阅读说明：本技术 一种提高大规格粉末轧制金属多孔板材均匀性的制备方法 (Preparation method for improving uniformity of large-size powder rolled metal porous plate ) 是由 赵少阳 汤慧萍 王建忠 谈萍 刘晓青 李增峰 王利卿 殷京瓯 沈垒 于 2019-11-29 设计创作，主要内容包括：本发明公开了一种提高大规格粉末轧制金属多孔板材均匀性的制备方法,该方法包括：一、向金属粉末中加入成型剂搅匀得粘结粉末；二、将粘结粉末喂入粉末轧制设备轧辊之间的缝隙后反转轧辊,使粘结粉末覆盖在轧辊的表面至饱和状态；三、将粘结粉末喂入到经粘结粉末覆盖饱和的轧辊的辊缝中后轧制得粉末轧制金属多孔生坯板材；四、将粉末轧制金属多孔生坯板材约束烧结得粉末轧制金属多孔板材。本发明将粘结粉末覆盖在轧辊表面至饱和状态,提高了轧辊的表面摩擦力并保持稳定状态,从而提高了轧制过程中轧辊对喂入的粘结粉末的咬合能力的稳定性,提高了大规格粉末轧制金属多孔板材的厚度和空隙率的均匀性,满足了工业生产中需求。(The invention discloses a preparation method for improving the uniformity of a large-size powder rolled metal porous plate, which comprises the following steps: firstly, adding a forming agent into metal powder and stirring uniformly to obtain bonding powder; secondly, feeding the bonding powder into a gap between rollers of the powder rolling equipment, and then reversing the rollers to enable the bonding powder to cover the surfaces of the rollers to be in a saturated state; thirdly, feeding the bonding powder into a roll gap of a saturated roller covered by the bonding powder and then rolling to obtain a powder rolling metal porous green plate; and fourthly, constraining and sintering the powder rolled metal porous green plate to obtain the powder rolled metal porous plate. The invention covers the bonding powder on the surface of the roller to a saturated state, improves the surface friction of the roller and keeps a stable state, thereby improving the stability of the occlusion capacity of the roller to the fed bonding powder in the rolling process, improving the uniformity of the thickness and the void ratio of the large-size powder rolled metal porous plate and meeting the requirements in industrial production.)

1. A preparation method for improving the uniformity of a large-size powder rolled metal porous plate is characterized by comprising the following steps:

step one, adding a forming agent into metal powder, and then stirring and uniformly mixing to obtain bonding powder;

step two, feeding the bonding powder obtained in the step one into a gap between rollers of powder rolling equipment, and then reversing the rollers to enable the bonding powder to cover the surfaces of the rollers to a saturated state;

step three, feeding the bonding powder obtained in the step one into the roll gap of the roller saturated by the bonding powder in the step two through a feeding device, and then rolling to obtain a powder rolling metal porous green plate;

cutting the powder rolled metal porous green plate obtained in the step three, removing floating powder, then carrying out constrained sintering, and flattening and cutting to obtain the powder rolled metal porous plate; the width of the powder rolled metal porous plate is more than 450mm, and the thickness deviation is +/-5%.

2. The method as claimed in claim 1, wherein the metal powder in step one is titanium powder, titanium alloy powder, stainless steel powder, nickel powder or nickel alloy powder.

3. The method of claim 1, wherein the metal powder in step one has a particle size of 1 μm to 600 μm.

4. The method as claimed in claim 1, wherein the forming agent is absolute ethyl alcohol, and the addition amount of the absolute ethyl alcohol is 0.1-5% of the mass of the metal powder.

5. The method of claim 1, wherein the stirring speed in step one is 5 to 60rds/min, and the stirring time is 1 to 10 min.

6. The method as claimed in claim 1, wherein the number of the two rolls in the step two is 500mm, the width of the gap between the two rolls is 0mm to 1.2mm, and the feeding mass of the cohesive powder is 1kg to 8 kg.

7. The method as claimed in claim 1, wherein the speed of the reverse roll in step two is 0.6-6 m/min, and the reverse time is 1-6 min.

8. The method as claimed in claim 1, wherein the feeding speed in step three is 20g/s to 150g/s, the gap width between the two rolls is 0mm to 1.6mm, and the rolling speed is 0.6m/min to 3 m/min.

9. The method for preparing a large-size powder rolled metal porous plate according to claim 1, wherein the constrained sintering temperature in the fourth step is 900-1400 ℃, and the holding time is 60-120 min.

10. The method of claim 1, wherein the constrained sintering is performed at a flow rate of 1m in step four³/h～4m³In a hydrogen atmosphere, or in a vacuum of not more than 1X 10^-2Pa under vacuum.

Technical Field

The invention belongs to the technical field of powder metallurgy, and particularly relates to a preparation method for improving the uniformity of a large-size powder rolled metal porous plate.

Background

With the national emphasis on environmental protection and the implementation of various environmental protection measures, the requirements of various industries in national economy on filtering materials are increasing day by day, and powder metallurgy porous materials as filtering elements are widely applied to the industries of filtering separation, energy environmental protection, fluid transportation and the like. The structure forms of the filter element comprise a tubular structure and a flat structure, the research on the tubular filter element is relatively mature at present, but the research on the large-size plate-shaped element is relatively lagged, mainly because the research on the forming technology of the large-size plate-shaped porous material is relatively lagged.

The powder rolling technology is the main preparation process for producing large-size plate-shaped filter elements at present, and the technology can continuously and stably produce the plate-shaped filter elements. In recent years, powder rolled plate-shaped filter elements have been applied to certain gas-solid and liquid-solid separation links in the industries of metallurgy, water electrolysis, medicine, petrochemical industry and the like. However, due to the limitations of the capacity of rolling equipment and the width of a roller, the feeding mode, a sintering device and the like, the width of the powder rolling metal porous plate prepared at home at present is smaller than 280mm, and the problems of uneven thickness and pore performance and the like exist, so that the requirements of industries such as water electrolysis, pharmacy, petrochemical industry and the like on large-size plate-shaped filter elements cannot be met.

Therefore, a preparation method for improving the uniformity of the large-size powder rolled metal porous plate is needed.

Disclosure of Invention

The technical problem to be solved by the invention is to provide a preparation method for improving the uniformity of a large-size powder rolled metal porous plate aiming at the defects of the prior art. The method firstly covers the bonding powder on the surface of the roller to reach a saturated bonding powder state, improves the surface friction force of the roller and keeps a stable state, thereby improving the stability of the occlusion capacity of the roller to the fed bonding powder in the rolling process, being beneficial to controlling the thickness and the porosity among the bonding powder after the rolling, and improving the uniformity of the thickness and the porosity of the large-size powder rolled metal porous plate.

In order to solve the technical problems, the invention adopts the technical scheme that: a preparation method for improving the uniformity of a large-size powder rolled metal porous plate is characterized by comprising the following steps:

step one, adding a forming agent into metal powder, and then stirring and uniformly mixing to obtain bonding powder;

step two, feeding the bonding powder obtained in the step one into a gap between rollers of powder rolling equipment, and then reversing the rollers to enable the bonding powder to cover the surfaces of the rollers to a saturated state;

step three, feeding the bonding powder obtained in the step one into the roll gap of the roller saturated by the bonding powder in the step two through a feeding device, and then rolling to obtain a powder rolling metal porous green plate;

cutting the powder rolled metal porous green plate obtained in the step three, removing floating powder, then carrying out constrained sintering, and flattening and cutting to obtain the powder rolled metal porous plate; the width of the powder rolled metal porous plate is more than 450mm, and the thickness deviation is +/-5%.

In the conventional preparation process of the powder-rolled metal porous plate, when powder is fed for rolling, the friction force of the smooth surface of a roller is small, the powder engagement capacity is weak, the surface of the roller is gradually adhered with the powder along with the rolling, the friction force of the surface of the roller is gradually increased, the powder engagement capacity is enhanced, namely the friction force of the surface of the roller in the whole powder rolling process is changed, so that the thickness and the porosity of the powder-rolled metal porous plate are changed, the uniformity is difficult to maintain, and especially the uniformity of the large-size powder-rolled metal porous plate is difficult to control.

The invention firstly feeds the bonding powder made of metal powder and forming agent into the roller gap of the powder rolling equipment and reverses, so that the surface of the roller is fully contacted with the metal powder, the surface of the roller reaches a powder-bonding state of covering saturation, the surface friction of the roller is improved and a stable state is kept, thereby improving the stability of the gripping capacity of the roller on the fed bonding powder in the rolling process, being beneficial to the control of the thickness and the porosity among the bonding powder after the bonding powder is rolled, and improving the uniformity of the thickness and the porosity of the large-size powder rolled metal porous plate.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that in the step one, the metal powder is titanium powder, titanium alloy powder, stainless steel powder, nickel powder or nickel alloy powder. The metal powder commonly used in the industrial production can be used in the preparation method of the invention, and the practical value of the invention is improved.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that the granularity of the metal powder in the step one is 1-600 microns. The metal powder with the granularity is easy to form by bonding, so that the subsequent bonding powder can be favorably and uniformly covered on the surface of the roller of the powder rolling equipment, and the subsequent rolling forming process can be favorably and smoothly carried out.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that in the first step, the forming agent is absolute ethyl alcohol, and the addition amount of the absolute ethyl alcohol is 0.1-5% of the mass of the metal powder. The absolute ethyl alcohol which is low in price and easy to obtain is selected as the forming agent, so that the metal powder is promoted to be adhered to form bonding powder, the addition amount of the absolute ethyl alcohol effectively controls the viscosity of the bonding powder, the covering effect is improved, and the rolling forming is facilitated.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that in the step one, the stirring speed is 5 to 60rds/min, and the stirring time is 1 to 10 min. The preferred stirring speed and time promote the metal powder and the forming agent to be fully mixed, and improve the uniformity of the bonding powder.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that in the second step, the number of the rollers is two, the width of each roller is 500mm, the width of a gap between the two rollers is 0 mm-1.2 mm, and the feeding quality of the bonding powder is 1 kg-8 kg. The large-width roller can be used for preparing large-size powder rolled metal porous plates, and the gap width between the two rollers ensures that bonding powder flows down from the gap of the roller in the subsequent rolling process and is compacted and covered on the surface of the roller to a saturated state when passing through a pressing area; the quality of the bonding powder selected according to the rollers can fill the gap and the stacking area between the two rollers to form complete continuous rolling, and the bonding powder is prevented from being accumulated in the feeding area to influence the feeding uniformity in the rolling process.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that the speed of the reverse roller in the second step is 0.6-6 m/min, and the reverse time is 1-6 min. The parameters of the reverse roller promote the full adhesion of the bonding powder on the surface of the roller, prevent the bonding powder covering the surface of the roller from being thrown and falling off, and are favorable for realizing the coverage of the bonding powder on the surface of the roller to a saturated state.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that the feeding speed in the third step is 20-150 g/s, the roll gap width of the two rollers is 0-1.6 mm, and the rolling speed is 0.6-3 m/min. The optimized parameters interact and are matched with each other, so that the smooth rolling process is realized.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that the temperature of the constrained sintering in the fourth step is 900-1400 ℃, and the heat preservation time is 60-120 min. The sintering parameters are selected according to the theoretical melting point and the particle size range of the commonly used raw material metal powder, so that the uniformity of the thickness and the porosity of the large-size powder rolled metal porous plate is further ensured.

The preparation method for improving the uniformity of the large-size powder rolled metal porous plate is characterized in that the constraint sintering in the fourth step is carried out at the flow rate of 1m³/h～4m³In a hydrogen atmosphere, or in a vacuum of not more than 1X 10^-2Pa under vacuum. The hydrogen atmosphere protection sintering or the vacuum sintering with low vacuum degree of the flow avoids the occurrence of sintering oxidation, improves the quality of the large-specification powder rolled metal porous plate, further improves the uniformity of the large-specification powder rolled metal porous plate, and avoids the waste of raw materials and energy consumption.

Compared with the prior art, the invention has the following advantages:

1. the invention firstly covers the bonding powder on the surface of the roller to reach a saturated bonding powder state, improves the surface friction of the roller and keeps a stable state, thereby improving the stability of the gripping ability of the roller to the fed bonding powder in the rolling process, being beneficial to controlling the thickness and the porosity among the bonding powder after the rolling, and improving the uniformity of the thickness and the porosity of the large-size powder rolled metal porous plate.

2. The width of the powder rolled metal porous plate prepared by the method is more than 450mm, the thickness deviation is +/-5%, and the porosity is uniform, so that the requirement of large-size powder rolled metal porous plates in industrial production is met.

3. The raw materials of the invention are widely and easily available, the preparation process is simple, and the prepared powder rolling metal porous plate can be widely applied to certain gas-solid and liquid-solid separation links in the industries of filtration separation, water electrolysis, medicine, petrochemical industry and the like.

The technical solution of the present invention is further described in detail by the accompanying drawings and examples.

Drawings

Fig. 1 is a schematic view of a connecting structure of a feeding device and a roll gap between two rolls used in embodiments 1 to 6 of the present invention.

Fig. 2 is a schematic structural view of a sintering apparatus used for constrained sintering in examples 1 to 6 of the present invention.

FIG. 3 is a schematic representation of a powder rolled metal porous plate made in example 1 of the present invention.

Description of the reference numerals

1-a charging bin; 2-a first hand wheel; 3-lifting the gate;

4-a second hand wheel; 5-opening the tongue; 6-metal powder;

7-a conveyor; 8, positioning bolts; 9-a feeder;

10 — a first roll; 11-a second roll; 12-a buffer reed;

13-green board; 14-a frame; 15, conveying belt;

16-a material rack; 17-a restraint block; and 18, preparing a plate to be sintered.

Detailed Description

As shown in fig. 1, the feeding device used in embodiments 1 to 6 of the present invention includes a charging bin 1 and a feeder 9, an opening tongue 5 controlled by a first hand wheel 2 and a second hand wheel 4 is provided on a lower bin wall of the charging bin 1, the first hand wheel 2 and the second hand wheel 4 are provided on a lower surface of the charging bin 1, a lifting gate 3 is provided on a lower portion of the opening tongue 5, metal powder 6 is driven by a conveyor belt 15 of a conveyor 7 to enter the feeder 9 mounted on a frame 14, a positioning bolt 8 is provided at an upper port of the feeder 9, a buffering tongue 12 is provided at a bottom of the feeder 9, and the metal powder 6 is fed from the feeder 9 into a gap between a first roller 10 and a second roller 11 to form a green sheet 13 by rolling.

As shown in fig. 2, the sintering device for constrained sintering according to embodiments 1 to 6 of the present invention is composed of a material holder 16 and a constraining block 17 connected to the material holder 16 for fixing a plate 18 to be sintered.