When the topic of metalworking is raised, most of us think of drilling a hole in a piece of metal or bending a metal part to form a component for an automobile. Not as many individuals realize that another process included under the realm of metalworking is heat treating or quenching.
Heat treatment is utilized to adjust the physical and mechanical properties of metals so that they can be used in subsequent metalworking applications. These properties are changed by the controlled heating and then cooling of metals. In many cases, the objective of heat treatment is to increase the strength of a specifi c metal alloy. Most operations are conducted on steel alloys, but nonferrous metals such as
aluminum and titanium also can be heat treated.
PRODUCTION OF ALTERNATIVE FUEL USING GASIFICATION BY SYNTHESIS OF FISCHER-TRO...IAEME Publication
The solid carbonaceous fuel is converted into combustible gas (energy) using limited amount of air it is called Gasification process the gases which evolve are known as “producer gas”. This is more suitable than the direct combustion of biomass gases. In this paper an updraft gasifier is construct and is used to carry out the experiment. updraft gasifier is one of the boiler. The waste material like coconut shells, sugarcane waste, and wood particles are used for the generation of producer gas. The sense of this paper is to study the effect of waste products (coconut shells, sugarcane waste, and wood particles) in form of biomass. The performance of the gasifier is evaluated in terms of zone temperature with different air velocity. By taking the different fuels and varying the air flow rate the temperature of the zones are analysed. The arrangement of tar is also seen in this apparatus. After analysis the maximum temperature give for coconut shell (waste) all three place as compare to other two .so coconut shell is the best suitable material for this gasifier.
Particulate Sintering of Iron Ore and Empirical Analysis of Sintering Time Ba...IOSR Journals
Particulate sintering of iron ore has been carried out using the necessary ingredients. Empirical
analysis of the sintering time based on the coke breeze input concentration and ignition temperature were also
successfully obtained through first principle application of a derived model which functioned as a evaluative
tool. The derived model;
S = (√T)0.95 + 0.0012α
indicates that amongst ignition temperature and coke breeze input, sintering time is more significantly affected
by the coke breeze input concentration. This is based on the higher correlation it makes with sintering time
compared to applied ignition temperature, all other process parameters being constant. The validity of the
model was rooted in the core expression S – Kα ≈ (√T )N where both sides of the expression are correspondingly
approximately almost equal. Sintering time per unit rise in the operated ignition temperature as obtained from
experiment, derived model and regression model were evaluated as 0.0169, 0.0128 and 0.0159 mins. / 0C
respectively. Similarly, sintering time per unit coke breeze input concentration as obtained from experiment,
derived model and regression model were evaluated as 4.0, 3.0183 and 3.7537 mins./ % respectively indicating a
significant proximate agreement and validity of the model. The standard error (STEYX) incurred in predicting
sintering time for each value of the ignition temperature and coke breeze input concentration considered, as
obtained from the experiment, derived model and regression model are 1.6646, 0.7678 and 2.98 x10-5 % as well
as 2.2128, 1.0264 and 1.2379% respectively. The maximum deviation of mode-predicted results from the
corresponding experimental values was less than 11%.
PRODUCTION OF ALTERNATIVE FUEL USING GASIFICATION BY SYNTHESIS OF FISCHER-TRO...IAEME Publication
The solid carbonaceous fuel is converted into combustible gas (energy) using limited amount of air it is called Gasification process the gases which evolve are known as “producer gas”. This is more suitable than the direct combustion of biomass gases. In this paper an updraft gasifier is construct and is used to carry out the experiment. updraft gasifier is one of the boiler. The waste material like coconut shells, sugarcane waste, and wood particles are used for the generation of producer gas. The sense of this paper is to study the effect of waste products (coconut shells, sugarcane waste, and wood particles) in form of biomass. The performance of the gasifier is evaluated in terms of zone temperature with different air velocity. By taking the different fuels and varying the air flow rate the temperature of the zones are analysed. The arrangement of tar is also seen in this apparatus. After analysis the maximum temperature give for coconut shell (waste) all three place as compare to other two .so coconut shell is the best suitable material for this gasifier.
Particulate Sintering of Iron Ore and Empirical Analysis of Sintering Time Ba...IOSR Journals
Particulate sintering of iron ore has been carried out using the necessary ingredients. Empirical
analysis of the sintering time based on the coke breeze input concentration and ignition temperature were also
successfully obtained through first principle application of a derived model which functioned as a evaluative
tool. The derived model;
S = (√T)0.95 + 0.0012α
indicates that amongst ignition temperature and coke breeze input, sintering time is more significantly affected
by the coke breeze input concentration. This is based on the higher correlation it makes with sintering time
compared to applied ignition temperature, all other process parameters being constant. The validity of the
model was rooted in the core expression S – Kα ≈ (√T )N where both sides of the expression are correspondingly
approximately almost equal. Sintering time per unit rise in the operated ignition temperature as obtained from
experiment, derived model and regression model were evaluated as 0.0169, 0.0128 and 0.0159 mins. / 0C
respectively. Similarly, sintering time per unit coke breeze input concentration as obtained from experiment,
derived model and regression model were evaluated as 4.0, 3.0183 and 3.7537 mins./ % respectively indicating a
significant proximate agreement and validity of the model. The standard error (STEYX) incurred in predicting
sintering time for each value of the ignition temperature and coke breeze input concentration considered, as
obtained from the experiment, derived model and regression model are 1.6646, 0.7678 and 2.98 x10-5 % as well
as 2.2128, 1.0264 and 1.2379% respectively. The maximum deviation of mode-predicted results from the
corresponding experimental values was less than 11%.
this ppt is useful for understanding the concept of heat treatment process in steel.
it gives the idea about the various stages of heat treatment process in details
Exhaust analysis of four stroke single cylinder diesel engine using copper ba...ijsrd.com
Exhaust emissions of much concern are Hydrocarbon (HC), Carbon Monoxide (CO) and Nitrogen Oxide (NOx) from the automotive vehicles. Catalytic converter oxidizes harmful CO and HC emission to CO2 and H2O in the exhaust system and thus the emission is controlled. There are several types of problems associated with noble metal based catalytic converter. These factors encourage for the possible application of non-noble metal based material such as copper as a catalyst, which may by proper improvements be able to show the desired activity and can also offer better durability characteristics due to its poison resistant nature. The present work is aimed at using copper as a catalyst for catalytic converter. Wire mesh copper catalytic converter is developed for a volume of 1.54 m3. The experiment is carried out on four stroke single cylinder CI engine. The optimum values of exhaust emissions found at full load are HC (126 ppm), CO (0.03 %). By using copper based catalytic converter it is found that HC is reduced by 33 % and CO by 66 % at full load.
Experimental and Finite Element Analysis of Single-V Groove Butt Weld on Weld...IJSRD
Gas Tungsten Arc Welding Process (GTAW) is widely used in fabrication of Aluminium and Aluminium Alloy material when precision is considered as a prime importance. Deformations in the object undergoing welding are one of the foremost problems encountered in the welding industry. Thus it is often required to study the factors which affect the deformations produced during welding to avoid errors in the geometry. Present investigation highlights Experimental and Finite Element Analysis of a Single-V Groove Butt Weld on Weld Pool Geometry of Aluminium Alloy Plate under Different Joint Parameters.Finite Element Method (FEM) has been employed to do the transient thermal and structural analysis of the assembly. The Finite Element Analysis has been done on ANSYS 14.5 Workbench. Number of factors is liable to produce effects in the job during the welding operation. Aim of this paper is the effect of welding parameters like as welding current, shielding gas flow rate and welding speed with mechanical Properties like tensile strength and hardness. After that finite element analysis for temperature distribution and distribution of the stresses in the welded Aluminium alloy plate. The results show that the larger the Welding current and smaller welding speed will lead to the maximum residual tensile stress. Therefore a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at different temperature. The higher yield strength at different temperature has higher material residual stress. Because of its higher thermal conductivity, aluminium alloy test specimens have small temperature differential.
Material Engineering,
Heat treating (or heat treatment) is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching
The presentation is about the fuels used in the Thermal Power Plants and the combustion taking place in large pulverised coal boilers. The calculations about the Air requirements for complete combustion of fuels in the boilers.
A low-carbon steel wire of AISI 1022 is used to easily fabricate into self-drilling tapping screws,
which are widely used for construction works. The majority of carbonitriding activity is performed to improve
the wear resistance without affecting the soft, tough interior of the screws in self-drilling operation. In this
study, Taguchi technique is used to obtain optimum carbonitriding conditions to improve the mechanical
properties of AISI 1022 self-drilling tapping screws. The carbonitriding qualities of self-drilling tapping screws
are affected by various factors, such as quenching temperature, carbonitriding time, atmosphere composition
(carbon potential and ammonia level), tempering temperature and tempering time. The quality characteristics of
carbonitrided tapping screws, such as case hardness and core hardness, are investigated, and so are their
process capabilities. It is experimentally revealed that the factors of carbonitriding time and tempering
temperature are significant for case hardness. The optimum mean case hardness is 649.2HV. For the case
hardness, the optimum process-capability ratio increases by about 200% compared to the original result. The
new carbonitriding parameter settings evidently improve the performance measures over their values at the
original settings. The strength of the carbonitrided AISI 1022 self-drilling tapping screws is effectively improved.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
heat treatment is the controlled heating and cooling of metals for the purpose of altering their properties.
it is used in manufacturing providing simple and low cost means of obtaining desired properties
this ppt is useful for understanding the concept of heat treatment process in steel.
it gives the idea about the various stages of heat treatment process in details
Exhaust analysis of four stroke single cylinder diesel engine using copper ba...ijsrd.com
Exhaust emissions of much concern are Hydrocarbon (HC), Carbon Monoxide (CO) and Nitrogen Oxide (NOx) from the automotive vehicles. Catalytic converter oxidizes harmful CO and HC emission to CO2 and H2O in the exhaust system and thus the emission is controlled. There are several types of problems associated with noble metal based catalytic converter. These factors encourage for the possible application of non-noble metal based material such as copper as a catalyst, which may by proper improvements be able to show the desired activity and can also offer better durability characteristics due to its poison resistant nature. The present work is aimed at using copper as a catalyst for catalytic converter. Wire mesh copper catalytic converter is developed for a volume of 1.54 m3. The experiment is carried out on four stroke single cylinder CI engine. The optimum values of exhaust emissions found at full load are HC (126 ppm), CO (0.03 %). By using copper based catalytic converter it is found that HC is reduced by 33 % and CO by 66 % at full load.
Experimental and Finite Element Analysis of Single-V Groove Butt Weld on Weld...IJSRD
Gas Tungsten Arc Welding Process (GTAW) is widely used in fabrication of Aluminium and Aluminium Alloy material when precision is considered as a prime importance. Deformations in the object undergoing welding are one of the foremost problems encountered in the welding industry. Thus it is often required to study the factors which affect the deformations produced during welding to avoid errors in the geometry. Present investigation highlights Experimental and Finite Element Analysis of a Single-V Groove Butt Weld on Weld Pool Geometry of Aluminium Alloy Plate under Different Joint Parameters.Finite Element Method (FEM) has been employed to do the transient thermal and structural analysis of the assembly. The Finite Element Analysis has been done on ANSYS 14.5 Workbench. Number of factors is liable to produce effects in the job during the welding operation. Aim of this paper is the effect of welding parameters like as welding current, shielding gas flow rate and welding speed with mechanical Properties like tensile strength and hardness. After that finite element analysis for temperature distribution and distribution of the stresses in the welded Aluminium alloy plate. The results show that the larger the Welding current and smaller welding speed will lead to the maximum residual tensile stress. Therefore a residual stress will arise from the restraint position. The ultimate residual stress of weldment is determined by material yield strength at different temperature. The higher yield strength at different temperature has higher material residual stress. Because of its higher thermal conductivity, aluminium alloy test specimens have small temperature differential.
Material Engineering,
Heat treating (or heat treatment) is a group of industrial and metalworking processes used to alter the physical, and sometimes chemical, properties of a material. The most common application is metallurgical. Heat treatments are also used in the manufacture of many other materials, such as glass. Heat treatment involves the use of heating or chilling, normally to extreme temperatures, to achieve a desired result such as hardening or softening of a material. Heat treatment techniques include annealing, case hardening, precipitation strengthening, tempering, carburizing, normalizing and quenching
The presentation is about the fuels used in the Thermal Power Plants and the combustion taking place in large pulverised coal boilers. The calculations about the Air requirements for complete combustion of fuels in the boilers.
A low-carbon steel wire of AISI 1022 is used to easily fabricate into self-drilling tapping screws,
which are widely used for construction works. The majority of carbonitriding activity is performed to improve
the wear resistance without affecting the soft, tough interior of the screws in self-drilling operation. In this
study, Taguchi technique is used to obtain optimum carbonitriding conditions to improve the mechanical
properties of AISI 1022 self-drilling tapping screws. The carbonitriding qualities of self-drilling tapping screws
are affected by various factors, such as quenching temperature, carbonitriding time, atmosphere composition
(carbon potential and ammonia level), tempering temperature and tempering time. The quality characteristics of
carbonitrided tapping screws, such as case hardness and core hardness, are investigated, and so are their
process capabilities. It is experimentally revealed that the factors of carbonitriding time and tempering
temperature are significant for case hardness. The optimum mean case hardness is 649.2HV. For the case
hardness, the optimum process-capability ratio increases by about 200% compared to the original result. The
new carbonitriding parameter settings evidently improve the performance measures over their values at the
original settings. The strength of the carbonitrided AISI 1022 self-drilling tapping screws is effectively improved.
International Journal of Engineering Research and DevelopmentIJERD Editor
Electrical, Electronics and Computer Engineering,
Information Engineering and Technology,
Mechanical, Industrial and Manufacturing Engineering,
Automation and Mechatronics Engineering,
Material and Chemical Engineering,
Civil and Architecture Engineering,
Biotechnology and Bio Engineering,
Environmental Engineering,
Petroleum and Mining Engineering,
Marine and Agriculture engineering,
Aerospace Engineering.
heat treatment is the controlled heating and cooling of metals for the purpose of altering their properties.
it is used in manufacturing providing simple and low cost means of obtaining desired properties
STUDY THE DAMPING EFFECT OF TWO TYPES OF METALS (CK 45, 40 X) USING OILS (AST...IAEME Publication
The aim of the study was to determine the effect of the circles of damping by using two types of oils ((ASTRALUBE and SHIELD)) as well as the use of central damping of a third oil resulting from the mixing of these two oils on the hardness and tensile strength of the two types of minerals have been chosen and two iron Carbon type (CK 45) and on alloy type (40 X) , where the operation took place by damping these metals to those medias oily three after he was placed in a furnace
dedicated to raise the temperature of each of them to ( 850 ) degrees Celsius and the installation of such class for an hour each and every one Lang .
Analysis of mechanical properties of heat treated mild steelSaugata Chowdhury
The aim of this project was to make a comparison between the changes in mechanical properties of mild steel quenched in various quenching mediums namely Vegetable oil, Brine solution, NaOH solution and Super-quenchant. Mild-Steel specimens for hardness test, tensile test and impact test were prepared and heated upto the austenizing range of temperature. After holding at that temperature for the necessary sintering time, they were immediately quenched in the four mediums.
Upon carrying the various tests, it was observed that hardness of all the specimens increased at the expense of toughness. Further the rate of cooling influenced the hardness of the specimens. Specimens quenched in NaOH exhibited maximum increase in hardness and tensile strength of steel. Oil quenched steel showed rise in hardness and tensile strength with least decrease in toughness among the four mediums. Brine also improved the hardness and tensile strength but maximum reduction in toughness was encountered. Finally, superquenchant was found to be the best quenching medium with appreciable rise in the hardness and tensile strength at very less reduction in toughness.
Reduction of cold start emissions in automotive catalytic converter using the...Asheesh Padiyar
Catalytic converters are used to convert harmful exhaust gases like CO, NOx and unburnt hydrocarbons released by
internal combustion engine of automobiles into less harmful gases like CO2, H2O and N2. During the start-up of engine run, catalytic converters suffer cold start problems as the catalyst does not remain active in cold conditions. This results in emission of unconverted harmful gases into the atmosphere. This work attempts to eliminate cold start problems using a heat storage system to keep the catalytic converter hot even under engine off conditions. A eutectic alloy of Mg-Zn-Al is used as the Phase Change Material (PCM) to store the heat around the catalyst. This alloy has high latent heat of fusion, high specific heat, suitable melting point and high thermal stability. Mg-Zn-Al eutectic alloy changes its state between liquid and solid on application and removal of heat. Thus this phase change material acts as a heat storage mechanism in the catalytic converter. Catalytic converter design also involves Rockwool insulation in order to aid longer heat storage. This thermal energy storage system as a combination of PCM and insulation, keeps the catalytic converter hot for several hours even after the engine is shut of
This presentation features ALD's DualTherm® two chamber Vacuum Furnace and it's numerous design and performance benefits including convective heating for faster cycles and minimized distortion, faster to temperature uniformity reversible gas flow during quenching, it's Dynamic-Quench® and that it can be integrated into automated lines.
Production Integrated Vacuum Heat Treatment Systems in the Automotive IndustryALD Vacuum Systems Inc.
To secure the required properties of highly stressed parts from the automotive industry these parts need to be heat treated, in many cases case hardened. This is traditionally performed in central hardening shops. However, the separation between machining and heat treatment involves great efforts regarding transport and buffering of parts leading to extended throughput times and therefore additional costs. The use of modern vacuum heat treatment technologies and the introduction of flexible, modular heat treatment systems allows for the integration of heat treatment into the mechanical production environment, and as of recently also directly into the process chain of part manufacturing.
Improved Material and Enhanced Fatigue Resistance for Gear ComponentsALD Vacuum Systems Inc.
Abstract
This paper shows the latest progress in steel grades and in case hardening technology for gear components.
To answer the demand for fuel-efficient vehicles, modern gear boxes are built much lighter. Improving fatigue resistance is a key factor to allow for the design of thin components to be used in advanced vehicle transmissions. The choice of material and the applied heat treat process are of key importance to enhance the fatigue resistance of gear components.
By applying the technology of Low Pressure Carburizing (LPC) and High Pressure Gas Quenching (HPGQ), the tooth root bending strength can be significantly enhanced, compared to traditional heat treatment with atmospheric carburizing and oil quenching.
Besides heat treatment, significant progress has been made over the past years on the steels being used for gear components. The hardenability of case hardening steels such as 5130H, 5120H, 20MnCr5, 27MnCr5, 18CrNiMo7-6 etc. has been stepwise increased in recent years. An important factor for fatigue resistance is the grain size after heat treatment. Therefore, grain size control is a key goal when developing new modifications of steel grades.
After enhancing grain size control, it was possible to increase the carburizing temperatures over the past years from 930°C to 980°C (1700°F to 1800°F) which resulted in shorter heat treatment cycles and thus in significant cost savings.
With the introduction of new microalloyed steels for grain size stability, carburizing temperatures can now be even further increased to temperatures of up to 1050°C (1920°F), leading to even more economic process cycles. By adding microelements such as Niobium or Titanium in the ppm-range, nitride and carbonitride-precipitates are formed. These precipitates effectively limit the grain-growth during the heat treatment process.
by V. Heuer, T. Leist, G. Schmitt
ABSTRACT:
Controlling distortion is of key importance during the case
hardening process for the production of automotive and
non-automotive metallic components. By effective control of
distortion and the variation of distortion, significant costs in
post heat treatment machining processes can be avoided. In
some cases it is even possible to eliminate all post-machining.
In other cases it may be possible to avoid the press-quenching
of individual components, resulting in huge cost-benefits.
A recently introduced new vacuum furnace design allows the
treatment of small batches in a single layer of parts (“2D-treatment”)
which allows for easy automated loading and unloading
of the fixture-trays. By using the small batch concept,
a continuous flow of parts can be established (“One Piece
Flow”). There is no need to wait until enough parts are collected
to build a large batch with multiple layers (“3D-batch”).
This compact furnace unit can be implemented into the heart
of the production chain and provides heat-treatment processes
which can be fully synchronized with the green and hard
machining-operations. When performing case hardening, the
components are Low Pressure Carburized (LPC) at high temperatures
(1050 °C) followed by gas quenching. The treatment
in single layers offers an optimum in quality regarding: temperature
homogeneity, quench homogeneity and distortion
control. Typical components for this technology come from
the automotive, aerospace and tool industry. The directly following
contribution in this Journal (A. Schüler et al., p. 90-98)
shows more results achieved with this technology on selected
truck-components such as gears and sliding-sleeves.
Distortion of Gears and Sliding Sleeves for Truck Gear Boxes – a Systematical...ALD Vacuum Systems Inc.
Case hardening is the most common heat treatment for gears,
shas and synchronizer parts used in gear boxes for automotive
and commercial vehicle applications. A combination of high fatigue
resistance as well as good machinability and reliable process
stability in heat treatment ensures transmission components with
maximum strength, excellent performance and cost efficient production.
Enhancing Energy Efficiency of Thermochemical Vacuum-Processes and SystemsALD Vacuum Systems Inc.
The energy optimization of thermoprocessing equipment is of great ecological and economical importance. Thermoprocessing equipment consumes up to 40% of the energy used in industrial applications in Germany. Therefore it is necessary to increase the energy efficiency of thermoprocessing equipment in order to meet the EU’s targets to reduce greenhouse gas emissions. In order to exploit the potential for energy savings, it is essential to analyze and optimize processes and plants as well as operating methods of electrically heated vacuum plants used in large scale production.
High Temperature Vacuum Carburizing for Large Carburizing Depths in Highly St...ALD Vacuum Systems Inc.
In order to complete the existing heat treatment
shop and expand capacity, the chain
works HEKO in Wickede was looking for a
modern, clean, ecological and, most of all,
flexible heat treatment process as an alternative
to conventional gas carburizing with
oil quenching.
ALD Holcroft® - Low Pressure Carburizing for Large Transmission PartsALD Vacuum Systems Inc.
Often, the required hardness qualities of parts manufactured from steel can only be obtained through suitable heat
treatment. In transmission manufacturing, the case hardening process is commonly used to produce parts with a hard and
wear-resistant surface and an adequate toughness in the core. A tremendous potential for rationalization, which is only
partially used, becomes available if the treatment time of the case hardening process is reduced. Low pressure carburizing
(LPC) offers a reduction of treatment time in comparison to conventional gas carburizing because of the high carbon
mass flow inherent to the process (Ref. 1).
By increasing the carburizing temperature, a further significant increase in productivity is obtained, which is not
possible in gas carburizing systems to this extent due to furnace component and process limitations (Ref. 2). By adding micro-alloy elements such as aluminium, niobium and titanium as well as properly adjusting the nitrogen content, modern case hardening steels have become sufficiently fine-grain resistant even in temperatures above 1,000°C (1,830°F)
(Ref. 3). Today’s vacuum carburizing systems are suited for heat treatment in temperature above 1,000°C.
Integrating heat treatment into the manufacturing line has been a topic of discussion for many years. Today’s production philosophy for gear components
usually relies on the traditional separation between
soft machining, heat treatment, and hard machining. Heat
treatment is performed in a central hardening shop, and
there is no continuous flow of production parts between
the different operations such as soft machining, heat
treatment, shot peening, and hard machining. Instead the
parts are first collected into batches and then moved from
operation to operation, so large numbers of production
parts are being stored in buffers or are in transit between
the different operations. A continuous flow of production
parts between operations is only occurring today between
some of the soft machining operations and some hard
machining operations. This discontinuous flow of production
results in increased logistical and documentation
efforts, increased turnaround times and, ultimately, in
increased production costs.
Dual chamber vacuum furnace for Low Pressure Carburizing (LPC) and High Press...ALD Vacuum Systems Inc.
Dual vacuum furnaces with separated heating and cooling processes are providing several advantages when compared to single chamber vacuum furnaces. This includes faster heating up, less energy consumption, more quenching severity and less maintenance. Accordingly a new, “second
generation” of dual vacuum furnace for low pressure carburizing and high pressure gas quenching, DualTherm®, was developed using proven technologies from the ModulTherm® series of vacuum furnace systems.
The first furnace was recently installed at a commercial heat treater and is now in three-shift-operation.
NO1 Uk best vashikaran specialist in delhi vashikaran baba near me online vas...Amil Baba Dawood bangali
Contact with Dawood Bhai Just call on +92322-6382012 and we'll help you. We'll solve all your problems within 12 to 24 hours and with 101% guarantee and with astrology systematic. If you want to take any personal or professional advice then also you can call us on +92322-6382012 , ONLINE LOVE PROBLEM & Other all types of Daily Life Problem's.Then CALL or WHATSAPP us on +92322-6382012 and Get all these problems solutions here by Amil Baba DAWOOD BANGALI
#vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore#blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #blackmagicforlove #blackmagicformarriage #aamilbaba #kalajadu #kalailam #taweez #wazifaexpert #jadumantar #vashikaranspecialist #astrologer #palmistry #amliyaat #taweez #manpasandshadi #horoscope #spiritual #lovelife #lovespell #marriagespell#aamilbabainpakistan #amilbabainkarachi #powerfullblackmagicspell #kalajadumantarspecialist #realamilbaba #AmilbabainPakistan #astrologerincanada #astrologerindubai #lovespellsmaster #kalajaduspecialist #lovespellsthatwork #aamilbabainlahore #Amilbabainuk #amilbabainspain #amilbabaindubai #Amilbabainnorway #amilbabainkrachi #amilbabainlahore #amilbabaingujranwalan #amilbabainislamabad
Cosmetic shop management system project report.pdfKamal Acharya
Buying new cosmetic products is difficult. It can even be scary for those who have sensitive skin and are prone to skin trouble. The information needed to alleviate this problem is on the back of each product, but it's thought to interpret those ingredient lists unless you have a background in chemistry.
Instead of buying and hoping for the best, we can use data science to help us predict which products may be good fits for us. It includes various function programs to do the above mentioned tasks.
Data file handling has been effectively used in the program.
The automated cosmetic shop management system should deal with the automation of general workflow and administration process of the shop. The main processes of the system focus on customer's request where the system is able to search the most appropriate products and deliver it to the customers. It should help the employees to quickly identify the list of cosmetic product that have reached the minimum quantity and also keep a track of expired date for each cosmetic product. It should help the employees to find the rack number in which the product is placed.It is also Faster and more efficient way.
We have compiled the most important slides from each speaker's presentation. This year’s compilation, available for free, captures the key insights and contributions shared during the DfMAy 2024 conference.
6th International Conference on Machine Learning & Applications (CMLA 2024)ClaraZara1
6th International Conference on Machine Learning & Applications (CMLA 2024) will provide an excellent international forum for sharing knowledge and results in theory, methodology and applications of on Machine Learning & Applications.
About
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Technical Specifications
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
Key Features
Indigenized remote control interface card suitable for MAFI system CCR equipment. Compatible for IDM8000 CCR. Backplane mounted serial and TCP/Ethernet communication module for CCR remote access. IDM 8000 CCR remote control on serial and TCP protocol.
• Remote control: Parallel or serial interface
• Compatible with MAFI CCR system
• Copatiable with IDM8000 CCR
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
Application
• Remote control: Parallel or serial interface.
• Compatible with MAFI CCR system.
• Compatible with IDM8000 CCR.
• Compatible with Backplane mount serial communication.
• Compatible with commercial and Defence aviation CCR system.
• Remote control system for accessing CCR and allied system over serial or TCP.
• Indigenized local Support/presence in India.
• Easy in configuration using DIP switches.
Overview of the fundamental roles in Hydropower generation and the components involved in wider Electrical Engineering.
This paper presents the design and construction of hydroelectric dams from the hydrologist’s survey of the valley before construction, all aspects and involved disciplines, fluid dynamics, structural engineering, generation and mains frequency regulation to the very transmission of power through the network in the United Kingdom.
Author: Robbie Edward Sayers
Collaborators and co editors: Charlie Sims and Connor Healey.
(C) 2024 Robbie E. Sayers
Using recycled concrete aggregates (RCA) for pavements is crucial to achieving sustainability. Implementing RCA for new pavement can minimize carbon footprint, conserve natural resources, reduce harmful emissions, and lower life cycle costs. Compared to natural aggregate (NA), RCA pavement has fewer comprehensive studies and sustainability assessments.
Recycled Concrete Aggregate in Construction Part III
MWF Heat Treatment: Solutions for a Critical Process by Dr. Neil Canter
1. COVER STORY
Dr. Neil Canter / Contributing Editor
How end-users have a
variety of options for annealing and
hardening metal alloys
hen the topic of metalworking is raised, most of us think of drilling a hole
in a piece of metal or bending a metal part to form a component for an
automobile. Not as many individuals realize that another process included under the
realm of metalworking is heat treating or quenching.
Heat treatment is utilized to adjust the physical and mechanical properties of
metals so that they can be used in subsequent metalworking applications. These
properties are changed by the controlled heating and then cooling of metals. In many
cases, the objective of heat treatment is to increase the strength of a specific metal
alloy. Most operations are conducted on steel alloys, but nonferrous metals such as
aluminum and titanium also can be heat treated.
Daniel H. Herring, president of The Herring Group Inc. in Elmhurst, Ill., says,
“The two main processes in heat treatment are annealing and hardening. In the case
of annealing, the microstructure of the metal is softened to restore its ductility, in-
crease toughness, adjust grain size and remove residual stresses. Hardening of fer-
rous alloys in particular is accomplished to increase the strength and wear properties
of the metals involved.”
For ferrous alloys, the objective is to increase the temperature above the upper
critical temperature (Ac3
), which is dependent on the composition of the alloy in
question so that the metal is completely in the austenite phase. The alloy is then
2 6
2. rapidly cooled by exposure to either a quenching fluid or
gas so that it can be converted into the harder martensite
phase. Final hardness is dependent upon the carbon content
of the steel. For example, martensite has a hardness of 30
HRC (0.10%C steel) to 55 HRC (0.40%C steel) to 65+ HRC
(0.80%C–1.25% C steel).
A sufficiently fast cooling rate is needed to minimize the
formation of bainite and pearlite phases which are softer
than martensite and, in some instances, will negatively im-
pact the physical properties of the steel. Bainite has a hard-
ness of 28–48 HRC (0.40%C steel) to 40–58 HRC (0.80%C
steel) and pearlite has a hardness of 80–90 HRC (0.40%C
steel) to 30–40 HRC (0.80%C steel).
A continuous cooling curve showing the cooling rate of a
ferrous alloy is shown in Figure 1. Conversion to martensite
starts at the Ms temperature while the complete transforma-
tion to this phase is shown at the Mf temperature.
The key to accomplishing this process is the uniform re-
moval of heat from the surface of the metal part in question.
Herring says, “The speed of heat treatment is considered by
some the most important aspect, but speed alone is not the
total answer. If no other factors are considered, a rapid heat-
treatment process alone will lead to distortion of the metal.”
Herring also points out that added metal distortion can
increase the number of post-operations which need to be
done on the heat-treated metal. He adds, “Post heat treat-
ment grinding of gears can be a big expense.”
Quenching of ferrous alloys occurs in three stages: the
vapor blanketing stage (Stage A), the nucleate boiling state
(Stage B) and the convection stage (Stage C). Stage A in-
volves the hot surface of the metal meeting the quenchant.
In most cases, the quenchant is a liquid which results in the
generation of vapor surrounding the metal part. Heat transfer
is very low at this stage and occurs mainly through radiation
from the vapor. Figure 2 shows how large a vapor blanket
can form when a piece of hot steel is immersed in water.
Stage B is characterized by the formation of boiling in
the quenchant in close proximity to the metal surface. At
this point, heat is rapidly moving away and the temperature
of the metal part drops rapidly to a point below the boiling
point of the quenchant.
With this cooling, the metal part moves to Stage C in
which cooling occurs mainly by convection. The rate of cool-
ing is dictated by the quenchant’s specific heat and thermal
conductivity. For the most part, heat removal is quite slow at
this stage of quenching.
The key to accomplishing this
process is the uniform removal of
heat from the surface of the metal
part in question.
The objective of heat treatment
is to increase the strength
of a specific metal alloy.
Most operations are conducted on steel alloys, but nonferrous metals
such as aluminum and titanium also can be heat treated.
2 7
Figure 1
(Courtesy of Houghton International, Inc.)
Figure 2
(Cour-
tesy of G.E. Totten & Associates, LLC)
3. The transition from Stage A to Stage B is shown in the
quenching of a cylindrical chromium, nickel steel alloy in oil
at a temperature of 60 C (140 F), as shown in Figure 3. In the
time frame between 4.3 seconds and 12.3 seconds after the
start of quenching, an interface between the vapor phase and
nucleate boiling slowly rises to the top of the sample.
Gajen Dubal, heat treating specialist for Heat Bath, Inc.,
in Detroit, says, “The ideal quenchant should have no vapor
phase, fast nucleate boiling and a slow convection stage.”
Herring adds, “If the nucleate boiling stage can be con-
trolled, then distortion of the metal is minimized.”
The main quenchants used are oils and polymers. Oils have
been utilized since the latter part of the 19th Century and are
the most popular quenchant today. Polymers use has become
significant, particularly during the past 40 years.
But there are other options that can be used including
molten salts and gases. A very recent technique known as
intensive quenching was developed 35 years ago and works
with either pure water or low concentration salt/water solu-
tions.
Advantages and disadvantages of each of these techniques
are described in the following paragraphs.
Dr. Scott MacKenzie, technical service laboratory manager
for Houghton International in Valley Forge, Pa., indicates
that oils are used for most heat-treating applications. He
says, “Oil viscosity can range from approximately 50 SUS to
in excess of 2,500 SUS (at 100 F). Oil selection depends on
the application, the type of steel heat treated and the quench-
ing temperature. For low temperatures [less than 100 C (212
F)], oils with viscosities of less than 150 SUS are used. Higher
viscosity oils are used at temperatures above 100 C (212 F)
because of the need to have a higher flash point and greater
thermal stability.”
Cold temperature oils are used in applications where dis-
tortion of the metal is not a major factor. For higher tempera-
ture applications up to 200 C (392 F), hot quenching oils are
needed to ensure that distortion is minimized. This process
is known as marquenching.
Complementing the base oil are additive packages that
improve quenching speed and contain antioxidants. The for-
mer is known as speed improvers. MacKenzie says, “Speed
improvers increase the wettability of the oil during the
quenching process. Typical additive classes used are alkali
sulfonates and complex organic polymers. Other additives
are used to boost the thermal stability of the base oil.” Fur-
ther information on the composition of oil quenchants can
be found in a recent article.1
If the proper packages are selected, low-temperature
quenching oils will not require any further additions of ad-
ditives while in use, according to MacKenzie. In contrast,
additive depletions in hot quenching oils due to temperature
and drag-out means that tankside addition of packages may-
be required to maintain performance. However, it depends
on the quality and type of additive package, as well as the
application.
MacKenzie believes that oils are generally robust and sim-
ple to use. But he maintains that they are expensive and may
be difficult to dispose of readily.
Dubal is mainly concerned about the safety and environ-
mental issue in oil quenching. He says, “In a safe quenching
process, the operating temperature of the oil should be 55
‘If the nucleate boiling stage
can be controlled, then
distortion of the metal
is minimized.’
2 8
Figure 3
(Courtesy of G.E. Totten & Associates, LLC)
Cold temperature oils are used in
applications where distortion of
the metal is not a major factor.
Oils have been utilized since the
latter part of the 19th Century
and are the most popular
quenchant today.
4. C to 83 C (130 F to 180 F) below its flash point.” Figure 4
shows the concern with fire that can occur when oil tem-
perature exceeds the flash point and the fire point.
The main type of polymer quenchant used is based on poly-
alkylene glycols (PAGs).2
These quenchants are aqueous
solutions of PAGs formulated with corrosion inhibitors and
biocides.
The performance of polymer quenchants is influenced by
their ability to become water insoluble at elevated tempera-
tures. This behavior is known as inverse solubility. When hot
metal is introduced into the polymer quenchant, a film of the
liquid polymer will deposit on the metal and facilitate heat
transfer.
Performance factors that must be considered include the
concentration of the polymer, agitation rates and quenchant
solution temperature. MacKenzie says, “Polymer quenchants
are generally cheaper than oil on a per gallon basis once they
are diluted, but more attention must be paid to concentra-
tion control, cleanliness, microbes (bacteria and fungus) and
the application.”
Dubal indicates that polyvinyl pyrrolidones (PVPs) also
can be used as a basestock for polymer quenchants. In some
cases, PVPs are considered to be an upgrade on PAGS.
Dubal cautions that bacterial growth can be a problem
in using some polymer quenchants. He says, “If a polymer
quenchant is only occasionally used and sits idle for a long
time without agitation, then bacterial growth can be an is-
sue, and biocides need to be added to control potential prob-
lems.”
Molten salts have been used for more than 60 years as quen-
chants. Dubal says, “The key is to keep the temperature
above the melting point of the salt. Operating temperatures
for molten salts range from 150 C to 590 C (300 F to 1100 F)
depending upon the composition of the salt.”
Most of the salts utilized in quenching are nitrate-based
with some prepared from chloride.3
The nitrate-based salts
are binary or tertiary mixtures of sodium and potassium ni-
trate and nitrite.
In contrast to oils and polymers, salts quench by a differ-
ent mechanism. Stage A (vapor blanketing stage) and Stage B
(nucleate boiling) of quenching do not occur with salts. The
quenching process moves directly into Stage C (convective
cooling), and most of the heat is removed during this stage.
This results in a more uniform heat removal with minimal
distortion of the part.
With the contact between salt and metal, there is an ex-
pectation that corrosion could be a problem. Dubal says,
“Not much corrosion is seen with molten salts. In most
cases, ordinary carbon steel can be used to contain the salt
bath. Corrosion inhibitors are used in follow-up operations
because the quenched parts are washed down with water.”
High-pressure gas quenching is the method of choice in heat
treatment in vacuum furnaces using inert gas or blends there-
of. Bill Gornicki, vice president of sales for ALD-Holcroft in
Wixom, Mich., says, “The pressure of the gas can range from
2 bar to in excess of 20 bar. It can be varied to adjust quench
intensity, which enables some degree of control to be exerted
over part distortion.”
The only phase of quenching that the parts go through
when gas is used is convection. Gornicki says, “In gas
quenching, the vast majority of systems in North America
impinge the quenching gas in a 360-degree nozzle pattern
aimed directly at the workload. The gas then exits the hot
zone, cycles through a water-cooled heat exchanger and is
once again cycled through the workload.”
Gornicki continues, “In the European market, the vast
majority of systems use directionally controlled gas flow
(top/down, bottom/up, side-to-side). The direction of the gas
flow can be altered during the quench sequence. These ca-
3 0
Figure 4
(Courtesy of Houghton Interna-
tional, Inc.)
Molten salts have been used for more than 60 years as quenchants.
High-pressure gas quenching is the
method of choice in heat treatment
in vacuum furnaces using inert gas
or blends thereof.
5. pabilities offer some additional control on quench intensity,
thereby offering more distortion control on the workload.”
Nitrogen, argon and helium are the most common gases
used in commercial heat-treating applications. Dr. Minfa Lin,
senior principal materials engineer for Air Products in Al-
lentown, Pa., says, “Gas blends of helium and argon provide
better cooling at a lower cost as compared to 100% helium.
We found that an ideal gas mixture is 85% helium and 15%
argon.4
A typical temperature for metal being quenched is
1150 C (2100 F) and a typical gas pressure used is 8 bar.”
Gas quenching has several advantages over the use of
oils, polymers and salts. Gornicki says, “Metal parts emerge
from the process bright and clean, which means there is no
need for post-quench washing. Intergranular oxidation of
the metal is eliminated if the process is done in a vacuum
furnace.”
Lin believes that quenching with gas provides much
more uniform cooling while keeping the part clean com-
pared with conventional methods such as oil. He adds, “The
reason for more uniform cooling by gas is that the cooling
occurs through convection only. In contrast, the four dif-
ferent modes of cooling by liquid quenchants may produce
larger temperature differences and distortion in the part if
not properly controlled.”
Gornicki is in agreement and says, “With gas quenching,
there is a greater capability to control distortional character-
istics of the part, thereby minimizing/eliminating post heat-
treat machining and/or straightening operations.”
But gas is not as effective in facilitating heat transfer as
compared to liquid quenchants. Lin says, “Gas cooling can-
not be used universally. Its use depends on composition
(hardenability), size, microstructure, cleanliness and unifor-
mity requirements of the part being quenched.”
Gornicki adds, “Materials to be quenched with gas must
have higher alloy content. Gas cannot quench low-alloyed
metals effectively.”
Intensive water quenching cools down metal at a much more
rapid rate than other approaches.5
Highly agitated water is
used during the quenching procedure to quickly and uni-
formly remove heat from the metal part. During conventional
oil quenching, parts usually develop high tensile stresses on
the surface that result in part distortion or even cracking. In-
tensive quenching takes advantage of the fact that high “cur-
rent” (while quenching) and residual compressive stresses
are formed on the part surface. These beneficial compressive
stresses eliminate part distortion and part crack formation.
An additional benefit of intensive cooling is the mechanical
property improvements such as strength, wear resistance and
fatigued life.
Joseph Powell, president of IQ Technologies Inc. in Ak-
ron, Ohio, says, “During rapid and uniform cooling of steel
parts, we have found that the austenite steel on the surface
quickly becomes uniformly martensite. Since the specific
volume of the martensite is greater than the specific vol-
ume of austenite, the faster the part shell is transformed to
martensitic, the higher the compressive stresses that can be
formed. These compressive stresses act like a die holding the
part together—both during the quench and as the part is in
service. The core of the metal part cools from the austen-
ite phase by rapid conduction through the cold shell, which
properly toughens the part core.”
The vapor-blanketing stage of quenching is non-uniform
and is therefore eliminated in intensive quenching. Powell
says, “The rapid cooling of the metal part moves quenching
to the nucleate boiling phase or to direct convection cooling.
Once the outer martensite shell is developed, the intensive
quenching process is interrupted and the part is moved into
the air to cool the core by rapid conduction until the tem-
perature equalizes throughout the part.”
This phenomenon is shown in Figure 5 as the difference
between intensive quenching and oil quenching for 1045 al-
loy steel are depicted. The important aspect is that after 10
seconds in intensive quenching (unlike in oil quenching),
the shell is formed when the part core is extremely hot and
more space is available for the core to expand as it cools.
Powell indicates that intensive quenching of a specific
steel alloy leads to improved physical properties as com-
pared to quenching with oil. He projects that the strength of
a quenched ferrous alloy can increase about 20% and at the
same time ductility is increased by up to three times that of
oil quenched parts. In addition, the improved material prop-
erties combined with higher compressive stresses can extend
part service life from 30% to 800%. A 6,000-gallon intensive
3 1
A
935oC
IQ
A
935oC
A
350oC
A
320oC
A
320oC
Oil quenching
= 3 seconds
= 10 seconds
= 25 seconds
= 40 seconds
= 0 seconds
Figure 5
(Cour-
tesy of IQ Technologies, Inc.)
6. quenching system is shown in Figure 6.
There are a lot of quenchant types to choose from and two
factors that must be assessed are distortion and the rate of
heat transfer. Herring points out that these two parameters
work against each other. A technique that provides minimal
distortion also does not generate a high rate of heat transfer
and vice versa.
The list of quenching options and how they rate from both
a distortion and heat transfer perspective are shown in Table
1. Air provides the lowest degree of distortion but also is very
poor from a heat-transfer perspective. In contrast, brine or
caustic provide good heat transfer but poor distortion.
Herring comments, “Heat treatment is comparable to a
teeter totter where the user must weigh many parameters.
Give and take is required to find the right combination of
parameters and balance them.”
Prior to heat treating a specific metal alloy, the quenching
formulator and end-user must do their homework to deter-
mine how the metallurgy of a specific alloy will respond to
the quenching process. Dubal says, “ASM Handbook Volume
4 on Heat Treating is a valuable reference.6
For a specific steel
or alloy, the two-volume Heat Treater’s Guide should be con-
sulted.7,8
Time-temperature-transformation and continuous
cooling transformation diagrams can be obtained from Atlas
of Time-Temperature Diagrams for Iron and Steels.9
”
MacKenzie indicates that there are differences in quench-
ing ferrous alloys as opposed to nonferrous alloys. For a fer-
rous alloy, the physical dimension of the specific part and its
mechanical properties must be known. He says, “The steel
alloy, its hardenability, cross-section thickness and distortion
are primary variables that must be considered, regardless of
whether the quenchant is an oil or a polymer. The type of
equipment also must be considered. As a general rule, the
mechanical properties (hardness and tensile properties) and
the propensity to residual stresses and distortion are the pri-
mary things to consider.”
Two other criteria that are important for steel are elonga-
tion and fracture toughness, particularly in applications such
as a landing gear.
Further details on the heat treatment of ferrous alloys is
found in a recent review.10
MacKenzie points out that nonferrous metals such as alu-
minum, some titanium alloys and beryllium-copper alloys
are quenched with water or diluted polymers. He adds, “For
some alloys (especially beryllium-copper) a very fast quench
is required, and only water is allowed to be used.”
Herring indicates that hardening of nonferrous alloys oc-
curs through a diffusion-related hardening mechanism as
compared to the phase transformation (austenite marten-
site) seen with ferrous alloys. He says, “Nonferrous alloys are
hardened in a two-step process starting with solution heat
treating and quenching followed by age or precipitate hard-
ening.”
In solution heat treating, the metal part in question is
placed in a saturated solution of the hardening elements that
need to be incorporated into the alloy. Soaking of the metal
part is conducted at a sufficiently high temperature to add
these elements. Rapid quenching is then accomplished to
ensure that the needed hardening components do not pre-
cipitate out of solution. As a result, a supersaturated solution
is retained at room temperature.
3 2
Age hardening of wrought aluminum and copper alloys usually takes
four to five days at room temperature.
Figure 6
(Courtesy of IQ Technologies, Inc.)
Table 1
(Courtesy of The Herring
Group, Inc.)
Quenching Options Rated from
Distortion and Heat Transfer
- Minimizing Distortion
Reduced
Heat Transfer
Quenching Option:
Air
Molten Salt
High Pressure Gas Quenching
Oil
Polymer
Water
Brine / Caustic
Increased
Distortion
7. Age hardening of wrought aluminum and copper alloys
usually takes four to five days at room temperature. Pre-
cipitation hardening also can be conducted at temperatures
above ambient, for example between 115 C and 200 C (240 F
to 390 F) for 5-48 hours. Herring says, “In precipitation heat
treatment, a precipitate or second phase forms on the grain
boundaries of the metal alloy. This leads to a change in the
internal structure of the metal.”
In gas quenching, a similar process is carried out to se-
lect the proper operating conditions. Gornicki says, “Among
the criteria to be evaluated are the metal alloy, largest cross
section of the specific material to be quenched, load size/
production throughput requirements and desired results. He
indicates that experimentation and cycle development are
usually done to ensure that the desired results are obtained.
Lin says, “Helium and argon are both inert and can be used
with both ferrous and nonferrous metals. Selection of the gas
is based on the final microstructure and the required cooling
rate for the metal. For example, in solution annealing of alu-
minum alloys, parts will need to be quenched very fast to pre-
vent second phase precipitation, and gas cooling may not be
suitable for this process due to its limited cooling capacity. In
the case of annealing pure titanium grades, it does not require
extremely fast cooling, so helium can be used.”
Higher gas pressures and faster gas flow speeds are need-
ed for hardening ferrous alloys that require a faster cooling
rate. Lin indicates that the gas pressure used in these applica-
tions is typically 20 bar with gas flow speeds in the range of
30 m/sec.
While suited for ferrous alloys, intensive quenching also
can be used to solution anneal aluminum and titanium al-
loys. Powell says, “We have found that the intensive quench-
ing system can be used to solution treat aluminum in a more
uniform manner than other techniques and without the need
for polymer quenchants. The high cooling rate also provides
a corrosion benefit to the aluminum.” One application cited
by Powell for this process is the preparation of aluminum
shovel handles for the U.S. Army. A similar benefit was found
in the preparation of titanium pucks for subsequent forming
operations.
In a similar manner to other types of metalworking fluids,
contamination of quenching fluids can lead to performance
problems and safety issues, particularly in the case of oils.11
Herring says, “Contaminants can cause great difficulties
with quenching depending upon the process. For example,
in case hardening steel, carbon is introduced in a process
known as carburization. This will lead to the creation of free
carbon (soot) that will find its way into the quench oil. Over
a longer term, buildup of soot will change the heat transfer
properties of the quenching oil and also accelerate oxidation
of the oil.” Soot is also a very fine particulate and very dif-
ficult to filter.
Water is a contaminant that can increase the possibility of
a quench oil fire. Herring remembers, “A maintenance man
who knew better poured half a cup of cold coffee into an
1,800-gallon integral quench oil tank several times over the
three- to five-day shutdown period. The result was a quench
oil fire when the unit was returned to service.”
Dubal feels that hydraulic fluid contamination can create
problems. He says, “If the hydraulic fluid is an oil type, its
leakage will alter the quenching performance of oil. But if
the hydraulic fluid is a water-based polymer, the result could
be disastrous. It may cause non-uniform quenching and fast
heat removal in Stage C, leading to excessive distortion and,
in extreme cases, cracking. It also poses a serious fire risk. So
no amount of water-based hydraulic fluid or water in oil is
considered acceptable. In comparison, polymer quenchants
can tolerate up to 1% hydraulic fluid of both types.”
The presence of hydraulic fluid of any type in molten salt
can become a major safety concern and can lead to fire or
explosion. This concern can be overcome by installing pneu-
matic systems in place of hydraulics.
Herring indicates since heat treatment affects the internal
structure of a material—at a level undetectable to the na-
ked eye—that the introduction of any unforeseen variables
or contaminants can lead to problems. He says, “Equipment
and process variables must be controlled very carefully to
ensure that the microstructure of the steel being heat treated
does not change. Of concern is that even with careful mainte-
nance, changes in the microstructure may not be seen when
quality control tests are run on the part.”
In gas quenching, there is a lower chance for contamina-
tion. Gornicki says, “Nitrogen, argon and helium all have
exceptionally high purity levels well in excess of 99.9%. The
primary source for contamination is a vacuum leak in the
furnace or in the backfill line from the reservoir where the
gas is stored to the vacuum furnace. If a leak is detected, then
the usual effect on the quenched metal part will be a change
in its color.”
The water used in intensive quenching does not cause
any contamination problems, according to Powell. He says,
“Since there is no boiling, scaling is not a problem even in
hard water. We have been using a 6,000-gallon tank for many
years for intensive quenching that has never been dumped.”
Powell indicates that any oil present on a metal part will
burn off during intensive quenching and not affect the pro-
cess.
Analysis of quenching fluids during use is just as important
as other metalworking fluids in providing the user with an
3 3
Water is a contaminant that can
increase the possibility of a quench
oil fire.
8. 3 4
assessment of performance. Standard type tests such as vis-
cosity, water content, flash point and total acid number are
recommended.12
One additional test of note is to determine the quench
speed. Two methods used are the GM Quench-o-meter and
cooling curves. Herring says, “One of the problems the heat-
treating industry faces is that end-users tend to ignore the
data. Quenching fluid suppliers who normally run these tests
must make sure samples are representative, are pulled from
the same location in the system and reported to the end-user
in a useable form.”
Herring notes that cooling curves evaluate how the spe-
cific fluid performs during the three stages of quenching.
Cooling curve shifts take place due to changes in contam-
inants, oxidation of the fluid, drag-out and agitation. Test
procedures run are based on ASTM D-6200-01 (2007) and
ISO-9950.
Drake Leithold, plant manager of Carolina Commercial Heat
Treater’s facility in Fountain Inn, S.C., mainly heat treats fer-
rous alloys. He says, “We have a continuous belt furnace with
two open quench tanks (one 2,500 gallons and the other 3,500
gallons) and an integral quench batch furnace with seven
quench oil tanks (five 2,000 gallons and two 5,000 gallons).
The oil used in both systems quenches in 8-10 seconds.”
During each shift, operators check the oil temperature,
degree of agitation and oil level alarms. The biggest problem
that Leithold sees in his plant is dirt and soot. He says, “Since
the early 1980s, we have encountered trouble with remov-
ing dirt and soot from metal parts. To counter this problem,
we have set up centrifuges to continuously remove contami-
nants from every oil tank. This has been very effective.”
Samples of each oil are sent out once every quarter for
testing of basic analytical properties, contaminants and
quenching speed. Leithold adds, “Our emphasis on main-
tenance combined with using a longer-lasting quenching oil
has led to a minimization in the amount of distortion seen in
finished parts.”
The biggest issue Leithold has is with the type of part
that he must quench. He explains, “We cannot control the
type or geometry of the part we heat treat. Variations in the
thickness and dimensions of parts cause parts to quench at
different cooling rates. In fact, different sections of the same
part can quench at different rates.”
Dubal discussed the challenge of quenching parts that
range in size from half-inch to 20 inches and are made from
the carbon steel alloys 4140, 4340 and 8630. These parts are
being used in mechanical tubing, wellhead adapters, valve
bodies, casing spools and machine parts.
PAG-based quenchants have been used but, unfortunate-
ly, a high incidence of cracking was seen. Dubal says, “The
problem is that a polymer quenchant needs to perform with
the effectiveness of oil at 840 C (1,545 F) (which is the tem-
perature at which 4140 steel totally enters the austenization
phase) yet stop the quenching process at 260 C (500 F).”
A PVP-based quenchant was tried next and provided the
desired quenching performance with minimal part distor-
tion. Dubal says, “The advantage of the PVP-based product
is that it enables quenching to move rapidly from the vapor
blanketing phase and provides an insulating polymer film
deposit for the ensuing phases of quenching. This film helps
to moderate the rate of conductive and convective heat trans-
fer.”
The result is that the dimensional integrity of the ferrous
alloys is maintained due to a reduction in transformational
stresses and the prevention of localized temperature devia-
tions. Oil skimming (to remove machining and hydraulic
oils, if any) and annual descaling of tanks are the only main-
tenance tasks required on the PVP quenchant system.
MacKenzie discusses how changing from a fast quenching
cold oil to a mar-tempering oil reduced the distortion experi-
enced with pinion gears. He says, “The switch to quenching
at 120 C (250 F) with a mar-tempering eliminated distor-
tions and saved approximately $10 million a year. Other ben-
efits realized included reduced transmission noise, reduced
fatigue failure and warranty repairs.”
Gornicki cites the use of gas quenching to minimize dis-
tortion in the manufacture of automotive gears. He says, “We
found that vacuum carburization followed by high-pressure
gas quenching is an effective way to heat treat thin-walled
Formulate Green
With Fruits & Beans
Palm Based Oleochemicals & Derivatives:
Fatty Acids Glycerine
Fatty Alcohols Fatty Acid Esters
Fractionated Methyl Esters
(C610, C8, C10, C12, C1214, C14, C16, C1618, C18)
Castor Oil & Derivatives:
12 Hydroxy Stearic Acid CO Fatty Acid
Hydrogenated Castor Oil Ricinoleic Acid
Methyl 12 Hydroxy Stearate Sebacic Acid
Visit our New Website: www.acme-hardesty.com
Call us for a free Oils & Fats Composition Chart
Acme-Hardesty Co.
450 Sentry Parkway East
Blue Bell, PA 19422
866.226.3834
9. parts made from low alloy steels. The quenching process is
conducted with helium at pressures up to 20 bar.”
One of the key elements is that the gas pressure and/
or gas flow velocity are varied to minimize distortion. This
technique is known as dynamic quenching. Initially, the con-
ditions are harsh to reduce the temperature quickly. This is
followed by a period of a milder quench to enable the tem-
perature to become equalized throughout the part. In a fi-
nal stage, the quench becomes severe again to complete the
process.
Gornicki noted that this technique is used successfully
to manufacture ring gears made from SAE 5130 steel and is
considered the key technology in heat treating the internal
gears of a new six-speed automatic transmission used world-
wide.
Powell discusses the use of intensive quenching in the
manufacture of parts made from the carburized steel al-
loy Pyrowear 53, which is well suited to meet the demands
of transmission gears in helicopters. He says, “Intensive
quenching very rapidly cooled down the steel alloy so that
it converted from the austenite to the martensite phase. This
process led to an improvement of 15% in the strength of this
ferrous alloy, increased load carrying capacity and reduced
fatigue life.”
Powell also noted that helicopter gears made from Py-
rowear 53 must pass a performance test in which they must
perform without any lubricant, e.g., the oil sump has a hole
shot in it. This procedure is done to ensure the helicopter
can fly long enough to land safely.
Herring indicates that the heat-treating industry continues
to develop new technologies in an evolutionary manner. He
says, “First, the industry started with salt as the dominant
media in the early 1960s, but there were problems using
barium additives from a safety perspective. Oil then moved
to the forefront in the late 1960s and has remained as the
dominant quench today.”
Herring revealed that salt did make a comeback for certain
applications recently. The next technology to emerge is gas
quenching. Herring says, “The use of gas in heat treatment
has a lot of potential but still must overcome certain prob-
lems. One of the reasons for this trend is the development
of a new class of steel that is gas quench friendly. The major
problem is that gas quenching is not effective at hardening
low-alloy steels at a cost comparable to oils. For this reason,
high-pressure quenching in hydrogen is being explored by
the industry.”
Eventually, Herring foresees that engineering materials
will be produced that no longer require heat treatment. He
says, “The goal in industrial production is to eliminate op-
erations and heat treatment as a primary candidate based on
regulatory drivers, energy savings and pollution.”
MacKenzie also sees long-term concerns for heat treat-
ment. He says, “Besides environmental regulations striving
for zero emissions, universities in the U.S. have changed their
emphasis from metallurgy to material science. This means
that it will be more difficult to find qualified individuals with
expertise in heat treatment in the future.”
Both Herring and MacKenzie recognize that educating
formulators and end-users is vital. As Herring observes, “For
heat treating to remain competitive in the 21st Century, it
must be the most cost-effective technology.”
Heat treatment of metals remains a pivotal metalworking
operation that is needed to improve the mechanical proper-
ties of the materials used in a wide range of applications that
power our modern society.
1. MacKenzie, D. (2009), “The Chemistry of Oil Quen-
chants,” Heat Treating Progress, 9 (6), pp. 28–32.
2. Totten, G. (1990), “Polymer Quenchants: The Basics,” Ad-
vanced Materials & Processes, 137 (3), pp. 51–53.
3. Dubal, G. (2003), “The Basics of Molten Salt Quenchants,”
Heat Treating Progress, 3 (5), pp. 81–86.
4. Baxter, W., Kilhefner, P. and Baukal, C. (1992), “Rapid Gas
Quenching Process,” U.S. Patent 5,173,124.
5. Aronov, M., Kobasko, N. and Powell, J. (2001), “Appli-
cation of Intensive Quenching Methods for Steel Parts, Pro-
ceedings of 21st ASM Heat Treating Society Conference, India-
napolis, Ind.
6. Davis, J. Ed. (1991), ASM Handbook Vol. 4 Heat Treating,
ASM International.
7. Chandler, H. (1995), Heat Treater’s Guide: Practices and Pro-
cedures for Irons and Steels, 2nd Edition, ASM International.
8. Chandler, H. (1996), Heat Treater’s Guide: Practices and
Procedures for Nonferrous Alloys, ASM International.
9. Voort, G. Ed. (1991), Atlas of Time-Temperature Diagrams,
ASM International.
10. Narazaki, M., Totten, G. and Webster G. (2002), “Hard-
ening by Reheating and Quenching,” in Handbook of Residual
Stress and Deformation of Steel edited by Totten, G., Howes, M.
and Inoue, T, ASM International, pp. 248–295.
11. MacKenzie, D., Gunsalus, L. and Lazerev, I. (2002), “Ef-
fects of Contamination on Quench-Oil Cooling Rate,” Indus-
trial Heating Magazine, 69 (1), pp. 35–41.
12. Herring, D. (2007), “Oil Quenching Part Two: What is
Your Quench-Oil Analysis Telling You?” Industrial Heating
Magazine, 74 (9), pp. 24–27.
Neil Canter heads his own consulting company,
Chemical Solutions, in Willow Grove, Pa. You
can reach him at