STRUCTURE AND PROPERTY OF DIFFUSION LAYERS OF HIGH SPEED STEEL CUTTING TOOLS TREATED WITH SOME MULTI-COMPONENT THERMOCHEMICAL TREATING.

Gases O-C-N-S, O-C-N-B and O-C-N-S-B multicomponent thermochemical treating processes for high speed steel drills were carried out at 540-560 degree C with dripping carbamide solution added with nitrogen, sulfur and boron bearing compounds. Comparing the oxynitriding process with carbamide solution the structure of diffusion layers is varied and the depth and hardness of diffusion layers and the hot hardness, bending strength, impact toughness and wear resistance are improved markedly. The durability of the drill which is treated with five component diffusion processes is increased to 2 times over that with oxynitriding.