Mag Welding of High-Strength Civil Constructions

There is an increasing interest in new, high-strength steel grades in civil constructions. They can be used on various truss elements such as truss nodes and other types of lightweight building structures. Steels for building structures should be characterized by high tensile strength and good yield strength. Joints made of high-strength steels (AHSS) are difficult to weld and do not guarantee comparable mechanical properties. The aim of this work is to find the right method of MAG welding constructions made of DOCOL 1300M steel, which allows obtaining quality joints without defects and with good mechanical properties. DOCOL 1300M is a new construction material with very high strength, but it still poses welding problems. For various filler materials the influence of different welding parameters, such as, electrode wires, shielding gases, the role of preheating and the temperature of the inter-fluid layers on the correctness of the MAG joint with a thickness of 4 mm was analyzed. Results show that a mandatory 100 ℃ preheating and an interpass temperature of no more than 170 ℃ are required to obtain a correct 4 mm DOCOL 1300M joint.