Investigation in Gas Carburizing of AISI 4140, EN36, and 16MnCr5 Steels Using the Grey Incidence-Based Taguchi (GIBT) Method

Table 3

Quality index (GIG values).

Trial	S/N ratio			Normalized S/N ratio			Grey incidence coefficient			GIG
	SH	DD	WL	SH	DD	WL	SH	DD	WL
1	55.276	35.265	33.271	0.307	0.753	0.450	0.419	0.669	0.476	0.5216
2	55.321	35.848	33.146	0.403	0.862	0.379	0.456	0.784	0.446	0.5619
3	55.186	35.559	32.770	0.114	0.808	0.165	0.361	0.722	0.374	0.4859
4	55.343	35.703	34.172	0.451	0.835	0.965	0.477	0.752	0.935	0.7210
5	55.283	36.585	32.482	0.323	1.000	0.000	0.425	1.000	0.333	0.5861
6	55.133	35.833	33.127	0.000	0.859	0.368	0.333	0.780	0.442	0.5185
7	55.599	35.489	34.100	1.000	0.795	0.924	1.000	0.709	0.868	0.8590
8	55.336	31.243	34.233	0.435	0.000	1.000	0.469	0.333	1.000	0.6009
9	55.417	35.984	33.566	0.610	0.887	0.619	0.562	0.816	0.567	0.6484