Welding process and treatment of stainless steel pipe fittings

Stainless steel pipe fittings are usually installed when the need for welding, due to the special nature of the material, stainless steel pipe fittings in the welding is different from the ordinary pipe welding. And welding finished the treatment of the weld is different, stainless steel pipe weld not only requires the beauty can not rust, then the stainless steel pipe welding and processing process is how it?

As the stainless steel pipe pieces of different sizes, according to the unique place of stainless steel pipe welding, as far as possible to reduce the amount of heat input, so the use of manual arc welding, argon arc welding two methods, d> Φ159 mm using argon arc welding, Arc welding cover. D ≦ Φ159 mm full of argon arc welding, stainless steel pipe welding technical requirements are as follows:

manual arc welding machine using DC reverse, argon arc welding with DC is followed.

welding should be welded with stainless steel wire brush off the surface of the oxide, and acetone washing, the electrode should be 200-250 ℃ drying 1h, with the take with the use.

Clean the oil in the range of 25 mm on both sides of the workpiece groove before welding, and wash the groove on both sides with 25 mm on both sides of the bevel.

argon arc welding, the nozzle diameter Φ2 mm, tungsten is extremely pot tungsten, specifications Φ2.5 mm.

TIG welding stainless steel, the back must be filled with argon protection, in order to ensure the back forming. Using the method of partial argon in the pipeline, the flow rate of 5-14L / min, positive argon flow rate of 12-13L / min.

When welding the thickness of the weld should be as thin as possible, and the root fusion outstanding, when the arc into a slow slope, if the arc shrinkage, the application of grinding machine wear off. Must be arc in the groove arc, arc should be filled with craters, to prevent cracks in the arc.

As the stainless steel pipe fittings for the austenitic stainless steel pipe, in order to prevent carbide precipitation and intergranular corrosion, should strictly control the inter-layer temperature and post-weld cooling rate, the requirements of the inter-layer temperature control between 60 , Immediately water-cooled, while the use of sub-welding. This symmetrical dispersion of the welding sequence, you can increase the joint cooling rate, but also reduce the welding stress.

Source: China Pipe Fittings Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)

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