ASTM A307 Bolts Grade A, B, Gr 307A Threaded Rod Tensile Yield Strength

0 498

ASTM A307 Bolts, Threaded Rod, Grade A, B

ASTM A307 bolts, threaded rod and studs, are the most commonly used fasteners, covering two grades of chemical and mechanical requirements from 0.25-4 inches in size.

  • ASTM A307 Grade A: Suitable for bolts, studs and screws for general applications, with a minimum tensile strength of 60 ksi.
  • ASTM A307 Grade B: Heavy-duty bolts, studs and screws, with a tensile strength of 60-100 ksi, used for flange connections in piping systems with cast iron flanges.

Note: This standard does not cover anchor bolt.

Product Marking

All A307 bolt heads, one end of studs 3/8 inches and larger, and studs smaller than 3/8 inches when feasible should be marked with the following grade mark:

  • Grade A: 307A
  • Grade B: 307B

A307 threaded rod shall be exempt from the marking requirements of relevant material specifications, unless otherwise specified by the buyer. Packaging and labeling requirements are mandatory in the applicable material specifications. If markings are required, they should be located at both ends of the threaded rod and should be raised or lowered according to the manufacturer’s choice.

Specifications

The following tables show ASTM A307 bolt grade and threaded rod properties and specifications (datasheet) including chemical composition, mechanical properties, etc.

A307 Steel Chemical Composition

Chemical requirements for A307 steel, 307B and 307A bolt grade, threaded rod, and studs is listed in the following table.

Chemical Requirements
Grades C Mn P S Condition
ASTM A307 Grade A 0.29 1.2 0.04 0.15 Heat Analysis
0.33 1.25 0.041 Product Analysis
ASTM A307 Grade B 0.29 1.2 0.04 0.05 Heat Analysis
0.33 1.25 0.041 0.051 Product Analysis

Mechanical Properties

Hardness Requirements for A307 Bolt, Stud, and Threaded Rod

Hardness Requirements
Grade Nominal Length, in. Hardness
Brinell Rockwell B
A307 Gr A Less than 3 x dia 121-241 69-100
3 x dia and longer ≤241 ≤100
A307 Gr B Less than 3 x dia 121-212 69-95
3 x dia and longer ≤212 ≤95

Tensile Requirements for Full-Size ASTM A307 Bolts, Studs, and Threaded Rod

Tensile Requirements
Bolt Size, in. Threads per inch Stress Area, in. Tensile Strength, lbf x 103 (kN)
Grade A, ≥ Grade,B
1/4 20 0.0318 1.9 (8.45) 1.9-3.18 (8.45-14.16)
5/16 18 0.0524 3.1 (13.79) 3.1-5.24 (13.79-23.31)
3/8 16 0.0775 4.65 (20.68) 4.65-7.75 (20.68-34.47)
7/16 14 0.1063 6.35 (28.25) 6.35-10.63 (28.25-47.28)
1/2 13 0.1419 8.5 (37.81) 8.5-14.19 (37.81-63.12)
9/16 12 0.182 11 (49) 11-18.2 (49-81)
5/8 11 0.226 13.55 (60) 13.55-22.6 (60-100)
3/4 10 0.334 20.05 (89) 20.05-33.4 (89-148)
7/8 9 0.462 27.7 (123) 27.7-46.2 (123-205)
1 8 0.606 36.35 (161) 36.35-60.6 (161-269)
1 1/8 7 0.763 45.8 (204) 45.8-76.3 (204-339)
1 1/4 7 0.969 58.15 (230) 58.15-96.9 (230-431)
1 3/8 6 1.155 69.3 (308) 69.3-115.5 (308-514)
1 1/2 6 1.405 84.3 (375) 84.3-140.5 (375-625)
1 3/4 5 1.9 114 (507) 114-190 (507-845)
2 4 1/2 2.5 150 (667) 150-250 (667-1112)
2 1/4 4 1/2 3.25 195 (867) 195-325 (867-1445)
2 1/2 4 4 240 (1067) 240-400 (1067-1779)
2 3/4 4 4.93 295.8 (1316) 295.8-493 (1316-2193)
3 4 5.97 358.2 (1593) 358.2-597 (1593-2655)
3 1/4 4 7.1 426 (1895) 426-710 (1895-3158)
3 1/2 4 8.33 499.8 (2223) 499.8-833 (2223-3705)
3 3/4 4 9.66 579.6 (2578) 579.6-966 (2578-4297)
4 4 11.08 664.8 (2957) 664.8-1,108 (2957-4928)
Tensile Requirements for Machined Specimens
Grades Tensile strength, ksi Yield point, min ksi Elongation in 2 in, %
ASTM A307 Gr A 60, ≥ 18
ASTM A307 Gr B 60-100 18

For inspection the sample size and acceptance number of hot-dipped or mechanically deposited zinc-coated threads

Lot Size Sample Size Acceptance Number
2 to 90 13 1
91 to 150 20 2
151 to 280 32 3
281 to 500 50 5
501 to 1,200 80 7
1,201 to 3,200 125 10
3,201 to 10,000 200 14
10,001 ≥ 315 21

Get real time updates directly on you device, subscribe now.

Leave A Reply

Your email address will not be published.

We use cookies to improve your experience on our website. By browsing this website, you agree to our use of cookies. Accept Read More