Sophisticated control deformation of the mold heat treatment production has become a key issue. Mold heat treatment deformation is one of the major flaws of the mold process, a number of sophisticated molds, often due to heat deformation and scrapped. Control sophisticated mold deformation of a heat treatment but the majority of workers in an important research topic.
The company tried to sophisticated mold deformation conditions Deformation studies to explore measures to reduce and control sophisticated mold deformation, to improve product quality and service life of the mold.
Effect of Mould Materials
Cr12MoV steel factory sent a number of more complex molds, dies after ¢ 60m m comes with a round hole, mold heat treatment, some die hole appears oval, resulting in mold scrapped. Generally Cr12MoV steel is micro-deformation of steel, there should be no large deformation. We are seriously deformed mold metallographic analysis, mold steel contains large amounts of eutectic carbides, and zonal and massive distribution.
(1) oval die (deformation) produced
This is because the presence of mold steel was a certain direction uneven distribution of carbide, carbide coefficient of expansion than the matrix structure about 30% of small steel, when heated it prevents mold hole expansion, cooling time and prevent mold shrinkage hole so that the mold Fasheng uneven deformation, so that the die hole appears oval.
(2) preventive measures
① in the manufacture of sophisticated molds, to try to choose a smaller die steel carbide segregation, do not pursue cheap, use a small steel mills production of the material is poor.
② the existence of serious carbide segregation die forging steel to be reasonable, to break the carbide crystal block, downgrading carbide uneven distribution, eliminate performance anisotropic.
③ to die after forging steel to quenching and tempering heat treatment, so as to obtain a carbide distribution, small and dispersed sorbite tissue, thereby reducing deformation after heat treatment sophisticated molds.
④ For large size can not be forged or die, can be double-thinning treatment solution, carbides refinement, distribution, edges rounded, then it can mold to reduce heat deformation purposes.
Mold during the heat treatment, especially in the quenching process, since the temperature of various parts of the mold sectional inconsistent heating and cooling rates caused the difference, when inequality combined with organizational changes and other reasons, so that the cross section of each mold section volume expansion uneven shrinkage organizational change is not uniform, causing thermal stress "the stress" and mold caused by the temperature difference between inside and outside. When the internal stress exceeds the yield limit of the mold, it will cause deformation of the mold.
