The degradation mechanisms of machine parts are well-known facts, usually resulting in replacement of components. However, in some cases, for instance, parts for large ship engines, repair will often seem more attractive. Time-wise, the vessel’s down-time will be reduced and the investment will be lower. This paper describes repair work performed on valve stems from a 52-year-old ship engine. Due to this long time in operation, the stems were damaged by wear and were no longer functional. The requirements for the stems were scarcely documented stating only a few specific requirements; therefore a short study of the possibilities concerning rebuild material and application method was initiated. This paper illuminates the manufacturing process used; twin wire arc spraying with Monel as the rebuild material. Monel is chosen to meet the requirements for hardness and the subsequent high precision machining. In addition, the mechanical and metallurgical properties of the rebuild coating are examined in regard to adhesion, microstructure and hardness to interpret and support the functionality.

The potential of additive manufacturing has reached a point where the techniques are considered highly relevant for production purposes. In general, the manufacturing industry greets the new approach with enthusiasm, as it offers innovative designs and potentially reduced production costs. However, questions arise concerning the durability of additively manufactured components. This paper describes industrial trials with laser cladding and precipitation hardening heat treatment of thin-walled structures with the 17-4 PH stainless steel alloy. Due to the great relevance of the AM production methods for the aviation industry, the mechanical strength of the alloy given by the MMPDS document is used as a baseline. In order to improve the properties of the produced specimens, hot isostatic pressing was applied. The results show that a post processing treatment consisting of a HIP cycle and a conventional precipitation hardening, vastly improves the mechanical strength and elongation values of printed specimens, causing them to exceed the specified values.

This paper discusses some of the practical uses of laser cladding and laser fusing in part manufacturing and component repair. It provides an overview of both processes and the types of surfaces they can produce. It presents application examples for each process and interprets corrosion and wear properties of the respective coatings. It also discusses the benefits of repair friendly surfaces.

This work evaluates the potential of using twin wire arc (TWA) spraying as an alternative to metal active gas (MAG) overlay welding in the production of agricultural equipment. Corthal 65, a flux-cored wire electrode, was applied to different types of steel using each method. Some of the samples were tested in a lab and some were evaluated under actual use in the form of plow tips and harrow teeth. SEM and EDX analysis revealed the presence of Cr, Nb, and W carbides and Al-rich oxides in the hardfacing layer. Field-tested samples were assessed based on porosity and hardness, providing a measure of abrasive wear and impact resistance. The TWA-sprayed coatings performed as well as the MAG overlay welds, but their potential to improve productivity and reduce costs make them the more appealing option.

Energy obtained by wind turbines can be foreseen to constitute a significant part of the future energy sources. A major challenge is however the large variation over time in wind energy production. Energy conversion from electricity to storable energy is therefore a key technology to master, and it is therefore important to develop compact, reliable, cheap and energy efficient equipment for this. An obvious solution is production of hydrogen based on water alkaline electrolysis. In the work presented the atmospheric plasma spraying (APS) of Raney nickel (50/50 Ni/Al) was used to develop electrodes with a large specific surface area as well as a considerable energy efficiency in high temperature water alkaline electrolysis. The coating process was analyzed using a plume analyzer as the primary tool and the coating properties were analyzed by a combination of bonding strength measurement, optical (OM) and scanning electron microscopy (SEM) as well as testing of the activated electrodes in a laboratory electrolysis cell. The results of the spraying process analysis are reported together with the electrochemical properties of the activated electrodes, and with regard to energy efficiency very positive results are obtained for the measured overvoltage.