A study on microstructure and erosion-corrosion performance of Fe–Cr–Ni–B alloy

The microstructure and erosion-corrosion performance of Fe–Cr–Ni–B alloy were studied. The experimental results were analyzed by hardness tester, energy spectrum analyzer, scanning electron microscope, X-ray diffraction analyzer. The results show that the Fe–Cr–Ni–B alloy consists of martensite and borocarbides [M₂(B, C) and M₇(B, C)₃], and M₂(B,C) and M₇(B,C)₃ borocarbides both have more chromium and less nickel than the matrix. After heat treatment, the hardness of the alloy reaches 52.3HRC. For the test alloys, the higher rotating speed test condition results in higher erosion-corrosion weight loss, and the erosion-corrosion weight loss increases first and then decreases with the increase of the impingement angle. Compared with Cr28 high chromium cast iron, in the erosion-corrosion surface of Fe–Cr–Ni–B alloy, the borocarbides are slightly broken, so, the Fe–Cr–Ni–B alloy exhibits excellent erosion-corrosion resistance under the borocarbide protection. (paper)