CO2Gas shielded welding wireis an efficient welding method widely used for welding low carbon steel and low alloy steel. Now, let's learn how to weld low carbon steel using CO2 gas shielded welding wire!

1. Choose welding wire for welding carbon steel and low alloy steel, and establish a new national standard, namely GB/T8110-1995 'Welding Wire for Gas Shielded Arc Welding of Carbon Steel and Low Alloy Steel', which is equivalent to the American AWS gas shielded welding wire.

To prevent the formation of pores, reduce spatter, and ensure high mechanical performance of the weld seam, CO2 gas shielded welding wire must contain deoxidizing elements such as Si and Mn. The purity of the CO2 gas must be above 99.5% by volume, and the moisture content must be below 0.005%. To reduce the moisture content in carbon dioxide, measures must be taken at the welding site to invert the new gas cylinder and let it stand for 1-2 hours, then open the valve to discharge the free water accumulated at the bottom. Depending on the amount of water, it can be drained 2-3 times, approximately every 30 minutes. Then refill the gas cylinder. To expel gases mixed with a large amount of air and moisture from the upper part, it is necessary to discharge gas for 2-3 minutes before use. High-pressure and low-pressure dryers should be set up in the gas channel system to further reduce moisture in the gas; desiccants are generally silica gel or dehydrated copper sulfate.

2. CO2Gas shielded welding wirePreparation before welding: Before welding, it is necessary to clean the weld joint and a range of 10-20mm on both sides from oil, rust, moisture, and paint.

3. Selection of welding parameters for CO2 gas shielded welding wire: When using CO2 gas shielded arc welding, two forms of droplet transition are usually adopted. One is short-circuit transition, characterized by low arc voltage and small welding current, suitable for thin plate and all-position welding; the wire diameter is fine, usually between 0.6-1.4mm. The other is fine particle transition, with larger welding current and strong arc penetration power, suitable for medium-thick plate welding; currently, wire diameters of 1.6mm and 2.0mm are commonly used.

1) Selection of short-circuit transition welding parameters: For short-circuit transition, choose low voltage; the welding current must match the wire diameter and arc voltage; the welding speed should neither be too fast nor too slow, generally around 30m/h. The gas flow rate under small wire diameter welding parameters is 5-15L/min; under moderate welding parameters, it is about 20L/min; power supply polarity generally uses direct current reverse connection; lead protrusion length should be within 10-20mm, rarely exceeding 20mm; to reduce spatter, inductance in the welding circuit needs to be adjusted in series.

2) Selection of fine particle transition welding parameters: In CO2 gas shielded welding, when the current increases to a certain value with appropriate arc voltage, fine particle transition can form. The migration of fine particles still uses direct current reverse connection. Since circuit inductance has no effect on suppressing spatter, an additional reactor may not be necessary.

The above introduces how to weld low carbon steel using CO2.Gas shielded welding wireIf you need more information, feel free to contact us!