Due to its characteristics of high manganese steel, will appear columnar crystal,coarse equiaxial crystal defects such as; easy to produce loose, casting defects such as crack and toughness reserve inadequate performance defect. When the high temperature casting, casting cooling speed, wall and center of big temperature gradient, cooling the strong direction
The growth, with columnar crystals, and even the formation of transgranular; when thehigh casting temperature, casting cooling speed, cooling poor directionality,crystallization undercooling, nucleation number less, will appear coarse equiaxedcrystal. Columnar crystal, coarse equiaxed grains is the defects of high manganese steel. In order to
Coarse columnar crystal grain is particularly serious. When the impact force isperpendicular to the columnar crystals, with good toughness; when the impact load in parallel with the columnar crystal, showed inferior toughness, have "broken bamboophenomenon", casting using only premature fracture. Equiaxed grain coarse alsoreduce toughness, but no etc.
Crystal serious. Pouring temperature can make coarse grains, appear columnar crystal, high pouring temperature and appear transgranular. Therefore, the best way to prevent the defects is to control the pouring temperature, pouring to low temperature. Such as the cone crusher vertebral body wall thickness, if 150mm,pouring temperature
Should be controlled at about 1440 ℃, cold iron cladding can basically eliminatetransgranular sand about 10mm, narrow columnar crystal zone. Addition of rare earthcan also prevent grain growth. But the most fundamental is to control the pouring temperature.
High manganese steel is easy to crack and easy to cold cracking. High manganese steel hot cracking occurred at 1300 ℃, cold cracking occurred at 650 ℃. Hot cracking:when the metal liquid in the formation of dendrite skeleton and contractility, blocked the contraction, the high manganese steel tends to zero, can not use plastic deformation
Relaxation shrinkage stress. When the shrinkage stress exceeds the strength of thetemperature of high manganese steel, the crack source, after the contraction crackalong the weak point of the grain boundary, the formation of thermal cracking.
Cold cracking: below 650 ℃, high manganese steel is in elastic state, the temperatureof high manganese steel grain boundary carbide network has been formed, thus reducing plastic; when blocked the contraction, shrinkage stress exceeds the strength of the temperature of high manganese steel, crack initiation at the grain boundary, the direction of stress function, transgranular fracture, shape
Into the cold crack. Mechanical precision casting factory according to the advantages and disadvantages of high manganese steel casting, "Yong" strictly in the production of high manganese steel jaw plate wear-resistant castings, every step, will do the best,so as to make quality products.