Excellence in Heat Treatment
Precision Tool shot sleeves are hardened in a vacuum or controlled atmosphere furnace. They are preheated to 1550 F for one hour after equalization with the furnace. The temperature is then raised to 1850 F and held for one hour per inch of cross section. The sleeves are air or nitrogen quenched and immediately tempered at 1100 F for a minimum of four hours. This usually provides a hardness of 48-51 Rc. A second temper is always performed usually at a slightly higher temperature to obtain a 46-48 Rc reading. Sleeves exceeding the desired hardness typically receive a third temper. Nitriding increases the wear and fatigue resistance of the shot sleeves and helps to reduce soldering. The standard cycle of 24 hours penetrates the surface and provides a hardened layer .008/.010 in. deep. A 72 hour nitriding cycle allows for penetration of .015 in.
Next: Excellence in Performance