316L stainless steel pipe composition on welding performance, do you know?

[guidebook] : 316L stainless steel pipe has a wide range of applications in the chemical industry because of its excellent corrosion resistance, 316 stainless steel pipe in the welding molding process, the metal composition of the weld properties have different effects. Stainless steel 316 pipe is mostly used as fluid piping

316L stainless steel pipe has a wide range of applications in the chemical industry because of its excellent corrosion resistance, 316 stainless steel pipe in the welding molding process, the metal composition of the weld properties have different effects. Stainless steel 316 pipe is mostly used as fluid piping, heat exchanger or mechanical structure of the fittings, so the quality of the weld is very high, today to give you a detailed introduction to the 316 stainless steel pipe composition on the impact of welding performance.

316L stainless steel pipe is ultra-low carbon pure austenitic stainless steel with good weldability and low intergranular lamination possibility. However, due to the low thermal conductivity and high coefficient of linear expansion of this steel, large tensile stresses are generated in the welded joints during cooling, the heat input of the weld is large, and thermal cracking, corrosion cracking and deformation are easily generated when the cooling rate is slow.

316L stainless steel pipe can be welded by all standard welding methods, according to the different uses in welding, can be used 316Cb, 316L or 309Cb stainless steel filler rod or electrode to weld; in the commonly used welding methods, MIG and TIG welding heat input is smaller, and argon flow in addition to the protection of high-temperature metal, but also possesses a certain degree of cooling effect, increasing the crack resistance of the weld to reduce weld distortion. Thus reducing welding deformation.

The use of 316L stainless steel pipe, generally do not carry out post-weld annealing treatment, austenitic stainless steel after welding is generally not de-stress annealing treatment. The reason is that austenite has good plasticity and toughness, the stress relief annealing after welding can not restore its properties. Secondly, in the temperature range of 450 to 850 ℃ is the sensitization temperature of austenitic stainless steel, austenitic stainless steel in this range of long-term heating, its corrosion resistance will be reduced. If there is a ferrite component in the weld, it may also produce 475°C embrittlement. Post-weld stress relief annealing heat treatment just within the temperature range (except solution treatment and stabilization treatment).

However, sometimes this situation is more special when the 316L stainless steel pipe welded to the post weld stress relief annealing heat treatment, a mainly for the stable development of society, the geometry of the equipment components, the need to eliminate the welding residual stress; another is the equipment safety staff in the environment that has a problem with the tendency to produce stress corrosion, the same need to eliminate the tensile residual stress.