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

Table 5

Experimental observation of L₂₇ array treated and untreated nozzle machining.

Trial runs	Gas pressure	Arc current	Cutting speed	Cryogenic treated nozzle		Untreated nozzle
				Surface roughness	Kerf width	Surface roughness	Kerf width
	(bar)	(A)	(mm/min)	(µm)	(mm)	(µm)	(mm)
1	4	110	1000	1.0350	1.1160	0.9999	1.2156
2		120		1.0790	1.3230	0.9526	1.4356
3		130		0.9599	1.4900	0.8797	1.5320
4		110	1400	0.8940	1.2369	0.9160	1.3245
5		120		0.8406	1.3818	0.8642	1.4356
6		130		0.7869	1.7022	0.8200	1.6876
7		110	1800	0.7456	1.3283	0.8530	1.4352
8		120		0.6877	1.4453	0.8288	1.5456
9		130		0.6304	1.6883	0.7970	1.7781
10	5	110	1000	1.0290	1.0283	0.9508	1.1678
11		120		0.9567	1.2171	0.8746	1.2902
12		130		0.8000	1.4054	0.8237	1.5098
13		110	1400	0.8103	1.0930	0.8673	1.0984
14		120		0.7582	1.2800	0.8345	1.3241
15		130		0.6900	1.4923	0.8065	1.5390
16		110	1800	0.6343	1.2300	0.8037	1.3483
17		120		0.6110	1.4030	0.7861	1.5031
18		130		0.5360	1.5100	0.6865	1.6834
19	6	110	1000	0.9540	0.9600	0.8725	0.9844
20		120		0.8500	1.0200	0.8258	1.1500
21		130		0.7446	1.3216	0.7710	1.3920
22		110	1400	0.7130	0.9700	0.8023	1.0300
23		120		0.5930	1.1200	0.7597	1.1945
24		130		0.6196	1.2310	0.6953	1.3982
25		110	1800	0.5760	1.0767	0.7698	1.1321
26		120		0.4670	1.2600	0.7399	1.3208
27		130		0.4920	1.3500	0.6856	1.521