What is the difference between SUS316 stainless steel ERW and TIG?

1. Core Concept: The Essential Difference Between ERW and TIG Welding
1. ERW (Electric Resistance Welding)
Principle: The edge of the stainless steel tube billet is heated to a plastic state by high-frequency current or low-frequency resistance heat, and then pressure is applied by an extrusion roller to fuse the metals on both sides to form a weld, without the need for filling wire (self-melting welding).
Typical Application: Mainly used for industrial production of stainless steel welded pipes (such as ERW welded pipes), suitable for large-scale, continuous manufacturing, and commonly used in medium and low-pressure pipelines and structural pipes.
2. TIG (Tungsten Inert Gas Welding)
Principle: Using tungsten as a non-melting electrode, the arc and the molten pool are protected by argon gas, and the weld is filled with filler wire (such as ER316L) after melting. The heat input is controllable and the weld is finely formed.
Typical Application: Commonly used for manual or semi-automatic welding, suitable for welding scenarios with thin-walled pipes, precision parts or high-quality requirements (such as pipeline docking and equipment assembly).

2. SUS316 stainless steel welding characteristics and compatibility of the two processes
1. Difficulties in welding SUS316 stainless steel
Risk of intergranular corrosion: Carbon is easy to combine with chromium at high temperature to form Cr₂₃C₆, resulting in chromium depletion at the grain boundary. It is necessary to control heat input and select low-carbon welding wire (such as ER316L).

2. Characteristics of SUS316 ERW process

High efficiency and low cost: No filling material is required, the welding speed is fast (up to tens of meters per minute), and it is suitable for large-scale production.
Weld consistency: Mechanized production, fixed weld position, suitable for standardized pipes (such as pipes with an outer diameter of Less than or equal to 610mm).
3. SUS316 TIG process characteristics

High-quality welds: Argon protection is sufficient, the molten pool is pure, the composition can be adjusted by filling the welding wire (such as reducing the carbon content), and the corrosion resistance of the weld is close to that of the parent material.
Flexible: Suitable for various joint forms (butt joint, corner joint, overlap joint), can weld ultra-thin pipes (wall thickness Less than or equal to 0.5mm) or thick-walled pipes (multi-layer multi-pass welding is required).
Defects can be controlled: The surface and internal defects of the weld can be easily detected by visual inspection or flaw detection (such as PT/RT), suitable for high-pressure and high-corrosion scenarios (such as chemical pipelines, medical equipment).

1. Decide by usage scenario

Requirements: large volume, low cost, medium and low pressure ( Less than or equal to 10MPa), non-harsh corrosive environment (such as ordinary industrial water, air).


Requirements: high corrosion resistance (such as seawater, acid and alkali media), high pressure ( Greater than or equal to 10MPa), high temperature ( Greater than or equal to 600 degree ) or precision scenarios (sanitary grade, flaw detection requirements).