One minute mentor: Quenching and Tempering

The as-quenched properties of powder metallurgy steels depend on the cooling medium and the steel’s hardenability. Quenching in water, salt, brine, and water-based polymer solutions improves the rate of heat transfer, leading to a faster quench. However, in many cases, it accelerates corrosion due to the residual quenchant trapped in surface pores.

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One Minute Mentor: Conditions of hardenability

With the variety of local chemical compositions present after sintering, different microstructures form on cooling unless completely pre-alloyed powders are used. The degree of local composition variation can be significant, so it is better to look at the concept of critical cooling speed in terms of these local variations.

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