Hardening. This is the process of heating to a temperature above the critical range, and cooling rapidly enough through the critical range to appreciably harden the steel.

淬火。这个工艺是把材料加热到临界温度范围之上，然后迅速冷却到临界温度范围以下，使钢材明显变硬。

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The lower heat-treating temperature of the case results from the fact that hypereutectoid steels are normally austenitized for hardening just above the lower critical point.

由于恰好高于低临界温度通常使过共析钢奥氏体化而硬化，所以对外层采用较低的热处理温度。

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Hardening is the process of heating a piece of steel to a temperature within or above its critical range and then cooling it rapidly.

淬火就是把钢件加热到或超过它的临界温度范围，然后使其快速冷却的过程。

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