The world’s strongest bolts are stainless


BUMAX® Ultra has proven itself as the world’s strongest bolt – in various highly-demanding critical fastener applications around the world where standard fasteners are simply inadequate.

The BUMAX® Ultra range is based on Nobel Prize winning technology that ensures ultra-high strength, and good resistance to corrosion and extreme operating temperatures.

BUMAX® Ultra – the world’s strongest bolt

Since its launch in 2014, the BUMAX® Ultra range has proven that it is capable of exceeding tensile strengths of between 1 500 to 1 700 MPa on various applications, with good corrosion resistance and an operating range of between -50 and 400°C. The BUMAX® Ultra range of fasteners are made at the BUMAX factory in Åshammar, Sweden.

BUMAX® Ultra is used for security lock systems, aerospace systems, high pressure applications and pump and valve systems – all with excellent results.

Nobel Prize winning technology

BUMAX produces the strongest fasteners in the world by drawing on Nobel Prize winning quasi-crystalline Precipitate technology. The technique uses strain hardening followed by precipitation hardening, which significantly increases tensile strength.

Demanding applications

BUMAX® Ultra is designed for applications that require ultra-high strength combined with high ductility and fatigue. The technique also provides better corrosion resistance than A2 (304) and with low thermal expansion it is suitable for high service temperatures. The extreme strength of BUMAX® Ultra fasteners also provides opportunities to downsize to new lightweight fastener options at lower cost.

Replacing carbon steel fasteners in critical applications

BUMAX® Ultra fasteners are increasingly used to replace high-strength carbon steel fasteners in critical applications with extreme requirements on strength, ductility and fatigue resistance. They have a coefficient of thermal expansion similar to that of carbon steel, which provide design advantages compared to austenitic stainless steels.

Application example: Lock manufacturer replaces carbon steel screw with BUMAX® Ultra

A leading European lock and locking system manufacturer originally used a DIN 912, M3x4 8.8 carbon steel screw for the critical latch screw. Following breakages that disabled the entire locking function, the manufacturer tested both 10.9 and 12.9 without solving the problem.

The manufacturer then fatigue-tested BUMAX® Ultra, which survived 500 000 strokes without a single breakage – compared with carbon steel screws that only lasted 10 000 strokes. BUMAX® Ultra screws are now a critical lock component that helps avoid lock failure.

BUMAX® est présent dans le monde entier

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