ASTM A193 B7 vs A320 L7 Stud Bolts
创建于03.25
ASTM A193 B7 vs A320 L7 Stud Bolts
ASTM A193 B7 is a Bolting specification for medium-high temperature applications. It is a heat treated Chromium Molybdenum steel and is considered for applications up to 450°C (840°F).
Steel is manufactured via Electric Arc Furnace, continuously cast followed by heat treatment and Bright conversion. It is typically used for the manufacture of Bolts, Fasteners, Studs and Studbolts in the Petrochemical industry. Available Drawn or Turned depending on the size in both Metric and Imperial sizes in standard and Thread Rolling Diameters. Typical stock size range 8mm to 4in Diameter in B7/L7 and 110mm to 130mm Diameter B7 only.
Mechanical Properties B7/L7
Grade | Size | Tensile ksi, min | Yield, ksi, min | Elong, %, min | RA % min |
B7 | Up to 2-1/2 | 125 | 105 | 16 | 50 |
L7 | Up to 2-1/2 | 125 | 105 | 16 | 50 |
Chemical Composition B7/L7
Element | B7(AISI 4140) | L7 (AISI 4140) |
Carbon | 0.37 - 0.49% | 0.37 - 0.49% |
Manganese | 0.65 - 1.10% | 0.65 - 1.10% |
Phosphorus, max | 0.035% | 0.035% |
Sulfur, max | 0.040% | 0.040% |
Silicon | 0.15 - 0.35% | 0.15 - 0.35% |
Chromium | 0.75 - 1.20% | 0.75 - 1.20% |
Nickel | ||
Molybdenum | 0.15 - 0.25% | 0.15 - 0.25% |
Alloy Steel Stud Bolting Materials
ASTM A193
The ASTM A193 is heavily utilized in petroleum and chemical construction applications. The ASTM standard covers alloy steel and stainless steel bolting materials for high temperature or high pressure service. This specification includes fasteners intended for use in pressure vessels, valves, flanges, and fittings. Although, this material is often available in national coarse (UNC) thread pitches, if being used in traditional applications, threads are specified 8 threads per inch (tpi) for diameters above one inch.
ASTM 193, Grade B7
Heat treated chromium-molybdenum steel recommended for medium high temperature service. (Liquid quench -50° to 900° F, Air quench -40° to 900° F)
ASTM A193, Grade B7M
Similar to B7 studs except that the minimum yield and tensile strength requirements are reduced and the hardness controlled to 235 Brinell maximum. Recommended for use in corrosive environments. (-50° to 900° F)
ASTM A193, Grade B16
A heat treated chromium-molybdenum-vanadium steel recommended for high pressure, high temperature service. (-50° to 1100° F)
ASTM A320, Grade L7
This grade is intended for low temperature service down to minus 150° F and has a minimum Charpy impact value of 20 ft. lbs. at this temperature. (-50° to 1100° F)
ASTM A320, Grade L7M
Similar to L7 studs except that the minimum yield and tensile strength requirements are reduced and the hardness controlled to 235 Brinell maximum. This stud is recommended for use in low temperature corrosive environments. (-50° to 1100° F)
ASTM A320, Grade L43
This grade is intended for low temperature service down to minus 150° F and has a minimum Charpy impact value of 20 ft. lbs. at this temperature. Available in sizes up to a 4 inch diameter. (-150° to 1100° F)
ASTM A193, Grade B8
These Chromium-Nickel (AISI 304) austenitic steel studs are recommended for use in corrosive environments. (-325° to 1500° F)
ASTM A193, Grade B8M
These chromium-nickel molybdenum (AISI 316) austenitic steel studs are recommended for use in corrosive environments. (-325° to 1500° F)
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