Effect of the Cryogenically Treated Copper Nozzle Used in Plasma Arc Machining of S235 Steel

Table 7

Grey relational analysis for untreated nozzle machining.

Trial runs	SN ratio		Normalized value		Deviation sequence		Grey relational coefficient		Grey grade	Rank
	SR	Kf	SR	Kf	SR	Kf	SR	Kf
	(µm)	(mm)	(µm)	(mm)	(µm)	(mm)	(µm)	(mm)
1	0.0011	−1.6958	0.0000	0.6432	1.0000	0.3568	0.3333	0.5836	0.9169	18
2	0.4218	−3.1407	0.1283	0.3618	0.8717	0.6382	0.3645	0.4393	0.8038	27
3	1.1138	−3.7052	0.3395	0.2519	0.6605	0.7481	0.4308	0.4006	0.8315	26
4	0.7618	−2.4410	0.2321	0.4981	0.7679	0.5019	0.3944	0.4990	0.8934	22
5	1.2673	−3.1407	0.3863	0.3618	0.6137	0.6382	0.4490	0.4393	0.8883	24
6	1.7235	−4.5454	0.5255	0.0883	0.4745	0.9117	0.5131	0.3542	0.8673	25
7	1.3810	−3.1382	0.4210	0.3623	0.5790	0.6377	0.4634	0.4395	0.9029	20
8	1.6314	−3.7819	0.4974	0.2370	0.5026	0.7630	0.4987	0.3959	0.8946	21
9	1.9708	−4.9989	0.6010	0.0000	0.3990	1.0000	0.5562	0.3333	0.8895	23
10	0.4380	−1.3474	0.1333	0.7110	0.8667	0.2890	0.3658	0.6337	0.9996	13
11	1.1642	−2.2131	0.3549	0.5425	0.6451	0.4575	0.4366	0.5222	0.9588	16
12	1.6849	−3.5784	0.5138	0.2766	0.4862	0.7234	0.5070	0.4087	0.9157	19
13	1.2366	−0.8152	0.3770	0.8147	0.6230	0.1853	0.4452	0.7296	1.1748	9
14	1.5715	−2.4384	0.4791	0.4986	0.5209	0.5014	0.4898	0.4993	0.9891	15
15	1.8679	−3.7448	0.5696	0.2442	0.4304	0.7558	0.5374	0.3982	0.9356	17
16	1.8981	−2.5957	0.5788	0.4680	0.4212	0.5320	0.5428	0.4845	1.0272	12
17	2.0902	−3.5398	0.6374	0.2841	0.3626	0.7159	0.5797	0.4112	0.9909	14
18	3.2672	−4.5237	0.9965	0.0925	0.0035	0.9075	0.9931	0.3552	1.3483	5
19	1.1843	0.1366	0.3610	1.0000	0.6390	0.0000	0.4390	1.0000	1.4390	2
20	1.6625	−1.2140	0.5069	0.7370	0.4931	0.2630	0.5035	0.6553	1.1588	10
21	2.2585	−2.8728	0.6887	0.4140	0.3113	0.5860	0.6163	0.4604	1.0767	11
22	1.9130	−0.2567	0.5834	0.9234	0.4166	0.0766	0.5455	0.8672	1.4126	3
23	2.3870	−1.5437	0.7280	0.6728	0.2720	0.3272	0.6476	0.6045	1.2521	7
24	3.1563	−2.9114	0.9627	0.4065	0.0373	0.5935	0.9306	0.4572	1.3878	4
25	2.2729	−1.0777	0.6931	0.7636	0.3069	0.2364	0.6197	0.6789	1.2986	6
26	2.6171	−2.4167	0.7982	0.5028	0.2018	0.4972	0.7124	0.5014	1.2138	8
27	3.2786	−3.6426	1.0000	0.2641	0.0000	0.7359	1.0000	0.4411	1.4411	1