Fabrication of Hardox 450 wear plate

Hardox steel is the most popular wearing plate known for its hardness, toughness, and abrasion resistance. 

1. Introduction

Hardox steel offers high performance in aggressive applications and wear environments meaning that it is ideal for a variety of uses that other grades of steel simply cannot perform. This is due to Hardox’s ultra-hard surface, and high level of toughness of the material composition.

Exceptional weldability is also synonymous with Hardox. Welding these metals to any type of weldable steel can be undertaken using any conventional method.

2. Hardox Fabrication
  • Cutting

Figure 1 Hardox Cutting

Hardox steel grades are suitable for all thermal cutting methods, including oxy-fuel cutting, plasma cutting and laser cutting. In some grades of hardox, preheating or post heating might be required in order to prevent cracking after cutting. Moreover, to overcome softening, submerged cutting is advised.

  • Bending

Figure 2 Hardox Bending

Metal Bending of high strength steel sheet and plate rarely proves to be difficult, however, there are certain parameters that must be considered.

    • Check the rolling direction of the plate. If possible, orient the rolling direction perpendicular to the bend line. The plate can often be bent tighter this way.
    • Check the surface quality of the plate. Uneven surfaces or impurities on the surface may affect bendability as it can cause of fractures
    • Grind the thermal cut and sheared edges.
    • The bending tools should be harder than the work piece for the longevity of the tool life.
    • Avoid re bending to correct the profile angle. Bending the same place significantly reduces the bendability
    • It is not possible accurately predict the spring back of a material when bending, since this depends to multiple factors. That is why trial bending is recommended.
    • The strong force applied to the high-strength steel plate can lead to cracks on the surface, therefore, it is important to ensure the bending radius is adequately large based on the work piece thickness.
  • Welding

Figure 3 Hardox Welding

For a high-quality welding, clean the weld area to remove dust, oil, corrosion or any impurities prior to welding. In addition to good welding hygiene, make especially sure you consider the following aspects;

    • Preheating

It is essential to follow the recommended minimum preheating temperature as well as the procedure for obtaining and measuring the temperature around the joint to avoid hydrogen cracking.

    • Heat input

Various welding processes have different thermal efficiency. Excessive heat input increases the width of the heat affected zone impairing the mechanical properties and the wear resistance. Welding with low heat input provides major benefits.

    • Weld sequence

Before tack welding, it is essential to maintain a root opening not more than 3 mm. A uniform gap size along the joint is desired. Moreover, it is recommended to avoid weld start and weld stops in highly stressed areas.

    • Welding Consumables

Unalloyed and low-alloyed consumables with a maximum yield strength of 500 MPa are generally recommended for Hardox steel. Low-alloyed consumables result in higher hardness of the work piece which can reduce the wear rate of the weld metal.

3. Advantages of Hardox Steels?
  • Durability

Hardox Steel exhibits outstanding hardness and toughness, enduring extreme pressure in heavy industrial environments. Thanks to its durability, it outperforms carbon steel in impact absorption and withstanding wear and abrasion without permanent deformation.

  • Precision

Hardox Steel retains its shape even after getting exposed to harsh environments. It provides predictable and reliable performance while facilitating severely tight tolerances for thickness, flatness.

  • Fabrication

Hardox wear plate has a slightly different nature of metal fabrication. Drilling, countersinking, tapping, turning, and milling is performed with high-speed steel tools. The uniform properties, close thickness tolerances and smooth surface make Hardox® wear plate well suited to free bending and roll-forming. Hardox wear plate has great weldability to any type of weldable steel. Flatness and narrow thickness tolerances make automatic welding easy, and shorten the time for fit-up and tacking.

  • Longevity

Hardox steel is a more expensive material compared to the carbon steel but when you take their longevity into account, it is much more cost effective than mild steel.

  • Strength to Weight Ratio

Hardox steel offers a very high strength to weight ratio which essential for application where the weight of the material significantly contributes to the financial feasibility of the end product. Hardox wear plate cuts down on weight and extends the service life of steel structures in comparison to mild steel.

  • Versatility

The variety of dimensions makes Hardox wear plate suitable for a wide range of designs and products. The outstanding qualities of the flat Hardox wear plate grades are also available in the form of tubes and round bars.

  • Identification

All Hardox products are clearly marked. A unique identification number is stamped on the plates and sheets for traceability. Other data such as dimensions, serial number and heat number are printed before delivery. Knowing the product’s unique identity makes workshop processing and quality control much easier.

4. Conclusion

For cost-sensitive and performance-oriented wearing applications, Hardox is the ideal option for the fabricators. Hardox steel is frequently used in the plant engineering fabrications, bulk material handling structures and hoppers & chutes, Although primarily intended as a wear plate, the unique combination of hardness and toughness allows it to perform as a load-carrying part in applications such as buckets, dump bodies and containers. With Hardox steel, structures that are wear-resistant, strong and lightweight can be designed at the same time.

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