According to the results,the intermetallic compound σ phase precipitates in the range of 900～1020 ℃,which affect the properties and microstructure,especially result in the steep decline of the steel's pitting corrosion resistance.

The microstructure,nonmetallic inclusions and the mechanical properties,weldability and sulphuric acid dew point corrosion resistance,atmospheric corrosion resistance and wear resistance of sulphuric acid dew corrosion resistant 12MnCuCr steel plates with minimum yield strength of 295 MPa have been studied.