Commonly used steel tempering heat treatment is calculated

Steel tempering hardness ( H） Depending on the tempering temperature ( T） And the tempering time ( t） , there is a certain functional relationship between, or H = f ( T, T) 。 When t is constant value, a function of H and t can be divided into four types: ( 1) Linear; ( 2) Parabolic; ( 3) Power function type; ( 4) Linear and power function of the composite. Because after two types when use, calculation and drawing is very inconvenience, so in most cases, it is simplified to linear and parabolic, with empirical equation can be expressed as: H = a1 + k1 TH = a2 + k2 T, a1, a2, k1, k2 for specific coefficient. According to the actual process test and related reference data, using the mathematical statistics method and correction, some commonly used steel tempering equations are obtained. Practice proves that these empirical formulas have important applied value. Steel quenching temperature/quenching medium tempering equation 45 / water H = 62-840 ( 1/9000) T 220 cr/oil H = 50-890 ( 2/45) T 38 crmoal oil/H = 64-930 ( 1/25) T（ T& lt; 550). H = 95 - ( 1/10) T（ T& gt; 550). 40 cr/oil H = 75-850 ( 3/40) T50CrVA oil/H = 73-850 ( 1/14) T60Si2Mn oil/H = 68-860 ( 1/11250) T 265 mn/oil H = 74-820 ( 3/40) TT8 / water H = 78-800 ( 7/80) Water TT10 780 / H = 82. 7 - ( 1/11) TCrWMn oil/H = 69-830 ( 1/25) TCr12　 　 980/