Process for preparing tungsten parts and components with complicated shape and high dimensional accuracy

Abstract

This invention provides a method for preparing complex-shape and high-accurate wolfram parts, belonging to injection moulding technology field, which is characterized by the following steps: a, using high-energy ball grinder to mill wolfram powder for 2-12 hours to get ball grinding; b, adding binder composed by 40-70% paraffin in weight, 15-35% high-density polyethylene, 10-30% polypropylene and 3-10% geoceric acid; c, mixing the ball grinding and binder to a uniform feeding with 50-62% powder in volume; d, moulding the feeding in the machine, with injection temperature being 120-170Deg.C, pressure being 80-140MPa; e, deflating and pre-sintering injection blank at temperature of 2100-2400Deg.C in sintering furnace, insulating for 1-10 hours, post-processing the production to get wolfram parts. The invention has the advantages of nearly 100% material utilization, purity more than 99% and lower product cost.

Description

technical field

[0001] The invention belongs to the technical field of injection molding, and in particular provides a method for preparing tungsten parts with complex shapes and high dimensional precision. Background technique

[0002] Metal tungsten has a high melting point (3410°C), high density (19.3g / m 3 ), high elastic modulus and strength, and low coefficient of expansion, etc., occupy an important position in engineering applications such as modern national defense, atomic energy industry, electric vacuum, and electric light source. Due to the high melting point and the high sintering temperature required for high-density tungsten, the vertical melting method is usually used for sintering. This method can only produce rods or bulk materials, and cannot sinter parts with complex shapes. In addition, tungsten has high hardness, High brittleness and poor processing performance make it difficult to directly manufacture tungsten parts with complex shapes and high dimensi...

Examples

Embodiment 1

[0016] The tungsten powder was ball milled in a high-energy ball mill for 4 hours. The binder was composed of 60% paraffin wax, 25% high-density polyethylene, 10% polypropylene and 5% stearic acid. The volume ratio of the powder was 56%. The powder was mixed with After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform. The feeding is injection-molded on the CJ80-E injection machine, and the injection temperature is 160 ℃, the injection pressure is 90MPa, the obtained injection body is extracted and degreased in trichlorethylene for 4 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 8 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, a...

Embodiment 2

[0018] The tungsten powder was ball milled in a high-energy ball mill for 6 hours. The binder was composed of 55% paraffin wax, 25% high-density polyethylene, 15% polypropylene and 5% stearic acid. The volume ratio of the powder was 56%. The powder was mixed with After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform. The feeding is injection-molded on the CJ80-E injection machine, and the injection temperature is 160 ℃, the injection pressure is 100Mpa, the obtained injection body is extracted and degreased in trichlorethylene for 2 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 8 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, ...

Embodiment 3

[0020] The tungsten powder was ball milled in a high-energy ball mill for 8 hours. The binder was composed of 50% paraffin wax, 25% high-density polyethylene, 15% polypropylene and 10% stearic acid. The volume ratio of the powder was 54%. The powder and After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform, and the feeding is injected on the CJ80-E injection machine at an injection temperature of 150 ℃, the injection pressure is 100Mpa, the obtained injection body is extracted and degreased in trichlorethylene for 4 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 6 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, and the sintering...

technical field

[0001] The invention belongs to the technical field of injection molding, and in particular provides a method for preparing tungsten parts with complex shapes and high dimensional precision. Background technique

[0002] Metal tungsten has a high melting point (3410°C), high density (19.3g / m 3 ), high elastic modulus and strength, and low coefficient of expansion, etc., occupy an important position in engineering applications such as modern national defense, atomic energy industry, electric vacuum, and electric light source. Due to the high melting point and the high sintering temperature required for high-density tungsten, the vertical melting method is usually used for sintering. This method can only produce rods or bulk materials, and cannot sinter parts with complex shapes. In addition, tungsten has high hardness, High brittleness and poor processing performance make it difficult to directly manufacture tungsten parts with complex shapes and high dimensi...

Examples

Embodiment 1

[0016] The tungsten powder was ball milled in a high-energy ball mill for 4 hours. The binder was composed of 60% paraffin wax, 25% high-density polyethylene, 10% polypropylene and 5% stearic acid. The volume ratio of the powder was 56%. The powder was mixed with After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform. The feeding is injection-molded on the CJ80-E injection machine, and the injection temperature is 160 ℃, the injection pressure is 90MPa, the obtained injection body is extracted and degreased in trichlorethylene for 4 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 8 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, a...

Embodiment 2

[0018] The tungsten powder was ball milled in a high-energy ball mill for 6 hours. The binder was composed of 55% paraffin wax, 25% high-density polyethylene, 15% polypropylene and 5% stearic acid. The volume ratio of the powder was 56%. The powder was mixed with After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform. The feeding is injection-molded on the CJ80-E injection machine, and the injection temperature is 160 ℃, the injection pressure is 100Mpa, the obtained injection body is extracted and degreased in trichlorethylene for 2 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 8 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, ...

Embodiment 3

[0020] The tungsten powder was ball milled in a high-energy ball mill for 8 hours. The binder was composed of 50% paraffin wax, 25% high-density polyethylene, 15% polypropylene and 10% stearic acid. The volume ratio of the powder was 54%. The powder and After the binder is mixed on the SK-160 open rubber mixing machine, it is then granulated on the PSJ32 mixing extruder to make the feeding more uniform, and the feeding is injected on the CJ80-E injection machine at an injection temperature of 150 ℃, the injection pressure is 100Mpa, the obtained injection body is extracted and degreased in trichlorethylene for 4 hours, then dried at 60 ℃ for 30 minutes, and then placed in an atmosphere degreasing furnace for thermal degreasing. The thermal degreasing time is 6 hours, and the degreasing The blank is pre-sintered in a hydrogen furnace at 1300°C for 1 hour, and then placed in a medium-frequency induction furnace for sintering. The sintering temperature is 2300°C, and the sintering...