Steel is the material that was first used in the construction
of top-of-the-range frames because of its superior mechanical
characteristics, most notably its superior fatigue resistance and
a breaking load second only to that of advanced composite materials.
Columbus research has always worked towards the customization and
development of materials with characteristics intended for cycling
use. The results are of international importance.
Columbus’s history is the creation of steels with patented
formulations such as the famous Nivacrom.
NIOBIUM
It’s a special micro alloyed steel with Manganese, Chrome, Nickel,
Molybdenum and Niobium. In the Columbus research and development tradition
it can be considered the evolution from of the Thermacrom and Nivacrom
alloy. It’s designed to provide better mechanical properties and
greater resistance to atmospheric corrosion than conventional carbon
steels. For every top-of-the-line and competition frames where lightness
and high reliability are fundamental. Like Vanadium in Thermacrom steel,
Niobium increases yield strength by precipitation hardening and acts
for refinement of grain size. Thanks to the special Columbus chemical
composition, the combined effect of precipitation strengthening, and
grain refinement the properties are incredibly increased inith respect.
To standard steels. Niobium is a more effective strengthening agent than
Vanadium. After mechanical deformation working and drawing, NIOBIUM undergoes
a special heat treatment that gives the steel its final characteristics;
this heat treatment is designed to minimize the tubes distortion and
decarbonization phenomena. Columbus heat treatment results in a super
fine high-strength microstructure of bainite, wich means high strength,
hardness and long fatigue life.
Mechanical characteristics:
Ultimate tensile strength = 1050 ÷ 1250 MPa
Yeld strength: min 750 MPa
Minimum elongation: 14%
NIVACROM
The Nivacrom steel for the Zona series undergoes a series of
processes and treatments, which, after drawing, homogenize the mechanical
characteristics of the tube, making it uniform along the longitudinal
axis. This makes the fatigue behaviour and weldability of the material
excellent.
Mechanical characteristics:
Breaking load = 950÷1050 MPa
Elongation > 10% |
 |
Steel is an iron/carbon
alloy that, with the addition of several elements such as
chrome, nickel, manganese, molybdenum, vanadium, etc., develops
specific characteristics such as tenacity, fatigue resistance,
workability and insensitivity to overheating. |
Why choose steel?
Steel ensures high performance at really low weights.
The new alloys, particularly Thermacrom, give
a weight close to that of the aluminum alloys,
together with a perfectly balancable elastic
response, that is appreciated in particular on long traits.
Unlike aluminum, steel is substantially stable
over time, not requiring onerous maintenance cycles.
If properly
rust-treated, under normal conditions of use, it has
almost unlimited
fatigue resistance.
It allows frames to
be built with excellent performances, rigid yet comfortable, suitable
for any type of use. |
|
Micrography of a standard
heat-treated low alloy steel: decarbonization process is visible, the mechanical
charateristics of the material are highly decreased |
|
 |
| |
|
|
Micrography of Columbus
NIOBIUM steel: low depth
of decarbonization processes grants incredible fine
and homogeneous structure,
and excellent mechanical characteristics. |
|
 |
XCR
In cooperation with Trafiltubi ed Aubert & Duval, the new Columbus seamless tube set in stainless steel named XCr, is created. Starting form a specific request of the military industry, looking for a valid substitute for cadmium plated temper hardening steels which could no longer be produced because of their highly polluting manufacturing process, a new martensitic stainless steel with high content of Chromium and Molybdenum and Nickel as alloy elements which increase the mechanical and weldability characteristics, was created. The martensitic main structure contains traces of austenite that reduces the possibility of crack formation especially during the welding process.
The great weldability properties of the new XCr stainless steel, together with its high fatigue resistance and its extraordinary geometrical stability at high temperatures, make this material the natural element for welded structures, such as bicycle frames. Thanks to the high stiffness/weight and UTS/weight ratios (better than titanium and aluminium alloys) together with the elevated characteristics of corrosion resistance, it is possible to manufacture triple butted tubes to build extremely light and indestructible frames. |
|
Carbon fiber