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Densification method of porous workpiece

A densification and workpiece technology, which is used in the densification of porous parts, sintered porous parts and castings, and can solve the problem that the parts cannot have connected pores, cannot achieve hot isostatic pressing, and the glass is brittle. and other problems, to achieve the effect of high density and mechanical properties, improved packing density and low production cost

Inactive Publication Date: 2011-09-21
HUAZHONG UNIV OF SCI & TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, there are some disadvantages in using this method to compact porous parts. For example, it is necessary to ensure that the relative density of the part before hot isostatic pressing reaches more than 92%, which is generally difficult to achieve, and there must be no communicating pores in the part. Otherwise, there will be gas in the glass envelope formed after the glass is melted, and the effect of hot isostatic pressing will not be achieved.
Another disadvantage of directly encapsulating porous parts with glass is that the glass is brittle and easily broken during handling, which increases the cost

Method used

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  • Densification method of porous workpiece

Examples

Experimental program
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Effect test

example 1

[0035] The bevel gear made of SLS sintered Ni625 alloy powder to be dense and porous is as follows: figure 1 As shown, its diameter is 60 mm, and the initial relative density is 45%. The bevel gear has been degreased at high temperature before being densified by this method.

[0036] (1) Process a cylindrical sheath with an inner diameter of 70mm and a wall thickness of 2mm by machining. The material is 45 steel.

[0037] (2) Fix the bevel gear to the inner center of the sheath, and perform sealing welding on the connection between the sheath and the end cap.

[0038] (3) Check for leaks on the package. If there is air leakage in the sheath, it is necessary to re-seal the joint between the sheath and the end cap until there is no air leakage. If there is no air leak, go directly to the next step.

[0039] (4) Borosilicate glass powder is filled into the inside of the bag, and its composition is 78.5% SiO 2 , 14.6% B 2 o 3 , 4.9% Na 2 O, 1.8%Al 2 o 3 And a small amount...

example 2

[0047] The porous part to be densified is a cylinder formed by SLM of 316L stainless steel powder, with a diameter of 40 mm and an initial relative density of 78%.

[0048] (1) Process a cylindrical sheath with an inner diameter of 50mm and a wall thickness of 2mm by machining, and the material is 45 steel.

[0049] (2) Fix the 316L stainless steel SLM part to the inner center of the sheath, and seal the joint between the sheath and the end cap.

[0050] (3) Check for leaks on the package. If there is air leakage in the sheath, it is necessary to re-seal the joint between the sheath and the end cap until there is no air leakage. If there is no air leak, go directly to the next step.

[0051] (4) Soda-lime-silica glass powder is filled inside the sheath, the main component of which is 72.5% SiO 2 , 13.1%Na 2 O, 11.2% CaO, 1.8% Al 2 o 3 and a small amount of MgO, K 2 O, etc., the softening point temperature test is 729 ° C, shaking and shaking on a vibrating table.

[00...

example 3

[0059] The porous product to be densified is a cylinder formed by SLM of Ti-6Al-4V powder, with a diameter of 20 mm and an initial relative density of 68%.

[0060] (1) Process a cylindrical sheath with an outer diameter of 30mm and a wall thickness of 2mm by machining. The material is 45 steel.

[0061] (2) Fix the cylindrical SLM part to the inner center of the sheath, and perform sealing welding on the connection between the sheath and the end cap.

[0062] (3) Check for leaks on the package. If there is air leakage in the sheath, it is necessary to re-seal the joint between the sheath and the end cap until there is no air leakage. If there is no air leak, go directly to the next step.

[0063] (4) Borosilicate glass powder is filled into the inside of the bag, and its composition is 85% SiO 2 , 13.4% B 2 o 3 and a small amount of Na 2 O, Al 2 o 3 etc., the softening point temperature test is 820°C, and it is shaken and shaken on a vibrating table.

[0064] (5) Ins...

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Abstract

The invention discloses a densification method of a porous workpiece. The method comprises the following steps: placing the porous workpiece in a jacket, and performing seal welding on a joint between the jacket and an end cover; performing leak detection for the jacket; after the tightness of the jacket is ensured, filling glass powder in the jacket, and shaking to be solid; vacuumizing the jacket and performing seal welding on a suction pipe to obtain a compact; performing hot isostatic pressing treatment on the compact; and after a hot isostatic pressing hearth is cooled, taking out the compact, and removing the glass and the jacket from the surface of the workpiece to obtain a dense workpiece. The method with a metal jacket and glass powder as force transfer media, can be used for processing any porous workpieces with complicated shapes and relative density being less than 90%, and is particularly suitable for densifying sintering pieces and castings such as SLS / SLM and the like.

Description

technical field [0001] The invention belongs to the field of material processing, and in particular relates to a densification method of porous parts, which is especially suitable for densification of sintered porous parts and castings. technical background [0002] Since the end of the 20th century, the method of direct forming of powder parts has taken up an increasing proportion in the processing and manufacturing industry. This method has the advantages of low cost, low energy consumption, and rapid production of parts. Its products are widely used in mechanical structural parts. , electrical parts, magnetic parts, heat-resistant parts and nuclear reactor materials and other fields. Porosity is a significant feature of powder direct forming parts. Porosity will lead to a decrease in the density of the part, and a significant decrease in mechanical properties, heat resistance and corrosion resistance. Improving the density of such parts has become a major challenge in th...

Claims

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Application Information

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IPC IPC(8): B22F3/16
Inventor 魏青松史玉升薛鹏举陆恒王基维刘国承
Owner HUAZHONG UNIV OF SCI & TECH
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