The welding process of seamless steel pipe(ASME SA53) includes: heating before welding, heat treatment after welding, quenching.

1. Heating

Before the seamless steel pipe arc welding, the key is to heat the seamless steel pipe, and gradually weld the seamless steel pipe after controlling the temperature for 30 minutes.

The heating and virtual beam quenching of arc welding are solved by the temperature control cabinet which is solved by temperature control. Use far-infrared tracking heat treatment equipment board. The intelligent type actively sets the trend graph and records the trend graph, and the heat transfer coefficient accurately measures the temperature. When heating, the distance between the measuring points of the heat transfer coefficient and the welding edge is 15mm-20mm.

2. Welding method

①In order to better avoid the welding deformation of seamless steel pipes, each column connector is welded symmetrically by two people, and the welding direction is from the middle to both sides. Welding is open to the inside and outside (the welding is close to the beam when the inside and outside are open), and the operation process starts from-layer seamless steel pipe and third layer seamless steel pipe. Small specifications must be developed, because its arc welding seriously harms welding deformation. After arc welding one to three layers, reverse planing should be carried out. After the use of carbon arc gouging, the welding industrial equipment must be polished, and the welding surface must be nitrided to show the metallic luster and avoid the surface carbonization to cause cracks. The outer hole is welded once, and the other inner threads are welded once.

②When arc welding = double-layer seamless steel pipe, the welding direction should be the reverse of that of the double-layer seamless steel pipe, and so on. The spacing between the butt welds of each layer is 15-20 mm.

③The welding current, welding rate and number of overlapped layers of several machines should be maintained.

④In arc welding, be sure to gradually weld from the pilot arc board and complete the welding on the pilot arc board. Disconnect, polish and clean after arc welding.

3. After heat treatment

After arc welding, quenching should be carried out within 12 hours. If it is not possible to immediately carry out heat treatment and heat treatment of seamless steel pipes, proposals for heat insulation and cooling should be sought. When quenching is carried out, the temperature of the two heat transfer coefficients should be accurately measured, and the heat transfer coefficients should be welded on both sides of the welding.