Air permeable steel for injection molding and preparation method thereof

A technology of air-permeable steel and powder, which is applied in the field of high-throughput air-permeable steel for injection molds and its preparation. It can solve the problems that the plastic melt cannot fill the cavity, the tensile strength is not high, and the melt is decomposed, so as to achieve excellent corrosion resistance. Ability, excellent mechanical properties, the effect of excellent mechanical properties

Active Publication Date: 2020-03-31
DAYA PRECISION MACHINERY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] During the injection molding process, high-pressure plastic melt is injected into the mold cavity. If the gas in the mold cavity cannot be discharged or is not discharged in time, various injection molding defects and adverse effects are prone to occur, such as: 1) The plastic melt cannot be filled Cavity; 2) High-pressure gas penetrates into the plastic, causing quality defects such as pores, cavities, and loose tissue
3) The gas is compressed and heated up, causing the melt to decompose, burn, and partially carbonize and burn
4) The speed of the melt entering each cavity is different, so it is easy to form flow marks and fusion marks, and reduce the mechanical properties of injection molded parts
5) Reduce the mold filling speed, reduce production efficiency and increase energy consumption
At present, metal porous materials are mostly used in the filtration industry, but their tensile strength is not higher than 150MPa, and the thickness is generally about 2mm. steel material

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0027] The iron-based pre-alloy powder containing 0.2wt% of C, 13wt% of Cr, 0.5wt% of Mo, 0.3wt% of V is ball milled, and the particle size of the powder is between 60 and 80 μm. After 6 hours of ball milling, the particles become smooth . Then, atomized spherical Cu powder with a particle size range of 10 μm and a water-based binder are added to the modified pre-alloyed powder for mixing, the Cu addition amount is 3%, and the mixed powder is granulated and dried. The granulated powder is put into a mold for pressing at a pressing pressure of 250 MPa, and the pressed green body is placed in a sintering furnace for sintering at a sintering temperature of 1200°C. The gas throughput of the prepared breathable steel is greater than 1L / cm2·min·bar (test thickness 15mm), the tensile strength is greater than 600MPa, the micro Vickers hardness is greater than 500HV, and the pore size of more than 95% of the micropores is between 10-20μm. And the holes are smooth.

Embodiment 2

[0029] The iron-based pre-alloy powder containing 0.3wt% of C, 14wt% of Cr, 0.6wt% of Mo, 0.4wt% of V is ball milled, and the particle size of the powder is between 80-100μm. After 10h ball milling, the particles become smooth ; Then the atomized spherical Cu powder with a particle size range of 15μm and a water-based binder are added to the modified pre-alloyed powder for mixing, the Cu addition is 5%, the mixed powder is granulated and dried; The granulated powder is put into a mold for pressing at a pressing pressure of 300 MPa, and the pressed green body is placed in a sintering furnace for sintering at a sintering temperature of 1200°C. The gas throughput of the prepared breathable steel is greater than 1.5L / cm2·min·bar (test thickness 20mm), the tensile strength is greater than 550MPa, the micro Vickers hardness is greater than 500HV, and the pore size of the micropores greater than 95% is 25-50μm. , And the holes are smooth.

Embodiment 3

[0031] Ball mill the iron-based pre-alloy powder containing 0.4wt% C, 15wt% Cr, 1wt% Mo, 0.5wt% V, the particle size of the powder is between 100-150μm, and the particles become round after 20h ball milling; Then add atomized spherical Cu powder with a particle size range of 20μm and a water-based binder to the modified pre-alloyed powder for mixing. The Cu addition amount is 5%. The mixed powder is granulated and dried; The good powder is put into a mold for pressing at a pressing pressure of 200 MPa, and the pressed green body is placed in a sintering furnace for sintering at a sintering temperature of 1250°C. The gas throughput of the prepared breathable steel is greater than 2L / cm2·min·bar (test thickness 18mm), the tensile strength is greater than 450MPa, the micro Vickers hardness is greater than 500HV, and the pore size of the micropores greater than 95% is between 50-100μm. And the holes are smooth.

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Abstract

The invention provides breathable steel. The breathable steel is prepared from, by weight, 1%-5% of Cu, 0.2%-0.4% of C, 12%-15% of Cr, 0.5%-1% of Mo, 0.3%-0.5% of V and the balance Fe. The invention further provides a preparation method of the breathable steel. The method comprises the steps that iron-based pre-alloyed powder containing C, Cr, Mo and V is ball-milled, and then modified pre-alloyedpowder is obtained; atomized spherical Cu powder, a water-based binder and the modified pre-alloyed powder are mixed, and then granulated and dried; and the granulated powder is packed into a mold tobe pressed, and a pressed green blank is put into a sintering furnace to be sintered. The prepared breathable steel has the advantages of being high in through-put, excellent in mechanical property,narrow and controllable in pore-size range, excellent in corrosion resistance and the like.

Description

Technical field: [0001] The invention relates to a high-flux gas-permeable steel for an injection mold and a preparation method thereof. [0002] technical background: [0003] Permeable steel is a kind of fine-particle round powder stainless steel that is sintered at high temperature. The interior is evenly covered with tiny vent holes in all directions. It is often used for injection mold exhaust. [0004] During the injection molding process, high-pressure plastic melt is injected into the mold cavity. If the gas in the cavity cannot be discharged or is not discharged in time, various injection molding defects and adverse effects are prone to occur, such as: 1) The plastic melt cannot be filled Cavity; 2) High-pressure gas penetrates into the plastic, causing quality defects such as pores, voids, and loose tissue. 3) The gas is compressed and heated up, causing the melt to decompose, burn, and locally carbonize and burn. 4) The speed of the melt entering each cavity is different...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C33/02C22C38/20C22C38/22C22C38/24
CPCC22C33/0285C22C38/20C22C38/22C22C38/24
Inventor 李程严伟法
Owner DAYA PRECISION MACHINERY
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