Repair of Injection Moulds by Welding for Pre-Hardened 1.2714 Hh Steel

Abstract

The welding of injection molds by laser deposition is a very common procedure in recent years in the maintenance departments of plastic injection factories. This is due to the advantages it has compared to traditional welding methods, namely the speed of the laser welding process, a lower deposition of the metal composition in the repaired area (small volume of deposited material), as well as the accuracy of the deposition on the surface the piece. But, in addition to these advantages, there are also a number of disadvantages compared to classic welding. As the main disadvantage in the case of laser welding of injection molds, the maximum weldable thickness is limited. This paper presents an analysis of weld quality and mechanical fracture of laser deposition according to deposition types and welding techniques of 1.2714 HH pre-hardened steel. The material 1.2714 HH is a basic material used in recent years in the production of molds due to its hardness, namely 40-45 HRC units. In laser welding, different welding strings are possible, each influencing the laser deposition preparation process, the possibility of performing the deposition in the respective area, as well as obtaining a desired mechanical stability. Starting from these considerations, a number of factors will be analyzed using 1.2714HH steel samples: welding strings, welding strings depth, filler material and welding parameters. V – notches were made and filled for welded samples with laser welding deposits. V – notches were made and filled for welded samples with laser welding deposits.