Application of Response Surface Methodology for Modeling of Postweld Heat Treatment Process in a Pressure Vessel Steel ASTM A516 Grade 70

Table 6

Analysis of variance for tensile strength.

Source	DF	Seq. SS	Adj. SS	Adj. MS
Regression	5	3554.36	3554.36	710.87	43.60	0.000
Linear	2	1419.14	1419.14	709.57	43.52	0.000
Square	2	1482.53	1482.53	741.27	45.47	0.000
Interaction	1	652.69	652.69	652.69	40.03	0.000
Residual error	30	489.11	489.11	16.30
Lack-of-fit	3	78.79	78.79	26.26	1.73	0.185
Pure error	27	410.32	410.32	15.20
Total	35	4043.47