1. In a comprehensive way, welder protection and compliance training should be carried out
What measures should be taken for the welding of steel structure in winter construction site: (1) before welding in low temperature environment, the welder should hold the theoretical teaching of low-temperature welding skills and low-temperature welding compliance practice.
(2) Before welding, the welder must have personal cold protection products, and have the ability to resist the cold for a long time and anti-skid ability.
(3) Low temperature welding has great physical energy consumption on the welder, and the shift time should be reduced properly.
(4) During the operation of low temperature welding, there should be a special guardian. The steel structure cost should monitor and judge the welder's situation. If necessary, it should accept the corresponding steps to ensure the smooth holding of welding matters and the safety of the welder.
(5) When high-altitude welding operation is carried out in snowy climate and after snow, special personnel shall be assigned to remove the passageway. In particular, thin ice shall be cleaned to ensure the peaceful passage of welders.
C-type steel structure of Jinan color steel tile
2. Then the steel structure welding equipment protection
(1) The welding machine should be placed in the movable protective shed of the welding machine to make the welding machine work under the normal temperature.
(2) Before use, the gas cylinders should be stored together as far as possible to ensure that the gas is available at any time; when the gas cylinders are used, they should be arranged in the welding machine shed to realize the normal temperature control, ensure the normal gasification of liquid gas and make the shielding gas stable and smooth.
(3) The winter construction of Jinan color steel tile C-type steel structure adopts the war type thermometer to control the preheating temperature, and the ordinary thermometer is used to monitor the temperature.
3. Secondly, welding materials
(1) The shielding gas should use CO2 gas with purity of 99.9% to ensure the anti cracking function discussed in welding.
(2) Strictly control the welding material warehouse, the welding rod must be dried according to the scale, the drying times shall not exceed two times, and the exposure time in the atmosphere shall not exceed 2 hours.
(3) The welding material warehouse must be equipped with dehumidification equipment, and the welding materials should be placed in accordance with the relevant regulations.
(4) In the course of using flux cored wire, moisture-proof step should be accepted. The protective cover of welding wire on the welding machine must be kept incomplete. The unused welding wire should be sent back to the welding material warehouse in real time to prevent moisture.
4. Welding essentials and skills
(1) Setting of preheating method: when δ ≥ 30mm, electric heating is accepted; when δ ≤ 25mm, flame preheating is accepted.
(2) The secondary goal of preheating temperature receiving flame heating is to dry the moisture in the welding area and realize normal temperature welding. The baking range is 50 mm on both sides of the weld, and the baking temperature is 20-40 ℃. Continuous welding is required during welding.
(3) The preheating temperature should be improved by 15 ~ 30 ℃ under the condition of high restraint. If there is no special explanation, the above-mentioned delimitation shall be implemented.
(4) For butt joint of different plate thickness, the preheating temperature of thicker plate shall be adopted.
5. Detailed delimitation of welding conditions
(1) In the case of low temperature welding, the temperature range is 0 ～ - 5 ℃, below - 5 ℃, it is necessary to stop welding operation. Welding operation should be carried out every day when the temperature is higher than 0 ℃.
(2) Wind proof installation is required for low temperature welding.
(3) During high-altitude welding operation, wind proof installation should be precise and thermal insulation, especially the bottom of the windbreak shed should be dense to prevent the formation of ventilation along the weld bead. Rain and snow are not allowed to fall on the hot weld.
(4) In case of operation in snowy days and after snow, the flame shall be accepted to dehumidify the welding area.