Plain Carbon Steel is classified into: 1) Low Carbon (less than 0.25% carbon) -Low strength, good formability -If wear is a potential problem, can be carburized (diffusion hardening) -Most stampings made from these steels -AISI 1008, 1010, 1015, 1018, 1020, 1022, 1025 2). Med Carbon (0.25% to 0.6%) -Have moderate to high strength with fairly good ductility -Can be used in most machine elements -AISI 1030, 1040, 1050, 1060* 3) High Carbon (0.6% to 1.4%) -Have high strength, lower elongation -Can be quench hardened -Used in applications where surface subject to abrasion – tools, knives, chisels, ag implements. -AISI 1080, 1095

1. Metal alloys
Plain Carbon Steels
Prepared by: P.Eng. Mahmoud Jad & P.Eng. Ahmed Abo-Alhareth
http://www.linkedin.com/in/mahmoudjad

2. OUTLINES
Introduction
Ferrous alloys
Designations of Steels
Low Carbon Content Steels
Medium Carbon Content Steels
High Carbon Content Steels
Options to get plain carbon steel
summary

3. Introduction
 Classification of Materials :
Metals and Alloys
Ceramics and Glasses.
Polymers.
Semiconductors.
Composites.

4. 4

5. Ferrous alloys
• those of which iron is the prime constituent
• are produced in larger quantities than any other metal type
• They are especially important as engineering construction materials
• Their widespread use is accounted for by three factors:
1) iron-containing compounds exist in abundant quantities within the earth’s crust
2) metallic iron and steel alloys may be produced using relatively economical extraction ,
refining, alloying, and fabrication techniques
3) ferrous alloys are extremely versatile, in that they may be tailored to have a wide range of
mechanical physical properties
• The principal disadvantage of many ferrous alloys is their susceptibility to
corrosion.
• They can be classified into:
steels &cast irons
5

6.  Plain carbon steel
• Steels in which carbon is the prime alloying element
• contain only residual concentrations of impurities other than carbon and a
little manganese.
• can be classified into: Low, Medium and High carbon steels.
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 Alloy steels
• Contain more alloying elements and they are intentionally added in specific
concentrations.
• Alloy Steels can be classified into:
Low Alloy steels and High Alloy Steels

7. Designations of Steels
• The AISI (American Iron and Steel Institute) and SAE (Society of Automotive
Engineers) and ASTM (American Society for Testing and Materials) and UNS
(uniform numbering system) provide designation systems
• The AISI/SAE designation for these steels is a four-digit number.
- The first two numbers refer to the major alloying elements present.
- The last two numbers refer to the percentage of carbon
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• For plain carbon steels, the first two digits are designated by 1 and 0
• alloy steels are designated by other initial two-digit combinations (e.g., 13, 41,
43)
• For example, a 1040 steel is a plain carbon steel containing 0.40 wt% C
• (UNS) is used for uniformly indexing both ferrous and nonferrous alloys

10. Low Carbon Content Steels
 Low carbon content is less than about 0.25 wt% C e.g. 080M15, 150M19,
220M07, AISI 1006, AISI 1009, AISI 1020. These steels cannot be effectively
heat treated, consequently there are usually no problems associated with
heat affected zones in welding.
 Batches which are free of 'tramp' elements such as chromium are ductile with
good forming properties, as little work hardening is exhibited. However,
chromium as low as 0.1% and vanadium and molybdenum contents as low as
0.05% can have a dramatic effect on hardenability.

11.  Surface properties can be enhanced by carburising and then heat treating the
carbon rich surface. High ductility results in poor machinability, although these
steels can be machined if high spindle speeds are employed. More commonly
sulphur and lead are added to form free machining inclusions. Low quality
steels with high quantities of sulphur and phosphorus will have better
machinability than good quality steels which are clean and free from oxides
and slag inclusions.
 This group represents the bulk of the market for general purpose steel, finding
usage in car bodies, ships and domestic appliances. Stainless steels and
aluminium alloys compete with these steels in certain areas.

12. Medium Carbon Content Steels
 Medium carbon content (0.25% to 0.6%C) e.g. 070M20, 080M40, 216M44,
AISI 1023, AISI 1030, AISI 1046. Heat treatment and work hardening are now
effective methods for modifying mechanical properties. Hardenability
increases in proportion to carbon content. Welders must now take note of the
hardening effects in the heat affected zone and take precautions against
excessive energy input, as increased hardenability results in an increased
likelihood of brittle structures forming. All common alloying elements increase
the hardenability and hence .a 'carbon equivalent' scale has been devised as
an approximate guide to weldability (in next slid).
 In the normalised condition, machinability is improved compared with low
carbon steels due to their lower ductility and it can be further enhanced with
the addition of sulphur or lead if special 'free machining' properties are
required. Ductility and impact resistance is, however, reduced.

13.  The corrosion resistance of these steels is similar to low carbon steel, although
small additions of copper can lead to significant improvements when
weathering performance is important. Most steels in this category contain
some silicon and manganese, which are added as deoxidizing and
desulphurising elements during manufacture. While the quantities present are
not considered to effect mechanical properties, an indication of the quality of
the steel is given by the phosphorus and sulphur content, where the lower the
content, the higher the quality.
 This category represents medium strength steels which are still cheap and command mass
market. They are general purpose but can be specified for use in stressed applications such
as gears, pylons and pipelines.

14. High Carbon Content Steels
 High carbon content (0.6% to 1.4%C) ) e.g. 050A86, 080A86, AISI 1086, BS
1407. Cold working is not possible with any of these steels, as they fracture at
very low elongation. They are highly sensitive to thermal treatments.
Machinability is good, although their hardness requires machining in the
normalised condition. Welding is not recommended and these steels must not
be subjected to impact loading.
 These steels can have UTSs greater than 1 GPa, and care needs to be taken to
avoid hydrogen embrittlement following electroplating. Advice should be
sought from the plating shop. As with the medium-high plain carbon steels,
steel with >0.8%C is used for components requiring high hardness such as
cutting tools, blades, etc.

15. Options to get plain carbon steel
HRS (hot rolled steel)
&
CRS ( cold rolled steel)

16. HRS
• HRS
– AKA hot finishing – ingots or continuous cast shapes rolled in the “HOT”
condition to a smaller shape.
– Since hot, grains recrystallize without material getting harder!
– Dislocations are annihilated (recall dislocations impede slip motion).
• HRS Characterized by:
– Extremely ductile (i.e. % elongation 20 to 30%)
– Moderate strength (Su approx 60 – 75 ksi for 1020)
– Rough surface finish – black scale left on surface.

17. CRS
• CRS
– AKA cold finishing – coil of HRS rolled through a series of rolling mills AT ROOM
TEMPERATURE.
– Since rolled at room temperature, get crystal defects called dislocations which
impede motion via slip!
– AKA work hardening
– Limit to how much you can work harden before too brittle.
– How reverse? Can recrystallize by annealing.
• CRS Characterized by:
– Less ductlie – almost brittle (i.e. % elongation 5 to 10%)
– High strength (Su approx 120 ksi for 1020)

19. 1. Low Carbon (less than 0.25% carbon)
• Low strength, good formability
• If wear is a potential problem, can be carburized (diffusion hardening)
• Most stampings made from these steels
• AISI 1008, 1010, 1015, 1018, 1020, 1022, 1025
2. Med Carbon (0.25% to 0.6%)
• Have moderate to high strength with fairly good ductility
• Can be used in most machine elements
• AISI 1030, 1040, 1050, 1060*
3. High Carbon (0.6% to 1.4%)
• Have high strength, lower elongation
• Can be quench hardened
• Used in applications where surface subject to abrasion – tools, knives, chisels, ag implements.
• AISI 1080, 1095
Summary
Plain Carbon Steel is classified into:

20. References
 Materials science and engineering 8th edition (callister)
 http:// www.azom.com/
 The science and engineering of materials Donald R. Askeland ,
Pradeep P. Fulay and Wendelin Wright 6th edition
 Dr. Mohamed Zaky Ahmed (lecture 08)

21. Thank you
for your nice attention 
Prepared by: P.Eng. Mahmoud Jad & P.Eng. Ahmed Abo-Alhareth
http://www.linkedin.com/in/mahmoudjad