Parameter Design in Carbonitriding of EN36, 16MnCr5, and AISI 4140 Steels Using Principal Component-Based Grey Incidence (PGI)

Table 1

Levels of carbonitriding inputs.

Inputs	Symbol	Units	Levels of parameters
			Level 1	Level 2	Level 3
Material substrate	A	—	EN36	16MnCr5	AISI 4140
Carbonitriding temperature	B	°C	800	850	870
Carbonitriding time	C	min	30	40	50
Flow rate of ammonia	D	lit/min	0.3	0.4	0.5