• Scope
• Chemical Composition
• Mechanical Properties

This specification² covers four grades of carbon steel forgings for boilers, pressure vessels, and associated equipment. Supplementary requirements are provided for use when additional testing or inspection is desired. These shall apply only when specified individually by the purchaser in the order.

Chemical Composition

Products	Composition, %
	Grades 1 and 2	Grade 3	Grade 4
Carbon, max	0.30	0.35	0.30
Manganese	0.40–1.05	0.80–1.35	0.80–1.35
Phosphorus, max	0.025	0.025	0.025
Sulfur, max	0.025	0.025	0.025
Silicon	0.15–0.35	0.15–0.35	0.15–0.35

Mechanical Properties

	Grade 1	Grades 2 and 4	Grade 3
Tensile strength, min, ksi [MPa]	60–85 [415–585]	70–95 [485–655]	75–100 [515–690]
Yield strength (0.2 % offset), min, ksi [MPa]	30 [205]	36 [250]	37.5 [260]
Elongation in 2 in. [62.5 mm], min, %	23 [21]	20 [18]	19 [17]
Reduction of area, min, %	38	33	30