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All steel material have their very own characteristics from the chemical composition to the recommended heat-treating process. There are many different types of heat treating processes, normalizing, stress relieving, surface hardening (coatings), harden quench and tempering to name a few.
Hardening is obtained when steel parts are heated and then rapidly cooled
(quenched) from their austenitizing or solution treating temperatures, typically from 1500 - 2100° F. The ability of a quench to hardened steel depends upon the cooling characteristics of the desired quench or cooling medium (water, oil, air, positive pressure 1-10 bar etc.) In the process, austenite crystalline structure is transformed into a different much tougher crystalline form such as martensite. After this process, tempering is not only to prevent cracking due to stresses but helps in the process to transform retained austenite into martensite.
Cryogenic treatment can help in transforming retained austenite into a fully martensitic structure.
NOTE: For every part to be made, be it punches, dies, gears, etc. must start out with the proper steel and with the proper heat-treating process. |
