Metal injection molding technology is commonly used in production of small and very complex parts. Residual porosity is unavoidable characteristic of P/M parts, affecting their final properties. During injection molding phase powder-binder separation can occur, causing green density variation through cross section of the part. This behaviour is particularly pronounced as complexity of the parts increases. As a consequence, zones with different density and residual porosity can be seen after sintering. In this regard, porosity and hardness distribution of the sintered ring-shaped part is analysed and presented in the paper.

The volumetric flow rate (injection velocity) and the holding pressure are metal injection molding (MIM) parameters that have a strong influence on the green parts density and density homogeneity, but their effect on sintered dimensions after sintering is still to a large extent unexplored. To reveal the relationship between the injection molding parameters and sintered dimensions, ring-shaped components were injection molded by using different values of injection velocities in combination with a rump-down and rumpup holding pressure profile. Afterwards, the green components were catalytically debound and sintered in the nitrogen (N2) atmosphere. Finally, the component dimensions: the height, inner and outer diameter were measured by using a coordinate measuring machine. The ready-to-mold granules Catamold 310N made of heat resistant stainless steel X40CrNiSi 25-20 (according to the EN standard) powder and polyacetal based binder were used. The results showed that the interaction between the injection velocity and the holding pressure profile can be used to systematically adjust shrinkage after sintering. This approach is based on the dependence of the binder crystallization temperature on pressure, when the powder/binder proportion changes with the injection velocity.

Metallurgical changes in weld nugget and heat affected zone (HAZ) during resistance spot welding of low carbon steel sheets is very important factor that determines final mechanical properties of welded joint. Thus, effect of spot welding parameters (current, welding time, holding time) on the mechanical and microstructural properties of weld nugget and heat affected zone were analysed in this work. Hardness was measured using Vickers method, while results were presented in the form of hardness distribution over a cross section of weld nugget and HAZ, for different welding parameters. It was observed that hardness in heat affected zone and melting zone is very dependent on welding parameters. Also, tensile tests showed that strength of the joint is very susceptible to welding parameters and thickness of the parent material. Microstructural changes in the weld nugget zone and heat affected zone were examined and analysed for some specific samples.

Influence of cooling fluid application on the tool wear, during longitudinal turning of hardened chrome nickel steel, on the basis of experimental investigations is presented in this paper. Cutting tool wear investigation through comparation dry machining and machining by cooling fluid application, for the same other machining conditions, are conducted. Tool wear size, tool wear shape and cutting tool life are taken into account by cutting tool wear investigation. Analysis of experimental results showed inverse proportion between coolig fluid application and flank wear size, as well as significance of influence on tool wear and its characteristics, via the flank wear shape. Also, analysis of experimental results showed significance of influence coolig fluid application on increase of cutting tool life.