Austenitic stainless steel weld quality problems and countermeasures

Austenitic stainless steel weld quality problems and countermeasures

Austenitic stainless steel still could have some weld quality problems , it is easier compared to the austenitic stainless steel and ferritic and martensitic stainless steel, but in some cases, there will still be following welding quality.

1. The corrosion resistance of austenitic stainless steel fittings

The corrosion resistance of austenitic stainless steel fittings including two corrosion: Intergranular corrosion and stress corrosion cracking. Intergranular corrosion of metal materials (including connectors) in a specific corrosive media along the grain boundary corrosion occurred. Suffers the intercrystalline corrosion the stainless steel or the attachment, sometimes on the surface does not have the trace, but when receives the stress, because the crystal grain has lost the relation, loses the intensity nearly completely, will occur along the intercrystalline cracking accident.There are three parts of the connector may appear to intergranular corrosion (see Figure 1),The weld on the intergranular corrosion (see Figure 2).B is the base metal zone sensitization to intergranular corrosion occurred in the thermal cycle peak temperature 600-1000 ℃ heat affected zone, C is knife shape corrosion, Occurred in the weld fusion line outside a very narrow range, narrow and deep shape, similar to the knife shape.The stress corrosion dehiscence is the metallic material (including attachment), in the stress and the corrosive medium simultaneously affect the low stress brittleness dehiscence phenomenon which in the situation occurs (to see Figure 3)

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