Features and challenges of manual arc welding of austenitic corrosion-resistant nitrogen-containing steels

The challenges of manual arc welding of austenitic high-nitrogen corrosion-resistant steels with a nitrogen content of up to 1% (wt.) are considered. Studies of the technological weldability of nitrogen-containing steels 04Kh20N6G11M2AFB and 05Kh16G11ASND developed in Russia have shown the possibility of obtaining high-quality defect-free corrosion-resistant steels with a very low level of magnetic permeability of welded joints during manual arc welding with coated domestic electrodes O3L-9A and foreign-made electrodes ESAB OK 69.25. A new electrode EA-868 OP for manual arc welding is proposed, providing the required level of quality and properties of welded joints. The metal of various zones of welded joints does not have ferromagnetic properties. Magnetic permeability does not exceed 1.002 Gs/Oe. When testing samples in a 3.5 % NaCl solution for 1,000 hours, it was found that the corrosion properties of welded joints correspond to the indicators typical of corrosion-resistant steels when used in sea water. Welding modes and recommendations for limiting weld heat input are given, when performing which all welded joints do not have pores. It was found that when welding in the weld metal, the nitrogen content decreases to 0.35–0.42 % (wt.), which leads to a decrease in their strength properties by 30–39 %, therefore, equal strength of welded joints can be achieved by a corresponding increase in the cross-section of the welds. The obtained results provide technologists with the opportunity to select the electrode brand among the studied welding materials depending on the design requirements (03L-9A, ESAB OK 69.25 and EA-868 OP) for manual arc welding of nitrogen-containing steels without restrictions on the thickness of the base metal and can be used to develop industrial welding technologies for corrosion-resistant parts and structures for critical purposes, which require low magnetization.