異型鋼管是經(jīng)冷拔制成各種異型的無縫鋼管。異型鋼管一般是根據(jù)斷截面來區(qū)分的，按材料來說又可分為無縫異型鋼管，鋁合金異型管，塑料異型管。不銹鋼異型管焊接時(shí)，應(yīng)該注意事項(xiàng)：焊接6mm以下薄板的異型管時(shí)，要具備焊縫成型美觀，焊接變形量小的特點(diǎn)。鎢極從氣體噴嘴突出的長(zhǎng)度，以4-5mm為佳，在角焊等遮蔽性差的地方是2-3mm，在開槽深的地方是5-6mm，噴嘴至異型管的距離一般不超過5mm。焊接電弧的長(zhǎng)度，焊接普通鋼時(shí)以2-4mm為佳，而焊接不銹鋼異型管時(shí)以1-3mm為佳，過長(zhǎng)則保護(hù)效果不好。

Special-shaped pipe is made of various special-shaped seamless steel pipe by cold drawing. Special-shaped pipe is generally distinguished according to the broken section. According to material, it can be divided into seamless steel pipe special-shaped pipe, aluminum alloy special-shaped pipe, plastic special-shaped pipe. When welding stainless steel special-shaped pipe, we should pay attention to the following points: when welding the special-shaped pipe with thin plate under 6mm, it should have the characteristics of beautiful weld shape and small welding deformation. The length of tungsten pole protruding from gas nozzle is 4-5mm, 2-3mm in places with poor shielding ability such as fillet welding, 5-6mm in places with deep groove, and the distance from nozzle to special-shaped pipe is generally not more than 5mm. The length of welding arc is 2-4 mm for ordinary steel, 1-3 mm for stainless steel special-shaped pipe, and too long is not good for protection.

為使氬氣很好地保護(hù)焊接熔池，和便于施焊操作，鎢極中心線與焊接處工件一般應(yīng)保持80-85°角，填充焊絲與管材表面夾角應(yīng)盡可能地小，一般為0°左右。焊接異型管時(shí)，采用垂直特性的電源，直流時(shí)采用正極性。保護(hù)氣體為氬氣，純度為99.99%。當(dāng)焊接電流為50-50A時(shí)，氬氣流量為8-0L/min，當(dāng)電流為50-250A時(shí)，氬氣流量為2-5L/min。有風(fēng)的地方，務(wù)請(qǐng)采取擋網(wǎng)的措施，而在室內(nèi)則應(yīng)采取適當(dāng)?shù)膿Q氣措施。為防止焊接氣孔之出現(xiàn)，焊接的異型管部位如有鐵銹、油污等務(wù)必要先清理干凈。對(duì)接打底時(shí)，為防止異型管底層焊道的背面被氧化，背面也需要實(shí)施氣體保護(hù)。

In order to protect the weld pool well by argon gas and facilitate welding operation, the tungsten pole center line and the workpiece at the welding site should generally maintain an angle of 80-85 degrees, and the angle between the filler wire and the surface of the pipe should be as small as possible, generally about 0 degrees. Vertical power supply and positive polarity are used in welding special-shaped pipe. The protective gas is argon with a purity of 99.99%. When welding current is 50-50A, the argon flow rate is 8-0L/min, and when welding current is 50-250A, the argon flow rate is 2-5L/min. In windy areas, please take measures to block the net, while indoors should take appropriate ventilation measures. In order to prevent the occurrence of welding blowhole, it is necessary to clean the irregular welded pipe if there is rust and oil stain. In order to prevent oxidation on the back of the bottom weld of the special-shaped pipe, gas protection is also needed on the back of the weld.