High hardness and toughness guaranteed
Machine parts used in abrasive environments wear out quickly. This is especially the case in mining and the transport industry. Steels with a high degree of hardness and wear resistance have decisive advantages as opposed to conventional constructional steels.
- High material hardness leads to less abrasion in parts that are subjected to high frictional stress and thus to a longer service life.
- Wall thicknesses can also be reduced while maintaining the same expected useful life of the components. Particularly in the transport industry, for example in dump trucks, this leads to less dead weight and higher payloads.
To achieve such advantages, the voestalpine Steel Division supplies two special grades:
- Wear-resistant durostat® carbon steels are direct hardened carbon steels that demonstrate the best processing properties.
- Wear-resistant altrix® steels include roll-clad multi-layer plates for an even longer service life.
durostat® is direct-hardened with guaranteed high toughness
With surface hardness values of up to 500 HB (Brinell hardness), durostat® steels are well suited to applications with high mechanical stress and high levels of abrasion. They are used in loading and conveying machinery, dredgers, wheel loader buckets, crushing plants, screening equipment and slides.
High hardness is achieved by annealing steels with relatively high carbon content in the heat-treating furnace and then quickly water-cooling them in the quencher. This is the conventional technology. The high carbon content makes steel hard, but also brittle, and high degrees of toughness are difficult to achieve. A thick layer of furnace scale is also produced during annealing and must be removed through expensive sand blasting. In order to prevent excessive rust during transport, it is necessary to paint the sand-blasted steel with a primer.
As a specialist in thermomechanical rolling and rapid cooling, the voestalpine Steel Division has developed a special manufacturing route for wear-resistant steels: direct hardening. Directly following hot rolling, the plate is rapid-cooled (hardened) in the rapid cooling line. Heat treatment in the annealing furnace is not necessary, which decisively shortens the production time.
altrix®: A strong combination
The product range of the voestalpine Steel Division includes altrix® multi-layer plates for extreme wear conditions. However, the especially high hardness would only allow a limited degree of toughness. That is why voestalpine uses a special trick and produces a composite material. This guarantees a constructional steel grade as the base material with sufficient toughness and good weldability. In hardened condition and with a hardness of up to 66 HRC, the coating material is characterized by extremely high wear resistance. The roll-cladding technology developed in-house is used to produce highly wear-resistant two-layer and three-layer plates that are delivered in as-rolled condition and hardened at the customer after being worked.
Typical applications of altrix® two-layer plates include suction dredger tubes (hard on the inside and tough on the outside), while three-layer plates are used in plow mold boards (tough on the inside, two hard outside layers).
Plate thicknesses range between 7 and 80 mm, and widths can be up to 3600 mm. The distribution of layer thicknesses can be individually adjusted to achieve the desired resistance to wear and failure. A thickness ratio of 50/50 between the cladding and the base material is typical for two-layer plates, and a ratio of 33/34/33 (hard/tough/hard) for three-layer plates.
With durostat® and altrix® , the voestalpine Steel Division is ideally prepared to supply the market with wear-resistant grades.
