The welding of steel pipes can be seen in various large-scale projects. Galvanized steel pipes are also widely used at present. There are many welding methods for galvanized steel. Generally, gas welding, manual arc welding, CO2 gas shielded welding, buried galvanized steel structures are commonly used in galvanized steel structures. Automatic arc welding, tungsten argon arc welding and other methods.
Gas welding, which was often used in the welding of galvanized pipes in the past, is basically eliminated in the installation industry due to the lack of heat input in gas welding, which is prone to defects and poor mechanical properties of the weld. Gas welding has great damage to the galvanized layer.
CO2 gas shielded welding has good welding performance on galvanized steel. When using appropriate welding specifications and matching shielding gas and welding materials, high-quality welded joints can be obtained. This method is rarely used in engineering practice.
TIG welding, the arc energy is concentrated, the damage to the galvanized layer is less, and it is easier to form a good single-sided welding and double-sided forming joints. It is a welding method worth using, but the welding speed, slow, cost more expensive.
The outer diameter of the DN15 model is 21.3mm
The outer diameter of the DN20 model is 26.9mm
The outer diameter of the DN25 model is 33.7mm
DN32 model outer diameter 42.mm
DN40 model has an outer diameter of 48.3mm
DN50 model has an outer diameter of 60 mm
The outer diameter of the DN65 model is 76.1mm
DN80 model has an outer diameter of 88.9mm
The outer diameter of the DN100 model is 114.3mm
The outer diameter of the DN125 model is 140mm
The outer diameter of the DN150 model is 168.3mm
The outer diameter of the DN200 model is 219.1mm.
Control from five aspects: people, materials, machines, methods and environment.
① The human factor is the key point of welding control. Therefore, before welding, a skilled welder with a welder certificate should be selected to carry out necessary technical training and disclosure. It should not be replaced at will, to ensure that the welding personnel of the pipeline are relatively stable.
② Control of welding consumables: ensure that the purchased welding consumables are from regular channels, have quality assurance certificates and certificates, and meet the process requirements; the recovery control of the electrode head is strictly controlled to ensure the flow direction and amount; the welding consumables must be baked strictly according to the process, and once Issue no more than half a day's supply.
③ Welding machine: The welding machine must ensure reliable performance and meet the needs of the process; the welding machine must have a qualified current and voltmeter to ensure the correct implementation of the welding process. The welding cable should not be too long, and the welding parameters should be adjusted when it is longer.
④ Welding process method: ensure the strict implementation of the special operation method of galvanized pipe, the welding process shall be checked before welding, the welding process parameters and operation methods shall be controlled, the appearance quality shall be checked after welding, and the post-weld non-destructive inspection shall be added if necessary. Control the welding level and the amount of welding consumables per pass.
⑤ Welding environment control: ensure that the temperature, humidity and wind speed during welding meet the process requirements.
Galvanized welded pipe, also known as galvanized steel pipe, is divided into two types: hot-dip galvanized and electro-galvanized.