A Varying Temperature Sintering Process of 25% Cr High Chromium Cast Iron and Its Products

Abstract

The invention provides a variable temperature sintering process of high chromium cast iron, which belongs to the field of powder metallurgy of metal materials, including: (1) atomization powder making; (2) molding blank: adding molding agent to pre-alloy powder, and pressing Blank; (3) variable temperature sintering: the compact is sintered at variable temperature, the upper limit sintering temperature is 1250-1280°C, the holding time is 10-30min, and then the temperature is rapidly lowered to the lower limit sintering temperature 1220-1245°C, and the holding time is 30-90min , to obtain a sintered sample body; (4) temperature-controlled cooling: the sintered sample body is cooled by temperature control, followed by furnace cooling or immediately air-cooled at room temperature. The invention greatly shortens the preparation time and reduces the difficulty of operation through the process of pre-alloy atomization powder making-molded blank-variable temperature sintering-temperature control cooling, and after obtaining carbides with simple appearance, small size and uniform distribution, the high While the impact toughness of the chromium cast iron is improved, the bending strength of the alloy is also greatly improved, which greatly improves the impact and wear resistance of the high chromium cast iron alloy.

Description

technical field [0001] The invention belongs to the field of powder metallurgy of metal materials, and relates to a variable temperature sintering process of 25% Cr high-chromium cast iron and a product thereof. Background technique [0002] High-chromium cast iron is an important class of high-strength wear-resistant and corrosion-resistant structural materials in Fe-C-Cr alloys. It is the third generation of wear-resistant cast iron after ordinary white cast iron and nickel-hard cast iron. It has excellent strength, toughness, Wear resistance and corrosion resistance, but its casting rejection rate is high and formability is poor. At present, the metamorphic casting method is most commonly used in the industry to produce high chromium cast iron. [0003] The metamorphic casting method can increase the nucleation rate and inhibit excessive oriented growth by creating a large number of high-temperature heterogeneous phases on the solid-liquid interface of the melt. The proc...

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Problems solved by technology

However, the metamorphic casting process needs to add a modificator, which will introduce impurities. At the same time, it requires a long time of high-temperature melting treatment, coupled with the subsequent heat treatment process, the process cycle is as long as 48h, the energy consumption is huge, and continuous production is not possible. Therefore, it is necessary to develop a new high- Chromium cast iron casting process is of great significance

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