Variable-temperature sintering technology for high-chromium cast iron

Abstract

The invention provides a variable-temperature sintering technology for high-chromium cast iron, and belongs to the field of the metal material powder metallurgy. The technology comprises the followingsteps: (1) atomizing and powdering; (2) mould-pressing and blank-making: adding a forming agent to pre-alloy powder, after pressing, to obtain a pressed blank; (3) variable-temperature sintering: performing the variable-temperature sintering on the pressed blank, wherein an upper limit sintering temperature is 1250-1280 DEG C, and heat-preserving time is 10-30 min, after that, rapidly cooling toa lower limit sintering temperature of 1220-1245 DEG C, wherein the heat-preserving time is 30-90 min, to obtain a sintering sample blank; and (4) temperature control cooling: performing the temperature control cooling on the sintering sample blank, furnace-cooling later or immediately air-cooling in a room temperature. The technology is capable of, through processes of pre-alloy atomizing and powdering, mould-pressing and blank-making, variable-temperature sintering, and temperature control cooling, greatly shortening preparation time, reducing operation difficulty, after acquiring a carbidewhich is simple in morphology, small in size and uniform in distribution, greatly improving bending strength of an alloy as well as enabling impact toughness of the high-chromium cast iron to be improved, and greatly improving shock-resisting and wear-resisting properties of the high-chromium cast iron alloy.

Description

technical field [0001] The invention belongs to the field of metal material powder metallurgy and relates to a variable temperature sintering process of high chromium cast iron. 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 process steps currently used for metam...

AI Technical Summary

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

Images