The patented UltraSTEEL™ process is a method of imparting a unique dimpled texture onto the surface of cold formed products. This is achieved prior to the main forming operation by passing the unformed flat strip through a set of mating UltraSTEEL™ rolls. See photograph below.
The material is then passed through standard roll-forming equipment until the finished product is formed.
- The process does not reduce the formability of the material and any thin gauge profile can be manufactured using UltraSTEEL™ that could be roll-formed in plain material.
- No extra equipment or expenditure is required, and the process is employed within a standard rollforming line.
UltraSTEEL™ differs from other more traditional processes associated with cold forming in the way that the material is made to flow by the shape of the UltraSTEEL™ rolls. The pattern of the UltraSTEEL™ strip is formed by working the material from both sides at once, producing the revolutionary “Double Helix” pattern. In so doing the material undergoes a great deal of localized stretching, unique to the UltraSTEEL™ process. The double helix shape also ensures that the pattern is uniform throughout the whole strip, with no overall thinning or weak points. Through every plane across through the cross section of the strip there is a consistent ‘wave’ pattern formed. Locally, this wave pattern has the effect of locally stiffening the strip in every direction, and improving the mechanical properties of the material.
Most significantly however, is the fact that the process does not require extra material to produce the dimples.
To explain the overall effect of the process on the finished part it requires an explanation of what occurs when the dimples are formed.
The Effects of the UltraSTEEL™ Process
In order to explain the overall effect of the process on the finished part it requires anexplanation of what occurs when the dimples are formed by the UltraSTEEL™ rolls detailed earlier. Other than merely shaping the dimples in the flat strip, the UltraSTEEL™ process actually improves the mechanical properties of the material,and therefore the end product.
At the microscopic level, the coil of steel being formed is composed of minute metallic particles or grains. During the process the pressure of the UltraSTEEL™ rolls on the material causes considerable deformation to these grains and they become longer,flatter and much stronger than they had previously been in flat form. This ‘local stretching’ effect is known as ‘work hardening’.
Extensive research has been carried out to establish the amount of ‘work hardening’that occurs during the process. Computer modeling has been used to show thatalmost all of the volume of material is work hardened to some extent, that is to saywork hardening occurs throughout the entire thickness of the material.
Edge View Finite Element Computer Model
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Computer Model of Work Hardening Rate in the Material
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The data from the theoretical models has been confirmed by independent microhardness tests conducted upon cross sections of UltraSTEEL™ samples. It was noted that the hardness of the material had increased throughout its entire thickness, thereby indicating that the whole strip had undergone work-hardening.