Carburizing,Carburizing Steel,Carburizing,Carburizing Steel,Carburizing,Carburizing Steel,Carburizing,Carburizing Steel
Carburizing of tool steels is usually restricted to special applications. Mold steels, however, are commonly carburizing
and then case hardened. A marked increase in surface carbon renders most tools too brittle for their intended uses.
However, tools made of shock-resisting steel, hot work steel, and especially the lower-carbon types of high-speed steel
are sometimes carburized to advantage for use in certain die applications involving severe wear. Carburizing is also useful
for applications such as cold work dies that require extreme wear resistance and that are not subjected to impact or highly
concentrated loading. All the common methods of carburizing (gas, pack, and liquid) have been employed for these
special applications (see the articles "Gas Carburizing," "Pack Carburizing," and "Liquid Carburizing and Cyaniding" in
this Volume). Case depths are shallower, about 0.05 to 0.25 mm (0.002 to 0.010 in.), rather than the 0.75 to 1.5 mm
(0.030 to 0.060 in.) that is common on conventional carburizing steels.
Carburizing temperatures, typically 1040 to 1065 °C (1900 to 1950 °F) are held for 10- to 60-min durations. The
carburizing treatment also serves as an austenitizing treatment for the whole tool. A carburized case on high-speed steels
has a hardness of 65 to 70 HRC but does not have the high resistance to softening at elevated temperatures exhibited by
normally hardened high-speed steel.

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