What is a carbon dioxide gas shielded welding machine? What are its advantages?
Answer: Carbon dioxide gas shielded welding is a welding method that uses mechanical wire feeding to automatically send out the carbon dioxide gas shielded welding molten pool. Because of its high efficiency, low power consumption, high weld quality, and good overall economic benefits, it is currently the state A new high-efficiency and low-consumption welding method that is vigorously promoted. Compared with other arc welding methods, carbon dioxide welding has the following advantages :
1) High production efficiency: Because of its strong arc penetrating power, large penetration, and high melting rate of the welding wire, the deposition speed is fast, and the production efficiency is much higher than traditional manual electric welding, which can reach 1-3 times , That is, in some occasions, it can be equivalent to the workload of two to four people in the original manual electric welding. With other conditions unchanged (no increase in personnel, no increase in wages and taxes, etc.), significant economic benefits can be added to the enterprise. (Tangshan Mining and Metallurgical Machinery Factory users report: Since the use of CO2 gas shielded welding, work efficiency has been greatly enhanced. At present, almost no one wants to use AC welding machines. CO2 welding machines* can use two reels of welding wire in a day, about 40kg. AC welding machine a day * Use about two packs of welding rods, about 10kg, and after removing the welding rod head and coating, the actual use of the weld metal, about 5kg)
2) Low welding cost: The carbon dioxide gas source is wide and the price is low. The deposition rate of carbon dioxide welding wire is much higher than that of manual welding. (Because there is no welding slag and fumes, there is no need to discard the welding rod head, so basically one ton of welding wire can be equivalent to Using two tons of electrodes) its welding cost can be reduced by 40-50% compared with traditional manual welding or submerged arc welding.
3) Low energy consumption: Compared with carbon dioxide welding and electrode arc welding, carbon dioxide welding consumes only about 70% of the electric energy per meter of the butt weld of 3 mm thick low carbon steel plate. For butt welds of 25 mm thick low-carbon steel plates, carbon dioxide welding consumes only 40% of the electricity per meter of ordinary manual welding. Therefore, carbon dioxide welding is a very good energy-saving welding method.
4) Wide application range: Carbon dioxide welding can be adapted to welding at any position in space; because carbon dioxide is decomposed into oxygen and carbon monoxide under the action of an electric arc, it will absorb a lot of heat during the decomposition, which has a cooling effect on the molten pool metal. Therefore, carbon dioxide welding is more suitable for vertical welding and overhead welding than manual welding, and the molten metal is not easy to flow.
At the same time, because oxygen can burn part of the carbon and other harmful elements in the weld metal composition at high temperatures, carbon dioxide welding can weld cast iron. After burning some of the carbon and harmful elements in the cast iron, the weld metal performance It is closer to pure steel, so the mechanical strength and toughness of the welded seam after welding are improved, and the brittleness is reduced. In addition, due to the absorption of heat when carbon dioxide decomposes during welding, the welding heat-affected zone can be reduced, and the deformation and cracks of the cast iron can be reduced.
In addition, due to the endothermic reaction of carbon dioxide and the stability of the low current of the DC power supply, the adaptability of carbon dioxide welding is also very wide. It can weld very thick and thin plates. When welding 0.8-1.0 plates, the welding deformation is very small. , And not easy to break down.
5) Strong resistance to rust and oil: strong resistance to pores caused by rust or oil. Due to the oxidation of carbon dioxide, it can significantly reduce the hydrogen content of the weld, increase the tensile strength of the weld, and reduce delayed cracks and Brittle fracture. Carbon dioxide welding is the lowest hydrogen content of the weld among all welding methods, so it can replace part of the basic low-hydrogen electrode.
6) Simple operation: no slag is generated during welding, and no slag removal is required after welding. There is very little welding fume during the welding process, which has less impact on the health of welders than manual electric welding. Carbon dioxide belongs to open arc welding. During the welding process, the welder can directly observe the flow of molten iron in the molten pool. It is not easy to produce welding defects such as false welding and false welding, which is convenient for operation and learning.
7) Disadvantages: When the voltage and current adjustments are not matched, the welding spatter is large, and the adjustment of the voltage and current is not easy to grasp, but generally can be approximated by the following formula: V (voltage) = 15 + 0.05I (current), small current It can be directly obtained from this formula, but when the current is large, it is better to increase the calculated voltage slightly, and the effect will be better. Generally, first determine the required current according to the workpiece and welding wire, and then calculate the required voltage from the current. The following is the relationship between the diameter of the welding wire and the current. Within this range, the current can be determined according to the welding wire and the workpiece:
0.8mm 50--120A 1.0mm 70--180A
1.2mm 80--350A 1.6mm 300--500A
At present, carbon dioxide welding is mainly used for welding low-carbon steel and low-alloy steel. Basically, the use of medium, low-carbon steel and low-alloy series electrodes can be replaced by carbon dioxide welding, and can achieve much better results than manual welding with electrodes.