Welding method of low carbon steel at a low temperature

Under the harsh winter conditions of low-carbon steel welding, due to the cooling speed of welded joint fastly make the crack tends to increase, especially in the first weld Heavy structures susceptible to cracking, for which the process must take the following measures:

  • preheat, welding process strictly maintain interpass temperature should not fall below the preheating temperature.
  • the use of ultra low hydrogen or hydrogen welding materials.
  • to increase the welding current when the tack welding, the welding speed slows down, due to increase tack-welded bead cross-sectional area and length, preheated if necessary.
  • the whole should be a continuous weld seam finish, avoid interruptions.
  • arc groove on the surface of the base material should not be beyond the need to fill the crater when extinction.
  • not possible under low temperature conditions, bending, straightening and assembly weldments.

Seamless pipe Specification, standard and identification

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.