How to Weld 316 Stainless Steel Pipes?

Jane

316 stainless steel pipe is used as a fluid conveying pipeline in metallurgy, chemical industry, food and other industries. It is often used in high-temperature and high-pressure fluid transportation pipelines, and generally has the advantages of corrosion resistance, heat resistance, high strength, and stable chemical properties. Generally, pipelines are required to have sufficient strength, good corrosion resistance and heat resistance to adapt to use under high temperature and high pressure conditions, such as below 900°C and pressure not exceeding 100 MPa.

How to Weld 316 Stainless Steel Pipes?

How to weld 316 stainless steel pipes? There are mainly: manual arc welding, argon arc welding and CO2 gas shielded welding.

1. Manual arc welding: suitable for welding weldments of various thicknesses, especially for weldingcarbon steeland low alloy steel weldments. It does not have high requirements on the appearance of the weld, is easy to operate, can use a variety of welding wires, has high welding efficiency, and is particularly suitable for working in narrow spaces. However, due to the limitations of welder proficiency and operating technology, manual arc welding can generally only weld low-alloy steel materials.
2. TIG welding: is a solid metal welding method. This method has the advantages of no pollution, small welding heat affected zone and beautiful weld. The disadvantage is that the purity of the argon gas used is relatively high (generally above 99.99%), which is expensive. In addition, cracks are prone to occur under low temperature and high current conditions. Arc welding has the advantages of high welding efficiency, multi-layer and multi-pass welding, and simple operation, but it is easy to cause defects such as pores, slag inclusions, and lack of fusion inside the weld of 316 stainless steel pipes.
3. Gas shielded welding: a welding method with enclosed arc. The arc is protected by gas, and the temperature of the molten pool is relatively high, so the molten pool is easy to form, and the weld metal is not easily oxidized and deoxidized; it can improve the performance of the joint; the joint quality is high; and it has a wide range of uses. It is widely used under high temperature and high pressure. It is suitable for welding workpieces with complex structures such as pressure vessels and boiler parts.
4. Resistance welding: It is a method that uses the resistance heat of the welding machine itself to heat the workpiece, forming resistance between the two workpieces and generating a large contact pressure between the two poles to achieve the welding purpose. Resistance welding equipment is simple, easy to operate and master, and is widely used in production.

The operation technology of 316 stainless steel pipes has a great influence on the quality of weld. During welding operation, we must pay attention to controlling the temperature and try to avoid defects such as cracks in the weld caused by excessive temperature. The pipes should be kept clean and tidy, and the welding slag, oxide scale, flux, etc. left on the pipe wall should be cleaned up in time. Otherwise, these substances will affect the quality of the weld. If these substances are accidentally left on the weld, they must be cleaned with a grinding wheel.

When choosing a welding method, the following factors need to be considered:

1. Material thickness: Different welding methods are suitable for materials of different thicknesses.
2. Welding quality requirements: If high-quality welds are required, TIG welding or plasma arc welding may be a better choice.
3. Productivity: MIG welding and resistance welding generally have high productivity.
4. Cost: Different welding methods have different costs and need to be selected based on actual conditions.

When welding 316 stainless steel pipes, you also need to pay attention to the following points:

1. Choose appropriate welding materials: According to the chemical composition and mechanical properties of 316 stainless steel pipes, choose appropriate welding materials to ensure the quality of the weld.
2. Control welding parameters: including welding current, voltage, welding speed, etc., which need to be adjusted according to the welding material and the thickness of the weldment to ensure welding quality.
3. Carry out preparation before welding: including cleaning oil, rust and other impurities on the surface of the weldment, and preheating the weldment to reduce the occurrence of welding defects.
4. Post-weld treatment: including grinding and polishing of the weld to improve the appearance quality and corrosion resistance of the weld.

Read more: How to Store 316 Stainless Steel Pipes?