Section I choose the basic points of the Carbon Steel Electrode Welding Electrode of a wide range of each electrode are certain characteristics and uses. Even if the electrodes of the same category, due to the different type of drug skin reflects the use of features Are different. Combined the weldment physical and chemical properties of the workpiece conditions (shape and stiffness of the structure), different construction conditions, should also consider the production efficiency and economic factors, The choice of these is bound to the electrode to bring some difficulties. Therefore, it is necessary to determine some of the principles, the use of alternative electrode. In practical work, in addition to seriously understand the Kinds of electrode composition, properties and uses of information must be combined with the weldment conditions, construction conditions and the welding process, and with reference to the following principles to be integrated Consideration, in order to correctly select the electrode. First, consider the physical and mechanical properties and chemical composition of the workpiece. 1, from point of view of strength, choose to meet the mechanical properties of Request of the electrode, or a combination of the weldability of the base metal, in favor of unequal strength, good toughness electrodes, and subject to change Change the weld structure, such as strength, stiffness requirements. 2, the deposited metal alloy composition in line with or close to the base metal. 3, when the carbon in the chemical composition of the parent material Higher or sulfur, phosphorus and other harmful impurities, crack resistance and anti-stomatal ability of the electrode should be selected, such as low hydrogen type electrode. Must be welded components on the mechanical properties and chemical composition is not balanced, some welding emphasis on strength, toughness, etc., while the The chemical composition does not necessarily require consistent with the base metal, such as the selection of structural steel electrode should first be given the highest priority between the weld metal and base metal strength, high toughness of the weld metal ; They may weldment emphasis on the chemical composition of requirements, such as the choice of heat-resistant steel, stainless steel welding rod, usually focused on considering the weld metal and base metal chemical into Points in the same; may sometimes be strict requirements on both in the choice of electrode should be prioritizing, considering. Second, consider the weldment working conditions and The use of performance weldment withstand dynamic load and impact load case, in addition to the requirements to ensure that the tensile strength, yield strength outside, on the impact toughness of plastic have a higher to Requirements. You should use low-hydrogen type, titanium, calcium or iron oxide-type electrode. 2, weldments in corrosive media, we must distinguish between the kind of medium, concentration, temperature, and Types of corrosion (general corrosion, intergranular corrosion, stress corrosion, etc.), so choose the stainless steel electrode. 3, weldments subjected to wear under the conditions of work are required to distinguish between general Wear or impact wear, metal abrasion or abrasive wear, wear, or at room temperature at a high temperature wear. Should also consider whether the work in the corrosive medium. To choose the right hardfacing electrode. 4, at low temperature or high temperature weldment should be selected to ensure low or high temperature mechanical properties of the electrode. Consider the complex of weldment Miscellaneous degree of stiffness the size of the weld groove preparation and welding parts of complex shape or thickness of the weldment, due to the weld metal in the cooling contraction of internal stress Large, easy to crack. Therefore, it must be good crack resistance electrode, such as low hydrogen electrodes, high toughness welding rod or iron oxide electrode. 2, welding parts in which the bit Set can not flip, you must select the all-position welding electrode. 3, due to limitations leaving some of the welding parts difficult to clean, you should consider using oxygen Strong resistance and rust, leather and oil spill response is not sensitive to acid electrode to avoid the holes and other defects. Fourth, consider the working conditions of welding and DC welding machine AC and DC welding rod should be used. Certain steel products (such as pearlitic heat-resistant steel) the need for post-weld heat treatment to eliminate residual stress. But equipment conditions or knot Structure and therefore can not be heat treated, should be used with the base metal chemical composition of the different electrodes (such as austenitic stainless steel electrode) to avoid heat treatment after welding. In addition, Should be based on the construction site conditions, such as field operations, welding work environment to a reasonable selection of welding rod. Consider to improve the welding process and to ensure workers' health in the acid Sexual electrode and alkaline welding rod to meet the place, in view of the alkaline welding rod to require high operating and construction, it should be acid electrode. In a confined capacity Should maximize the use of low dust and low toxicity electrode inside or poorly ventilated spaces welding or acid electrode. 6, considering the economy, guarantee performance under the premise, try to use price Grid of low-cost electrodes. According to China's mineral resources, we should vigorously promote the ilmenite type electrode. Different requirements of the primary and secondary welds, using different electrode performance, do not film The surface of the pursuit of the comprehensive performance of the electrode. According to the structure of the working conditions, reasonable selection of the electrode alloy system, such as general corrosion conditions at room temperature for stainless steel Steel, you do not use stainless steel containing niobium electrode. 7, considering the volume of the structure of the efficiency of the welding work, conditions should maximize the use of high efficiency electrode, such as iron powder electrode, High-efficiency stainless steel electrode and gravity electrode, or the selection of the bottom electrode, a special electrode stand down electrode and the like in order to improve welding productivity.