Preheating

Asme viii div 1 appendix r nonmandatort 

R-1 P-NO. 1 GROUP NOS. 1, 2, AND 3

(a) 175°F (79°C) for material which has both a speci-

fied maximum carbon content in excess of 0.30% and a

thickness at the joint in excess of 1 in. (25 mm);

(b) 50°F (10°C) for all other materials in this

P‐Number.

R-2 P-NO. 3 GROUP NOS. 1, 2, AND 3

(a) 175°F (79°C) for material which has either a speci-

fied minimum tensile strength in excess of 70,000 psi

(480 MPa) or a thickness at the joint in excess of 5

/8 in.

(16 mm);

(b) 50°F (10°C) for all other materials in this

P‐Number.