Effect of Cyclic Cryogenic Treatment on Wear Resistance, Impact Toughness, and Microstructure of 42CrMo Steel and Its Optimization

Table 2

Levels of factors in cryogenic treatment.

	Levels
Factors (j)	1	2	3
Cryogenic temperature (A)/°C	−120	−160	−196
Holding time (B)/h	2	12	24
Cycles number (C)	1	2	3