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制造承压制件,特别是管道和各种设备零件时,它们的尺寸及结构形状使得不可能进行额外的加工或者封底焊,对焊缝根部及过渡区的焊着金属要用特种保护气体的焊接方法来获得必需的质量。当使用保护气体时,焊缝根部的氧化作用降低。用不同种类的(铜,碳,石英等)盖板或垫板来减少焊缝根部金属的氧化作用是有限制的,并且经济上不是经常有效。用保护气体以不大的速度流经焊件内腔,是保证可靠的防止焊缝氧化的最简单和最有效的方法。应用由比重1.25公斤/公尺~3的氮和氢组成的气体(商
When manufacturing pressure-bearing parts, especially pipes and various equipment parts, their size and structure make it impossible to make additional machining or back-end welding. Weld metal at the base of the weld and in the transition zone is protected by a special protective gas Welding method to get the necessary quality. When using a shielding gas, the oxidation of the root of the weld decreases. Reducing the oxidation of the weld metal at the root of the weld with different types of (copper, carbon, quartz, etc.) covers or shims is limited and economically not always effective. Using shielding gas to flow through the weldment lumen at a slow rate is the simplest and most effective way to ensure reliable weld bead oxidation prevention. Application of a gas consisting of nitrogen and hydrogen with a specific gravity of 1.25 kg / m ~ 3