The Resistance to Wear and Thermal Cracking of Laser Surface Engineered P20 Steel

Abstract

This study reports the microstructure and surface properties of P20 steel processed by laser surface engineering (involving surface hardening and melting), which are carried out using a fiber laser with the maximum power of 2 kW. Ultrafine martensite laths with high boundary density are formed both in the laser surface hardened layer and in the melted layer. This dramatically improves the surface hardness of the P20 steel. However, the laser surface melted layer exhibits a relatively lower hardness than the laser surface hardened layer. It can be attributed to the remarkable autotempering effect and the vaporization of alloy elements in the melted layer. The wear resistance and thermal cracking resistance of the samples treated by laser surface engineering show a significant improvement compared with the as received material. The surface hardened layer exhibits superior wear and thermal cracking resistance due to its relatively high surface hardness and plastic deformation resistance, which can effectively suppress the formation of cracks during wear and thermal cracking tests.

Overview of Surface Modification Strategies for Improving the Properties of Metastable Austenitic Stainless Steels

“…Improved surface texture and roughness, increased hydrophobicity, enhanced biocompatibility [83] Medical implants, aerospace components, and other high-performance materials [84] High precision and accuracy, can create complex shapes and patterns [85] Limited to small areas, expensive [86] Laser surface hardening (LSH) Medical devices, electronics, and other highperformance materials [90] High precision and accuracy, can create complex patterns and textures [91] Limited to small areas, potential for material damage or surface roughening [92] Laser Shock Peening Laser shock peening (LSP) (Figure 7) is one of the common methods for improving the mechanical and surface properties of metals in industries. In this method, a laser is applied to the surface, and then residual stresses occur in the underlying layers, which improves mechanical properties such as fatigue, and some articles have even reported improvements in corrosion properties [93,94].…”

“…Fatigue fractography in air displayed transgranular fatigue fractures with flat facets, while specimens tested in H 2 S solution or gaseous hydrogen exhibited quasi-cleavage fractures associated with hydrogen-enhanced crack growth. The presence of distinct striations on the fracture surface of embrittled specimens indicated hydrogen-activated slip processes ahead of the crack front [86,175,176]. Table 6 summarizes the effect of different surface modification techniques on the improvement of fatigue life.…”

The effect of shot peening on the contact fatigue performance of C40 steel gears after laser surface melting

“…For instance, Gong et al [1] utilized a high-power laser beam to irradiate SS420 martensitic stainless steel, generating a hardened layer with a depth of nearly 1 mm and a hardness of 805 HV 0.2 . Zhao et al [2] observed that LSM treatment resulted in an ultrafine martensite microstructure and fundamentally improved wear resistance and hot crack resistance of P20 steel. Hashemi et al [3] applied LSM treatment to Al-Corare earth (Ce-La) alloys, achieving a refined and uniform microstructure and improved corrosion resistance.…”

Aplicación de láser a recubrimientos de proyección térmica base níquel, sobre acero al carbono

“…Las aplicaciones más comunes están asociadas a producir endurecimiento superficial, especialmente en el caso de materiales ferrosos (Sayed et al, 2017;Zhao et al, 2023), a generar recubrimientos a partir de la fusión de polvos , Lisiecki et al, 2019, Poloczek et al, 2020Rezayat, et al, 2023), lo que usualmente se conoce como laser cladding en inglés y a conseguir formar aleaciones y combinaciones diversas entre las nuevas superficies y los sustratos :, Jeyaprakash et al, 2019Kotarska et al, 2021) lo que comúnmente se denomina como laser alloying, en inglés.…”