1 construction preparation
1. I. Material requirements
00 Cr 18 nil 0 pipe f6O×3.5, carbon content.
Welding wire H00Gr2 1Ni 10 must have quality certificate or material certificate.
Requirements for argon in 1.2
The purity of argon used must be ≥ 99.99.
1.3 machine requirements
The welding equipment is ZX7-400 inverter welding machine; Welding wire barrels, stainless steel hammers and stainless steel wire brushes used by welders;
The welder observes the spotlight flashlight, weld inspection ruler and contact thermometer formed at the root.
1.4 operating conditions
Welders must hold the material certificate of this project to meet the welding requirements; On-site prefabrication, on-site installation, indoor operation, no windproof measures.
2 welding
Figure 1 joint diagram
Groove making: before welding, use grinder to polish and brush stainless steel.
Clean up, groove form and size according to the figure.
Assembly requirements: when assembling, the offset of inner wall shall be ≤ 0.5 RAM. Before pairing, scrub the grooves within 20 mm on both sides with acetone.
Clean (oily stolen goods).
3 welding method
All welded joints shall be sealed and covered by TIG welding.
All welds consist of single-sided welding and double-sided welding.
Four key points of operation
During TIG welding, the included angle between the welding torch and the workpiece is 75 ~ 80 degrees, and the included angle between the welding wire and the workpiece is 2o ~ 3o degrees, which reduces the heating of the workpiece and increases the arc blowing.
Force, weld root fusion is good; The nozzle diameter of TIG welding gun is 10ram, the protruding length of tungsten electrode is 3 ~ 4 RAM, and the distance between nozzle and weldment is 8 RAM.
Before welding, the tube is filled with argon for protection; Intermittent wire feeding is adopted, and the welding wire is within the argon protection range.
Drop by drop to root bath; The interlayer temperature is controlled at 65438 000℃; After the joint is welded and cooled, mark the welder's steel seal, welding slogan and pipeline number with a marker 50 mm away from the weld.