Use of a low transformation temperature effect for the targeted reduction of welding distortion in stainless chromium-nickel steel for an application in rail vehicle construction Nutzung eines Niedrigtransformationstemperatureffektes zur gezielten Reduzierung von Schweißverzug in korrosionsbeständigem Chrom-Nickel-Stahl für die Anwendung im Schienenfahrzeugbau

Abstract

Due to their low thermal conductivity and high thermal expansion, austenitic chromium-nickel steels have an increased tendency to distortion during welding. In industrial sectors such as rail vehicle construction, there is a high demand for geometrical precision that is not met by distorted components. Introducing a low transformation temperature (LTT) effect in the weld seam influences the stress distribution, which effects the formation of welding distortion. The low transformation temperature effect is achieved by in situ alloying using commercially available materials. The demonstrators made of stainless steel (X2CrNiN18-7/1.4318) were welded with a low-alloy filler metal G4Si1. The low transformation temperature effect is assessed by energy dispersive x-ray spectroscopy and hardness measurements. The effect on distortion was investigated by measuring the demonstrators with a coordinate measuring system and the results were compared with the reference stainless steel demonstrators with stainless filler metal. The alloying process resulted in a reduction of the alloy content to 14.4 m% chromium and 5 m% nickel and a medium-high hardness of 361 HV 0.2 to 383 HV 0.2. The low transformation temperature effect achieved leads to a significant reduction in welding distortion of up to 78 % compared to the similar reference demonstrators.