Offshore steel structure drilling platforms use a large number of high-strength steels with thicknesses greater than 50mm and grades of DH32/36, EH32/36, EH40, FH40, etc., and even ultra-high-strength steels such as EQ43/47/51/63/70 with higher yield strength. . A major problem encountered when welding these steels under certain conditions is hydrogen-induced cracking. This kind of crack also has some other names, such as under-bead crack, cold crack, or delayed crack. It usually appears immediately when cooling to a temperature below 93°C or appears a few hours after welding.
To solve the above problems, an air-cooled electromagnetic induction heating machine can be used to preheat offshore steel structure drilling platforms before welding. It can quickly heat steel plates over 50MM thick to 500℃. Its flexible electromagnetic heating tape can be covered according to the shape of the weld, and its preheating can reduce the cooling rate of the deposited metal and the base metal (heat-affected zone), forming a ductile metallographic structure with excellent crack resistance, that is Reduces the risk of forming a hardened martensite microstructure and reduces the internal stress generated by the shrinkage of the weld and adjacent base metal. Use electromagnetic heating tape to insulate the weld seam to allow the hydrogen element in the weld seam to escape and reduce the probability of hydrogen dissolving in the weld metal, thereby reducing the potential risk of hydrogen-induced cracks. This portable electromagnetic heater can quickly change working areas with workers without requiring additional cooling water and is suitable for outdoor working environments. Compared with traditional preheating methods, the initial investment and daily use costs of air-cooled electromagnetic induction machines are lower.
Offshore oil drilling platform steel structure fillet welds are preheated to 300°C
