Wire for Grade 5 Fasteners
Grade selection guide for SAE J429 Grade 5 bolt production — medium-carbon and alloy CHQ wire grades with reliable heat-treat response.
Grade 5 is the workhorse fastener specification for medium-strength bolts and cap screws (SAE J429). The minimum tensile strength requirement is 120,000 psi for diameters up to ¾”. Hitting that strength reliably starts with the right wire grade — typically medium-carbon, with chemistry tight enough to respond predictably to heat treatment.
Grades we commonly stock for Grade 5 production
C1038 — medium-carbon plain steel. The traditional choice for Grade 5 bolts in diameters up to about ½”. Cost-effective and well-understood.
10B21 — boron-treated low-alloy. Used by manufacturers who want consistent through-hardening on smaller diameters or thin-wall sections.
4037 — chromium-molybdenum alloy. When customers need Grade 5 strength with additional toughness, or when section size pushes plain carbon grades to their limits.
Condition
Wire for Grade 5 bolts is typically supplied SAFS for cold heading, occasionally SAIP when downstream forming demands a lighter final draw. See the SAFS vs SAIP guide for detail.
Specifying for your program
Specifying wire for a Grade 5 bolt program is a balance between chemistry, size, and heat-treat capability. We can help you match the grade to your process. Request a quote or check current stock.