Methods to Prevent Welding Spatter
1. Prevention of CO2 welding spatter
- Using activated wire can refine metal droplet, reduce spatter and improve weld formation. The so-called activation treatment is a thin layer of alkaline earth metal or rare earth metal compounds on the surface of the welding wire to improve the ability of the welding wire to emit electrons. The most commonly used activator is cesium (CS) salts such as CSCO3, such as a little K2CO3, NA2CO3, the effect is more pronounced.
- The carbon content in the welding wire is limited to 0.08 ~ 0.11% . For this reason, the ultra-low carbon welding wire, such as Ho4mn2sitia, can be used.
- If necessary, use flux-cored wire to cover the surface of the droplet with slag to reduce spatter and make the weld in full bloom.
- Adding a small amount of AR gas into CO2 gas can improve the thermal characteristics and oxidation of arc and reduce spatter.
Methods to Prevent Welding Spatter - The pole pressure at the end of the welding wire is lower by using direct current reverse connection.
- Choose the best welding specifications, welding current, welding voltage is not too large or too small.
- Choosing the best inductance value, the current growth rate of CO2 Gas metal arc welding is related to the inductance, namely: didt = (U0-iR) l: u0-no-load voltage of power supply, i-instantaneous current; R-resistance in the welding circuit; l-inductance in the welding circuit.
- A coating of silicone oil or anti-blocking agent on the nozzle can effectively prevent the nozzle from clogging. Using welding spatter remover, spray on the workpiece, can prevent the spatter and the base metal direct contact with spatter, spatter with a steel wire brush can be a light brush to remove the spatter.
2. According to the different causes of spatter formation under different droplet transfer forms, different methods of spatter reduction should be adopted
- In the process of droplet free transfer, the reasonable welding current and voltage should be selected to avoid the use of large droplet repulsive transfer, and the high quality welding materials should be selected, for example, the welding wire H08Mn2SiA with low content of C and Mn and Si can be used to avoid spatter caused by gas precipitation or expansion due to metallurgical reaction of welding materials.
- In short circuit transition, (AR + Co2) gas mixture can be used instead of CO2 to reduce spatter. If φ (Ar) = 20% ~ 30% AR is added. This is due to the change of arc shape and droplet transfer characteristics with the increase of argon content. When the arc is burning, the arc root expands and the droplet axial property increases. On the one hand, the droplet is easy to meet with the molten pool, and the short-circuit bridge appears between the welding wire and the molten pool. On the other hand, under the action of axial force, the droplet has a more uniform short-circuit transition process, and the short-circuit peak current is not too high, which is beneficial to reduce the splash rate.
3. Anti-spatter for welding
From the shape of points, anti-splash welding flux is divided into: oil-based, water-based and paint type. From the packaging, divided into sprays and barreled. Form point of view, oil-based anti-spatter because of its difficult to clean after welding, price is not too much advantage, has been eliminated by the market. The water-based anti-splashing agent has good slag removal effect, competitive market price and no adverse effect on post-welding spray painting, etc. , and the use of convenience, consumption saving, welding workpiece is also more beautiful than before many advantages, currently in the market to occupy a leading position. Paint-based anti-splash agent spread better than water-based effect, and can be repeated many times welding, but the price is much higher. From the perspective of cost-effective, in addition to a small number of automotive industry and shipbuilding industry and other parts of the use in the market share is small.
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