Improving the Quality of the Friction Welding Process of Steel Components

The aim of the study was to implement an integrally configured method of quality control of frictional welding of piston forgings intended for Diesel Man trucks. The use of the method (consisting of the 5W2H method, the Ishikawa diagram and the ABCD - Suzuki method) would contribute to the detection of the causes of non-compliance and consequently to the elimination of non-compliant products. Steel pistons have become the subject of research due to significant problems with maintaining their expected level of quality after the introduced structural and technological changes. The proposed method has helped to identify the root cause of non-compliance. It was: incorrect design of the combustion chamber in terms of diameter and depth. The study shows that it is advisable to use an integrated approach to finding the causes of quality problems on the example of the friction welding process. This was a new solution for the company, as no in-depth analyses of quality problems using a sequence of quality management techniques have been carried out so far.

A Method to Predict Temperature Fields During Frictional Welding by Introducing the Heat Input Coefficient and the Heat Input Surface Transfer

A method to predict the time evolution of temperature fields during the frictional welding of stainless steel bars is proposed. The features of the proposed method are the introduction of the heat input coefficient and the transfer of the heat generating plane proportional to the shortening of the work. The heat input coefficient is the multiplication of the heat conversion efficiency of mechanical work and the dynamic friction coefficient. The values of heat input coefficient are decided experimentally. The frictional welding experiments were conducted for the austenitic stainless steel bars with welding conditions. The measured temperature at several points on the surface of the stator agrees with the calculated temperature. Despite the welding conditions, the heat input coefficient shows little difference. Therefore, using the proposed method, by deducing the heat input coefficient from several experiments, the time evolution of temperature fields for work with other diameters might be able to be predicted precisely.