies Schweizerische Aluminium AG andminum sections similar to the space frame of the the German company Kassbohrer presented to ¨Audi A8 (Fig. 2.28). These profiles are welded the International Automobile Association (IAA) in 1987 a study commissioned by the Ministrytogether as shown in Fig. 2.30. The body panels for Research and Technology of a bus manufac-are attached with suitable joining techniques. tured of aluminum using the bolted design underBuses built entirely of aluminum according to the name SETRA CONCEPT BUS. This bus is shown in Fig. 2.31 and the design of the bolted corner joints of the Alusuisse system M5438 in Fig. 2.32. The bolted design of the supporting aluminum lattice frame had considerable advantages over a similar welded design. The bus superstructure can be produced extremely economically and quickly without labor-intensive reworking as a result of welding distortion. There is also the advantage for the vehicle owner that accident repairs can be carried out in a relatively short time and to a relatively high quality. This assem- bly system has been successful in many coun- tries. Moreover, the Swiss have also used this method of assembly for light rolling stock for passenger traffic. The carriage bodies of the ex- perimental vehicles of the magnetic levitated Transrapid described in the section “RollingFig. 2.30 Old lattice design for coach construction as shown Stock” and Fig. 2.16 are built from bolted ex- in Fig. 2.20 manufactured from extruded alumi-num sections. Source: Alusuisse truded aluminum sections.Fig. 2.31 The study of a coach presented at IAA 1987 with bolted, supporting lattice frame construction in extruded aluminum sections. Source: Alusuisse
  21. 21. Chapter 2: Extruded Products / 29 The increase in the transport capacity can be achieved in two ways: ● By increasing the size of the freight vehicles, which has also been carried out in the past. Today, freight vehicle sizes have reached their limit because of the permitted road loads. ● By reducing the vehicle weight using spe- cific lightweight construction without any further increase in the road loading. This ap- proach offers potential for the future. Specific aluminum alloys and, in the future, also magnesium alloys, are available for the de- velopment of lightweight commercial vehicles. These alloys are characterized by the low den- sities, adequate material properties, corrosion, and weather resistance with low maintenance costs as well as optimum design capabilities. As in many such applications, extruded semifin- ished products are particularly suitable, particu- larly sections with their unlimited cross-sec- tional shapes. The relatively simple recycling of these materials as secondary materials also plays a role. Systems for the assembly of truck planking, in particular, truck sides, had already been de- veloped in the first half of the 1960s by the alu-Fig. 2.32 Bolted Alusuisse system M5438. Source: Alusuisse minum industry in conjunction with the manu- facturers of freight vehicle superstructures. The sidewalls manufactured from extruded hollow Road Freight Vehicles. For a long time, trans- sections shown in Fig. 2.33 have proved to beport companies in Europe have been subjected more stable and require less maintenance thanto increasing ruinous competitive pressure with the old wooden sidewalls and also are decora-increasing costs. Consequently, there is ongoing tive. It is possible today to produce on largegreat interest in freight vehicles with low presses small truck sides in one piece as shownweights, but with optimum load capacity and by the profiles in Fig. 2.34. Trucks with the oldlow maintenance costs. This leads to a reduction wooden superstructures disappeared within aof the transport costs and an increase in the com- few years with aluminum profiles replacingpetitiveness. wood for many loading space floors.Fig. 2.33 Typical aluminum hollow sections for goods vehicle sides in the alloy AlMgSi0.5. Source: Alp 94
  22. 22. 30 / Extrusion, Second Edition The use of aluminum alloys for truck and Planked superstructures in extruded alumi-trailer constructions for the transport of bulk num sections have also proved successful asgoods and liquids has proved to be particularly shown in Fig. 2.37. In spite of the higher ma-economic, for example the silo rolling stock in terial costs for aluminum alloy designs, these areFig. 2.18. This also applies to coarse bulk goods viable because of the increase in load capacitytransported with road vehicles. Silo trailers are derived from the weight saving. In contrast tofrequently manufactured entirely from alumi- other European countries, in Switzerland, thenum alloys. The chassis of the trailer is fre- planked trailers are made completely from alu-quently manufactured from extruded aluminum minum, including the load-carrying parts of thesections. In Europe, silo and liquid transporters chassis. In the United States, the use of alumi-predominantly use this type of aluminum super- num alloys for goods vehicles raises fewer ques-structure [Koe 88]. Figure 2.35 also shows a tions than in Europe.loose-goods vehicle for building sites, with a tip- The use of aluminum components made fromping aluminum body made in AlMg4.5Mn extruded semifinished hollows for superstruc-sheets with transverse reinforcement (round tures as well as chassis, but also from strip andspars) of extruded AlMgSi1 sections. Finally, sheet for the manufacture of containers andFig. 2.36 shows a trailer with a covered tipping wheel rims and so forth, will increase in the fu-body made entirely of aluminum sections. All ture for goods vehicles. The aim is an optimumaluminum tipping body shells have low wear. low vehicle weight with optimum carrying ca-Fig. 2.34 Five-core hollow section for goods vehicles sides with a width of 530 mm and a height of 25 mm and a six-core side section 800 mm wide and a height of 25 mm manufactured in AlMgSi0.5, F 25. Source: AlusuisseFig. 2.35 (a) Tipping wagon with welded tilting body in aluminum sheet reinforced with round spars of extruded aluminum sections. Source: Alusuisse. (b) Tilting body from (a) constructed from: 1 and 2, sheets of AlMg4.5Mn; 3, extruded aluminum curvedsection in AlMg4.5Mn; 4, round spar with AlMgSil extruded aluminum sections and a cross-sectional geometry of 4.1: 5, top edge inextruded aluminum section
  23. 23. Chapter 2: Extruded Products / 31pacity. Aluminum is well suited for this. Finally, in the future the dominating metallic-base ma-the recycling of the used aluminum from old, terial for the manufacture of aircraft in the formno longer usable goods vehicles is relatively of plate, sheet, extruded sections, and cast com-simple. ponents. Aluminum alloys still have potential Aircraft manufacture is one of the oldest ap- for further development. The aircraft outer skinplications of aluminum. As early as 1897, alu- will still be made from aluminum alloys. Im-minum-base materials were used for the con- portant parts of the wings, stiffeners in the shapestruction of airships, and age-hardening of spars and stringers are also made from high-aluminum alloys enabled the German aircraft strength aluminum alloys as well as windowmanufacturer Junkers to introduce the complete frames, connection nodes, and landing gearmetal airplane (Ju-4) in 1917. Whereas today, components, including the forged aluminumcertain components of modern aircraft such as wheel rims. However, in spite of their being theelevators, rudders, and landing flaps are made dominant materials used, the trend is for the usefrom specific weight saving and carbon fiber- of aluminum alloys in the entire Airbus fleet toreinforced plastics (CFP), aluminum will remain reduce, as shown in Fig. 2.38. Carbon fiber-Fig. 2.36 Tipping trailer with covered body made entirely from extruded multicore hollow sections for the transport of fine pow- dered goods. Source: AlusuisseFig. 2.37 Trailer with planked construction and chassis in extruded aluminum sections. Source: Alusuisse
  24. 24. 32 / Extrusion, Second Editionreinforced plastic materials do have a lower den- fuselage in the form of stringers. Figure 2.39sity and much higher mechanical properties, but shows stringer profiles as longitudinal stiffeningthey also have a high impact crack sensitivity of an airbus fuselage where the external skin iswith low ductility and toughness. Moreover, produced from roll clad aluminum sheets in thetheir manufacture involves complex production alloy 2024. Extruded sections are used for theand quality control processes. They are therefore seat rails and the floor transverse supports. Thecorrespondingly expensive [AlH 71, Alt 88, Alp latter can also be easily seen in Fig. 2.39. The94]. cross-sectional geometry and the relative size of Extruded sections are used in aircraft in dif- the extruded profiles used are shown in Fig.ferent places for load-carrying or reinforcement 2.40. Spars for transverse stiffening of the fu-functions. For example, they are used as longi- selage skin as shown in Fig. 2.39 are made fromtudinal stiffeners for the sheet skin of the aircraft AA2024 strip.Fig. 2.38 The percentage of metallic materials in the Airbus fleet. Source: Daimler Benz Aerospace AirbusFig. 2.39 Airbus fuselage cell with roll clad AA2024 sheet skin longitudinally reinforced with extruded stringer sections in AA2024 and with transverse reinforcement of spars in roll clad AA2024 sheet. The clearly visible cabin floor supports are man-ufactured from AA7075 extruded sections. Source: VAW
  25. 25. Chapter 2: Extruded Products / 33 The fraction of extruded profiles within the aluminum industry has focused on the aim oftotal of semifinished products used for aircraft producing high-strength alloys that can be hotin the Airbus fleet is around 11%; in contrast to and cold worked. The alloy groups AlCuMg andBoeing aircraft, where it is 41%. As Fig. 2.41 AlZnMgCu, as well as the new somewhat dif-shows, with Boeing, the fraction of extruded ficult AlLi alloys, offer the aircraft industry alu-aluminum profiles used dominates when com- minum alloys that can be statically and dynam-pared with other semifinished products. With the ically loaded to high stresses and processed toAirbus fleet, sheet forms the largest fraction. semifinished products by rolling, forging, and Weight reduction also plays an important role extrusion. Aluminum alloys with high hotin modern aircraft manufacture. The demand is strengths are also available for supersonic air-for low-density materials with good mechanical craft [Alp 94].properties that can be stressed optimally to the The classic aluminum alloys for aircraft con-operating safety limit. Since Wilm’s chance dis- struction have been modified over the years andcovery in 1909 at the Durener Metallwerke of ¨ their heat treatment so specialized that today,the age-hardening capability of AlCuMg, the they not only achieve optimum materials prop-Fig. 2.40 Extruded sections for the Airbus aircraft in aluminum alloys AA2024 and 7075. Source: Daimler Benz Aerospace AirbusFig. 2.41 Distribution of the semifinished products used in (a) the Airbus fleet compared with (b) the Boeing fleet. Source: Daimler Benz Aerospace Airbus
  26. 26. 34 / Extrusion, Second Editionerties, but also largely meet the corrosion re-quirements of the aerospace industry. In con-trast, the aluminum alloy AA8090 has beenrecently developed specifically for aircraft con-struction. Compared with other high-strengthaluminum alloys, it has a density 10% lowerwith good static and dynamic properties and anE-modulus that is approximately 10% higher[Ren 97]. Because of the extreme material load-ing in aircraft, the aerospace industry naturallystill demands the further development of exist-ing aluminum alloys and the development ofnew aluminum alloys with even higher mechan-ical properties. Further developments for theAirbus fleet concentrate at the moment on thehigher-strength alloys in the AlZnMgCu alloyfamily with better corrosion resistance and thenew development of particle reinforced alumi-num alloys. An AlMgSiCu alloy Aluminum As-sociation 6113 (AA6113) reinforced with25% volume SiC particles has an E-modulusdouble that of nonreinforced alloy variants [Ren97]. The development of high-strength aluminum Fig. 2.42 Extruded tube with integral stringers in the alu- minum alloy AA6013. Source: Daimler Benzalloys for aircraft construction and the require- Aerospace Airbusment for ever larger and more expensive sec-tions has naturally had an effect on extrusionplants. The high-strength aluminum-base alloysare all difficult to extrude. To meet the materialsproperties required by the aerospace industry,they have to be handled carefully after extrusion.Not only are optimum material properties forstatic as well as dynamic loading required foraircraft alloys, but also the residual stresses ofthe first type have to be as low as possible forstress and machining purposes. There is not only ongoing further develop-ment in aerospace materials, but also, naturally,in aircraft construction itself. New fuselage con-structions with integrated stringer sections arebeing developed for the Airbus fleet. These en-able the aircraft fuselage sections to be manu- Fig. 2.43 Extruded tube from Fig. 2.42 opened out for the fuselage skin. Source: Daimler Benz Aerospacefactured with 10% less weight and are up to 25% Airbusless expensive than the conventional rivetedmethod of construction. Two concepts are fa-vored: num large section technology used in the● External skin in sheet, which is welded to- manufacture of ICE wagons. gether to form the fuselage and then bonded with extruded aluminum stringer sections by Both concepts are associated with the replace- laser welding ment of the roll clad sheet material 2024 by the● Extruded external skin with 1.6 to 4 mm wall new weldable materials AA6013 and AA6056 thickness and integrated stringer sections as based on the AlMgSiCu family. shown in Fig. 2.42 to 2.44, e.g., in principle The second concept leads to a new perspec- an aircraft fuselage using the welded alumi- tive in the use of very wide extruded profiles for
  27. 27. Chapter 2: Extruded Products / 35 ● The draft of the ship can be reduced. ● Painting and other surface protection mea- sures can be spared by the use of seawater- insensitive materials including AlMg3, AlMg5, and AlMg4.5Mn for ship compo- nents that come into contact with seawater. This reduces maintenance costs. ● The antimagnetic properties of the aluminum alloys simplify navigation. In spite of this, the complete aluminum ship has not prevailed. Some examples were built in the decades after World War II, for example, the Binnentanker motorboat Alumina in the 1960s in Germany with a draft of 1000 metric tons, asFig. 2.44 Extruded cross-sectional geometry of the extruded external skin with integrated stringers. Source: well as in 1967, in the United States, the sea shipDaimler Benz Aerospace Airbus Sacal Borincano. Its construction required ap- proximately 345 metric ton of sheet and ex- truded sections in the alloy AlMg4.5Mn. Thethe fuselage external skin, a special demand on 119 m long completely aluminum ship with aaluminum extrusion plants with large extrusion welded design was used to transport semitrailerspresses. Whereas the fuselage construction to- between Miami and Puerto Rico.day involves sheets 2500 mm wide, even the Today, the production of entirely aluminumlargest extrusion press in the industrialized ships is limited to small ferries and passengercountries cannot, at the moment, produce equiv- ships for coastal and inshore operation as wellalent sections with a flat cross-sectional geom- as special ships such as rescue boats and hov-etry. Therefore, the production of extruded sec- ercraft. Private yachts, in particular, are madetion tubes with integrated stringers as shown in entirely of aluminum. The usual method of con-Fig. 2.42 has been considered among other struction preferred for these ships is a combi-ideas. They can be opened out into a wide profile nation of spars in extruded AlMgSi1 sectionsas shown in Fig. 2.43. Using this production and an outer skin of AlMg or AlMgMn weldedmethod, which is not unusual for extrusion, ex- sheet. The extruded profiles used are, therefore,ternal skins up to 2100 mm wide can be pro- the load-carrying structural components.duced. However, the required wall thickness of The superstructure of large ships with steel1.4 to 4 mm presents process-related extrusion hulls is completely different. The superstructureproblems. It is not possible to avoid a certain is preferably made using aluminum lightweightvariation in wall thickness in the extruded tube construction techniques for stability reasons.because of the tendency of the mandrel to ec- The lightweight construction technique enablescentricity, i.e., movement from the press axis. the center of gravity of the ship to be loweredTherefore, extremely serious considerations be- or the height of the superstructure increaseding given within extrusion plants for the solution without impairing the stability of the ship withto this problem, assuming a solution is indeed a higher center of gravity. The design of the su-possible. perstructure in the lightweight construction Watercraft. A low weight also brings signifi- method has to take into account the different E-cant advantages to ships. As with other methods modulus of iron and aluminum alloys to copeof transport, low weights can be achieved by the with the temperature-dependent stresses that oc-use of low-density construction materials. Suit- cur between the two materials, as well as preventable aluminum alloys are also available for wa- contact corrosion at steel/aluminum joints by thetercraft. Lightweight construction methods pro- use of insulating elements [Alh 71, Alt 88, Alpvide the following advantages to watercraft: 94].● The carrying capacity of the watercraft is in- Large ships need considerable quantities of creased: its radius of action can thus be in- aluminum semifinished products in the form of creased. sheet and profiles for aluminum superstructures● The stability of the ship is improved by light- (Fig. 2.45). The superstructures of the passenger weight superstructures lowering the center of ships United States, Norway, and the Queen gravity. Elizabeth II each required approximately 2000
  28. 28. 36 / Extrusion, Second Editionmetric tons of aluminum. Modern large aircraft porting structures within the superstructures ofcarriers require similar large quantities of alu- the ships.minum semifinished products for their super-structures. Finally, large section technology has Machine Manufacture, Electricalalso been used for lightweight construction tech- Machines, and Electricalniques in ship superstructures. The use of largeprofiles reduces the assembly costs. Equipment Extruded large multicavity sections are used, The manufacture of machinery and electricalfor example, in ships in the fishing industry as machines was, for a long time, dominated byrack floors with through flowing coolant for the iron-base materials, but with time this hasstorage of fish in the cold rooms. Mobile inter- changed. Other materials with their favorablemediate decks for ships for the transport of ani- properties are threatening the domination of themals can be produced from large aluminum pro- iron-base alloys. During the past 20 years, per-files for economic reasons, as shown in Fig. sonnel costs have increased more rapidly than2.46. The alloys AlMgSi0.5, AlMgSi0.7, and the material costs. Aluminum-base materialsAlMgSi1 are used for these and for the sup- with their very specific materials properties haveFig. 2.45 Aluminum superstructure of a passenger ship. Source: AlusuisseFig. 2.46 Multicore hollow section for mobile intermediate ship decks for sheep transport. Source: Alusuisse