The Effects of Laser Surface Hardening on Microstructural Characteristics and Wear Resistance of AISI H11 Hot Work Tool Steel

Abstract

The present study deals with the effects of laser surface treatment on microstructure evolution and wear resistance of AISI H11 hot work tool steel in quenched and tempered condition. The most upper laser-affected zone is characterized by re-melted microstructure consisting of dendrite cells with fresh non-tempered martensite, retained austenite and inter-dendritic carbidic network. The subsolidus microstructure just beneath the re-melted zone represents the most laser surface hardened zone consisting of fresh non-tempered martensite with fine and coarse carbides as a result of overheating the original QT substrate microstructure. The highest microhardness values in the range from 775 to 857 HV were measured for the LSH microstructure and the most softened microstructure exhibited the minimum hardness of 530 HV. The laser treated samples showed the improvement of their surface wear resistance by 35%.

Laboratory Analysis of Hardfacing Material Applied by Plasma and Tig Welding

“…Compared to laser and electron devices, plasma welding equipment is significantly cheaper. The main advantages of plasma welding are small deformations, good weld appearance, welding of refractory metals and the possibility of welding very thin materials [Sebek 2017]. The disadvantages are higher equipment costs compared to TIG welding equipment and higher qualification requirements for welders.…”

“…TIG welding is a related process. This method is a welding process that uses the heat released from the ignited arc maintained between the non-fusible electrode (tungsten) and the workpiece [Sugar 2009]. Creating a suitable structure on the surface of the exposed surfaces of the tool should ensure that the tool does not succumb to early wear and thus rapid decommissioning.…”

Analysis of Hard Facing Material Designed for Application on the Forestry Tools

“…According to [3,10,12], the weld deposit with WC has a typical composition -around 60% particles of WC and the remainder is low-carbon steel. It is characterized by excellent resistance to abrasive and erosive wear, but the weld deposit tends to crack during the hard facing.…”

Impact of Laser Machining on the Structure and Properties of Tool Steels

“…Laser technologies associated with remelting require a higher density of radiation power (10 4 -10 10 W / cm 2 ) than the modification of a surface layer without remelting and the time of interaction of the beam with the material of 10 -1 -10 -9 s. High power lasers Nd: YAG and CO 2 with a continuous and pulse operation are mainly used [6]. The modification of a surface layer using laser technology is based on the process of rapid remelting and crystallization of a thin layer at the surface of the material [9,10].…”