DC-grade steel materials are soft products with excellent formability. With our DC-grade steel products, i.e. traditional low carbon steel strip, we offer deep-drawing steel grades for a wide variety of requirements – from simple drawing operations to automated stamping and forming processes with complex end product geometries. DC-grade steels are used, for example, to construct telescopic rails in filing cabinets, which are expected to easily, silently and reliably extend and collapse while supporting weights of over 100 kg (220 lb) – and this for several years on end.
Waelzholz DC grades are always the first choice when it comes to precisely manufactured parts. This is because of very tight tolerances within which we are able to produce our steelstrips. The ability to achieve an ultra-low thickness tolerance significantly increases the uniformity of the formed part (thickness tolerance =< 1/3 C-tolerance, see info box “Standard thickness tolerances”). This is supported by a planar anisotropy (depending on the requirements) of <0.3 to enable an extremely uniform wall thickness (earing z < 1 percent) for rotationally symmetrical parts, or by a microstructure with an r bar > 1.6 orientation to achieve optimal deep drawing properties.
In addition, surface finishing is one of our specialties – applying a zincphosphate coating to the surface of our low carbon steel strip makes it easier to carry out difficult forming operations and helps minimize tool wear.
The industry standard EN 10140 specifies three thickness deviation classes: A, B and C. Class C is the class with the tightest tolerance specification. With its DC-grade steels, Waelzholz can achieve a 3rd of the C thickness tolerance. This significantly increases the uniformity of the formed product.
For the thickness tolerances for nominal width < 125 mm (< 4,921") please see the respective data sheet.
We primarily manufacture soft and unalloyed materials such as our DC-grade and case-hardening steel in non-earing or low-earing versions. With a thickness ranging from 0.1 to 6 mm and a width ranging from 10 to 1,000 mm, this NE strip (non-earing strip) can be used for a wide range of applications. In contrast to conventional cold rolled strip steel, NE strip has an extremely fine, isotropic grain structure and thus exhibits uniform flow behavior both longitudinally and transversely to the direction of rolling. The result is a material with an extremely low level of earing of approx. 0.5% which does not exhibit any internal stresses (see diagram “Influence of microstructure on earing”). As such, our NE strip grades are the perfect material for complex, multi-stage forming operations. They are used, for example, in the production of guide sleeves for dual clutch transmissions or tension and idler pulleys for belt drives in automotive applications.
In addition to the microstructure, the material surface also has a major influence on the deep drawability of a material. This is why we offer our low-earing and non-earing grades with a variety of surface finishes such as rough, matt, smooth, or glossy in accordance with DIN EN 10139. A notable surface finish in this context is a coating of zinc phosphate – the combination of a carrier layer and soap lubricant enables even more complex forming processes for particularly demanding deep-drawing applications.
Thanks to their fine grain structure, our non-earing DC-grade materials (NE strip) exhibit an extremely low degree of earing of < 1% compared with conventional cold rolled steel strip.
Guide sleeves in dual clutch transmissions are made from non-earing DC grades or case-hardening steel (NE strip). The fine grain structure of the material results in uniform flow behavior both longitudinally and transversely to the rolling direction and therefore makes it possible to produce the long and rotationally symmetrical guide sleeves without any earing.
