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SA-537 Class 1 & 2

Overview

This grade is commonly used in pressure vessel applications where low temperature resistance to notch sensitivity is needed and added strength levels are needed. Class 1 is normalized and the tensile is in the 70,000 – 90,000 level. Class 2 is quenched and tempered with a tensile range of 80,000 – 100,000. Minimum yield strength for class 1 is 50,000 and for class 2 is 60,000.

Chemical Requirements

*Elements represented in percentage

Element Composition %
Carbon, max 0.24
Manganese:
1 1/2in. (40 mm) and under in thickness
Heat analysis 0.70-1.35
Product analysis 0.64-1.46
Over 1 1/2in. (40 mm) in thickness
Heat analysis 1.00-1.60
Product analysis 0.92-1.72
Phosphorus, max 0.025
Sulfur, max 0.025
Silicon
Heat analysis 0.15-0.50
Product analysis 0.13-0.55
Cooper, max:
Heat analysis 0.35
Product analysis 0.38
Nickel, max:
Heat analysis 0.25
Product analysis 0.28
Chromium, max:
Heat analysis 0.25
Product analysis 0.29
Molybdenum, max:
Heat analysis 0.08
Product analysis 0.09

Tensile Requirements

Class 1
ksi(MPa)
Class 2
ksi (MPa)
Tensile strength, ksi (MPa)
2-1/2 in. and under 70-90 80-100
(65mm and under) (485-620) (550-690)
Over 2-1/2 to 4 in., incl 65-85 75-95
(Over 65 to 100 mm, incl) (450-585) (515-655)
Over 4 to 6 in., incl 70-90
(Over 100 to 150 mm, incl) (485-620)
Yield strength, min.
2-1/2 in. and under 50 60
(65mm and under) (345) (415)
Over 2-1/2 to 4 in., incl 45 55
(Over 65 to 100 mm, incl) (310) (380)
Over 4 to 6 in., incl 46
(Over 100 to 150 mm, incl) (315)
Elongation in 2 in.
(50 mm), min. %
4 in. (100 mm) and under 22 22
Over 4 in. (100 mm) 20
Elongation in 8 in.
(200 mm), min, % 18
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