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Prevent air hole when welding flexible waterproof casing

Time: 04-27 󰃯 Reading times: 880 󰃳 Editor in charge: The sea 󰃗 Column: product focus

Introduction: The welding porosity of flexible waterproof casing refers to the cavitation caused by the gas in the molten pool not escaping before the metal solidifies during welding. The gas may be absorbed by the bath from the outside, or it may be generated by the reaction in the process of welding metallurgy. (1) Flexible defense

flexibility Waterproof casing Welding porosity refers to the cavitation caused by the gas in the molten pool not escaping before metal solidification during welding. The gas may be absorbed by the bath from the outside, or it may be generated by the reaction in the process of welding metallurgy.
(1) Flexible waterproof casing Classification of welding porosity
The stomata can be divided into spherical stomata and striped wormlike stomata in appearance, and can be divided into single stomata and group stomata in total. The cluster stomata can be divided into evenly distributed stomata, aggregated stomata and chain distributed stomata. According to the gas composition in the pores, there are hydrogen pores, nitrogen pores, carbon dioxide pores, carbon monoxide pores, oxygen pores, etc. The pores of fusion welding are mostly hydrogen and carbon monoxide.
(2) Formation mechanism of welding porosity in flexible waterproof casing
In the process of molten metal solidification, a lot of gases can only dissolve metal from the molten gas at room temperature. When the solidification rate exceeds the gas escape rate, pores are formed.
(3) Key reason of porosity caused by welding of flexible waterproof casing
Due to the high temperature of the welding rod, the oil and gas in the welding rod will be increased due to the oil and gas content of the welding rod, which will be dissolved in the surface of the welding rod. If the welding line kinetic energy is too small, the cooling rate of the bath is large, which is not conducive to the gas escape. Insufficient deamination of welding metal will also raise oxygen porosity.
(4) Damage of welding Blowhole in flexible waterproof casing
The welding porosity of flexible waterproof casing reduces the reasonable cross-sectional area of welding, makes the weld loose, thus reduces the strength of the joint, reduces the plastic deformation, and will continue to cause leakage. Porosity is also a factor causing stress. Hydrogen pores will also promote cold cracking.
(5) Countermeasures to avoid blowholes
a. Eliminate grease, rust, moisture and sundries on welding wire, groove and surrounding surface during operation.
b. Choose alkaline electrode and flux, and dry them thoroughly.
c. Reverse arc welding is used.
d. Preheat before welding to reduce cooling rate.
e. Welding shall be carried out according to the standard with higher strength.