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 M-7(B,C)(3), M-2(B,C) borocarbides and the martensite matrix; the matrix has less chromium and more nickel than those in the M-2(B,C) and M-7(B,C)(3). The microstructures in heat-treated, boron-bearing stainless steel consist of M-7(B,C)(3), M-2(B,C) and M-23(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.