Stainless steel pipe welding technology to meet the conditions
Publish Time: 2016-09-19 Origin: Site
Due to the stainless steel pipe sizes, according to the welding of stainless steel pipe fittings unique place, as far as possible reduce the amount of heat input, the manual electric arc welding, argon arc welding is adopted two kinds of methods, d > Φ 159 mm adopts argon arc welding, manual arc welding surface.D ≦ Φ 159 mm all use argon arc welding.Stainless steel pipe welding technology to meet the conditions.
(1) manual arc welding with welding machine adopts dc reverse connection, when using dc argon arc welding is pick up;
(2), it should be before welding wire with oxide coating on the surface of the stainless steel wire brush to brush off, with acetone to wash;Electrode should be in 200-250 ℃ drying 1 h, as you take;
(3) the workpiece before welding groove on both sides of the 25 mm within the scope of the clean up oil pollution and so on, with acetone to wash groove on both sides of the 25 mm;
(4) argon arc welding, the nozzle Φ 2 mm in diameter, extremely rich tungsten tungsten electrode, specifications Φ 2.5 mm;
(5) argon arc welding of stainless steel, the back must be filled argon gas protection, to ensure forming on the back.Using the method of partial argon filling in the pipe flow for 5-14 l/min, positive argon gas flow is 12 13 l/min.
Backing welding seam thickness should be thin as far as possible, and the roots of the fusion outstanding, when you receive arc into a gentle slope shape, if there are any are-receive shrinkage cavity, polishing machine grinding.Must be within the groove arc arc, arc should fill arc crater and prevent the crack of arc crater.
Because the stainless steel pipe fittings for austenitic stainless steel pipe, in order to prevent the carbide precipitation sensitization and intergranular decay, should strictly control the interpass temperature and cooling rate after welding, the welding interlayer temperature control under 60 ℃, must immediately after welding water-cooled, by subsection welding at the same time.The symmetrical dispersed welding sequence, can increase the cooling rate of joint, but also decrease the welding stress.