This work is focused on the analysis of the influence of welding on the properties and microstructure of the AISI316L stainless steel tube produced by 3D printing, specifically the SLM (Selective Laser Melting) method. Both non-destructive and destructive tests, including metallographic and fractographic analyses, were performed within the experiment. Microstructure analysis shows that the initial texture of the 3D print disappears toward the fuse boundary. It is evident that high temperature during welding has a positive effect on microstructure. Material failure occurred in the base material near the heat affected zone (HAZ). The results obtained show the fundamental influence of SLM technology in terms of material defects, on the properties of welded joints.

This work is focused on the influence of heat treatment of a part produced by the SLM (selective laser melting) method of stainless steel, 316L. Two heat treatment regimens were tested and compared with the state without heat treatment. Subsequently, TIG (tungsten inert gas) welds were created on the base materials processed in this way. All welds were subjected to mechanical tests and microstructural analysis. The tensile test was performed both for the welded joint and for the base material in the transverse and longitudinal directions. The tensile strength values of the samples with the welded joint were compared with the values required for the base material, 316L forged steel (1.4404). Microstructural analysis revealed significant differences between samples with and without heat treatment. The results of these tests are supported by SEM analysis. EDAX (energy dispersive analysis of X-rays) semiquantitative analysis confirmed the presence of ultra-fine pores in the structure. The results of mechanical tests show that the solution annealing at 1040 °C for 0.5 h gives better results than the same heat treatment with a duration of 2 h.

The MM Science Journal, published since 2008, is a world respected scientific journal. The journal, published in English, is double peer reviewed and competitive in distributing knowledge among domestic and international academics and professionals. Full texts are available on-line on the journal...

This paper deals with the evaluation of the surface of structural steel whose samples were deliberately contaminated with transparent spray primer, adhesive label glue, and welding sprays prior to hot-dip galvanizing. The galvanized samples were studied by optical microscopy, GDOES, adhesion tests, and condensation humidity tests. The effect of surface contamination on the quality of the zinc coating was found to be significant. In some cases, the zinc coating is damaged (after contamination with welding sprays), in others, it is completely absent (after contamination with spray primer or adhesive label glue).

Residual stress occurs in many machined components and parts. Over time, several methods have been developed for the investigation of residual stress in the material - destructive and non-destructive. This article deals with the evaluation and comparison of residual stress in the material when machining steel C45 and 11CrMo9-10, when the tool enters into the cut and stands out in conditions of an interrupted cut. A non-destructive method, based on X-Ray diffraction, was applied to evaluate the residual stress. The points were measured on the last machined slat by using interrupted cut simulator. An irregular interrupted cut was achieved by gradually machining 4, 3, 2 and 1 slat. The experiments were realized in co-operation with the Faculty of Mechanical Engineering, VSB - Technical University of Ostrava, Czech Republic and the Faculty of Mechanical Engineering, the University of Zilina, Slovakia.