Optimization of Deformation Behaviors during Continuous Forming Extrusion of C18150 Copper Alloy through Response Surface Methodology

Table 6

Estimated regression coefficients for the extrusion load relevance/importance test for C18150.

Terms	Coefficients	Standard error coefficient	t-value	value
Constant	8490.71	194.673	43.615	0.000
x1	73.75	2.885	25.567	0.000
x2	−8.22	0.124	−66.128	0.000
x3	−23.80	0.121	−196.154	0.000
x4	−310.00	372.869	−0.831	0.422
	−2.31	0.031	−73.808	0.000
	−0.00	0.000	−35.159	0.000
	0.00	0.000	2.743	0.018
	−8000.00	200.520	−39.896	0.000
	0.01	0.001	9.933	0.000
	0.15	0.001	104.085	0.000
	−126.25	2.894	−43.621	0.000
	0.00	0.000	64.783	0.000
	9.25	0.116	79.900	0.000
	22.55	0.116	194.782	0.000

x₁, wheel velocity; x₂, feedstock temperature; x₃, friction factor; x₄, die temperature.