Predict the Temper Embrittlement Extent of Turbine Rotor Steel by Using Chemical Corrosion Method

The segregation of phosphorus on steel grain boundary will lead to temper embrittlement, and turbine rotor steel´s FATT (Fracture Appearance Transition Temperature) will raise. In this test the solution of picric acid and SDBS (sodium dodecyl benzene sulfonate) were used to corrode the turbine rotor steel sample. Phosphorus on grain boundary can be prior dissolve, so the grain boundary corrosion happen. After etch, width of etch groove on the grain boundary were measured and analyze by Photoshop. Then find out all relevant parameters with FATT which represents the degree of temper embrittlement. And then the predict model of FATT was established by make multiple linear regression analysis on all relevant parameters. The verifying experiment show that the model´s error range is about plusmn20degC.