Ternary protective gas mixt. for MIG welding of carbon steels - contains argon, carbon di:oxide and oxygen, and minimises the formation of noxious gases entering the environment

摘要

The gas contains by vol. 8-12% CO2, 3-5% oxygen, and the remainder of 83-89% is argon. The pref. gas mixt. contains 10% CO2, 4% oxygen, and 86% argon. This gas mixt. is pref. used as the inert gas in the welding of carbon steels by either the "Pulsarc" (RTM), or the "Sprayarc" (RTM) processes. The ternary gas mixt. provides excellent welds, but also reduces atmos. pollution due to CO and NOx formed by the electric arc. Although CO2 and gas mixts. contg. CO2 and argon have been widely used in the past as protective gases during welding, they produce undesirably high concns. of CO and NOx in the environment adjacent to the welding zone. The invention avoids this.