This paper explores a protective stellite coating on 1.4922 martensitic steel. Stellite coatings are often used to improve the properties of the part's surface. The microstructure of the sample was analysed and its hardness measured. Protective coatings enhance mechanical and corrosion properties of the substrate, and thus extend the life of the respective part. They can be created by galvanizing, ion implantation, thermal spraying, or by more recent methods, such as laser cladding, DED (directed energy deposition) and others. DED is one of the metal deposition processes that fall in the AM category (additive manufacturing). It was used to deposit the protective coating in the present study. DED is an evolving technology which is suitable not only for prototype development, but also for promising applications involving surface treatment and repairs of functional parts. DED uses a laser beam as a thermal source to melt powder which is blown concentrically with the laser beam and the protective gas. The unique advantage of this method is a very good cohesion and bonding between the substrate and the deposited layer with a smaller HAZ (heat-affected zone). It produces comparatively few inhomogeneities and defects, which makes it a promising technique for protective layer applications. Stellite was chosen as a protective coating material because this group of alloys exhibits excellent properties such as high wear resistance, abrasion resistance, superior corrosion resistance and erosion resistance. These are relevant in many industrial sectors, such as power generation, aerospace and others. Stellite 21 was used in the present study.

<p class="AMSmaintext"><span lang="EN-GB">Nitriding with subsequent heat treatment in combination with deep cryogenic treatment (DCT) produces nitrided layers with specific properties. Layers with unique properties result from the dissolution of subsurface layers of iron nitrides and subsequent nitrogen diffusion into the substrate during austenitisation. Fine precipitates of carbonitrides eventually form during DCT and tempering. Intermediate deep cryogenic treatment was performed between the quenching and tempering steps. This work is based on comparing nitrided layers obtained using conventional treatment parameters with nitrided layers from novel processes. The experimental material was DIN 1.3343 (Czech Standard 41 9830) high-speed steel. Several treatment methods were compared in terms of the resulting hardness and metallographic characteristics.</span></p><p> </p>

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One of the main advantages of additive manufacturing is the possibility of custom-made machine parts. Additive manufacturing enables the production of components with fine details that would be difficult to manufacture with conventional production. This, however, brings some difficulty in the case of the acquisition of conventional test specimens that might exceed the size of the product. Mechanical properties of the tested materials via standard and microtensile test specimens were analysed. The materials AlSi10Mg and MS1 in as-built (AB) and heat treated (HT) conditions were produced by laser powder bed fusion. The aim of the research is to observe the influence of parameters (sample size, direction of testing) on the resulting mechanical properties. Mechanical testing is supported by metallographic and fractographic analysis.