Surface Engineering of Metals - Principles, Equipment and Technologies Part 12

Tham khảo tài liệu 'surface engineering of metals - principles, equipment and technologies part 12', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 1 - Titanizing 3500-4000 HV layer mm 2 - Vanadizing 2300-3600 HV layer mm 3 - Chromizing 1000-1400 HV layer mm 4 - Oxynitriding 600-900 HV layer mm 5 - Bonding 1200-2000 HV layer mm 6 - Nitriding 270-1600 HV layer mm 7 - Carburizing 400-950 HV layer mm 8 - Carbonitriding 750-1100 HV layer mm 9 - Surface hardening 520-800 HV layer mm 10 - 9 burnishing HV greater than in 9 layer greater than 9 by up to 40 11 - Ion implantation 500-1500 HV layer pm Fig. Orientation values of thickness and hardness of some superficial diffusion layers. In addition to surface hardness the measurement of which was introduced to industry as late as the 20th century it is important to know the hardness of structural elements of the particular zones of the superficial layer . grains and structural components especially on cross-sections. This last parameter known as microhardness came into use only after World War II 28 . Distance from surface mm Fig. Hardness profile a Nitralloy 135M hardened and tempered to 30 2 HRC 1 - glow discharge nitrided at 520 C for 9 h 2 - implanted by nitrogen ions with energy of 100 keV and ion dose of 2-1017 ions of N2 per cm2 3 - electron beam hardened with power density of 2230 kW cm2 and exposure time s 4 - laser hardned with power density of kW cm2 and exposure time of s b 18HGT grade steel gas nitrided at 530 C for 36 h 1999 by CRC Press LLC Hardness microhardness is one of the most basic universally accepted properties of materials especially of metals and their alloys easily measured by various methods and connected with many other properties of the superficial layer . wear resistance strength residual stresses plasticity. Usually the higher the stress loading to which the part is subjected the higher should be the hardness of the surface. Unfortunately a rise in hardness is often connected with a rise in brittleness. Hardness .