| Size range | Proof | Yield min | Tensile min | Core hardness |
|---|---|---|---|---|
| 1/4 in through 4 in | not specified | not specified | 60 ksi (414 MPa) | Rockwell B69 to B100 |
Inch grades are published in ksi and metric classes in MPa. The other column on every row is a conversion at 1 ksi = 6.894757 MPa, rounded to the nearest whole unit - it is arithmetic on the published figure, not a second published figure.
Marked 307A on the head.
The specification and grade letter stamped in full, not a line count.
Count the radial lines and add two. That rule identifies exactly two grades - SAE Grade 5 with three lines and SAE Grade 8 with six - and it fails everywhere else. Grades 1, 2 and 4 carry no marking at all, so an unmarked head is not evidence of Grade 2; it is evidence of nothing, and unmarked hardware that meets no standard looks exactly the same. ASTM grades are stamped with the specification (A325, A490, BC, BD, 307A) rather than lines, and metric classes are stamped with the class number. Four marking systems share one bin.
Low carbon steel. Non-structural and lightly loaded connections, anchor bolts.
A307 specifies a tensile strength and nothing else: there is no proof load and no minimum yield in the published tables, so both are left blank here rather than borrowed from a similar grade.
Over 1/4 in through 4 in, ASTM A307 Grade A requires a minimum tensile strength of 60 ksi (414 MPa), a minimum yield of not specified and a proof load of not specified.
Marked 307A on the head.
Low carbon steel. Non-structural and lightly loaded connections, anchor bolts.
Twenty-two grades and classes: the SAE J429 inch grades, five ASTM specifications and the ISO 898-1 property classes. It is not every grade in circulation. Stainless classes (ISO 3506 A2 and A4, ASTM F593), the ASTM A193 and A320 high and low temperature grades, ASTM F1554 anchor rod grades and SAE grades 3, 5.1 and 8.1 are not carried here.
Dimensions are as defined by ASTM A307. This site is an independent reference and is not affiliated with, endorsed by or approved by any standards body.
Every value on this page was cross-checked against 4 independent published sources:
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