SAE J429

SAE J429 is a widely recognized standard that specifies the mechanical and material properties of inch-series fasteners commonly used in the automotive, construction, and related industries. The standard applies to bolts and screws up to 1-1/2 inches in diameter, ensuring consistent strength, durability, and performance across applications.

While the most frequently used grades are highlighted in summaries, the specification also includes several additional grades and variations such as Grades 4, 5.1, 5.2, 8.1, and 8.2, which address more specialized requirements.

SAE J429 Mechanical Properties of Inch-Series Bolts:

Grade	Nominal Size (in.)	Proof Load (psi)	Yield Strength (min, psi)	Tensile Strength (min, psi)	Elongation (min, %)	Reduction of Area (min, %)	Core Hardness (Rockwell)	Minimum Tempering Temp.
1	1/4 to 1-1/2	33,000	36,000	60,000	18	35	B7 – B100	—
2	1/4 to 3/4	55,000	57,000	74,000	18	35	B80 – B100	—
2	Over 3/4 to 1-1/2	33,000	36,000	60,000	18	35	B70 – B100	—
5	1/4 to 1	85,000	92,000	120,000	14	35	C25 – C34	800°F
5	Over 1 to 1-1/2	74,000	81,000	105,000	14	35	C19 – C30	800°F
8	1/4 to 1-1/2	120,000	130,000	150,000	12	35	C33 – C39	800°F

Typical Chemical Limits & Markings — SAE Fastener Grades:

SAE Grade	Typical Material	Carbon (C)	Phosphorus (P)	Sulfur (S)	Typical Marking
1	Low to medium carbon steel	0.55% max	0.030% max	0.050% max	No grade imprint
2	Low to medium carbon steel	0.15 – 0.55%	0.030% max	0.050% max	No grade imprint
5	Medium carbon steel (heat treated)	0.28 – 0.55%	0.030% max	0.050% max	Marked with 3 radial lines
8	Medium carbon alloy steel (heat treated)	0.28 – 0.55%	0.030% max	0.050% max	Marked with 6 radial lines