Solid particle erosion behaviour of 13Cr–4Ni and 21Cr–4Ni–N steels

Abstract The 13Cr–4Ni martensitic stainless steel (termed as 13/4 steel and popularly known as CA6NM steel) is currently being used for fabrication of under water parts in hydroelectric projects. There are, however, several maintenance problems associated with the use of this steel. A 21Cr–4Ni–N nitronic steel (termed as 21-4-N steel) has been developed as an alternative with the specific aim of overcoming these problems. A comparative study has been made on the erosion behaviour of as cast 13/4, and as cast and hot rolled 21-4-N steels by means of solid particle impingement using gas jet. It is observed that the hot rolled 21-4-N nitronic steel possesses excellent resistance to erosion followed by as cast 21-4-N and 13/4 steels. The austenitic matrix of the hot rolled 21-4-N steel possesses high hardness coupled with ductility, high tensile toughness and work hardening ability, which result in higher erosion resistance. The erosion damages are in agreement with studies of eroded surfaces on scanning electron microscope (SEM).