Mechanical and tribological characteristics of laser-deposited nickel-containing powders on chromium steels

This paper presents the results of a study of various processing modes during the laser surfacing process. Various grades of steel were used as samples, and the resulting coatings were based on two grades of powders. The microhardness values were obtained both for the main steel material and for the coatings obtained on the samples. The values of the friction coefficients of the coatings are obtained, on the basis of which the graphs of standard deviations are constructed. The results are summarized using graphs and figures.

Porosity in Medical Drills Caused by Fractured Carbides – A Review

Just as 10 years ago, an examination of drills used in human medicine revealed cracks in the microstructure which can be attributed to fractured carbides. The drills are made of corrosion-resistant chromium steels with special carbides which are of the composition (Cr,Fe)23C6 and (Cr,Fe)7C3 (e. g. material no. 1.4125 or 1.4112). The cracks occur in the coarser carbides during the forming of the drills. It was considered problematic that the cracks are filled with contaminants which cannot be fully removed in the cleaning process. One of the drills examined for this study also contained MnS inclusions which is consistent with a “rust and acidresistant steel / free-machining steel” (e. g. material no. 1.4005).