Application In Pressure Vessels By MAG Welding

Launched a comprehensive and systematic study of argon-rich gas shielded arc welding welding Q345R,15CrMo, and austenitic stainless steel, the study is the arc shape of the pressure vessels commonly used materials Q345R,15CrMo and austenitic stainless steel, welding process, mechanical properties, as well as macro microstructure analysis.The results show that:the parent material for the Q345R arc contraction, with the increase of CO2 content in the argon-rich shielding gas increased with the increase of the welding current.100% CO2 shielding gas, the larger spatter, uneven weld surface oxide; shielding gas 100%Ar, weld forming uneven weld high and narrow; protective gas 20% CO2 +80% Ar, the weld uniform, smooth scale pattern. The oxygen content in the weld impact value of the weld is a negative correlation; assessment of the argon-rich gas shielded arc welding of metal inclusions in 1.5; grain the greater the greater the heat-affected zone of welding current, shielding gas on the heat-affected zone the grain has little effect. The test panels of a of JB/T4730-2005 ray detection of two standard argon-rich gas welding, mechanical properties of pressure vessel standard.Welding 15CrMo, adding 20% CO2 shielding gas, the arc will shrink 47%; groove angle of welding current on arc obvious. The shielding gas of 20% CO2 +80% Ar weld shape than that of pure Ar. Two protective gas welding heat affected zone of pearlite+ferrite, no hardened organizations. Mechanical properties, the back bending of the test plate welding in pure Ar crack,20% CO2 +80% Ar welding test plate of the pressure vessel standards.Welded austenitic stainless steel 0Crl8Ni9, When the welding current is 240A, the protective gas the ratio of O2 from 2% to 5% to 8%, arc contracted by 38% and 12.5%; When the current is 280A, the arc contraction 17% and 20%. Protection of gas and current welds of Cr and Ni obvious. Protection of gas to 5% O2 +95% Ar weld surface bending and back bending crack. The protective gas for the 2% O2 +98% Ar welds to intergranular corrosion and mechanical properties of pressure vessel standards.