Abstract: Welding is the material of the workpiece to be welded (same or different), by heat or pressure or a combination of both, and with or without filling materials, the material of the workpiece reaches the atomic bond to form a permanent connection process. . So what are the main points and precautions for stainless steel welding? The following small series is introduced in detail for everyone.
What welding rods are used for welding stainless steel? Stainless steel welding points and precautions How to weld stainless steel
What welding rod is used for welding stainless steel
Stainless steel welding rods can be divided into chrome stainless steel welding rods and chrome-nickel stainless steel welding rods. Those of these two types of welding rods that meet the national standards are evaluated according to the national standard GB/T983-2012. Chromium stainless steel has certain corrosion resistance (oxidizing acid, organic acid, cavitation) heat resistance and corrosion resistance. Usually selected as power plant, chemical, petroleum and other equipment materials. However, the chrome stainless steel generally has poor weldability, and attention should be paid to the welding process, heat treatment conditions and selection of suitable welding electrodes. The chrome-nickel stainless steel electrode has good corrosion resistance and oxidation resistance and is widely used in chemical, fertilizer, petroleum and medical machinery manufacturing. In order to prevent intergranular corrosion due to heating, the welding current should not be too large, about 20% less than the carbon steel electrode, the arc should not be too long, the layer is fast cold, and the narrow bead is suitable.
Stainless steel welding points and precautions
1. Power supply with vertical external characteristics, positive polarity when DC (wire connected to negative electrode)
1. It is generally suitable for the welding of thin plates of 6mm or less, and has the characteristics of beautiful weld bead formation and small welding deformation.
2. The shielding gas is argon with a purity of 99.99%. When the welding current is 50~150A, the argon flow rate is 8~10L/min. When the current is 150~250A, the argon flow rate is 12~15L/min.
3. The length of the tungsten electrode protruding from the gas nozzle is preferably 4~5mm, 2~3mm in the place with poor shielding such as fillet welding, 5~6mm in the deep groove, and the distance from the nozzle to the work is generally not more than 15mm.
4. In order to prevent the occurrence of welding vents, the welding parts must be cleaned such as rust and oil.
Stainless steel welding points and precautions How to weld stainless steel
5, welding arc length, when welding ordinary steel, 2 ~ 4mm is better, and when welding stainless steel, 1 ~ 3mm is better, too long, the protection effect is not good.
6. When the butt is bottomed, in order to prevent the back side of the bottom bead from being oxidized, the back side also needs to be protected by gas.
7. In order to make the argon gas protect the weld pool well and facilitate the welding operation, the tungsten center line and the welding workpiece should generally maintain an angle of 80~85°, and the angle between the filler wire and the workpiece surface should be as small as possible. Usually about 10 °.
8, wind and ventilation. In windy places, take measures to block the net, and indoors should take appropriate ventilation measures.
Second, stainless steel MIG welding points and precautions
1. Use flat characteristic welding power source, reverse polarity when DC (wire is connected to positive electrode)
2, generally use pure argon (purity of 99.99%) or Ar + 2% O2, flow rate of 20 ~ 25L / min is appropriate.
3, arc length, stainless steel MIG welding, generally under the conditions of the injection transition welding, the voltage should be adjusted to the arc length of 4 ~ 6mm.
4, windproof. MIG welding is susceptible to wind, and sometimes breeze creates pores. Therefore, wind speed should be taken at a speed of 0.5 m/sec or more.
Third, stainless steel flux cored wire welding points and precautions
1. It adopts flat characteristic welding power source, and reverse polarity is used for DC welding. The welding can be carried out using a general CO2 welder, but the pressure of the wire feed wheel should be slightly loosened.
2. The shielding gas is generally carbon dioxide gas, and the gas flow rate is preferably 20~25L/min.
3. The distance between the tip and the workpiece is 15~25mm.
4, dry elongation, the general welding current is about 15mm when the temperature is below 250A, about 20~25mm when 250A or more is more suitable. Stainless steel welding rods can be divided into chrome stainless steel welding rods and chrome-nickel stainless steel welding rods. Those of these two types of welding rods that meet the national standards are evaluated according to the national standard GB/T983-2012. Chromium stainless steel has certain corrosion resistance (oxidizing acid, organic acid, cavitation) heat resistance and corrosion resistance. Usually selected as power plant, chemical, petroleum and other equipment materials. However, the chrome stainless steel generally has poor weldability, and attention should be paid to the welding process, heat treatment conditions and selection of suitable welding electrodes. The chrome-nickel stainless steel electrode has good corrosion resistance and oxidation resistance and is widely used in chemical, fertilizer, petroleum and medical machinery manufacturing. In order to prevent intergranular corrosion due to heating, the welding current should not be too large, about 20% less than the carbon steel electrode, the arc should not be too long, the layer is fast cold, and the narrow bead is suitable. 
Editor in charge: Zhao Hongli
Lithium Tetrafluoroborate (LiBF4) is white or yellowish powder, easily soluble in water, carbonate solvent and ethers compounds. The melting point of LiBF4 is 293-300℃, with the relative density of 0.852g/cm3.LiBF4 has excellent chemical and thermal stability and is mainly used as an additive in LiPF6 based electrolyte system to improve cycle life and performance of lithium batteries.
Lithium Tetrafluoroborate
Shandong Zhongshan Photoelectric Materials Co., Ltd , https://www.cnzsem.com