Oil and gas pipeline preheating
Process means for heating the overall or welding region of welding is called welding preheating.
Why is the oil natural gas pipeline preheat preheating?
For steel materials with high welding strength, steel materials with hardening, thermally conductive properties, high thermal conductivity, high thickness, and when the ambient temperature around the welding area is too low, the welding is often preheated before welding. In general, the welding of important components, welding and welding of alloy steel and welding of alloy steels are required to be preheated before welding. Pre-heating preheating can reduce the cooling speed of the welded joint after welding, and substantially does not affect the time at high temperature, which is very ideal. Therefore, when welding has a steel material having a hardening, reducing the main process measures of the fermentation tendency to reduce the quenching tendency, it is preheating, rather than increasing line energy.
Benefiping preheating for oil gas pipelines:
(1) Preheating can slow down the cooling speed of the welded joint after welding, which is advantageous for the essence of diffusion hydrogen in the weld metal to avoid hydrogen caison. At the same time, it also reduces the hardening degree of weld and thermal influence zone, and improves the crack resistance of welded joints. (2) Preheating can reduce welding stress. Homochildly partially preheat or integrate preheating, it can reduce the temperature difference between the welding region being soldered (also referred to as a temperature gradient). On the other hand, the welding stress is reduced, and on the other hand, the welding strain rate is reduced, which facilitates the avoidance of welding cracks.
(3) Preheating can reduce the restraint of the weld structure, which is particularly obvious to the reduction of the corner joint joint, as the preheating temperature increases, the incidence of cracks decreases, the oil gas pipeline sensation heating equipment is:
1) The efficiency of the whole machine is ≥95%, 30-40% by the electronic pipe equipment;
2) Small size, light weight, low failure rate
3) Energy saving and the welding point is firm and beautiful, and the welded geometry is not limited
4) The metal internal crystal structure is unchanged, the annealing range is small, no obvious welding