Krzysztof Żaba - Academia.edu (original) (raw)

Uploads

Papers by Krzysztof Żaba

Materials

The paper presents the results of an analysis of the process of drawing AISI 321 stainless steel ... more The paper presents the results of an analysis of the process of drawing AISI 321 stainless steel thin-walled seamless tubes on a floating plug. The influence of the geometry of dies and plugs, drawing velocity, and lubricants on the possibility of carrying out the pipe drawing process without a loss of strength of the lubricating film and, consequently, disturbance of the forming process and tube cracking, and also on the temperature in the drawing process, the mechanical properties of the tubes drawn, and the microhardness and roughness of the inner and outer surface of the tubes was investigated. The parameters of the drawing tools used were as follows: angle of drawing dies α = 16° and floating plugs with angles of inclination of the conical part of the plug β = 11.5°, 13°, and 14°. The drawing dies and floating plugs were made of G10 sintered carbide. Drawing speed was varied over the range 1 to 10 m/min. The study used several lubricants. Tubes with dimensions (outer diameter D...

Archives of Foundry Engineering, 2010

The results of assessments of the welded steel tubes with the Al-Si coating intended for the moto... more The results of assessments of the welded steel tubes with the Al-Si coating intended for the motorization needs – are presented in the paper. The measurement of mechanical properties, tube diameters and thickness, internal flash heights as well as the alternative assessment of the weld quality were performed. The obtained results are presented by means of tools available in the Statistica program and macroscopic observations.

Archives of Metallurgy and Materials, 2010

Archives of Metallurgy and Materials, 2011

Wear Resistance of Aluminized Steel Plates The results of the abrasion resistance measurements of... more Wear Resistance of Aluminized Steel Plates The results of the abrasion resistance measurements of aluminized steel strips are presented in the hereby paper. Steel strips of DX52D+AS120 grade, before and after a heat treatment at temperatures of 200-1000°C for 1 - 5760 minutes, were tested. Tests of the abrasion resistance were carried on in a specially built device: rotating disk - sample performing a plane-rotary motion, with an application of a lubricating medium. Examinations of the abrasion resistance were also performed by means of the block-on-ring tester. Estimations of a coating mass loss, roughness and thickness changes were carried on. The obtained results are illustrated by diagrams and macro- and micro-observations. Phase analysis investigations were also performed on samples selected after the abrasibility testing. The range of the heat treatment parameters - after which the Al-Si coating increased its abrasion resistance - was estimated.

The paper presents a solution to the problem of multi-process designing forming processes technol... more The paper presents a solution to the problem of multi-process designing forming processes technology, particularly in the selection of tools in situations where some of these tools are available, but should be verified their usefulness, and missing should be designed. An example would be drawing processes of small wires on the multi-drawing machines. One set of tools (dies) for one, the simplest machine can count up about twenty pieces. Number of dies in the average steeldrawing can range from a few to several thousand units.

Advances in Mechanical and Materials Engineering

This article assesses the tribological performance of new composite tool sets for stamping dies. ... more This article assesses the tribological performance of new composite tool sets for stamping dies. Four sets of composite countersamples were tested. These consisted of polyurethane resin with mineral filler (base variant) and modified with aluminium powder (10wt%) and roving fabric (5wt%). Strip samples for the strip drawing tests were cut from AMS5599 (Inconel 625) corrosion-resistant nickel alloy, AMS5510 (321) corrosion and heat-resistant steel and AMS6061-T4 heat treatable aluminium alloy sheet metals. The influence of the type of sample material on the coefficient of friction (COF) was observed. The smallest values of the COF over the entire range of clamping force values used on AMS5599 and AMS5510 sheets were observed during tests with countersamples made of the base variant of composite. When testing the AMS6061-T4 aluminium alloy sheet, the countersamples modified with roving fabric provided the lowest value of COF, which stabilised at a value of about 0.197 as pressure was ...