The welding rod is composed of a welding rod core and a coating. One of the functions of the welding rod core is to conduct electricity as an electrode. At the same time, it is also the main material for forming the weld metal. Therefore, the quality of the welding rod core directly affects the performance of the welded joint, and the materials are specially manufactured. The high-quality steel-welded carbon steel electrode core is usually 0.08% C low carbon steel. The most widely used H08 and H08A carbon content and sulfur and phosphorus harmful impurities have extremely severe restrictions on the commonly used electrode diameter ( That is, the diameter of the electrode core is 2.5 to 6 mm, and the length is 350 to 450 mm. Although the electrode has the ability to resist external damage under normal circumstances, it cannot be ignored that it is easily damaged due to poor storage. The electrode is a ceramic product. He can't resist impact like a steel core, so he can't drop it when loading and unloading.
Welding rods packed in cartons cannot be handled with hooks. Certain types of electrodes, such as alkaline electrode coatings for special drying requirements, should be handled with care. In general, the welding electrode is packed in plastic bags and carton. In order to prevent moisture absorption, it cannot be disassembled before use of the electrode. Try to use it as soon as possible. If possible, the remaining electrode after welding is sealed. . Acidic electrodes are not sensitive to moisture, while organic rutile electrodes allow for higher water content. Therefore, according to the specific conditions of the damp, dry at 70-150 ° for one hour, the storage time is short and the package is good, and it can not be dried before use.
The alkaline low-hydrogen electrode must be dried before use to reduce the hydrogen content of the electrode and prevent defects such as pores and cracks. The drying temperature is usually 350 ° C for one hour. Do not suddenly put the electrode in the high temperature furnace or suddenly cool it to avoid dry cracking. For special requirements on hydrogen content, the drying temperature should be increased to 400-500 ° C for one to several hours. The dried alkaline electrode is preferably placed in another low temperature drying oven controlled at 50-100 ° C and used as needed. When drying the electrode, each layer of welding rods should not be stacked too thick (generally 1-3 layers) to avoid uneven heating and moisture during electrode drying. When operating in the open air, the electrode must be properly stored overnight and not allowed to be stored in the open air. It should be stored at a constant temperature in the low temperature box, otherwise it must be re-dried before use the next day.
The term "expiration" does not mean that the storage time exceeds a certain time limit, but refers to a change in the degree of quality (deterioration). Various types of electrodes are stored for a long time, and sometimes white crystals (hairs) are found on the surface of the electrode. This is usually caused by water glass. These crystals are not harmful. It means that the electrode is stored for a long time and is damp. For the electrode that has been stored for many years, the process shall be tested and the electrode shall be dried at the specified temperature. There is no abnormal change in the process performance of the electrode during the welding, such as the phenomenon of blockage of the coating, and defects such as pores and cracks, the mechanical properties of the electrode are generally guaranteed. Due to the slight rust of the wetted core, the electrode will not affect the performance basically, but it is not suitable if the welding quality is high.
The electrode is heavily rusted and can be downgraded as appropriate or used for general component welding. It is best to test its mechanical properties according to national standards and then determine the scope of its use. If the welding paint contains a large amount of iron powder, the relative humidity is high and the storage time is long, the welding rod is damp, and even the paint is rusted. Although the electrode is dried, the pores or the diffusion hydrogen are still high during welding. And therefore have to be scrapped. It is required to improve the packaging to prevent the electrode from absorbing moisture and must be kept in storage. All kinds of welding rods have been seriously deteriorated, and the coating has been seriously peeled off. This batch of welding rods should be scrapped.
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