Основной каталог Kyocera 2016-2017 - страница 924

Heat Treatment and Hardness Expression  Heat Treatment One of the ways to determine the hardness of steel is the heat treatment and it is classified to 3 types. Heat Treatment (1) Quenching (Tempering) (2) Normalizing (3) Annealing Heat Treatment Method Detail Effect ·Quenching After heating to over 727℃ , cool rapidly Quenching makes steel hard Very Slowly (Tempering) down to 550℃ in water or oil. because it cools down red-hot steel very rapidly in water or oil, Temperature Rapidly but it may promote internal stress. 727˚C Rapidly Quenching Slowly In order to remove such internal stress, tempering is used. 600˚C (After cooled down once, reheat it to 200°C~600°C) (1) Slowly Normalizing(2)Annealing Rather Rapidly(3) ·Normalizing After heating to over 727℃ , cool down It miniaturizes the crystals. (Steel is also composed of small 550˚C rapidly to 600℃ and then to normal cells.) It is used to improve the mechanical character or temperature. machinability. Time ·Annealing After heating to over 727℃ , cool down very It miniaturizes the crystals like the process of normalizing, but the slowly to 600℃ , then to normal temperature. crystal size is bigger than that of normalizing. It targets machinability improvement and distortion correction.  Hardness Expression Hardness Reference Standard Example Explanation of Example 250HB Hardness Value :250, Hardness Symbol : HB Brinell Hardness JIS Z 2243:1992 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 R Vc= π×Dm×n Technical Information R4