Seamless steel pipe heating

Before arc welding of seamless steel pipe, the key to seamless steel pipe to carry out heating, manipulating the temperature for thirty minutes and then gradually welding.

The heating of electric arc welding and the virtual-like beam temperature quenching solution by temperature control solution of temperature control cabinet actively practical operation. The far infrared ray tracking heat treatment equipment board is selected. Intelligent type positively set the trend graph and record the trend graph, heat transfer coefficient accurately measure the temperature. Heat transfer coefficient measurement point spacing welding edge 15mm-20mm when heating up.

Seamless steel pipe welding method

1. In order to better avoid the welding deformation of seamless steel pipe, each column joint head is welded symmetrically by two people, and the welding orientation is from the middle to both sides. Welding inside and outside open (inside and outside open when welding close to the beam), the operation process from - layer seamless steel pipe third layer seamless steel pipe road must carry out small specification models, due to its arc welding seriously endanger the key cause of welding deformation. After arc welding one to three layers, should carry out back planing. After the use of carbon arc gas planer, the welding industrial equipment must be polished and polished, the welding surface layer of nitriding finishing, indicating the metal luster, to avoid surface charring caused by cracks. The outer hole is welded once and the other inner thread is welded once.

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

3. The welding current, welding rate and number of overlapping superimposed layers should be maintained for several hummers.

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

Seamless steel pipe quenching

After welding arc welding, quenching solution should be carried out within 12 hours. If you can not immediately carry out heat treatment heat treatment solution for seamless steel pipe, you should seek the proposal of heat insulation insulation and slow cooling. When carrying out quenching solution, the temperature of the 2 heat transfer coefficients should be measured accurately and the heat transfer coefficients should be welded on both sides of the weld.

Seamless steel pipe processing characteristics

(1) Finely rolled pipe should be peeled, the amount of peeling is generally 5 mm;

(2) because the steel is hard, finish-rolled tube to be cut with co2 laser or sawing;

(3) because the heat transfer of chromium-molybdenum-vanadium steel is lower than that of carbon steel, the heating rate should be slow, heating temperature of 1120 ~ 1180 ℃, breaking the hole temperature of 1100 ~ 1160 ℃;

(4) this steel in the 1000 ~ 1100 ℃ section has excellent plastic deformation and low deformation resistance, so the hole-breaking characteristics are good, deformation of the main parameters can be low carbon steel or carbon steel (such as The main parameters of deformation can be selected according to low carbon steel or carbon steel (such as 30CrMnSiA);

(5) after rolling seamless steel pipe to quench and quenching, quenching temperature of 950 ~ 980 ℃, quenching temperature of 730 ~ 750 ℃, insulation insulation time of 2 ~ 3h;

(6) Seamless steel pipe standard tolerances are tighter to ensure professional counterpart welding; pipe length as long as possible to help reduce the total number of welds.