Engineering project: Heat treatment?

Question

Define the temperature, time at heat, quenching medium, quench temperature and the tempereing temperature.The material is 9 Cr-1 Mo steel.

Answer 1

I have no idea why you want to heat treat this material. What properties are you trying to enhance?

Here are a few randomly selected sites which may provide useful links:
http://www.osti.gov/energycitations/product.biblio.jsp?osti_id=5251861

http://www.zianet.com/ebear/metal/heattreat7.html

http://www.wisetool.com/designation/toolsteel.htm

http://www.hoeganaes.com/Publications/15.pdf

Answer 2

interior the USA, there are some states (including California and Washington) that require a separate license to be a structural engineer. You first develop right into a registered civil engineer. After gaining a pair of years of layout experience as a civil engineer, you're then eligible to take the structural engineering try. there has been some communicate approximately requiring structural engineers to have a minimum of a masters degree yet i do no longer think of that that's a call for everywhere yet.

Answer 3

Thsi is going to be long.

Stainless steels are often heat treated; the nature of this treatment depends on the type of stainless steel and the reason for the treatment. These treatments, which include annealing, hardening and stress relieving, restore desirable properties such as corrosion resistance and ductility to metal altered by prior fabrication operations or produce hard structures able to withstand high stresses or abrasion in service. Heat treatment is often performed in controlled atmospheres to prevent surface scaling, or less commonly carburisation or decarburisation
The austenitic stainless steels cannot be hardened by thermal treatments (but they do harden rapidly by cold work). Annealing (often referred to as solution treatment) not only recrystallises the work hardened grains but also takes chromium carbides (precipitated at grain boundaries in sensitised steels) back into solution in the austenite. The treatment also homogenises dendritic weld metal structures, and relieves all remnant stresses from cold working. Annealing temperatures usually are above 1040°C, although some types may be annealed at closely controlled temperatures as low as 1010°C when fine grain size is important. Time at temperature is often kept short to hold surface scaling to a minimum or to control grain growth, which can lead to "orange peel" in forming. Annealing of austenitic stainless steel is occasionally called quench annealing because the metal must be cooled rapidly, usually by water quenching, to prevent sensitisation (except for stabilised and extra-low carbon grades)

All martensitic and most ferritic stainless steels can be subcritical annealed (process annealed) by heating into the upper part of the ferrite temperature range, or full annealed by heating above the critical temperature into the austenite range, followed by slow cooling. Usual temperatures are 760 to 830°C for sub-critical annealing. When material has been previously heated above the critical temperature, such as in hot working, at least some martensite is present even in ferritic stainless steels such as grade 430. Relatively slow cooling at about 25°C/hour from full annealing temperature, or holding for one hour or more at subcritical annealing temperature, is required to produce the desired soft structure of ferrite and spheroidised carbides. However, parts that have undergone only cold working after full annealing can be sub-critically annealed satisfactorily in less than 30 minutes.

The ferritic types that retain predominantly single-phase structures throughout the working temperature range (grades 409, 442, 446 and 26Cr-1Mo) require only short recrystallisation annealing in the range 760 to 955°C.

Martensitic stainless steels are hardened by austenitising, quenching and tempering much like low alloy steels. Austenitising temperatures normally are 980 to 1010°C, well above the critical temperature. As-quenched hardness increases with austenitising temperature to about 980°C and then decreases due to retention of austenite. For some grades the optimum austenitising temperature may depend on the subsequent tempering temperature.

Preheating before austenitising is recommended to prevent cracking in high-carbon types and in intricate sections of low-carbon types. Preheating at 790°C, and then heating to the austenitising temperature is the most common practice
Stress relieving at temperatures below 400°C is an acceptable practice but results in only modest stress relief. Stress relieving at 425 to 925°C significantly reduces residual stresses that otherwise might lead to stress corrosion cracking or dimensional instability in service. One hour at 870°C typically relieves about 85% of the residual stresses. However, stress relieving in this temperature range can also precipitate grain boundary carbides, resulting in sensitisation that severely impairs corrosion resistance in many media. To avoid these effects, it is strongly recommended that a stabilised stainless steel (grade 321 or 347) or an extra-low-carbon type (304L or 316L) be used, particularly when lengthy stress relieving is required.

Full solution treatment (annealing), generally by heating to about 1080°C followed by rapid cooling, removes all residual stresses, but is not a practical treatment for most large or complex fabrications.