The 2nd term to discuss is the hardening process and what transformation the steel goes through during the hardening process.

HM-407 revisedHardening (A specific heating and cooling process based on the chemistry of the material) is performed on all ferrous steels to develop the proper microstructure and optimal properties of the material.

The 1st stage of hardening is the preheat cycle.  Preheating the steel helps to prevent thermal shock & helps the material adjust to the higher hardening temperatures.

During the heat treating cycle, the material goes through many transformation stages, usually 10-12 stages.  During this process the material will shrink & grow.  It will form austenite (material will shrink and become non-magnetic), then martensite (Growth larger than its starting size at room temperature), then tempered martensite (returns to dimensions very close to starting datums at the start point).

Note: Proper hardening processes will produce as close to a homogeneous (tight) microstructure as possible, which produces a better tool or part.

At Hudson, our goal is to “Make Tool Steel Easy”. We hope the discussion in future posts will help you gain a better understanding of materials and processing through asking the right questions.  Have a question for us?  Call us at 800-996-0411 or send an inquiry through our “Have a Question?” form.  We look forward to helping you with any of your tool steel questions.