Welding Wire storage and quality management
Welding Wire quality and quality management In order to ensure the quality of the Welding Wire structure, in addition to the correct choice of welding material, but also in the welding construction attention to the welding material storage and quality management. In the Welding Wire packaging, in addition to the use of plastic bags, some bags also add a small package of moisture-proof agent, there are carton packaging, but the moisture is still in the custody of the Welding Wire must be considered. Because of the moisture absorption of the Welding Wire, the deposited metal can increase the diffusion of hydrogen content, resulting in pits, holes and other defects, welding process performance and weld metal mechanical properties deterioration, serious can lead to weld cracking, which with other Welding consumables are the same. Of course, because the flux in the flux-cored Welding Wire is very tightly wrapped in the steel strip, the powder is in contact with the air, and there is no material that is easy to absorb moisture in the electrode, so that the moisture absorption Very small, but if long-term high temperature and humidity placed in the environment, in addition to rust on the surface of the Welding Wire, the same will absorb moisture.
1 Welding Wire storage requirements require that the Welding Wire is not opened in the recommended storage conditions. The Welding Wire should be stored in a dry, well-ventilated warehouse.
2 Welding Wire in the use of management after the opening of the Welding Wire should be completed within 2 days. After the opening of the Welding Wire to prevent the surface condensation condensation, or rust, grease and other hydrocarbons contaminated to keep the Welding Wire surface clean and dry
In order to obtain a well-welded welded joint, the Welding Wire suitable for the base material should be selected as the filling material from the purpose of the use of the welding member.
(1) weld crack susceptibility
The choice of filler metal with a melting temperature lower than that of the base metal can greatly reduce the tendency of intergranular cracking in the heat affected zone. So the alloy content is higher than the base metal Welding Wire for filling metal, usually to prevent weld metal cracks. If the 6061 alloy with 0.6% silicon, if the 6061 for filling the metal, the crack sensitivity is great, but with 5% silicon 4043 Welding Wire for the filler metal, the melting temperature is lower than the base metal, in the cooling process than the base metal has Better plasticity to eliminate shrinkage stresses that cause cracks, so good crack resistance. Should also be careful to avoid the production of cracks in the weld metal parts, such as aluminum alloy welds do not want a combination of magnesium and copper, so 5000 series Welding Wire is also used in welding 2000 series base metal; surface 2219 Welding Wire should not be used in 5000 Series of base metal.
(2) joint strength
The strength of the welded joint varies with the alloying element content of the Welding Wire. That is, for the non-heat treatment alloy welded joint strength, according to 1000 series, 4000 series and 5000 series order. In the 5000 series with magnesium, manganese and other content increased, the strength of welded joints by 5554,5654,5356,5183,5556 in the order of increase.
(3) Machinability of the joint (plastic)
The need for bending of the welded joints, the general processing of the impact of plasticity, and plasticity decreases with increasing strength. Especially those containing 3% magnesium or more (5154,5056,5082,5182,5083,5086) must avoid the use of silicon-containing Welding Wire (4043,4047). This combination forms a large amount of Mg2Si, and the plasticity decreases.
(4) color difference after anodic oxidation treatment
In order to improve the corrosion resistance, the electrode is often subjected to anodic oxidation treatment. If the composition of the weld metal is significantly different from that of the base metal, or the casting structure of the weld metal is different from the calendering structure of the base metal, the weld metal after the anodic oxidation process Produce color difference. For example, the welds of silicon-containing 4000 series Welding Wires are gray-black after anodic oxidation, and the 2000, 5000 and 6000 base materials are silver-white. So if the appearance of color matching is an important indicator, the choice of Welding Wire must be considered when the formation of weld tissue composition and organization.
(5) mechanical properties and corrosion resistance of joints under high temperature
The 5000 series of Welding Wires (5654,5356,5556,5183) containing 3% magnesium or more should be avoided in structures with a temperature above 65 ° C because these alloys are sensitive to stress corrosion cracking and occur in the above temperature and corrosive environment Stress corrosion cracking.