Oct. 30, 2020
The type and size of welding current are generally selected according to the workpiece material. The size of welding current is the most important parameter to determine the depth of welding seam. It is mainly selected according to the workpiece material, thickness, joint form, welding position, and sometimes considering the welder's technical level (argon arc tungsten) and other factors.
Gas flow rate and Nozzle Diameter Under certain conditions, there is an optimal range of gas flow rate and nozzle diameter, at this time, the gas protection effect is the best, the effective protection area is the largest.If the gas flow rate is too low, the airflow stiffness is poor, and the ability to remove the surrounding air is weak, the protection effect is not good: the flow rate is too large, which is easy to become turbulent, and the air is involved, which will also reduce the protection effect.Similarly, when the flow sub is timed, the nozzle diameter is too small, the protection range is too small, and the flow velocity is too high, resulting in turbulence.The nozzle is too big, not only obstructs the welder observation, but also the airflow velocity is too low, stiffness is small, the protection effect is not good.Therefore, the gas flow rate and nozzle diameter must have certain coordination.
Welding speed the selection of welding speed is mainly based on the workpiece thickness and with welding current, preheating temperature and so on to ensure that the required depth and width of fusion.At high speed automatic welding.The influence of welding speed on gas and protection effect should also be considered.If the welding speed is too high and the airflow is seriously deviated, the tungsten electrode, arc column and molten pool may be exposed to the air.Therefore, measures such as increasing the flow of protective gas or tilting the torch forward to a certain Angle must be taken to maintain a good protective effect.
The greater the distance between the nozzle and the workpiece, the worse the gas protection effect will be, but the distance too close will affect the welder's line of sight, and it is easy to make the tungsten electrode contact with the molten pool and short circuit, resulting in tungsten clamping. Generally, the distance between the nozzle end and the workpiece is between 8 ~ 14mm.
