This page has the Bolting Grades and Markings (PB-TD-204) as a printable PDF. It shows grade markings and mechanical properties for ASTM A193, A320 and A453 studs and A194 heavy hex nuts. Values are for reference; confirm against the current edition of the governing standard. Send us your print for a quote or call (281) 581-0176.
Related: Torque Reference Charts · All technical docs
About the Bolting Grades and Markings chart
This sheet lists the common stud, bolt and nut grades used in flange bolting: ASTM A193, A320 and A453 for studs and bolts, and A194 for heavy hex nuts. For each grade it gives material, diameter range, minimum tensile and yield strength, maximum hardness, stud end marking and typical use.
How to read the chart
- Specification and grade: For example A193 B7. The grade you order.
- Diameter: Size band. Strength minimums change with diameter.
- Tensile and yield: Minimum strength, ksi. For example B7 through 2-1/2 inch is 125 tensile and 105 yield.
- Hardness max: Brinell or Rockwell. For example B7M is limited to 235 HBW for sour service.
- Marking: Stud end stamp. Grade symbol plus the maker’s identification mark.
Ordering from Patriot Bolt
Patriot Bolt manufactures stud bolts, heavy hex nuts and special flange bolting from certified round bar in B7, B7M, L7, B16, stainless and nickel grades, with coatings on request. Mill test reports come with every order.
Common questions
What impact test applies to A320 grades?
L7, L43 and L7M require 20 ft-lbf average and 15 ft-lbf minimum single value at the listed test temperature.
Do Class 2 stainless studs need a special marking?
Yes. Strain-hardened Class 2 grades carry their own marking, and the class must be stated on the order.
See also: Stud Bolts · Sour Service Bolting · Fastener Materials Matrix · Request a quote