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.