Unlock instant, AI-driven research and patent intelligence for your innovation.

A method for preparing powder high-speed steel by multi-atmosphere assisted sintering

An auxiliary sintering and high-speed steel technology, which is applied in the field of powder high-speed steel preparation, can solve the problems of insufficient mechanical properties, high sintering temperature, narrow sintering window, etc., and achieve excellent mechanical properties, improve mechanical properties, and promote liquid phase flow.

Inactive Publication Date: 2018-05-25
CENT SOUTH UNIV
View PDF5 Cites 0 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] Aiming at the shortcomings of the traditional molding / sintering process, such as high sintering temperature, narrow sintering window, low sintering density, and insufficient mechanical properties, the present invention provides a method for preparing powdered high-speed steel by multi-atmosphere assisted sintering

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0029] Step 1, the master alloy powder and additives are placed in a V-shaped mixer and mixed evenly. Among them, the master alloy powder is common M3:2 high-speed steel powder on the market, and the additives are carbon powder and zinc stearate. The dosage relative to the total amount of the master alloy is: carbon powder 0.1wt.% and zinc stearate 0.6wt .%.

[0030] In step 2, the mixed powder is molded and preformed using a press with a pressure of 600MPa.

[0031] Step 3, first sinter the pressed sample at 1000°C for 60 minutes in a vacuum atmosphere of 1 Pa, heat the compact to 1070°C and pass in 1 bar of nitrogen (to promote the in-situ formation of nitride strengthening phase), and then the compact Heat to 1150°C and hold for 60 minutes, then raise the temperature to 1230°C, feed a certain amount of argon and hold for 30 minutes, keep the pressure in the furnace at 5MPa, and finally release the pressure and cool to room temperature with the furnace. After testing, the ...

Embodiment 2

[0035] Step 1, the master alloy powder and additives are placed in a V-shaped mixer and mixed evenly. The master alloy powder is the common M3:2 high-speed steel powder on the market, and the additives are carbon powder and zinc stearate, and the amounts thereof are respectively: 0.4wt% of carbon powder and 1wt% of zinc stearate relative to the total amount of the master alloy.

[0036] In step 2, the mixed powder is molded and preformed using a press with a pressure of 800MPa.

[0037] Step 3, put the pressed sample in 10 -2 Sintering under Pa vacuum atmosphere, when the compact is heated to the temperature at which the liquid phase begins to form, 0.2 bar of nitrogen is passed (to promote the in-situ formation of the nitride strengthening phase), and then the compact is heated to 1200 ° C and kept for 60 minutes, and then the temperature is raised to 1270°C, feed a certain amount of argon and keep it warm for 30 minutes, keep the pressure in the furnace at 20MPa, and finall...

Embodiment 3

[0041] Step 1, the master alloy powder and additives are placed in a V-shaped mixer and mixed evenly. The master alloy powder is common T15 high-speed steel powder on the market, and the additives are carbon powder and zinc stearate, and the amounts thereof are respectively: 0.4wt% of carbon powder and 0.8wt% of zinc stearate relative to the total amount of the master alloy.

[0042] In step 2, the mixed powder is molded and preformed using a press with a pressure of 800MPa.

[0043] Step 3, put the pressed sample in 10 -1Sintering under Pa vacuum atmosphere, when the compact is heated to the temperature at which the liquid phase begins to form, 0.5 bar of nitrogen is passed (to promote the in-situ formation of the nitride strengthening phase), and then the compact is heated to 1180 ° C and kept for 60 minutes, and then the temperature is raised to At 1250 ° C, a certain amount of argon gas was introduced and kept for 30 minutes to keep the pressure in the furnace at 10 MPa. ...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

PropertyMeasurementUnit
particle sizeaaaaaaaaaa
particle sizeaaaaaaaaaa
oxygen contentaaaaaaaaaa
Login to View More

Abstract

The invention relates to a method for preparing powder high-speed steel, in particular to a method for preparing the powder high-speed steel by adopting multi-atmosphere auxiliary sintering. According to the method disclosed by the invention, pre-alloyed high-speed steel powder and additive powder are uniformly mixed and formed in a cold-pressing manner; a pressed blank can be sintered by one time by three-stage atmosphere control on vacuum atmosphere, nitrogen atmosphere during the middle and later stages and argon pressurized atmosphere. During a low-temperature stage, the vacuum atmosphere is adopted to remove a shaping agent and also eliminate most of pores inside the pressed blank in order to obtain relatively high pre-sintered compactness; by sintering in the nitrogen atmosphere, a nitride strengthening phase can be generated in site by the powder high-speed steel, the mechanical properties of the sintered powder high-speed steel are improved, and the highest sintering temperature is reduced; in the later stage of sintering, argon atmosphere is pressurized to crush the residual pores in order to further increase the compactness of the powder high-speed steel. Compared with a traditional sintering method, the atmosphere assisting sintering process provided by the invention is easy to control and has the advantages of reducing the sintering temperature, also enlarging a sintering window and improving the compactness and mechanical properties of the powder high-speed steel.

Description

technical field [0001] The invention relates to a method for preparing powder high-speed steel; in particular, it relates to a method for preparing powder high-speed steel by multi-atmosphere assisted sintering. Background technique [0002] Powdered high-speed steel is a high-speed steel product (PM HSS for short) made by forming fine powder of high-speed steel and sintering or subsequent processing. Powder high-speed steel has the characteristics of no segregation, fine grains, less inclusion content, and uniform structure. Therefore, its mechanical properties such as hardness, strength, and toughness are significantly better than ordinary high-speed steel prepared by traditional smelting-casting and forging methods. It is widely used in Turning tools, milling cutters, gear hobs, drills, molds and other high temperature and wear resistant parts. [0003] Forming and sintering are key preparation steps that determine the shape and properties of high-speed steel. Tradition...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Patents(China)
IPC IPC(8): B22F1/00B22F3/02B22F3/10C22C33/02
CPCB22F1/0003B22F3/02B22F3/101B22F2999/00C22C33/0228B22F2201/20B22F2201/02B22F2201/11
Inventor 李松林欧阳齐黄雍平张丰丽滕浩
Owner CENT SOUTH UNIV