Effect of Preheating on Microstructure and Properties of K360 Wear-Resistant Steel Surfacing Layer

Wear-resistant steels have been widely used in various applications in industry due to their excellent wear resistance and strength, particularly the K360 steel which is highly resistant to wear, corrosion and impact. The performance of the K360 wear-resistant steel is often improved by applying preheat treatment prior to the hard facing process, which can helps to improve the physical and mechanical properties of the hard facing layer. This article will discuss the effects of preheat on the microstructure and properties of the K360 wear-resistant steel surfacing layer.
    
Microstructural Characteristics of K360 Wear-Resistant Steel
K360 wear-resistant steel is a high alloy wear-resistant steel composed of 1 to 4.5% C, Cr and W carbides, 16 to 20% Cr, 0.6 to 1.2% Si and 0.3 to 0.8% V. It has a high carbon content and complex composition, which results in a high hardness and excellent wear and corrosion resistance. The microstructure of K360 steel consists of austenite matrix and hard alloyed MC particles. The austenite matrix provides strength and toughness properties, while the MC particles provide superior wear and impact resistance.
    
Effect of Preheating on Microstructure
Preheating of K360 wear-resistant steel prior to hard facing improves the diffuse boundary of hard alloy particles. It also increases the amount of austenite matrix present in the microstructure, resulting in uniform microstructures with less porosity and cracks and therefore, better mechanical properties of the hard facing layer.
    
Preheat also helps to reduce residual stresses and minimize the risk of the part cracking during hard facing. Furthermore, preheat increases the transformation temperature of austenite to martensite and enhances the diffusion speed of alloying elements, resulting in a homogeneous distribution of alloy elements in the hard facing layer.
    
Effect of Preheating on Mechanical Properties
Preheat increases the hardness and wear resistance of the K360 wear-resistant steel hard facing layer. The wear resistance is further improved due to an increase in the hard alloy phase content and a homogeneous distributed of the alloy elements, resulting in superior mechanical properties of the K360 wear-resistant steel layer.
    
Moreover, preheat treatment helps to reduce the risk of part deformation and cracking during welding, which results in enhanced surface quality and fatigue strength.
    
Conclusion
In conclusion, preheat improves the microstructure and mechanical properties of the K360 wear-resistant steel hard facing layer. It increases the hardness, wear and fatigue resistance of the part and minimizes the risk of deformation and cracking during welding. It is therefore recommended to preheat K360 wear-resistant steel prior to hard facing for improved mechanical properties.

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