Weathering steel fasteners combine corrosion resistance and unique aesthetic features to improve the durability of your projects without compromising on appearance.
Weathering steel exhibits enhanced atmospheric corrosion resistance without specialised coatings such as galvanising or painting. In suitable environments, the steel develops an oxide layer (patina) that effectively protects the underlying steel from further corrosion, making it ideal for structural connections in bridges, high rise, roads and rail infrastructure.
Associated with trademark names REDCOR® and COR-TEN®, weathering steel has demonstrated its effectiveness in steel structures in North America, Europe and Japan since the 1960s. While major standards organisations such as ASTM, EN and ISO have specifications for weathering steel plate, there is limited guidance for weathering steel structural bolting assemblies.
ASTM A325/M is the standard specification for high-strength bolts: 120ksi (inch series) or 830MPa (metric). In purpose, it is equivalent to AS/NZS 1252 and EN 14399-3. The main consideration is an extended shank length to allow designers to maximise bolt shear capacity in snug (/S) and tensioned bearing (/TB) connections.
Currently, most weathering steel fasteners imported into Australia are sourced from North America and are inch series. This often clashes with local steel structure codes AS 4100 and NZS 3401, and bridge design code AS/NZS 5100.6. To combat this, we provide Metric PC 8.8 ASTM A325/M Type 3 structural assemblies in common bridge diameters (M24/M30).
Hobson upholds Australia and New Zealand’s standards through the diligent performance of Rotational Capacity Testing for weathering steel structural assemblies. This is the ASTM sister test to the AS/NZS Appendix D – Assembly Test. It aims to ensure quality and improve ease of installation by verifying that the required tension can be reliably obtained through the tightening methods specified in AS/NZS 5131.
Our weathering steel structural assemblies have a phosphate-oil coating on both the nut and bolt, protecting against premature weathering and giving you more time to tension the assemblies after initial fit-up.
All factory production control (FPC) and verification testing are performed at ILAC mutual recognition arrangement (MRA) accredited laboratories, which are equivalent to Australian NATA accredited laboratories. They possess strict Quality Management Systems (QMS) to ensure accuracy and reliability.
All Hobson structural bolts possess a unique three-character code that allows weathering steel structural assemblies to be easily traced. By simply entering it in the website, the trace code can conveniently retrieve all relevant quality documentation, even if the bolts have been installed and the original packaging disposed of.
Hobson’s weathering steel range reflects commitment to quality and continues to exceed expectations, making it the perfect choice for your next weathering steel project.
