Laser welding of 18ct gold and stainless steel

Abstract

In jewelry manufacturing, joining dissimilar materials is usually achieved by soldering, but this technique has several disadvantages as compared for example with laser welding. However, laser welding of metals with significantly different physical properties such as gold and steel can result in the formation of new intermediate phases affecting the mechanical properties and the sensitivity to cracking of the joint. Also, chemical composition differences can induce strong solute-driven Marangoni flow.In the present study, a thorough analysis of the gold-steel system has been conducted, partially based on the binary Au-Fe. This includes thermodynamics calculations of metastable phases, differential thermal analysis (DTA) and directional Bridgman solidification. Based on these results, a new and simple method for producing gold-steel laser welds with suitable properties has been devised.In jewelry manufacturing, joining dissimilar materials is usually achieved by soldering, but this technique has several disadvantages as compared for example with laser welding. However, laser welding of metals with significantly different physical properties such as gold and steel can result in the formation of new intermediate phases affecting the mechanical properties and the sensitivity to cracking of the joint. Also, chemical composition differences can induce strong solute-driven Marangoni flow.In the present study, a thorough analysis of the gold-steel system has been conducted, partially based on the binary Au-Fe. This includes thermodynamics calculations of metastable phases, differential thermal analysis (DTA) and directional Bridgman solidification. Based on these results, a new and simple method for producing gold-steel laser welds with suitable properties has been devised.