1, the electrode should not be placed directly inside the baking temperature Electrode prior to use to make the necessary baking and drying the alkaline electrode placed in temperature controlled at 100 ° C insulation barrel, used with the check. Unused alkaline electrode placed in the air a long time, easy to absorb moisture, but also the next day re-baking. By removing the electrode within the water and water of crystallization, in order to ensure the quality of the welding process, arc stability and weld metal. But it is noteworthy baking electrodes, welding rod should be placed in the electric oven is gradually warming up, should not be placed directly inside the baking temperature, especially due to improper care and serious damp electrodes, due to a sudden the high temperature , too late to evaporate moisture and sudden expansion, So that the electrode drug skin rupture.
2, drying of the electrode should not be exposed too long in the air After drying of the electrode should be placed in the drying box or deposited in the electrode insulation barrel used with the check. If the drying of the electrode exposed to the air long storage time, the electrodes drug skin will quickly get damp, so that a significant increase in the diffusible hydrogen content in the electrode drug skin, especially exposed to the air the first 1 to 2 hours to absorb moisture the fastest, will this The moisture absorption of the electrode used for welding of important structures, the welding quality will be adverse effects. Therefore, in the welded construction, the drying of the electrode is removed from the dry box, it should be used up within two hours of high strength steel welding rod should be used within 1 hour, or need to re-baked; or electrode from out of the Welding Electrode box, immediately placed in 150 ° C in the electrode insulation tube insulation storage, used with the check should not be stored in the open for too long.
3, subject to certain conditions, restrictions can not be cleaned low carbon steel weldments, should not use alkaline electrode Alkaline welding rod welding process less sensitive to rust, oil, water, clean-up requirements are also higher on the surface of the groove, if the weldment is not completely clean up, it is easy to produce holes and other defects in the welding process. Therefore, subject to certain conditions, restrictions can not be cleaned low carbon steel weldment surface there are oxide, oil, dirt, the inappropriate use of alkaline electrode. Should be selected welding process better acid electrode, acid electrode anti-stomatal performance, not to rust, grease and moisture sensitivity.
4, for the important structural welding on impact toughness and crack resistance require a higher, should not use the acid electrode Acid electrode drug skin contains more oxides of strong oxidation, the oxygen content of the weld metal more alloying elements burning larger. Drug skin dioxide part of the silicon in the form of silicon oxide inclusions in the weld, therefore, the weld of the poor mechanical properties, especially ductility and impact toughness than the alkaline electrode. In addition, the acid electrode drug skin does not contain fluorite (CaF2), the dehydrogenase capacity is low; weld metal hydrogen content is high, resistance to cold cracking; and desulfurization elements manganese content in the weld, the desulfurization effect. Therefore, the thermal crack resistance is also poor.
Welded structure should not use the acid electrode should be used in low oxygen content of weld metal, alloy transition coefficient, low sulfur content and hydrogen content of alkaline electrode. Weld metal mechanical properties and crack resistance than the acid electrode.
5, should not use carbon steel electrode welding stainless steel weldments. Welding of austenitic stainless steel, welding generally do not need to take special measures of the process. However, if the Mig Electrode is the inappropriate choice will produce welding defects. For example, the choice of carbon steel electrode welding stainless steel, stainless steel will produce intergranular corrosion by intergranular corrosion of stainless steel will lose the ability of anti-corrosion, and will fracture along the grain boundaries under stress, the intensity is almost completely lost, is an austenitic the stainless steel is the most dangerous failure modes. Since carbon is caused by intergranular corrosion of the main elements, and therefore, the welding of stainless steel should be selected low-or ultra-low carbon stainless steel electrode, such as the Olympic 102, Olympic 132, Olympic 002 electrode.
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
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
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.