The invention relates to a
welding technique in equipment manufacture industry, which is a
welding speciality technique of a
welding casing of an MCL-typed horizontal
cutting centrifugal compressor, in particular to a
welding process of the welding casing of the
centrifugal compressor with low-temperature steel 09MnNiDR material at -70 DEG C. The
gas protection welding is adopted; the welding wire grade is HS09MnNiDR and the
diameter of the welding wire is Phi1.2mm; the polarity of the power supply is reversed DC power. The invention comprises a
processing before welding, a
welding process and a
processing after welding; wherein, the process parameters in the
welding process are that the welding current ranges from 150A to 200A, the welding
voltage ranges from 24V to 28V, the protection gas is the
mixed gas with 80% of Ar and 20% of CO2 according to the
volume percentage, the welding speed ranges from 250mm / min to 280mm / min, the dry elongation ranges from 10mm to 15mm, and the
gas flux ranges from 20L / min to 25L / min. The welding wire of the
gas protection welding of the invention is not required to be dried, the welding wire is automatically fed in the welding process, and a welding rod is not required to be replaced; as the heat of the MAG melting polar
gas protection welding is concentrated, the invention has the advantages of narrow
thermal effect area, little deformation, beautiful forming, good quality, low cost, fast welding speed, high welding efficiency, etc.