Novel filler material for repair of high-performance steel tools by laser deposition weldingTuesday (27.09.2016) 17:30 - 17:45 Part of:
The increasing processing of high-strength alloys and composites in automotive industry and mechanical engineering requires robust, high-performance tools. In order to extend the service lifetime of the highly loaded tool components, repair welding provides a cost-efficient and resource-conserving alternative compared to a continuous acquisition of new tool parts. Especially for complex profiles (e.g. mold inserts, nozzles, punching plates) and localized geometries, laser deposition welding using thin filler wires is a favorable method to rebuild worn areas as well as damaged edges and surfaces. For this use innovative filler materials are continuously required.
The presented work describes the implementation of the high-strength Fe85Cr4Mo8V2C1 (wt%) cast alloy  as novel filler metal for laser repair welding of high-performance steels applied for e.g. sheet-bending or injection molding tools. This iron-based cast alloy exhibits high macrohardness (≥ 59 HRC), excellent compressive strength (up to 5500 MPa) and high wear resistance . After the development of a suitable processing technology to fabricate filler wires with diameters down to 0.6 mm, the laser welding process for different wire diameters was adjusted to transfer the excellent properties of the FeCrMoVC alloy on the base material. Therefore, the correlation between laser process parameters (e.g. pulse duration, laser power) and the resulting deposition microstructure was investigated. Furthermore, wear tests were performed on the surface layer. By comprehensive welding tests with competing welding materials, a lower susceptibility to cracking and a higher hardness as well as an enhanced wear resistance of the Fe85Cr4Mo8V2C1 deposition layers could be confirmed.
Altogether, by applying a suitable combination of laser parameters for processing of Fe85Cr4Mo8V2C1 a tailored multi-phase microstructure can be formed resulting in high hardness and excellent tribological properties of the generated deposition layers. This offers a wide field of application for the presented alloy as filler material in the high-performance tool manufacturing.