RESEARCHES ON WEAR PERFORMANCE OF 40CR STEEL STRENGTHENED BY LASER CLADDING

摘要

In order to increase the wear life of 40Cr steel, laser cladding techniques were adopted with Fe-based alloy powders. By simulating the operating conditions, the laser clad coatings were obtained on the 40Cr steel substrate. The wear tests were carried out by using laser clad coatings as lower sample and GCr15 steel as upper sample with HT-500 wear tester. And the comparative tribological behaviour of dry friction and lubricant condition with the same load were studied. Moreover, the depth and width of wear scars were measured by surface roughness profiler. As the tests show, under dry sliding condition, with the increase of temperature and wear time, the wear course becomes stable. The average friction coefficient reduces. The wear rate raises. The wear resistance declines. The clad coating has better wear performance than the 40Cr steel substrate at 350℃ and 400℃. The wear performance under lubricant condition is better than that under dry friction condition. The friction coefficient fluctuates in a small range below 200℃. When the temperature rises up to 200℃ and above, the oil film is decomposed and reveals failure.