Nickel hard castings can effectively improve the hardness of castings due to unreasonable composition design during its low temperature heat treatment. Modification treatment can improve the impact toughness of nickel hard cast iron. In the process of making nickel hard castings, it is better to use metal mold casting to produce nickel hard cast iron because it is necessary to obtain its martensite structure in the as-cast state.
The cooling rate of the castings of nickel hard castings in the metal type is very fast. In the process of operation, it can effectively restrain the transformation of the pearlite in austenite, avoid graphitization and guarantee the main purpose of the white cast iron, because the cooling rate is fast, the primary nodal structure is fine and the mechanical properties are far higher than the sand castings.
For nickel-hard castings with simple shape and thick-walled cast iron, such as roll, head of roll, grinding ball of wet ball mill, liner and so on, metal mold casting should be used as far as possible. A special cast iron with white or hemp mouth is formed by cooling some parts of carbon in the form of combined carbon.
In the process of making nickel hard castings, cold hard ductile iron rollers are mainly used, and nickel hard cast iron and high chromium cast iron rollers are adopted in the world, which makes the production of cold hard cast iron have new development. Process factors include hot metal temperature, overheating time, pouring temperature, inoculation place. The nickel-hard alloy was studied more deeply. The effects of Cr-Si and Ba-Mo-RE on the microstructure and properties of the alloy were studied. The composition of the alloy was adjusted more carefully, and the control range of the composition of the alloy was determined.
Nickel hard cast iron shows advantages under the condition of impact loading during operation. To a certain extent, it has effects on the alloy composition, heat treatment system and microstructure of the alloy on the wear resistance. An alloy to improve carbide morphology in nickel hardened infinite cold hard cast iron is to add vanadium with a mass percentage of 3-6% on the basis of the existing nickel hardening infinite cold hard cast iron, and to properly control the melting and casting process, Cast iron with uniform spherical carbides can be obtained.http://www.wuxiorient.com/