1. What Kinds of Welding Electrodes should be used on Stainless Steel Welding?
There are Cr & Cr+Ni Types of Stainless Steel Welding Electrodes specified in AWS A5.4 Clause.
①Cr Type Stainless Steel has certain anti-corrosion (oxidizing acid, organic acid, air moisture corrosion) performance and thus usually being chosen as the materials in power station, chemical equipment, petroleum equipment, etc. But the weldability of Cr type stainless steel is poor, you have to be careful with the welding parameters and heat treatment conditions when you need to weld Cr type stainless steel. The right welding electrodes are critical too. Fox Alloy, as a professional manufacturer of filler metals with decades of expertise, can offer you full range of welding electrodes to meet different welding demands.
②Cr & Ni Type Stainless Steel welding electrodes have excellent anti-corrosion and anti-oxidant performance, thus they are widely used in chemical, fertilizer, petroleum and medical equipment industries. To avoid intergranular corrosion caused by heat, the welding current should be 20% lower than same dia. mild steel electrodes, the arc length should be shorter, quick cooling down actions be taken and narrow welding pass should be chosen.
2. Tips on Stainless Steel Tig Welding
DC- should be applied in Tig welding ( wires on negative).
①Tig welding is usually chosen to weld thin plates with thickness under 6mm, and featured with beautiful weld bead and less welding deformation.
②Shielding gas is 99.99% purity Argon and correct gas flow should be chosen according the the welding current.
Gas flow should be 8-10L/min for welding current 50-150A and 12-15L/min for current 150-250A.
③Tungsten electrodes protruding length should be 4-5mm in normal situation and 2-3mm in fillet welding, 5-6mm in deep groove welding. The nozzles to weld piece distance should be kept under 15mm.
④To avoid gas holes, rust, oil and other impurties should be removed before welding
⑤Arc length should be 1-3mm in stainless steel Tig welding, too long arc length will lead to poor gas shielding.
⑥Gas shielding in the back should be applied in butt backing welding to avoid oxidation on the back of bottom welding passes .
⑦The angle between tungsten electrodes and weld pieces should be 80-85 degrees for better gas shielding performance and easier operation; The angles between Tig rods and weld pieces should be as small as possible, 10 degrees in normal situation.
⑧Wind proof actions should be taken for better gas shielding performance in places where there is wind; Ventilating actions should be taken for welders health consideration in indoor welding.
Full range of Tig welding rods made by Fox Alloy have been sold to dozens of countries all over the world and applied in different important projects. They are widely recognized for the outstanding performance with competitive prices as always in decades.
3. Tips on Stainless Steel Mig Welding
①DC+ application ( wires on positive )
②Pure argon (purity 99.99%) or Argon+2% O2 as shielding gas, gas flow 20-25L/min
③In stainless steel Mig welding, spray transfer is requested in normal situation, thus suitable voltage should be chosen so as to ensure the arc length within 4-6mm
④Gas holes can easily be found in Mig welding, thus wind proof actions should be taken in places where wind speed is over 0.5m/sec.
4. Tips on FCAW Welding
①DC+ application ( wires on positive ), normal Mig welding machine is ok for FCAW welding, but the pressure of wire feeding wheels should be smaller than mig welding.②100% CO2 as shielding gas with 20-25L/min gas flow
③Distance between welding nozzles & weld pieces should be 15-25mm
④Wire extension length should be about 15mm when welding current is below 250A and 20-25mm when current is over 250A.