Steel structure is mainly composed of steel materials, which is one of the main types of building structures. The structure is mainly composed of steel beams, steel columns, steel trusses and other components made of profiled steel and steel plates. Welds, bolts or rivets are usually used to connect the components or components. Because of its light weight and simple construction, it is widely used in large-scale factory buildings, venues, super high-rise and other fields.
The general sequence of welding is: pre-welding inspection preheating and rust removal installation of welding pad and arc-triggering plate welding inspection.
1. Check groove angle, blunt edge, gap and amount of mistake before welding. Rust spot, oil stain and oxide scale inside and on both sides of groove should be cleaned up.
2. Preheating. Before welding, the base metal of groove and its sides are heated uniformly by gas welding or special baking gun, and the temperature is measured by surface thermometer to prevent temperature from not meeting the requirements or local oxidation of the surface and preheating temperature.
3. Re-check the preheating temperature, if the temperature is not enough, it should be re-heated to meet the requirements.
4. The surface cleanliness of the welded pad and arc-starting plate should be the same as that of the groove surface. The pad and base metal should be tightly bonded, and the arc-starting plate and base metal should be firmly welded.
5. Welding: The weld bead of the first layer should seal the connection between base metal and cushion plate in groove, and then weld layer by layer to fill groove. After each weld is welded, slag and spatter must be removed. Welding defects should be abraded and repaired in time.
6. An interface must be welded continuously. If it has to be stopped in the middle, it should be treated with heat preservation and slow cooling. Before re-welding, it should be heated again according to the regulations.
7. Should stop welding in rainy and snowy days, and should stop welding when the wind speed is greater than 5 m/s. When the ambient temperature is below zero, preheating and post-heating measures should be taken according to the regulations.
8. Carbon structural steel should be cooled to ambient temperature and low alloy structural steel should be inspected after 24 hours.
9. Welders and inspectors should fill in the work record form carefully.