Carbon Steel Grade 12.9 -ISO7379 Hex Socket Shoulder Bolt-Shoulder Screw

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1.Extreme Performance – Machined from quenched-and-tempered 40Cr alloy steel, class 12.9 hex-socket shoulder bolts deliver ≈ 180 ksi / 1 240 MPa tensile strength and 1 100 MPa yield, matching the load capacity of socket cap screws while providing a precision ground shoulder held to ±0.0003 in (±8 µm). The hardened (HRC 38-44) shoulder doubles as a durable bearing pin, with black-oxide or phosphate coating adding basic rust protection and a low-friction running surface for high-cycle pivoting applications.

2.Broad Application Range – Used as pivots, slide guides, and locating dowels in injection-molding dies, robotic joints, linear-motion stages, packaging and printing machinery, press tooling, automotive suspension linkages, and high-performance bicycle shocks—any assembly that demands both an accurate slip-fit shaft and ultra-high clamp load.

3.Easy to Operate – A deep internal hex allows high torque transfer with standard Allen keys or power bits, avoiding cam-out even under impact tools. The relieved thread-to-shoulder transition seats squarely without creating stress risers, while rolled ISO metric or UNC threads start smoothly and resist stripping. Chamfered tips guide quickly into tapped holes, speeding assembly and preventing cross-threading.

4.Verified Quality – Produced under ISO 9001 systems and fully compliant with ISO 7379 / ASME B18.3.3 dimensions and ISO 898-1 mechanical requirements for class 12.9. Every lot is shoulder-diameter gauged, surface-hardness tested, tensile tested, magnetic-particle inspected, and laser-etched with heat-lot codes. EN 10204 3.1 material certificates guarantee full traceability, ensuring consistent, long-service performance in demanding industrial environments.