Low-temperature submerged-arc automatic welding method for Q370qE steel

Abstract

The invention discloses a low-temperature submerged-arc automatic welding method for Q370qE steel and belongs to the field of welding methods. In the low-temperature submerged-arc automatic welding method, the temperature condition during the whole welding process of the Q370qE steel at environment temperature of 0-minus 15 DEG C is controlled by the steps as follows: dehumidification and pre-heating of a parent metal before welding, drying and temperature keeping of a welding rod and welding flux, and temperature keeping and slow cooling on the welding zone after welding. Especially, during welding, a crawler-type ceramic electric heater which needs electrifying before heating is laid on and covers a welding joint and 100-150mm parts at two sides of the welding joint, so that the temperature of welding joint layers and passes is controlled to 160-200 DEG C, and the crawler-type ceramic electric heater can be adjusted manually to control temperature, so that the temperature among the welding joint layers and passes can be simply and conveniently controlled. After the whole welding process is subjected to such-ordered temperature control, the welding process can be prevented from being influenced by low temperature environment as much as possible; the cooling speed of the welding joint during the welding process is slowed, so that the cold cracking, hardness and brittleness possibilities of the welding joint are reduced; and the low-temperature impact toughness of the submerged-arc automatic welding joint of the Q370qE steel is effectively ensured, the impact dynamic load performance of a bridge steel structure is enhanced and the service life of a bridge is prolonged.

Description

technical field

[0001] The invention discloses a low-temperature welding method for automatic submerged arc welding of Q370qE steel, which belongs to the field of welding methods. Background technique

[0002] According to the requirements of the current low-temperature welding specification for welding materials, the minimum ambient temperature allowed for Q370qE steel is 0°C. No matter in the north or the south, the temperature is often lower than 0°C in winter, and even reaches -15°C in the north.

[0003] The bridge steel structure generally bears the impact dynamic load of the vehicle operation, so there is a high requirement for the low temperature impact toughness of the Q370qE steel welded joints constituting the bridge. Submerged arc automatic welding is one of the most commonly used welding methods in the manufacture of bridge steel structures. When welding in a low temperature environment, the cooling rate of the welded joint is accelerated, which is prone to pro...

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