The deposited metal welded with alkaline electrode by manual arc welding has good mechanical properties and crack resistance, so it is widely used in the welding of alloy steel and important carbon steel structure. Alkaline electrode is also called low hydrogen electrode because the hydrogen content of the deposited metal is the lowest among all electrodes. Compared with acid electrode, the water content in the coating of alkaline electrode and diffusive hydrogen in deposited metal require very low. If the electrode is not properly preserved, it is easy to be damped or rusted, seriously affecting the quality of welding, so we must pay attention to the storage of alkaline electrode.
Storage conditions of alkaline electrodes
The alkaline electrode should be stored in a special warehouse. The warehouse should be well ventilated and clean indoors. The warehouse must maintain a certain temperature and humidity. The temperature should be 10~20 C and the relative humidity is less than 60%.
The electrode should be placed on the shelf, the height of the shelf from the ground should not be less than 30 cm, the distance from the wall should not be less than 30 cm. The electrode should be classified and stacked according to the type, brand, batch and specifications. The electrode in each area should be clearly displayed to avoid mixing.
Domestic welding rods are generally packed in plastic bags, placed in cartons or rubber boxes, the sealing is poor; while foreign welding rods are mostly vacuum sealed iron sheet packaging, completely sealed. Packing should not be damaged when welding rod is checked and moved in warehouse, so as not to cause improper sealing and moisture absorption. In addition, the deposited electrode should be checked regularly, whether it is damped, damaged, and whether the temperature and humidity are within the required range. The warehouse should check at least once a day.
Drying of alkaline electrode
The alkaline electrode shall be dried according to the baking thermometer specified in the instruction. The alkaline electrode should be dried at 350-400 C for 1 hour. The baking temperature of low hydrogen electrode with special requirements for hydrogen content can be raised to 400-450 C. The welding rod of vacuum sealing packing of iron sheet is still in a dry state and can be put directly into the insulating cabinet or the insulating barrel of welding rod. The temperature of the oven should rise slowly, and the cold welding rod should not be put into the high temperature oven or cooled suddenly to prevent the coating from cracking. When drying electrode, should be laid into layers, each layer of electrode can not be stacked too thick (generally 1-3 layers), to avoid electrode drying when uneven heating and moisture should not be removed. The dried electrode should be placed in the heat preservation cabinet, and the temperature in the cabinet should be controlled within 100~150 C. The welder receives the electrode and then put it in the welding rod insulation cylinder for 100~150 degrees.
When the sealed package containing alkaline electrodes is broken or opened, the electrodes are exposed to the air for more than 4 hours, or even if the electrodes are not damaged, they are placed in a particularly humid environment, and the electrodes will be damped. According to the degree of moisture, the alkaline electrode affects the welding quality to varying degrees.
If the alkaline electrode coating absorbs only a small amount of moisture, it may lead to the formation of pores in the weld, such internal pores need X-ray or damage test to be found. If the base material has high hardenability, only a slight wetting of the electrode will result in the crack below the weld.
When the alkaline electrode absorbs a large amount of moisture and is relatively humid, if the welding is carried out, there will be internal pores in the weld and surface pores visible to the naked eye on the weld.
When alkaline electrode is seriously damped, besides a large number of pores will be produced in the weld, there will also be weld cracks or cracks under the weld. By re-drying the damped electrode, the alkaline electrode can restore its good weld quality and avoid welding defects. In the process of production, the proper electrode and drying temperature should be determined according to the type of the basic electrode and its moisture content.
Matters needing attention
Redrying alkaline electrode at a certain temperature below the specified baking temperature for several hours is not the same as baking at the specified temperature for one hour. Therefore, in order to ensure the performance and welding quality of alkaline electrode, alkaline electrode should be dried strictly according to the specified baking temperature and time.
The number of alkaline electrodes can not be repeated more than two times.铜焊丝,Copper Welding Rods,铝焊丝,aluminium welding wire,镍焊条,Nickel electrode,药皮焊条,Flux Coated Brazing Welding Rods