Engineered for high-pressure piping, structural connections, and extreme operational environments with full MTR (Material Test Report) traceability.
Providing custom-engineered high tensile fastening solutions for extreme mechanical loads, pressure integrity, and severe thermal cycles.
As a leading OEM/ODM high tensile bolts factory, our facility leverages multi-station automated cold formers and precision CNC hot forging lines. Fastener integrity relies entirely on grain flow continuity; cold heading preserves structural fiber lines along the bolt head junction, offering superior fatigue resistance compared to traditional machined bar stock.
For large-diameter fasteners (M36 to M100 / 1-1/2" to 4"), our induction-heated hot forging presses execute controlled deformation under strict optical pyrometer monitoring. This eliminates internal micro-voids, ensuring compliance with ASTM A193 Grade B7, B16, and ISO 898-1 Property Class 10.9 and 12.9 parameters.
Every single batch of alloy and stainless steel raw stock undergoes Positive Material Identification (PMI) via X-ray Fluorescence (XRF) spectroscopy before entering production. We eliminate grade mix-ups at the source.
Direct comparison guide for procurement engineers, structural designers, and QA/QC inspectors.
| Material / Grade Standard | Tensile Strength (MPa / ksi) | Yield Strength (0.2% MPa) | Core Hardness Range | Typical Industrial Applications |
|---|---|---|---|---|
| ISO 898-1 Class 8.8 Carbon Steel | 800 MPa (116 ksi) min. | 640 MPa | 22 - 32 HRC | General machinery, structural framework, automotive chassis assemblies. |
| ISO 898-1 Class 10.9 High Tensile | 1040 MPa (150 ksi) min. | 940 MPa | 32 - 39 HRC | Heavy earthmoving equipment, automotive engine heads, tower crane joint bolting. |
| ISO 898-1 Class 12.9 Ultra High Tensile | 1220 MPa (177 ksi) min. | 1100 MPa | 39 - 44 HRC | High-stress hydraulics, aerospace tooling, compact automotive engine blocks. |
| ASTM A193 Grade B7 Cr-Mo Alloy Steel | 860 MPa (125 ksi) min. | 725 MPa (105 ksi) | 35 HRC max | Oil & gas pressure vessels, ASME B16.5 pipeline flanges, valves, high-temp service. |
| ASTM A193 Grade B16 Cr-Mo-V Alloy Steel | 860 MPa (125 ksi) min. | 725 MPa (105 ksi) | 35 HRC max | Superheated steam lines, power generation plants, extreme elevated temp (>525°C). |
| ASTM A320 Grade L7 Low-Temp Alloy | 860 MPa (125 ksi) min. | 725 MPa (105 ksi) | 35 HRC max | LNG terminals, cryogenic valves, arctic offshore drilling platforms (Impact tested @ -101°C). |
| Stainless Steel A2-70 / A4-80 Austenitic Stainless | 700 - 800 MPa | 450 - 600 MPa | 210 - 300 HV | Chemical processing plants, marine hardware, food processing equipment, water treatment. |
How digital supply networks, advanced anti-corrosion coatings, and sustainability mandates are transforming OEM buyer requirements.
Traditional hexavalent chromium electroplating is being rapidly phased out under global REACH and RoHS regulations. Modern EPC contractors and automotive OEMs now require Zinc-Flake Coatings (e.g., Geomet, Dacromet) and non-electrolytic fluoropolymer PTFE finishes.
Zinc flake delivers over 1,500 hours of neutral salt spray testing (ASTM B117) without causing Hydrogen Embrittlement—a major failure mechanism in Class 10.9 and 12.9 ultra-high tensile bolts.
The global energy transition is expanding offshore wind farm installations. Mega-watt wind turbines demand massive M36–M72 structural tower bolts and foundation anchor studs capable of withstanding cyclic dynamic bending stresses and turbulent wind forces.
Super Duplex (UNS S32750) and heavily coated Grade B7M fasteners with strict 100% Ultrasonic Testing (UT) for internal flaws are experiencing unprecedented market demand.
Global buyers are moving away from spot-market trading toward direct partnerships with verified OEM/ODM high tensile bolt factories. Direct factory sourcing ensures guaranteed production slot allocation, raw material hedging against steel price volatility, and full digital batch traceability from ingot to packaged pallet.
Preventing catastrophic joint failures in heavy machinery, high-pressure pipelines, and load-bearing steel structures.
High tensile bolts with hardness exceeding 39 HRC (such as ISO Class 12.9 or ASTM A490) are exceptionally susceptible to Hydrogen Embrittlement. When atomic hydrogen enters the crystal lattice during acid pickling or electroplating, micro-cracks propagate silently under sustained tensile stress, leading to sudden brittle fracture without prior plastic deformation.
Our Factory Protocol: We utilize mechanical cleaning (shot blasting) instead of acid pickling for all high tensile carbon steels. When plating is mandatory, high-temperature de-embrittlement baking at 200°C–230°C is executed within 2 hours of electroplating for a minimum of 8 to 24 hours.
Galling (cold welding) frequently occurs during the torque-up of austenitic stainless steel (SS304/SS316, A2/A4) and nickel alloy studs (Inconel 625, Monel 400). High frictional heat strips the protective passive oxide film, resulting in thread seizure.
OEM Solution: We offer custom silver-plated nuts, specialized anti-seize dry-film lubricants, and precision thread profile roll-forming to minimize friction coefficients during automated assembly.
Essential guidance on OEM customization, quality certifications, minimum order quantities, and technical compliance.
OEM (Original Equipment Manufacturer) and ODM (Original Design Manufacturer) services involve producing fasteners strictly customized to technical engineering drawings, non-standard dimensional pitch requirements, unique head markings, and tailored material chemistry. Standard off-the-shelf fasteners often lack specialized surface coatings or non-standard thread lengths needed for high-stress industrial machinery, turbine casings, and proprietary structural joints.
Our quality control program covers the complete production lifecycle: raw material verification via XRF spectroscopy, continuous atmospheric heat treatment monitoring, optical dimensional sorting, tensile and proof-load testing via computerized hydraulic pull testers, Charpy impact testing, and 100% thread ring gauge verification. Every delivery includes an EN 10204 3.1 Material Test Certificate detailing chemical analysis and mechanical test results.
For aggressive marine and offshore splash zones, we recommend Hot-Dip Galvanizing (HDG) to ASTM A153 for structural bolts, Fluoropolymer PTFE / Xylan coatings for flange stud bolts requiring predictable torque coefficients, or upgrading the base alloy to Duplex 2205 (UNS S31803) / Super Duplex S32750 for complete immunity to chloride pitting corrosion.
Yes. We specialize in supplying fully matched bolting packages. For example, pairing ASTM A193 Grade B7 stud bolts with heavy hex ASTM A194 Grade 2H nuts, or ASTM A320 Grade L7 studs with Grade 4/7 nuts. Matching hardness profiles ensures that nut threads do not strip prior to reaching the bolt's maximum proof load during tensioning.
Standard lead times for custom OEM/ODM production typically range between 15 to 30 days depending on raw material availability, bolt diameter, secondary operations (such as CNC drilling, safety wire holes), and surface coating requirements. Rapid tooling setups allow us to expedite urgent breakdown orders for plant maintenance turnarounds.
Export shipments are accompanied by a comprehensive document package: Mill Test Certificates (MTC EN 10204 3.1), Certificate of Origin (COO), Commercial Invoice, Packing List with Heat Number Line-Item Mapping, Third-Party Inspection (TPI) reports (SGS, TUV, BV available upon request), and ISPM-15 compliant heat-treated wooden crate packing documentation.
We strictly enforce post-plating baking procedures in accordance with ASTM B849/B850. Plated ultra-high strength fasteners undergo immediate hydrogen relief baking at 200°C–220°C for 8 to 24 hours depending on fastener diameter and tensile rating. Alternatively, non-electrolytic zinc flake coatings (such as Geomet) are recommended to completely eliminate acid immersion steps.
For standard metric/imperial sizes stocked in raw wire rod, our MOQ starts as low as 500 pieces. For non-standard custom alloys (e.g., Inconel 718, Titanium Grade 5, Hastelloy C276), MOQs are evaluated based on minimal mill heat-run bar stock weights. Contact our engineering desk for tailored quantity assessments.
Send us your engineering drawings, bill of materials (BOM), required standards, and coating specifications. Our technical engineering sales team responds within 4 business hours with comprehensive pricing and production schedules.
