Fields of use

Scraper bars for snow-ploughs, cutting edges/wear plates for excavator shovels, cutlery steel and cutting edges for shovels, anti-wear strips for shovels

Description

Cutlery steel, anti-wear strips, cutting edges and structural steel are pre-finished products provided by BOROX AB in Sweden. These profiles are rolled in a soft state, thus receiving their cross-sectional form and are then water-hardened.

Properties

BOROX wear-resistant steel is a water-hardened boron steel with a unique combination of wear resistance and workability.  Thanks to rolling of the products in a soft state and subsequent water hardening, no postprocessing is needed, such as bevelling the cutting edges or chamfering the welding edges, etc. The waste that arises from the manufacture of these products from wear plates is not created and there is also no softened zones, like those that arise through oxygen cutting for example.

What is wear actually?

In general language use, wear is also described as abrasion. But wear can also be described as the progressive material loss from the surface of a solid body (base plate), effected by mechanical causes.

In the field of use of earthmoving machinery and dumper trucks, three important types of wear can be described:
1. Sliding wear
2. Impact wear
3. Sticking wear

In practice, it has been proven that a greater hardness increases the wear resistance for practically all types of wear. At the same time, it must also be taken into account that the demands on the processing increase with the increasing hardness. In practice, it has been shown that a wear plate hardness of 400HB or 450HB produces very good results in a great number of applications.

Sliding wear

Sliding wear develops when abrasive materials slide over a surface, e.g. the gravel when emptying a dumper truck. If the bulk solids are hard enough, the damage results from the formation of chips on the surface of the trough. If the material of the trough is replaced by a harder substance, chips are no longer formed. Instead, there is simply a three-dimensional distortion (e.g. grooves). The lifespan can be considerable increased by this measure. Summary: Harder plates reduce the wear considerably.

Impact wear

If abrasive materials fall onto a surface or hits it, this is impact wear. This fall occurs, for example, when material from the excavator shovel falls onto the surface of a dumper. In this case, the size and form of the abrasive material, the impact angle on the surface and the impact speed all play a role. Summary: If these are very small, sharp-edged particles with a high speed, soft sheets reduce the wear better than hard ones. This can, for example, be the case in a feed pipe with a high flow speed of liquid or air mixed with sand. In all other cases, on the other hand, harder plates reduce the wear.

Sticking wear

If abrasive material gets between two rigid surfaces, this is known as sticking wear. This occurs, for example, when grinding in a jaw crusher. There are different situations, in which sticking wear can occur:
1. Both surfaces are equally hard and the relative movement of the surfaces is running parallel. Summary: Harder plates reduce the wear.
2. The surfaces have different hardness grades and the relative movement of the surfaces runs parallel. Summary: A harder plate in the harder surface reduces the wear in both surfaces and the harder plate becomes more worn out.
3. With converse movement of the surfaces, a harder plate reduces the wear.

This hardening procedure is made up of two processes, the carburizing and the actual hardening.

Product offers from Stahl-Contor from the Embrach service centre