04 Nov 2021
The main equipment used in the welding process of electrode arc welding is arc welding machine, the main welding material is electrode, and the auxiliary equipment and tools of electrode arc welding include welding tongs, welding cable, mask and other protective tools. Today we mainly talk about welding rods and main equipment welding machines for arc welding with electrodes.
Welding rod is a melting electrode coated with a coating for arc welding of welding rods. It consists of a welding core and a coating. In the electrode arc welding process, the electrode is not only used as an electrode to conduct the welding current, maintain the stable combustion of the arc, but also protect the molten pool, and can be used as a filler metal to directly transfer to the molten pool and merge with the liquid base metal. A series of metallurgical reactions, after cooling and solidification, form weld metal that meets the requirements of mechanical properties. Therefore, the quality of the welding rod largely determines the quality of the weld.
What are the principles for choosing welding rods? Let's talk about them one by one. The first is the principle of equal strength. Generally used for welding low carbon steel and low alloy steel. For workpieces or structures that bear static or general loads, electrodes with the same tensile strength as the base metal are usually used. The second is the principle of equal ingredients. Generally used for welding metal materials such as heat-resistant steel and stainless steel. The third is the low-cost principle. Under the condition of satisfying the performance and operating process, try to choose low-cost and high-efficiency welding rods. The fourth is the principle of anti-crack. When the content of carbon, sulfur, phosphorus and other elements in the base metal is high, the weld is prone to cracks, and low-hydrogen electrodes with good crack resistance should be used. Fifth, the principle of anti-stomata. For weldments that are difficult to clean or have poor ventilation conditions such as rust and oil stains on the welds, acid electrodes that are highly oxidizing and insensitive to rust and oil stains are generally selected. Sixth, the principle of equal conditions. The choice is mostly based on the working conditions and characteristics of the workpiece or welding structure. Seventh, the principle of equal resilience. That is to say, the ductility of the deposited metal and base metal of the electrode is or similar. Eighth, the principle of dissimilar steel welding. When welding dissimilar steels, the choice of welding rod generally requires that the strength of the weld metal or joint is not lower than the minimum strength of the two metals to be welded. The ninth is the welding principle of stainless clad steel plate. When welding stainless clad steel plates, three types of electrodes with different properties should be selected for the welding requirements of the base layer, the cladding layer and the transition layer.
Next, let’s talk about the electrode arc welding machine. According to the different nature of the output current, the arc welding machine in use can be divided into two categories: DC welding machine and AC and DC welding machine; according to the different structure, it can be divided into arc welding rectifier, There are three types of arc welding transformer and arc welding generator. It is worth noting that the inverter arc welding rectifier will be widely used in the future due to its small size and low energy consumption. In use, the type of welding machine can be selected according to the product's technical requirements, economic benefits, working conditions and actual production needs, and can also be selected by referring to the advantages and disadvantages of various welding machines.
According to the law of arc combustion and the needs of welding technology, the requirements for the welding machine have the following aspects, which can also be used as the standard for selecting the welding machine. The first requirement is to have an appropriate no-load voltage to ensure easy arc ignition. No-load voltage is the voltage at the two output terminals of the welder before welding. The higher the no-load voltage, the easier it is to ignite the arc and maintain the stable combustion of the arc, but too high voltage is not conducive to the safety of the welder, so generally the no-load voltage of the welder is limited to less than 90V. The second requirement is to have a steep drop in external characteristics. This is an important requirement for the welding machine. It can not only ensure the stable combustion of the arc, but also ensure that the welding machine will not be burnt out due to excessive current generated during a short circuit. The third requirement is to have good dynamic characteristics. During the welding process, a short circuit of the welding circuit often occurs. Welding with a welder with good dynamic characteristics is not only easy to start the arc, but also the arc length changes during the welding process and it is not easy to extinguish the arc, and there is less spatter. The welder obviously feels that the welding process is very stable and the arc is very soft. The fourth requirement is to have good regulation current characteristics. Before welding, the welding current is generally determined according to the weldment material, thickness, welding position and welding method. From the perspective of use, the wider the range of current adjustment is required, the better, and it can be adjusted flexibly and uniformly to ensure welding quality. The fifth requirement is simple welding structure, reliable use, low energy consumption and convenient maintenance. All parts of the welding machine are firmly connected, there is no big whole building and noise, and it can work continuously under the conditions that the temperature rise of the welding machine allows. At the same time, the safety of users should be ensured so as not to cause electric shock accidents.
An excellent electrode arc welding machine should be able to meet all the above requirements, and our Kingsiri brand MMA series welding machine meets all the requirements of an electrode arc welding machine. Innovative technologies such as intelligent start-up, thrust control, built-in anti-sticking control, thermal arc control and pulse manual welding technology, etc., even people who have never used an electric welder can weld fish scales better than advanced welders. Welding seams can help welders solve many problems in welding work and achieve a higher level of welding technology.
Keywords: welding machine
Originally published 04 Nov 2021, updated 04 Nov 2021.