When the chemical composition and matrix hardness of the hot metal are controlled in the small range mentioned above, the main factors determining the cold depth are: the size of the cold iron, the amount of inoculation, the inoculation temperature (or the temperature of hot metal discharging), the pouring temperature, etc; The main factors that determine the hardness of cam peach tip (including the hardness of lifting section) are the size of chill, the cold depth, the purity of chill (or the depth of pitting in the transition zone), etc.
As shown in Figure 1, the blank of customer a (2 mm machining allowance): the depth of chilling layer at the top of cam surface is ≥ 7 mm, and the hardness of peach point a, B and C is ≥ 50 HRC; The depth of chilling layer in lifting section is more than or equal to 4 mm, and the hardness of D and e points in lifting section is more than or equal to 38 HRC (F, G and H points are matrix hardness points).
As shown in Figure 2, customer B product blank (2 mm machining allowance): chilling layer depth at the top of cam surface ≥ 7 mm, peach point hardness 1, 2 and 3 ≥ 48 HRC; The depth of chilling layer in lifting section is more than or equal to 4 mm, and the hardness of 4 and 5 points in lifting section is more than or equal to 40 HRC (7 points are matrix hardness points).