ASTM A193 B7 / ASTM A320 L7

The ASTM A193 B7 / ASTM A320 L7 specification is intended for bolt applications in medium-high temperature environments.

The specification refers to a chromium molybdenum steel that has undergone heat treatment and is capable of withstanding temperatures up to 450°C (840°F).

  • Excellent wear resistance
  • Exceptional strength
  • Exceptional toughness
  • For bolting applications

While ASTM A320 L7 steel shares similar chemical and physical properties with ASTM A193 B7 steel, it is specially designed for low-temperature applications and includes additional Charpy V Notch tests conducted at -101°C (-150°F). This further testing makes the alloy steel ideal for use in environments with extremely low temperatures.

Chemical Composition (weight, %)
B7 C Mn P S Cr Ni Mo
Min. 0.38 0.75 0.80 0.15 0.15
Max. 0.48 1.00 0.035 0.040 1.10 0.35 0.25
* Properties as per ASTM A193 (B7), ASTM A320 (L7)
L7 C Mn P S Cr Si Mo
Min. 0.38 0.75 0.80 0.15 0.15
Max. 0.48 1.00 0.035 0.040 1.10 0.35 0.25
ASTM A193 B7 / ASTM A320 L7 bolting grade alloy steel
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Both B7/L7 steel bolts are widely used in the oil and gas industry for applications such as pipeline construction, refineries, and oil drilling rigs. Bolts are commonly used in power plants, specifically in steam turbines and boilers, where they are exposed to high-pressure and high-temperature conditions. The material also finds use in general construction.

Both alloys are known for their excellent wear resistance. This makes it ideal for use in high wear and tear applications, such as heavy machinery and equipment. B7/L7 steel exhibit wear resistance because they develop a tough and compact oxide layer on their surface. This layer helps protect the steel from abrasion, erosion, and other types of wear.

With their exceptional strength, toughness, and other advantageous characteristics, ASTM A193 B7 / ASTM A320 L7 are dependable and versatile steel grades well-suited for various industrial applications.

We stock ASTM A193 B7 / ASTM A320 L7 in round and square bars.

Our steels are used in the most demanding operating markets

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