Molybdenum Hafnium Carbon Uses
Why are we using molybdenum hafnium carbon(MHC alloy)?
Molybdenum Hafnium Carbon used in new die.
Temperature: Before the first extrusion operation, heat the die to at least 350 °C. The temperature of the die should not fall below 250 °C during the intervals between press operations. After use, cool the die to ambient temperature and note that MHC dies should not be cooled with water.
Shrinkage of die inserts: Despite the low coefficient of thermal expansion, the shrinkage of MHC inserts is very manageable at 5.6 • 10-6 m/mK. The application of caulking at various points prevents the insert from being pulled out of its holder. During the first extrusion operation, the die may retract by 0.1 to 0.15 mm in the area of the sliding surface which imparts the shape to the workpiece. But there's no cause for alarm: This effect disappears again after the appropriate correction has been made during the subsequent press operations. After correction, the die remains non-deformable and dimensionally stable.
Hairline cracks: Sometimes hairline cracks may occur at the inlet radii. These do not impair the functioning of the part. Only if the pressed material adheres to these hairline cracks is it necessary to retouch the die. To do this, we recommend manual polishing using a fine linen cloth and diamond paste.