STS Industrial - Bolts & Screws

ASTM A307


SCOPE:

ASTM A307 covers the chemical and mechanical requirements of two grades of inch series bolts and studs in sizes 1/4 in. through 4 in. ASTM A307 Grade C has been replaced by ASTM F1554.

A307A Bolt and Stud Marking

ASTM A307 Grade A

All bolt heads, and 1 end of studs 3/8″ and larger, shall be marked as shown above.

A307B Bolt and Stud Marking

ASTM A307 Grade B

All bolt heads, and 1 end of studs 3/8″ and larger, shall be marked as shown above.

MATERIAL PROPERTIES:

GRADE

DIAMETER

BOLT OR STUD LENGTH

TENSILE STRENGTH

MIN ELONG IN 2”

CORE HARDNESS

Grade A 1/4 through 4” Less than 3 X diaA 60,000 psi Min 18% B69 to B100
3 X dia and Longer 60,000 psi Min 18% B100
Grade B 1/4 through 4” Less than 3 X diaA 60,000 to 100,000 psi 18% B69 to B100
3 X dia and Longer 60,000 to 100,000 psi 18% B100
Required hardness applies to measurements taken anywhere on the surface or through the cross section. Core hardness listed is Maximum acceptable unless a range is specified.

A Also bolts with drilled or undersized heads. These sizes and bolts with modified heads shall meet the minimum and maximum hardness as hardness is the only requirement.

Sources: ASTM Standards for Mechanical Fasteners and Related Processes 2nd Edition, Inch Fastener Standards 8th Edition

Note: All material included on this page is informational only, and should not be used as one’s sole source for design purposes. STS Industrial, Inc. and its affiliates do not guarantee the accuracy of the information on this site, and retain no liability for the use or misuse of the information contained on this site.