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

Table 3

CCD design with 3 center points for the tensile strength test.

Block
1	−1	−1
1	1	−1
1	−1	1
1	1	1
1	0	0
1	0	0
2	−α	0
2	α	0
2	0	−α
2	0	α
2	0	0
2	0	0