• Surface-hardened steel offers properties like a composite material

Surface-hardened steel offers properties like a composite material

LSV Lech-Stahl Veredelung GmbH has been a reliable supplier of steel to the metalworking industry for more than 10 years. Customers place high demands on the material supplied for further processing through to component production. Regardless of the application, the material is exposed to particularly high stresses. The service life of a component always goes hand in hand with its mechanical and technological properties, in many cases particularly its resistance to wear.

LSV takes these requirements into account by offering inductive surface hardening as an additional process step in steel finishing. Induction surface hardening makes it possible to generate a material with properties similar to those of a composite material. This process creates a hard and wear-resistant surface on the previously produced bright steel without changing the chemical composition. The existing properties of the bright steel are retained unchanged in the core area. As only the outer edge area of the round steel has to be partially heated to austenitising temperature by the hardening inductor, the bar only passes through a short process zone. Heat conduction into the core area is specifically prevented by frequency control. This is followed by quenching of the surface layer, which results in a strong, localised increase in hardness.  Quenching transforms the previously formed austenite into fine martensite, which is decisive for the wear-resistant properties in the surface area. This is usually followed by tempering at low temperatures in order to significantly reduce the risk of cracking due to high stresses.

Illustration of induction surface hardening of steel

The entire process chain of induction surface hardening is geared towards a homogeneous and reproducible heat treatment result. Downstream processes can be significantly shortened and even replaced by surface hardened material. Compared to surface layer hardening on the customer's already manufactured short piece, this results in an immense cost advantage. By providing support in the selection of materials, the use of cost-intensive alloy concepts can also be scrutinised and optimised if necessary.

The advantages for customers in the metalworking industry can be summarised as follows:

  • Shortening of their own process chain
  • Savings due to the elimination of surface hardening on the component
  • Less material loss
  • Optimised material selection possible for every application
  • No impairment of weldability compared to partial surface hardening

LSV's expertise benefits the processing customer, as they receive a semi-finished product that already has some of the properties ultimately required of the finished components. Considering the entire value chain, this can lead to a competitive advantage for the customer. If higher strengths and toughnesses are required in the core for particularly demanding component loads, LSV can combine this process very well with induction through-hardening.

Surface hardening fully utilises the potential of the materials used in terms of chemical analysis and the resulting mechanical and technological properties. Compared to conventional annealing methods, induction processes also enable CO2 emissions to be saved. LSV sees enormous potential here for further measures in terms of sustainability.

Single rod surface-coated

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