CN1583328A

CN1583328A - Hard alloy formation by low-pressure injection

Info

Publication number: CN1583328A
Application number: CN 200410040002
Authority: CN
Inventors: 何�泽; 蒋勇; 江绍平
Original assignee: CHENGDU BANGPU ALLOY MATERIALS Co Ltd
Current assignee: CHENGDU BANGPU ALLOY MATERIALS Co Ltd
Priority date: 2004-06-16
Filing date: 2004-06-16
Publication date: 2005-02-23

Abstract

A low-pressure injection moulding method for hard alloy includes such steps as pugging the mixture of powdered metal and adhesive, preparing wax blocks, low-pressure injection moulding, precalcining for dewaxing, and vacuum sintering.

Description

The carbide alloy LPIM

1, technical field carbide alloy LPIM is an a kind of novel near-net forming technology of making hard metal article, is subordinate to metal powder injection molding.

2, the background technology carbide alloy is the liquid-phase sintering composite powder metallurgy material of forming with infusible compound and binding metal, and its technological process is as follows: metal dust preparation → carbide alloy mixture preparation → shaping → binder removes → sintering → subsequent treatment → hard metal article.Wherein common carbide alloy forming technique has: mold pressing, extruding, etc. static pressure etc.Carbide alloy injection moulding is a kind of new forming technique that grows up the 1980s.Metal powder injection molding is a kind of novel near-net forming technology that the prior powder metallurgy technology combines with the modern plastics injection molding technology, injection pressure is generally about 100MPa, the maximum characteristics of this technology of product substance little (being no more than 300g) are can directly produce to have or near the complicated abnormal shape parts of final size and shape, its product allowance is few, the precision height, even tissue, excellent performance, low cost of manufacture, being 20%～60% of traditional handicraft only, is the most popular current parts forming technique.The carbide alloy LPIM is under the jurisdiction of the metal powder injection molding technology, but its injection pressure only is 0.5～5MPa, 5% of not enough traditional injection molding technology injection pressure, can be used to make complex-shaped carbide alloy and other metallic article, the production efficiency height, cost is low, and its technological process is: 1. metal dust and binding agent are mixing, the system wax stone; 2. LPIM; 3. pre-burning dewaxes; 4. vacuum-sintering.

3, summary of the invention adopts highly effective binder, and injection pressure is reduced to below 0.5～5MPa, compares with traditional injection moulding, has realized that successfully injection pressure reduces an order of magnitude.

4, the specific embodiment is introduced the present invention in detail in conjunction with example

4.1, wax stone preparation: binding agent and the cemented carbide powder that contains WC, Co are put into the de-airing mixer batch mixer, under 70～120 ℃ of temperature, mixed 1～2 hour, vacuum is less than 50Pa, press 6～8% of the heavy percentage of compound and add binding agent, binding agent composition and prescription are: paraffin 40～80%, plasticizer 2～20%, stearic acid 2～20%.

4.2, injection moulding: above-mentioned wax stone is added in the injector with 70～120 ℃, and injection pressure 0.5～5MPa under 10～50 ℃ of conditions of mould temperature, is injected into base substrate.

4.3, the dewaxing pre-burning: base substrate is put into the self-control dewaxing furnace, under nitrogen hydrogen mixeding gas protection, dewaxing pre-burning to 900～1000 ℃, 12～48 hours time.

4.4, sintering: take out pre-burned base substrate, put into the vacuum drying oven sintering, 1450～1520 ℃ of temperature, temperature retention time 60～90 minutes, vacuum is less than 50Pa.

The hard metal article that uses the present invention to make, interior tissue is even, and Metallographic Analysis reaches A02B02 C00, and density reaches 99～100% of solid density, good mechanical property, the dimensional accuracy height, once-forming need not back processing.

Claims

1, a kind of carbide alloy injection molding technology of low-pressure.Comprise following technological process:

1.1, metal dust and binding agent put into batch mixer add thermal agitation, vacuumize, mix, binding agent is paraffin (40～80%), plasticizer (2～20%), stearic acid (2～20%)

1.2, LPIM: 70～120 ℃ of injection temperatures, operating pressure 0.5～5MPa, single products weight maximum can reach 1000g.

1.3, the dewaxing pre-burning: the shaping base substrate is placed in the dewaxing pre-burning stove, feeds the N2+H2 mist, the pre-burning that dewaxes, 900～1000 ℃ of calcined temperatures, 12～48 hours pre-burning time of dewaxing.

1.4, sintering: adopt vacuum-sintering, 1450～1520 ℃ of sintering temperatures, temperature retention time 60～90 minutes, vacuum 5～50Pa.

2, according to this claim 1 described LPIM technology, it is characterized in that the wax stone preparation: press 6～8% of compound percentage by weight and add binding agent, binding agent composition and prescription are: paraffin (40～80%), plasticizer (2～20%), stearic acid (2～20%).In blender, vacuumize and stirred 1～2 hour.

3, LPIM technology according to claim 1 is characterized in that: in the low head injection operation, and 70～120 ℃ of injection temperatures, operating pressure 0.5～5MPa, single products weight maximum can reach 1000g.

4, LPIM technology according to claim 1, the pre-burning operation that it is characterized in that dewaxing is that the shaping base substrate is placed in the dewaxing pre-burning stove, logical N2+H2 gaseous mixture dewaxing pre-burning, 900～1000 ℃ of calcined temperatures, 12～48 hours pre-burning time of dewaxing.

5, LPIM technology according to claim 1 is characterized in that in the sintering circuit, adopts vacuum-sintering, 1450～1520 ℃ of sintering temperatures, temperature retention time 60～90 minutes, vacuum 5～50Pa.