Name of Material Type of Material Breaking Load Yield Load Elongation
Alloy 550 N/mm2 (in T6) 510 N/mm2 (in T6) >12%
Alloy >420 N/mm2 380 N/mm2 10%
Alloy 420 N/mm2 370 N/mm2 9%
Steel 1250-1450 N/mm2 1100 N/mm2 >12%
Steel 1200 N/mm2 1030 N/mm2 12%
  Steel 900 N/mm2 830 N/mm2 12%
  Steel 800 N/mm2 760 N/mm2 12%
  Steel 700 N/mm2 650 N/mm2 12%

The main products of Columbus' research in the metallurgical field are as follows:

Al-Si-Mg 6000 Alloy

This special alloy from the 6000 series supplied in F, is not self tempering and thus necessitates a full heat treatment of the welded frame. Excellent TIG weldability. Very good resistance to corrosion, without trace of the intergranular corrosion phenomenon.

It is necessary to heat treat the frame as follows:

535 C for 35 minutes, cooling in water and additives solution. Artificial ageing at 180 C for 10 hours. See Columbus construction manual for latest details.

See Table at top for mechanical characteristics.

Suggested welding rod: 4043/4145

Al-Zn-Mg 7000 Alloy with Zirconium

Supplied as T6. The addition of Zirconium to the chemical composition of the alloy allows for reduced grain size, improved strength and resistance to recrystallization, improved resistance to hot cracking, good weldability, and the best recovery of mechanical characteristics after welding.

The best material performance is achieved through the following specific heat treatment: 135 C for 5 hours and 150 C for 2 hours. This operation maximizes the alloy features. 

See Table at top for mechanical characteristics.

Al-Zn-Mg 7000 Alloy

Exact designation is 7005 T6. Excellent TIG and MIG weldability. High corrosion resistance. Heat treatment is recommended.

Suggested welding rod: Al Mg Si 05 (USA 6063) - CASTO MAG 45802

See Table at top for mechanical characteristics.

Al-Mg 5000 Alloy

Good TIG and MIG weldability. Remarkable mechanical resistance thanks to the typical Columbus cold drawn butted tubes. Heat treatment is not necessary.

Suggested welding rod: Al Mg Si 05 (USA 6063) - CASTO MAG 45802

See Table at top for mechanical characteristics.

Thermacrom

This is the latest result of recent studies on the new welding methods and on the behaviour of the structure under successive heat cycles. Thermacrom can be considered to be a development of the nivacrom alloy and the ultra-fine structures resulting from the secondary precipitation of stable carbides. The aim is always to improve the mechanical benefits of the frames, maintaining a high coefficient of safety with even small thicknesses. The final weight is very closed to that of the best aluminium frames. Thermacrom is a steel microalloyed with manganese, chrome, molybdenum and vanadium. These elements produce a marked increase in temperability, a reduction in sensitivity to overheating (which ensures that a fine grain metal structure will be obtained after welding, more able to withstand fatigue stresses), better characteristics of strength and tenacity and better characteristics of resistance to corrosion and wear. After mechanical deformation, working and drawing, Thermacrom undergoes  heating and cooling cycles that give the steel its particular microstructure. The treatment, which only ends at the time of welding by the frame maker, enhances the mechanical characteristics of the material by giving it high breaking loads (1250-1450N/mm2) permitting completely safe reductions in thicknesses. Thermacrom is used for very top of the range frames that require the highest benefits.

See Table at top for mechanical characteristics.

Nivacrom

This is the most famous of Columbus' patented steels, specifically designed to make tubes for bicycle frames. It has the advantage over other steels of combining extremely high mechanical characteristics with great tenacity in the welding area. Alloy elements, vanadium and niobium, precipitate in the metal matrix blocking any grain growth and the resulting decline in  mechanical characteristics, even at temperatures exceeding 1000C. It should be noted that, following the introduction of Nivacrom, the automobile industry began to use similar steels for producing bearing and reinforcement structures. Nivacrom though has been developed for top of the range competitive bicycle frame use.

See Table at top for mechanical characteristics.

Cyclex

Chrome/molybdenum alloy with an excellent capacity to withstand overheating. At Columbus the Cyclex mark indicates seamless tubes with final mechanical characteristics obtained solely by work hardening. Used for high performance frames.

See Table at top for mechanical characteristics.

25CrMo4 Steel

The chemical composition of this steel, specifying a higher percentage of Chromium, gives the material good resistance properties to overheating. The formation of carbides prevents the grain enlargement: the steel maintains its properties during brazing and welding and even in the malleable raw state it features excellent characteristics.

See Table at top for mechanical characteristics.

Carbon Manganese Steel

A middle weight alloy; hardness and toughness are the most important features of this alloy.

See Table at top for mechanical characteristics.