XAR (eXtra Abrasion Resistant) steel has a high degree of hardness and is used where there are problems with wear and attrition, also called abrasion. This steel is made by ThyssenKrupp Steel Europe. The special chemical composition of XAR steels and their hardening and tempering reduces wear to a minimum and therefore increases the durability of the product significantly. With thicknesses of 3 to 100mm, this steel is used especially in mining, steelworks technology and in cement works.

Optimum wear resistance is achieved by the special alloying of niobium and chromium. The wear resistance under impacting loads and cold working are ensured with the help of niobium micro alloying. Due to the composition of the XAR steels machining such as cutting, welding and bending with small bending radii is easier.

XAR is available as different variants. These differ according to sheet and plate thicknesses and Brinell hardness (HBW). In the Brinell hardness test method a sintered carbon metal ball is pressed into the surface for 10 to 15 sec. with a defined test force. This causes a round impression to be made in the workpiece. The diameter of this impression is then used to calculate the Brinell hardness.

An overview of XAR steel grades

XAR 300

  • Sheet thickness 4 – 50 mm
  • Brinell hardness ≥ 270

This steel is characterised by its good cost effectiveness with very good surface quality. It is used where little wear resistance is necessary.

XAR 400

  • Sheet thickness 3 – 100 mm
  • Brinell hardness 370 – 430

This steel is characterised by its high wear resistance. It is especially suitable for cold forming (bending) and welding.

XAR 400 W

  • Sheet thickness 3 – 50 mm
  • Brinell hardness 360 – 440

This steel is the heat-proof variant of XAR 400, and is always used where high hardness and wear resistance are required at temperatures up to 400°C.

XAR 450

  • Sheet thickness 3 – 100 mm
  • Brinell hardness 420 – 480

This steel corresponds to the general quality of XAR 400 however has higher wear resistance.

XAR 500

  • Sheet thickness 4 – 100 mm
  • Brinell hardness 470 – 530

This steel, which is even more resistant to loads, is particularly suitable for forming and welding.

XAR 550

  • Sheet thickness 4 – 100 mm
  • Brinell hardness 500 – 580

XAR 550 was developed for particularly high loads and wear.

XAR 600

  • Sheet thickness 8 – 40 mm
  • Brinell hardness >550

This steel grade is used for Wearing parts, which are subjected to extreme attrition. It should be noted that these wearing parts must not be subjected to impacting or percussive loads. This steel is also not suitable for cold working such as bending.

Working XAR

Due to the composition of the wear-resistant steels, machining these metallic microstructures is always subject to difficult conditions. When drilling XAR 400 or 450 a first-class HSS-E spiral drill bit must be used, which has a cobalt alloy. Carbide drill bits are necessary for XAR 500, 550 and 600. Only XAR 300 can be machined with conventional drilling tools. In all cases, however, it is necessary to avoid vibrations, the workpieces must always be securely clamped and short drill bits must be used.

Thermal cutting is also possible in principle with XAR steels. Oxyacetylene torches, laser cutting and plasma cutting are possible methods. It should be noted that with these cutting methods, extremely high temperature occurs for a short period and results in expansion of the cutting edge. The highest cutting speeds are achieved with plasma cutting. However, cutting with a laser beam is becoming increasingly popular. Sheet and plate thicknesses up to 20mm can be cut at high cutting speed with low workpiece distortion and minimum heating of the cutting edge.

XAR – steels are also characterised by good weldability. All standard welding procedures can be used. Arc welding and MAG welding are particularly good methods.