Black Oxide Heavy Hex Head Bolt

Black Oxide Heavy Hex Head Bolt belongs to high-strength structural fasteners for high-pressure industrial scenes. The raw material of Black Oxide Heavy Hex Head Bolt is alloy steel, processed through quenching and tempering at 870℃ quenching temperature plus 560℃ tempering temperature, the finished tensile strength reaches minimum 830MPa, fully meeting mainstream international manufacturing standards. We supply multiple standard systems and complete size ranges, covering small to large diameter specifications.

Production & Quality Inspection Standard

All finished Black Oxide Heavy Hex Head Bolt must pass three mandatory physical tests before delivery, including Rockwell hardness test (target HRC 22-32), salt spray test for 48 hours without red rust, and thread dimensional tolerance inspection within ±0.02mm. Ningbo Gangtong Zheli Fasteners Co., Ltd equips full sets of professional testing machines to finish all detection links in self-owned workshop, avoiding third-party inspection delays. Every batch retains test reports for 3 years to support client quality traceability.

Application & Custom Service

Black Oxide Heavy Hex Head Bolt is widely matched with heavy hex nuts for pressure vessels, chemical pipelines, power steel frames and petrochemical equipment assembly. For special working environments, we support customized length and thread pitch adjustment according to engineering drawings. Ningbo Gangtong Zheli Fasteners Co., Ltd maintains stable stock of conventional sizes, and accepts customized bulk orders for global engineering purchasers.