WO2013102356A1

WO2013102356A1 - Molybdenum crucible manufacture method

Info

Publication number: WO2013102356A1
Application number: PCT/CN2012/080195
Authority: WO
Inventors: 张灵杰
Original assignee: 洛阳科威钨钼有限公司
Priority date: 2012-01-04
Filing date: 2012-08-16
Publication date: 2013-07-11
Also published as: CN102699327B; CN102699327A

Abstract

A molybdenum crucible manufacture method with molybdenum powders as the raw material comprises the following steps: shaping the molybdenum powders with a cold isostatic press; sintering; cooling the intermediate frequency sintering furnace with circulating water for 9-10 hours after sintering; taking the molybdenum rod out and putting it into the muffle furnace; forging 30-40 times by means of an air hammer with 1000kg impact force after heating; mechanically forming a groove on the rod, and further fine turning the cylindrical and the end surfaces such that the molybdenum crucible have a surface roughness of Ra1.6-Ra3.2μm. The method has the advantages of saving process, reducing cost, having low requirement for equipment. As a solid powder cylindrical blank is formed and then crystallized at a high temperature twice to refine the grains, the strength and the high temperature resistance of the crucible is improved.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molybdenum crucible used as a container for an LED sapphire crystal growth furnace, and more particularly to a process for producing molybdenum crucible. BACKGROUND OF THE INVENTION Molybdenum crucible is mainly used as a container for LED sapphire crystal growth furnace. In this field, molybdenum crucible is required to have high thermal stability, material compactness and high strength. Conventional methods for preparing molybdenum crucible are generally: sintering molding, followed by After the machining is completed, the compactness of the crucible prepared by this process is very poor, and the high temperature resistance is poor, so the strength is also low, the service life is short, and the cracking phenomenon often occurs during use in a high temperature environment. SUMMARY OF THE INVENTION An object of the present invention is to provide a process for producing molybdenum crucible, which has the advantages of simple process and low cost, and the relative density of the product is 10.2 g/cm ³ , and the high temperature resistance of the material is improved. More than %, the service life is increased by 3-5 times. The technical solution adopted by the present invention is as follows: a preparation process of the molybdenum crucible, using molybdenum powder as a raw material, the purity of the molybdenum powder is > 99. 95%, the particle size is 2. 4 - 3. 2 μ m, and the production steps are as follows:

Step 1. The molybdenum powder is placed in a pre-formed mold on a cold isostatic press at a pressure of 180-220 MPa, and the holding time is 10-20 minutes. The solid powdery cylindrical body is prepared and taken out. Step 2: The powdery cylindrical body obtained in the first step is placed in an intermediate frequency sintering furnace, and hydrogen is introduced into the furnace to be sintered at a temperature of 1890 ° C to 1910 ° C for a sintering time of 29-32. Hours, sintering into molybdenum rods, stopping sintering; Step 3: Cooling the intermediate frequency sintering furnace with circulating water for 9 10 hours, then taking out the molybdenum rod, placing it indoors, naturally cooling to room temperature, and standby;

Step 4, the molybdenum rod prepared in the third step is placed in a muffle furnace, heated at a temperature of 1390-1410 ° C for 13 hours, and then taken out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, align the air hammer with the end face of the molybdenum rod, forge, forge 30-40 times, stop forging, Forming a molybdenum tire blank, taking it out from the air hammer, cooling it under normal temperature for 35 hours, and standby;

Step 6. Place the molybdenum green tire blank prepared in step 5 on the lathe, adopt mechanical processing method, and pull out a groove, and then refine the outer circle and the end surface, so that the surface roughness of the molybdenum crucible reaches Ral.6~Ra3. .2 m, made of molybdenum crucible.

The beneficial effects of the invention are:

First, the method is firstly made of molybdenum crucible by powder pre-compression molding, first high-temperature sintering, pre-cooling, second high-temperature heating, forging, to ensure that the blank is forged after two strengthening treatments. Improve the strength and compactness of molybdenum crucible; secondly, sequentially process each step to accurately set the process parameters, for example; pre-forming molding stage: guarantee pre-pressure, holding time; first high-temperature sintering time and its sintering temperature, cooling time Etc.; the second high temperature heating, etc., the above process makes the high temperature resistance and strength of the formed molybdenum crucible improved.

Secondly, the method has simple manufacturing process, low requirements on equipment, saves process flow, reduces input cost, and improves production efficiency. At the same time, the method firstly forms a solid billet cylindrical billet, and then passes through a secondary high temperature environment. Recrystallization, grain refinement, proved by a large number of tests: When the first high temperature sintering temperature is controlled at 1900 °C, the time is 30 hours, and the second time is heated at 1400 °C for 2 hours, under the control of this parameter The relative density of the prepared molybdenum crucible is 10.3 g/cm ³ or more, and the high temperature resistance of the product is improved by more than 30%, the strength is further improved, and the use effect is better. Third, after high-temperature sintering, the circulating water cooling time is reasonably controlled, and the intermediate frequency sintering furnace is cooled by circulating water for 9-10 hours, and then the sintered molybdenum rod is taken out to room temperature, and the test proves: When the water circulation cooling time is controlled at 9 At the hour, the compactness of the material is further improved, and the service life of the obtained product is more than three times higher than that of the conventionally prepared product in the same high temperature environment. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a process flow diagram of the present invention.

2 is a schematic view showing the structure of molybdenum crucible.

Reference numerals: 1, groove, 2, wall. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT As shown in Fig. 1, a molybdenum crucible is produced by using a molybdenum powder as a raw material, a molybdenum powder having a purity of 99.95% and a particle size of 2. 4 - 3. 2 μ πι.

Step 1. The molybdenum powder powder is placed in a mold prepared in advance on a cold isostatic press at a pressure of 180-220 MPa, and the holding time is 10-20 minutes, and taken out to obtain a solid powdery cylindrical body. Pre-press to ensure that the powdery cylindrical body is stable and ready for use;

Step 2: The silty cylindrical body prepared in the first step is placed in an intermediate frequency sintering furnace, and hydrogen is introduced into the furnace to be sintered at a temperature of 1890 ° C to 1910 ° C for a sintering time of 29-32. Hours, sintered into molybdenum rods, stop sintering;

Step 3: Circulating cooling water pipe is arranged on the outer furnace wall surface of the intermediate frequency sintering furnace, and the intermediate frequency sintering furnace is cooled by circulating water for 9-10 hours, then the molybdenum rod is taken out, placed indoors, naturally cooled to room temperature, and spared. ;

Step 4, the molybdenum rod prepared in the third step is placed in the muffle furnace, and added at a temperature of 1390-1410 ° C. After 1 3 hours of heat, take it out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, align the air hammer with the end face of the molybdenum rod, forge, forge 30-40 times, stop forging, Forming a molybdenum green tire blank, taken out from the air hammer, cooled in a normal temperature environment for 3 hours, and spared, the temperature of the forged molybdenum rod in this step needs to be maintained between 1350 and 1 410 ° C, that is, in forging If the temperature of the molybdenum rod is lower than the temperature index during the process, it needs to be heated and then forged. In the conventional production, the operation technician judges it according to experience. Generally, forging for 2 to 3 times requires heating. Continue to forge;

Step 6: Place the molybdenum green tire blank prepared in step 5 on a lathe, using a mechanical processing method, as shown in Fig. 2, the vehicle out of a groove 1, and then the outer circle and the end surface of the wall 2 of the car, so that molybdenum The surface roughness of the crucible reaches Ral.6~Ra3.2 m, and it is made into molybdenum crucible.

Embodiment 1:

The preparation process of the molybdenum crucible is made of molybdenum powder as the raw material, the purity of the molybdenum powder is > 99.95%, and the particle size is 2. 4 - 3. 2 μ m. The production steps are as follows:

Step 1. The molybdenum powder powder is placed in a previously prepared mold, and then the mold is placed on a cold isostatic press, and the pressure is 180 MPa, and the holding time is 10 minutes, and taken out to obtain a solid powdery cylindrical billet. Body, after pre-pressing, spare;

Step 2: The powdery cylindrical body obtained in the first step is placed in a medium frequency sintering furnace, and hydrogen is introduced into the furnace to be sintered at a temperature of 1890 ° C for a sintering time of 29 hours. Stop sintering;

Step 3: Circulating cooling water pipe is arranged on the outer furnace wall surface of the intermediate frequency sintering furnace, and the intermediate frequency sintering furnace is cooled by circulating water for 9 hours, then the molybdenum rod is taken out, placed indoors, naturally cooled to room temperature, and used; Step 4, the molybdenum rod prepared in the third step is placed in a muffle furnace, heated at a temperature of 1390 ° C for 1 hour, and then taken out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, align the air hammer with the end face of the molybdenum rod, forge, forge 30 times, stop forging, form molybdenum The tire blank is taken out from the air hammer and cooled in a normal temperature environment for 3 hours. The temperature of the forged molybdenum rod in this step needs to be maintained between 1350-1410 °C. Generally, forging 2 3 times need to be heated to continue to forge;

The test proves that the service life of the molybdenum crucible prepared by this step is more than 5 times longer than that of the conventionally prepared molybdenum crucible, and the relative density of the product reaches 10.2 g/cm ³ or more.

Embodiment 2:

Step 1. The molybdenum powder is placed in a pre-formed mold on a cold isostatic press at a pressure of 200 MPa and a dwell time of 15 minutes. The solid powdery cylindrical body is obtained and pre-pressed. Standby

Step 2: The powdery cylindrical body obtained in the first step is placed in a medium frequency sintering furnace, hydrogen is introduced into the furnace, and sintering is performed at a temperature of 1900 ° C for 30 hours, and is sintered into a molybdenum rod. Stop sintering;

Step 3: Circulating cooling water pipe is arranged on the outer furnace wall surface of the intermediate frequency sintering furnace, and the intermediate frequency sintering furnace is cooled by circulating water for 9 hours, then the molybdenum rod is taken out, placed indoors, and naturally cooled. At room temperature, spare;

Step 4, the molybdenum rod prepared in the third step is placed in a muffle furnace, heated at 1400 ° C for 2 hours, and then taken out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, align the air hammer with the end face of the molybdenum rod, forge, forge 35 times, stop forging, form molybdenum The tire blank is taken out from the air hammer and cooled in a normal temperature environment for 4 hours. The temperature of the forged molybdenum rod in this step needs to be maintained between 1350 and 415 ° C. Generally, forging 2 3 times need to be heated to continue to forge;

The test proves that the service life of the molybdenum crucible prepared by this step is more than three times longer than that of the conventionally prepared molybdenum crucible in the same high temperature environment, and the relative density of the product reaches 10.3 g/cm ³ or more.

Embodiment 3:

Step 1. The molybdenum powder powder is placed in a mold prepared in advance on a cold isostatic press, the pressure is 220 MPa, the holding time is 20 minutes, and the solid powdery cylindrical body is obtained, and then pre-pressed. Standby

Step 2: The powdery cylindrical body obtained in the first step is placed in a medium frequency sintering furnace, and hydrogen is introduced into the furnace to be sintered at a temperature of 1910 ° C for 32 hours to form a molybdenum rod. Stop sintering;

Step 3: Circulating cooling water pipes are arranged on the outer furnace wall surface of the intermediate frequency sintering furnace, and the circulating water pair is used. The intermediate frequency sintering furnace is cooled down for 10 hours, after which the molybdenum rod is taken out, placed indoors, naturally cooled to room temperature, and used;

Step 4, the molybdenum rod prepared in the third step is placed in a muffle furnace, heated at a temperature of 1410 ° C for 3 hours, and then taken out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, align the air hammer with the end face of the molybdenum rod, forge, forge 40 times, stop forging, form molybdenum The tire blank is taken out from the air hammer and cooled in a normal temperature environment for 3-5 hours. The temperature of the forged molybdenum rod in this step needs to be maintained between 1350-1410 °C. Generally, forging 2 to 3 times need to be heated to continue to forge;

The test proves that the service life of the molybdenum crucible prepared by this step is more than 5 times longer than that of the conventionally prepared molybdenum crucible in the same high temperature environment, and the relative density of the product reaches 10.3 g/cm ³ or more.

Claims

Claim

1. A process for producing molybdenum crucible, characterized in that: molybdenum powder is used as a raw material, the purity of the molybdenum powder is > 99. 95%, and the particle size is 2. 4 - 3. 2 μ m, and the production steps are as follows:

Step 1: Put the molybdenum powder into a mold prepared in a cold isostatic press at a pressure of 180-220 MPa, hold the pressure for 10-20 minutes, and take it out to obtain a solid powdery cylindrical body. Step 2: The powdery cylindrical body obtained in the first step is placed in an intermediate frequency sintering furnace, and hydrogen is introduced into the furnace to be sintered at a temperature of 1890 ° C to 1910 ° C for a sintering time of 29 -32 hours, sintered into a molybdenum rod, stopping sintering;

Step 3: Cooling the intermediate frequency sintering furnace with circulating water for 9 10 hours, then taking out the molybdenum rod, placing it indoors, naturally cooling to room temperature, and standby;

Step 4, the molybdenum rod prepared in the third step is placed in a muffle furnace, heated at a temperature of 1390-1410 O for 13 hours, and then taken out;

Step 5: Place the molybdenum rod heated in step 4 under the air hammer, use an air hammer with an impact force of 1000 kg, aim the hammer on the end face of the molybdenum rod, forge, forge 30-40 times, stop forging , forming a molybdenum green tire blank, taken out from the air hammer, cooled in a normal temperature environment for 3 5 hours, standby;

Step 6. Place the molybdenum green tire blank prepared in step 5 on the lathe, adopt mechanical processing method, and push out a groove, and then refine the outer circle and the end surface of the car to make the surface roughness of the molybdenum crucible reach Ral.6~ Ra3.2 m, made of molybdenum crucible.