Assessment of laser cladding as an option for repairing/enhancing rails

This paper presents results of testing carried out to assess the wear and RCF performance of laser clad rail. Stronger and harder materials can be laser clad on top of the working surfaces of standard (e.g. 260 grade) rail in order to improve wear and RCF life. A twin-disc method has been used to assess the suitability of various candidate cladding materials. The materials were clad on top of 260 grade rail discs and were tested against a disc of standard wheel material. Wear was measured by weighing the discs before and after each test. An Ellotest B1 differential eddy current crack detector was used to detect RCF cracks in the rail disc. Four clad materials were used namely, Hadfield, Stellite 6, Maraging and 316 Stainless Steels. In the tests carried out, wear was not always reduced with the cladding. It is assumed that these tests were not long enough for some of the materials to fully work harden and therefore wear rates would improve with a greater number of test cycles. However, all but the Stainless Steel showed that they did not deform under the cyclic loading applied and would offer a greatly enhanced RCF life.