Jerzy Winczek

Analysis of thermomechanical states in single-pass GMAW surfaced steel element

In the paper the model of temperature field, phase changes and stress states calculation during single-pass arc weld surfacing have been presented. In temperature field solution the temperature changes caused by the heat of weld and by electric arc have been taken into consideration. Kinetics of phase changes during heating is limited by temperature values at the beginning and at the end of austenitic transformation, while progress of phase transformations during cooling has been determined on the basis of time-temperature-transformation (TTT) - welding diagram. The analysis of stress state has been presented for S235 steel flat assuming planar section hypothesis and using integral equations of stress equilibrium. It has enabled a clear interpretation of influence of temperature field and phase transformation on stresses caused by surfacing using Gas Metal Arc Welding (GMAW) method.

The Effect of Additional Shielding Gas on Properties and Erosion Resistance of High Chromium Hardfacing

The wear-resistant layers of the chromium cast iron structure can be made by traditional casting methods as well as by the use of welding methods. The use of hardfacing allows for the creation of a protective layer on existing elements, often in the place of their use. Especially the use of hardfacing using self-shielding core wires allows obtaining layers with the desired properties. The paper presents the results of research on high-chromium hardfacings made in self-protective technology as well as using shielding gas. It was noted that the addition of shielding gas has a positive effect on the stability of the surfacing process and on the appearance of hardfaced surfaces. The hardness tests and erosive wear tests carried out also indicate a positive effect of shielding gas on the properties of hardfacings.