Effect of Laser Traverse Speed during Laser Hardening on Hardness Distribution and Microstructure of Hot Work Tool Steel H11

• Main Authors: Hodek, J. (Author), Hradil, D. (Author), Koukolíková, M. (Author), Nový, Z. (Author), Szyszko, A. (Author)
• Format: Article
• Language: English
• Published: Jan-Evangelista-Purkyne-University 2023
• Subjects: Carbides; Computer software; EDS analysis; Energy dispersive spectroscopy; Energy dispersive spectroscopy analyse; Experimental materials; Hardened depth; Hardening; Hardness; Hardness distribution; Hardness drops; Heat affected zone; Heat-affected zones; Hot working; Hot-work tool steel; Initial state; Laser hardening; Microstructure; Numerical model; Numerical models; Scanning electron microscopy; Tool steel; Traverse speed
• Online Access: View Fulltext in Publisher

 The paper describes the effect of laser traverse speed during laser hardening on hardness and microstructure. The experimental material is hot work tool steel AISI H11 with samples sized 100×100×35 mm. The initial state of the material before laser hardening is quenched and tempered. The laser hardening temperature is constant at 1100 °C, selected laser traverse speed was 1, 2, 4, and 6 mm/s. A numerical simulation performed in DEFORM-3D software before the experiment showed tendencies of temperature displacement and expected course of hardness. Increasing traverse speed leads to decreased laser-hardened depth and decreased hardness drop in the heat-affected zone (HAZ). The experimental program confirmed the results of the numerical model. The differences in the microstructure were investigated by light (LM) and scanning electron microscopes (SEM), which revealed an evident difference between the surface area and the locality with the lowest hardness. Local differences from the perspective of presence of carbides were analysed by energy dispersive spectroscopy (EDS). This investigation was performed to optimize laser traverse speed to improve the subsurface hardness profile, which is essential for the lifetime and reliability of forging dies. © 2023 Manufacturing Technology. All rights reserved.