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Introduction of Nozzle
Nozzles are often an overlooked welding accessory in welding operations. In the past technical service process, we found that welding defects often occurred due to improper use of nozzles. Selecting the proper nozzle material, size and type can help reduce downtime, lower costs and improve weld quality and productivity.
The role of the nozzle is to guide the shielding gas to the molten pool and protect the molten pool from contamination. Choosing a nozzle can ensure that the gas with a suitable flow rate enters the welded molten pool. If the proper nozzle is not selected, the weldment can have a number of problems including excessive spatter and porosity, which can eventually lead to downtime due to rework. So how to choose the correct nozzle is extremely important. The following introduces several common nozzles and their advantages and disadvantages.
straight nozzle
#StraightNozzles
Straight nozzles are the most common nozzle type. The advantage is that it is widely used and can be applied to a variety of welding scenarios, and the gas shielding effect is better; the disadvantage is that due to the thick front end of the nozzle, it cannot penetrate deep when the groove is narrow, and the long stick-out length of the welding wire will cause the arc to be unstable and affect the gas. At the same time, the front end blocking the line of sight will also affect the observation of the molten pool and arc during welding.
#ConeNozzle
Conical nozzles are generally used in narrow gap groove welding. The front end is conical. Its advantage is that the front end is small, it can go deep into the narrow groove, and it is convenient to observe the shape of the molten pool and the arc; the disadvantage is that the outer diameter is small, which will affect the gas flow. To protect the quality, air holes may be generated during welding, and the spatter during welding is more likely to block the nozzle, and the replacement frequency will increase during long-term welding, which will increase the cost.
From nozzle to contact tip
The relationship between the nozzle and the contact tip has a significant effect on the quality of the weld. The contact tip can be lower than the nozzle or higher than the nozzle. A contact tip lower than the nozzle can provide better gas shielding quality, but at the same time it will shorten the stick-out length of the welding wire, making it difficult for the welding torch to enter the groove. Conversely, a contact tip that is higher than the nozzle is better for access to a restricted area or bevel, but the quality of the gas protection will be poor.
Therefore, the welding operator needs to choose a more suitable nozzle after weighing the advantages and disadvantages.
Post time: Dec-06-2022