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

A high-chromium cast iron, 25% cr technology, applied in metal processing equipment, transportation and packaging, etc., can solve the problems of high energy consumption, introduction of impurities, and inability to continue production, so as to achieve sufficient precipitation, improve impact and wear resistance, The effect of reducing the difficulty of operation

Active Publication Date: 2020-08-25
HUNAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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

Method used

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

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Effect test

Embodiment 1

[0032] The invention provides a variable temperature sintering process of high chromium cast iron, comprising the following steps:

[0033] (1) Atomized powder making: mixing materials with 25Cr% high chromium cast iron alloy, and then fully atomizing molten water to obtain pre-alloyed powder;

[0034] (2) Molded blank: add 1.0wt% styrene-butadiene rubber to the pre-alloyed powder as a molding agent, the pressing method is unidirectional steel mold pressing, the pressing pressure is 200-300MPa, and the holding time is 60s. Blank;

[0035] (3) Variable temperature sintering: the compact is subjected to variable temperature sintering, the sintering temperature of the first stage is 1270°C / 15min+the sintering temperature of the second stage is 1245°C / 62min, and a sintered sample is obtained;

[0036] (4) Temperature-controlled cooling: the sintered sample body is lowered to a temperature of 500°C, the cooling rate is 2°C / min, and then immediately air-cooled at room temperature, ...

Embodiment 2

[0038] The invention provides a variable temperature sintering process of high chromium cast iron, comprising the following steps:

[0039] (1) Atomized powder making: mixing materials with 25Cr% high chromium cast iron alloy, and then fully atomizing molten water to obtain pre-alloyed powder;

[0040] (2) Molded blank: add 1.0wt% styrene-butadiene rubber to the pre-alloyed powder as a molding agent, the pressing method is unidirectional steel mold pressing, the pressing pressure is 200-300MPa, and the holding time is 60s. Blank;

[0041] (3) Variable temperature sintering: the compact is subjected to variable temperature sintering, the sintering temperature of the first stage is 1265°C / 15min+the sintering temperature of the second stage is 1245°C / 67min, and a sintered sample is obtained;

[0042] (4) Temperature-controlled cooling: the sintered sample body is lowered to a temperature of 450°C, the cooling rate is 4°C / min, and cooled to room temperature with the furnace, and ...

Embodiment 3

[0044] The invention provides a variable temperature sintering process of high chromium cast iron, comprising the following steps:

[0045] (1) Atomized powder making: mixing materials with 25Cr% high chromium cast iron alloy, and then fully atomizing molten water to obtain pre-alloyed powder;

[0046] (2) Molded blank: add 1.0wt% styrene-butadiene rubber to the pre-alloyed powder as a molding agent, the pressing method is unidirectional steel mold pressing, the pressing pressure is 200-300MPa, and the holding time is 60s. Blank;

[0047](3) Variable temperature sintering: the compact is subjected to variable temperature sintering, the sintering temperature of the first stage is 1265°C / 15min+the sintering temperature of the second stage is 1240°C / 67min, and a sintered sample is obtained;

[0048] (4) Temperature-controlled cooling: the sintered sample body is lowered to a temperature of 400°C, the cooling rate is 4°C / min, and cooled to room temperature with the furnace, and f...

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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...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): B22F3/10
CPCB22F3/1017B22F3/1035B22F2998/10B22F1/10B22F3/02B22F9/082
Inventor 肖平安顾景洪肖璐琼李忠涛肖利洋石管华肖雨桐古思敏吕蓉
Owner HUNAN UNIV
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