Welding process of 37Mn5 oil casing pipe

Welding process of 37Mn5 oil casing pipe:

(1) Gas shielded welding using 80% Ar+20% CO2 is the chosen welding technique.

The choice of welding materials is made using ER55-G, a 3.2 mm-diameter welding wire.

Welding parameters: voltage 26–30V, current 250–320A;

Welding speed: 35–50 cm/min; preheating temperature: 100°C; this ensures that the interlayer temperature cannot be 30°C higher than the preheating temperature nor lower than it.

Air cooling without any heat treatment is the post-weld treatment.

(2) The 80% Ar+20% CO2 gas shielded welding method was chosen.

The choice of welding materials is made using ER55-G, a 3.2 mm-diameter welding wire.

Welding parameters: voltage 26–30V, current 250–320A;

Welding speed: 35–50 cm/min; preheating temperature: 100°C; this ensures that the interlayer temperature cannot be 30°C higher than the preheating temperature nor lower than it.

After welding, the temperature is tempered to 600±20°C for four hours, with a heating rate of 50°C per hour and a cooling rate of 50°C per hour.