624 Каталог KYOCERA 2016 Металлорежущий инструмент для токарной обработки на станках Стр.R4

Каталог KYOCERA 2016 Токарные резцы с пластинами Стр. R4 0624 ENG Lab2u

TECHNICAL HEAT TREATMENT AND HARDNESS EXPRESSION I Heat Treatment One of the ways to determine the hardness of steel is the heat treatment and it is classified to 3 types. Quenching (Tempering) After heating to over 727°C, cool rapidly down to 550°C in water or oil. Quenching makes steel hard because it cools down red-hot steel very rapidly in water or oil, but it may promote internal stress. In order to remove such internal stress, tempering is used. (After cooled down once, reheat it to 200°C 600°C) Normalizing After heating to over 727°C, cool down rapidly to 600°C and then to normal temperature. It miniaturizes the crystals. (Steel is also composed of small cells.) It is used to improve the mechanical character or machinability. Annealing After heating to over 727°C, cool down very slowly to 600°C, then to normal temperature. It miniaturizes the crystals like the process of normalizing, but the crystal size is bigger than that of normalizing. It targets machinability improvement and distortion correction. Heat Treatment Method Hardness Value Hardness Reference Standard Example Explanation of Example Brinell Hardness JIS Z 2243:1992 250HB Hardness Value 250, Hardness Symbol HB 200 250HB When the hardness has the range Vickers Hardness JIS Z 2244:1998 640HV Hardness Value 640, Hardness Symbol HV Rockwell Hardness JIS Z 2245:1992 60HRC Hardness Value 60, Hardness Symbol HRC Shore Hardness JIS Z 2246:1992 50HS Hardness Value 50, Hardness Symbol HS R4 Kyocera