HInoxTube® is an exclusive patented special tube, produced by Trafiltubi using the stailess steel UNI X4CrNiMo16-5-1 [Werkstoff 1.4418 • DIN X4CrNiMo16-5-1 • also known as APX4]: this is a special martensitic stainless steel high corrosion resistant (level of corrosion resistance between a 13%); chromium steel and the 18-8 series. Resistant to sea water, saline atmosphere and salt spray. Very good resistance to organic acids and some mineral acids. Very suitable where a high polish is required. Good weldability.

Thanks to its specifications Hinoxtube® represents the best technological solution so far achieved in the construction of light structural frames (as well as welded tubular frames in general) aimed for dynamic use under extreme conditions.

The special raw material used to produce it (originally used in the aeronautical and military industries, and more recently in Formula1 cars), was the result of the need of the military industry to replace cadmium coated tempering steel (whose considerable inconvenience is the highly polluting production process) with an innovative steel, with high mechanical properties, weldable and corrosive resistant.

Nowadays, thanks to Trafiltubi innovation, it is possible to use this material also for the piping products, in order to create highly resistant and long lasting welded frames.

HInoxTube® is a stainless steel material with a high Chrome content, together with Molybdenum and Nickel alloys that highlight its resistance and tenacity properties. Its martensitic structure presents some traces of austenite that minimize the risk of cracks during the welding process. So it combines in an innovative way the best properties of both martensitic and austenitic materials.

Thanks to the high balance between rigidity/weight and resistance/weight (better than the one of titanium, and aluminium), to its workability and to its resistance to corrosion, HInoxTube® allows the production of tubing with triple thickness used for extremely light frames that can be almost indestructible.

In the cycle industry, HinoxTube® is used to produce our Gilco frames and, by Columbus, for the production of the double butted stainless steel tubes known as XCr. It was recognized as the best steel tube for bikes in the world. 

Differences of HInoxTube®
 compared to other stainless steel pipes

Different from the austenitic stainless steels, HInoxTube® has a very high tensile and yield limit that makes it extremely long lasting to cycling stresses.
It s highly resistant against salt-water corrosion and against organic acids, even if not protected by any coating. Therefore, the frame does not require any additional painting and also its internal surfaces, which are always difficult to be protected and worked, can became naturally resistant to corrosion after a simple pickling.

The tubular elements can be joined or by using the TIG welding technique, or with the fillet-brazing technique, or with junctions.

Once the frame has been welded, the external surfaces can be pickled in order to eliminate any impurity and calamine and then passivated. Alternatively the external surface can be mechanically or electrically polished, without any further treatment.

As known, normal maraging stainless steels are used for the production of electro welded tubes, that are manufactured from a longitudinally welded sheet. On the contrary, HInoxTube® is a seamless tube (manufactured from a billet by extrusion): it is extremely stable and has no need to be heat treated in order to regain its mechanical characteristics in those areas thermally altered by the welding process (ZTA). This will improve its resistance to impacts.

Thanks to these seamless tubes and their excellent workability due to the cold drawing process, it is possible to achieve extremely thin thicknesses without compromising the frame's rigidity or durability.

Last but not least, the HInoxTube® project was created with a special focus on environmental protection. One of its challenges, indeed, was to foreshadow a finished product whose life cycle had an environmental impact lower than all the previous products.