Heavy Steel Structural Hex Bolts
Product grade: 10.9s
Surface treatment: Blackening/phosphating
Material: 20MnTiB/35VB
Specifications: M16, M20, M22, M24, M27, M30, etc.; customisation available
Place of origin: Hebei
Product Description
We are a specialist manufacturer of steel structure fasteners, specialising in heavy-duty steel structure 10.9s high-strength large hexagonal bolts. We source our raw materials exclusively from major steel mills, and produce bolts, nuts and washers in complete sets with matching furnace batch numbers. Each batch is accompanied by a stamped material certificate, mechanical properties report and torque coefficient test report. We strictly control the variability of torque coefficients and conduct 100 per cent outgoing inspections; our products have a high pass rate in third-party re-inspections, eliminating the risk of joint slippage or brittle fracture on site. We support witness sampling, maintain stable production capacity during peak seasons, and can arrange delivery in batches.
Why Choose Us
Controlled sourcing of raw materials, eliminating the use of inferior substitutes
10.9s utilises specialised 20MnTiB steel billets, sourcing exclusively from major domestic steelworks. Each furnace is assigned a unique code, ensuring full traceability of the batch throughout the production process; we refuse to use recycled materials or downgraded billets. We retain the furnace number for each batch, ensuring that material certificates correspond one-to-one with the physical products. We do not pass off standard 10.9-grade products as 10.9s, thereby eliminating the risks of insufficient low-temperature impact strength and delayed fracture from the source.
Complete sets from the same furnace batch, addressing the industry’s biggest pain point
A common industry issue: bolts, nuts and washers from different furnace batches are mixed, resulting in significant fluctuations in torque coefficients.
We insist on producing bolts, nuts and washers as a complete set from the same furnace batch and shipping them in the same package. With a matched heat treatment process for the entire set, the torque coefficient is stable with low variability, and the K-value for large hexagons is consistently controlled within the national standard range of 0.11–0.15. Each batch is accompanied by a stamped torque coefficient test report, allowing installation teams to set torque directly according to the K-value of that batch, thereby reducing the risk of slippage on site.
Strict Process Control to Prevent Hydrogen Embrittlement and Thread Defects
All threads are formed by rolling; no machined threads are used;
Optional corrosion protection: phosphating, hot-dip galvanising, Dacromet, zinc-aluminium coating;
Important note: Electrogalvanising is not recommended for 10.9s high-strength components; if hot-dip galvanising is required, it must be accompanied by dehydrogenation and baking treatment to mitigate the risk of hydrogen embrittlement and delayed fracture in high-strength bolts.
Threads are fully protected; packaging includes desiccants to prevent moisture and rust, and the threads are safeguarded against impact damage during long-distance transport.
Comprehensive testing ensures worry-free supervision and third-party re-inspection
The factory operates its own physical and chemical laboratory, conducting in-house inspections on every batch prior to dispatch: hardness, tensile strength, impact testing and torque coefficient testing.
A complete set of stamped documentation accompanies the goods: product certificate of conformity, material guarantee certificate, mechanical properties report and torque coefficient report.
We support on-site witness sampling and testing for projects. The contract explicitly stipulates that should a third-party re-inspection fail, we will bear the testing costs, arrange for returns or replacements, assume corresponding quality liability, and eliminate the risk of re-inspection failures—the greatest concern for purchasers.
Production Capacity & Delivery Advantages of Our Physical Factory
We operate our own heat treatment and thread rolling production lines, ensuring stable scheduling for large-volume orders;
We can arrange delivery in batches as required to align with project hoisting schedules;
We support price-locked stockpiling for projects to mitigate the risk of rising steel raw material prices;
Packaging features unique identification, with goods packed by furnace batch number; outer boxes are clearly labelled with specifications, grades and furnace numbers, simplifying on-site warehousing and sorting.
Comprehensive Services for Hassle-Free Implementation
We provide reference guidelines for installation torque;
Technical support is available to liaise with on-site technicians, addressing queries regarding the installation, storage and pre-tensioning of high-strength bolts;
Arrangements for the disposal of project offcuts can be negotiated to reduce procurement stock build-up.
Suitable applications: Heavy-duty connection joints in steel structure workshops, steel space frames, bridge supports, tower cranes, utility tunnels and large-scale equipment steel structures.