Alloy Steel Bolting Materials
Alloy steel fasteners are specifically designed for high temperature and low temperature service applications. These materials offer superior mechanical properties and temperature resistance compared to carbon steel.
High Temperature Service
ASTM A193 B7
Chromium-molybdenum steel
Temperature: -29°C to 538°C
Most common high temp grade
ASTM A193 B7M
Modified B7 with tighter hardness
Temperature: -48°C to 538°C
Improved low temp properties
ASTM A193 B16
Chromium-molybdenum-vanadium
Temperature: Up to 593°C
Enhanced elevated temp strength
ASTM A453 Grade 660
Precipitation hardening steel
Temperature: -196°C to 649°C
Classes A, B, C, D available
Low Temperature Service
ASTM A320 L7
Low temperature B7 equivalent
Temperature: -46°C to 427°C
Cryogenic service
ASTM A320 L7M
Modified L7 with tighter hardness
Temperature: -101°C to 427°C
Deep cryogenic applications
ASTM A320 L43
Nickel alloy steel
Temperature: -196°C to 427°C
LNG service
Nuclear & Special Applications
ASTM A540 B23
Alloy steel for nuclear service
Classes 1-5 available
High strength applications
ASTM A540 B24
Alloy steel bolting
Nuclear and pressure vessel service
Classes 1-5 available
Specifications & Standards
| Standard | Grade | Temperature Range | Application |
|---|---|---|---|
| ASTM A193 | B7, B7M | -48°C to 538°C | High temperature bolting |
| ASTM A193 | B16 | Up to 593°C | Very high temperature |
| ASTM A320 | L7, L7M | -101°C to 427°C | Low temperature service |
| ASTM A453 | Grade 660 A/B/C/D | -196°C to 649°C | Wide temperature range |
| ASTM A540 | B23, B24 | Nuclear applications | Nuclear & pressure vessels |
Material Composition
| Grade | C % | Cr % | Mo % | Other Elements |
|---|---|---|---|---|
| B7 | 0.37-0.49 | 0.75-1.20 | 0.15-0.25 | Si, Mn, P, S |
| B16 | 0.36-0.44 | 0.80-1.10 | 0.45-0.65 | V 0.20-0.30 |
| Grade 660 Class A | ≤0.05 | 13.0-14.0 | ≤0.50 | Ni 4.5-5.5 |
Applications
Pressure Vessels
High pressure and temperature applications
Power Plants
Boilers, turbines, steam systems
Petrochemical
Refineries, crackers, reactors
LNG Plants
Cryogenic service applications
Nuclear Power
Reactor vessel bolting
Oil & Gas
Wellhead equipment, high pressure piping
Mechanical Properties
B7: Tensile Strength: 860-1034 MPa, Yield Strength: 724 MPa (min)
B16: Tensile Strength: 827-1000 MPa, Yield Strength: 655 MPa (min)
Grade 660 Class A: Tensile Strength: 965 MPa (min), Yield Strength: 760 MPa (min)
L7: Similar to B7 with enhanced low temperature impact properties