2205　duplex　stainless　steel　is　often　welded　on　the　surface　contact　of　the　corrosive　media　in　projects　to　prevent　stress　corrosion　in　petrochemical　facilities.　To　explore　the　application　scope　and　feasibility　of　the　solution,two　welding　processes　(automatic　welding　and　manual　welding),　three　kinds　of　the　common　corrosion　environment　(saturated　hydrogen　sulfide,　magnesium　chloride,　calcium　chloride)　are　studied　by　constant　load　tensile　and　micro-fracture　analysis　methods,　its　stress　corrosion　is　evaluated　comprehensively　and　the　mathematical　model　of　stress　life　is　established　based　on　the　experimental　results.　The　results　indicate　that　constant　tensile　load　threshold　sigma　th　automatic　welding　is　the　0.45R(P0.2),　manual　welding　is　the　0.4R(P0.2)　in　saturated　H2S　environment,　and　the　difference　is　17%;　all　the　samples　remain　intact　after　96　hours　in　0.9R(P0.2)　stress　test　of　the　calcium　chloride　environment,　which　shows　excellent　resistance　to　chloride　stress　corrosion.　But　the　material　doesn＇t　work　well　in　the　environment　of　boiling　magnesium　chloride　solution.