Diffusible Hydrogen Concentration in Drawn Arc Stud Weldments

Abstract

AbstractThe mechanized drawn arc stud welding is a well established process in steel construction for joining technique for pin shaped elements, especially in the field of composite constructions. Therefore, the process is commonly applied on construction sites under different climatic conditions. The process is characterized by its relatively high heat input due to high current and a weld pool protection that is realized by a ceramic ferrule holding the metal vapor as a shielding gas. However, turbulences inside the ferrule during welding cause contaminations with atmospheric humidity. Furthermore, a high cooling rate results in a strongly hardened heat‐affected zone and a considerable residual stress state in the parent material. Thus, there is a risk of hydrogen assisted cold cracking, especially for stud welding on high strength steels or under adverse welding conditions. The knowledge about the expectable hydrogen concentration is fundamental for evaluating the cold cracking susceptibility. In this study, the effect storage conditions of the consumables and atmospheric conditions are investigated and evaluated regarding their effect on the resulting hydrogen concentration in weld metal. For determination of diffusible hydrogen concentration in stud weld metal a method based on the carrier gas hot extraction is used.