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Stainless steel bonded pipe calls for deep penetration, no oxide inclusion and also tiny heat impacted zone, the weld joints substantially affects the formability of stainless-steel pipeline. One of the most typical welding method for stainless steel is hand welding (MMA), complied with by steel electrode gas welding (MIG/MAG) as well as tungsten inert gas welding (TIG).

hands-on welding( MMA).

Manual welding is an extremely usual and also easy-operate welding method, can be utilized to bond nearly all products and also any setting even under water. In electrode welding, the size of the arc is readjusted by hand, which is identified by the size of the gap in between the electrode and the work surface. Most of the times, the welding is performed by straight existing, and the electrode is used as both arc provider and also weld filler material. The electrode is made up of alloy or non-alloy steel core cord and also electrode cover. This layer of coating to secure the welding seam from air damage, at the exact same time can maintain the arc, the electrode can be titanium type electrode, however also fundamental, which depends on the thickness and also structure of the finish.

MIG/MAG.

This is an automatic gas secured arc welding method. The arc is warmed between the cord of the existing carrier and also the work surface under the shielding gas, as well as the cable fed by the machine melts under its very own arc as the electrode. As a result of its flexibility and also different benefits, MIG/MAG welding is still the most widely used welding approach in the world, relevant to steel, non-alloy steel, reduced alloy steel as well as high alloy product. When welding stainless-steel, MAG can satisfy the demands of sheet steel as thick within 0.6 mm. The protective gases used here are reactive gases such as carbon dioxide or combined gases.

Strategies for stainless steel MIG welding.

( 1) Flat attributes of the welding power supply, DC utilizing reverse polarity (welding cord linked to the positive electrode).

( 2) Pure argon (purity of 99.99%) or Ar +2% O2, circulation rate of 20|25L/min is ideal.

( 3) Stainless steel MIG welding is normally under the problems of jet shift welding, voltage to get used to the arc length in 4|6mm.

( 4) Windproof: MIG welding is susceptible to the impact of the wind to generate pores, so the wind speed above 0.5 m/s need to be taken windproof steps.

( 5) Moisture-proof: exterior welding must secure the work surface from moisture in order to optimize the result of securing gas.

TIG welding:.

The arc is created between refractory tungsten electrode and also the workpiece, which is a welding method using argon, helium and also various other inert gas as the securing gas. The welding is secure and also created well. TIG welding stainless-steel with upright external characteristics of the power supply, using positive polarity when DC (welding wire is attached to the unfavorable electrode) due to the fact that it has a deep penetration ability. TIG welding can be used to bond slim and also moderate density stainless steel sheets, as an origin pass on a thicker area.

Tricks for stainless-steel TIG welding.

( 1) The welding joint is good and also the welding deformation is tiny, appropriates for the welding of stainless steel sheet under 6mm.

(
weldermetals.com ) Argon is a safety gas with a pureness of 99.99%. When the welding current is 50|150A, the flow price of argon is 8|10L/min, as well as when the present is 150|250A, the flow price is 12|15L/min.

( 3) The length of the tungsten electrode from the gas nozzle to 4|5mm, in the place of fillet welding is 2|3mm, where with the deepness of the groove is 5|6mm, the range from the nozzle to the work is generally not more than 15mm.

( 4) The corrosion and also oil in the welding component must be cleaned up to avoid welding pores.

( 5) The arc size of 1|3mm is the most effective, and also the protection result is bad if it is too long.

( 6) When butt support, the back side also requires gas security in order to protect against the rear of the lower grain from oxidation.

( 7) In order to secure the welding pool well with argon as well as facilitate the procedure, the Angle in between the center line of tungsten electrode and also the work surface at the welding site should typically be maintained at 80|85 °, and the Angle between the filler cable and the workpiece surface must be as little as possible, typically about 10 °.