Determination of Crack and Influencing Factors Analysis of 2205 Duplex Stainless Steel by Intergranular Corrosion Test

The cracks of 2205 duplex stainless steel after the intergranular corrosion test with copper-16% sulfuric acid-copper sulfate were determined by optical microscope and transmission electron microscope. The influencing factors of cracking were analyzed by tensile property test, residual stress test and roughness test. The results show that after sensitization at 675℃ for 1 hour, a small amount of(Mo, Si) riched compounds are precipitated at the ferrite boundary and the ferrite-austenite phase boundary, and dispersed carbides are precipitated in the ferrite grains. There is a little non transformed ferrite in the austenite grains. The cracks produced by bending are transgranular cracks, and the materials have no intergranular corrosion sensitivity. The mechanical properties of the experimental DP steel can meet the standard of 2205 DSS. The small residual tensile stress and elbow diameter have little influence on the crack generation. The specimen with a surface roughness of 1.6 μm after bending has cracks, and the specimens with a surface roughness of equal to or less than 0.9 μm have no cracks. Therefore, it is necessary to control the surface roughness of the sample before the intergranular corrosion test with copper-16% sulfuric acid-copper sulfate.