Investigations of microstructures and erosion–corrosion performance of cast boron-bearing stainless steel

The microstructures and erosion–corrosion properties of boron-bearing stainless steel were researched by an erosion–corrosion tester, energy dispersive X–ray spectrometry, scanning electron microscope and X-ray diffraction analysis. The microstructures of as-cast, boron-bearing stainless steel contain M₇ (B,C)₃, M₂(B,C) borocarbides and the martensite matrix; the matrix has less chromium and more nickel than those in the M₂(B,C) and M₇ (B,C)₃. The microstructures in heat-treated, boron-bearing stainless steel consist of M₇ (B,C)₃, M₂ (B,C) and M₂₃ (B,C)₆ borocarbides and ferrite, and the Rockwell hardness of heat-treated, boron-bearing stainless steel is lower than that of as-cast steel. For Cr28 white cast iron and boron-bearing stainless steel, the mixing wheel with higher rotating speed leads to a higher erosion–corrosion weight loss, and as the impingement angle increases, the erosion–corrosion weight loss increases first, and then decreases. For any erosion– corrosion experiment conditions, the erosion–corrosion resistance of boron-bearing stainless steel is better than that of Cr28 white cast iron.