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Surface Treatments
Certifications
- ISO 9001 - 2015 Certified
- PED 2014/68/EC
- NACE MR0175/ISO 15156-2
- NORSOK M-650
- DFAR
- MERKBLATT AD 2000 W2/W7/W10
ASTM A320/A320M Grade L7M Alloy Steel Bolting
Low Temperature Service Bolts, Studs & Fasteners - AISI 4140/4142 Modified
ASTM A320/A320M Grade L7M is a specialized chromium-molybdenum alloy steel bolting material specifically engineered for low temperature pressure vessel applications. Unlike standard L7 grade, L7M undergoes quenching and tempering at a minimum of 1150°F, resulting in enhanced toughness and reduced hardness with a maximum of 235 HBW or 99 HRB. ASTM A320/A320M Grade L7M is particularly valued in sour gas environments and cryogenic applications where superior notch toughness is mandatory.
ASTM A320/A320M Grade L7M Stud Bolts Properties
ASTM A320/A320M Grade L7M Stud Bolts Chemical Requirements
Ferritic Steels
| Grade Symbol | Description | C | Mn | P, max | S, max | Si | Cr | Mo | |
|---|---|---|---|---|---|---|---|---|---|
| ASTM A320 L7M | Cr - Mo - B | Range,% | 0.38 - 0.48C | 0.75 - 1.00 | 0.035 | 0.04 | 0.15 - 0.35 | 0.80 - 1.10 | 0.15 - 0.25 |
| Product Variation, % Over or Under | 0.02 | 0.04 | 0.005 over | 0.005 over | 0.02 | 0.05 | 0.02 | ||
ASTM A320/A320M Grade L7M Stud Bolts Mechanical Requirements
Ferritic Steels
| Class and Grade, Diameter, in. [mm] | Heat Treatment | Minimum Tempering Temperature, °F [°C] | Tensile Strength, min, ksi [MPa] | Yield Strength, min, ksi [MPa] (0.2 % offset) | Elongation in 2 in. or 50 mm, min, % | Reduction of Area, min, % | Hardness, max |
|---|---|---|---|---|---|---|---|
| ASTM A320 L7M 21/2[65] and underA | quenched and tempered | 1150 [620] | 100[690] | 80[550] | 18 | 50 | 235 HBWBor 99 HRB |
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