Effect of TiN on toughness of high strength wear-resistant steel and its mechanism analysis

    
    The high strength wear-resistant steels with excellent wear resistance have been widely applied in mining machinery, mining tools and metal cutting tools, etc. To increase the toughness of high strength wear-resistant steel, titanium nitride (TiN) can be used as a surface treatment to increase the fatigue strength and wear resistance. In this article, the effects of TiN on the toughness of high strength wear-resistant steel and its mechanisms are discussed.
    
    1. Effect of TiN on Wear-Resistant Steel Toughness
    
    Titanium nitride (TiN) has been used to increase the toughness high strength wear-resistant steel. TiN is produced by plasma-assisted physical vapor deposition (P-PVD) deposition process, which is applied as a thin surface layer onto the substrate. TiN provides good lubrication and wear resistant properties, which improves the life and performance of materials subjected to friction wear, such as high strength wear-resistant steel. It is worth noting that TiN increases wear resistance without affecting the other properties such as strength and hardness, which makes it a suitable surface treatment to increase the toughness.
    
    When applied to steel substrates, the TiN surface layer affects the tribological properties of the surface, such as improving the wear resistance. The wear resistance of the TiN layer is improved due to the low coefficient of friction and the self-lubricating properties of the TiN coatings. In addition, the TiN layer also has a damping effect on crack propagation, which decreases the amplify the effects of cyclic loads on the steel. This reduces the rate of fatigue and increases the fatigue strength of the material. Furthermore, fracture toughness of high strength wear-resistant steel is also improved by TiN surface treatment due to the nanostructured interface that is created between the TiN layer and the steel surface.
    
    2. Mechanism of Toughness Improvement
    
    The mechanism of toughness improvement of high strength wear-resistant steel due to TiN surface treatment can be understood by looking at the microscopic level of the surface. Titanium nitride (TiN) layer has a nanostructured interface that is formed between the TiN layer and the substrate surface. The increased surface roughness of the steel due to the presence of the TiN layer improves the interaction between substrates and the environment. The TiN layer also has a damping effect on the propagation of cracks, which reduces the effect of cyclic loading on the steel.
    
    In addition, the TiN layer is reinforced by a strong bond between the TiN and steel. This strong adhesion prevents delamination of the layers, which improves the adhesion and wear resistance of the steel. Furthermore, the lubricant properties of the TiN layer reduce the friction between the steel surface layers and the environment, which further improves the fatigue strength and wear resistance of the steel. This improvement in fatigue strength and wear resistance translates to a higher toughness of the high strength wear-resistant steel.
    
    3. Conclusion
    
    In summary, titanium nitride (TiN) surface treatment has been demonstrated to increase the toughness of high strength wear-resistant steel due to its lubricant properties and self-lubricating properties. The nanostructured interface between the TiN and the steel also enhances the adhesion and wear resistance of the steel. The strong bond between the titanium nitride and the steel also helps to prevent the delamination of the layers, which further increases the wear resistance of the steel. As such, titanium nitride offers an effective surface treatment for improving the toughness of high strength wear-resistant steel.

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