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Forward and reverse superplastic bulging method capable of changing friction condition

A variable friction, positive and negative technology, applied in metal processing equipment, forming tools, manufacturing tools, etc., can solve the problem of uneven thickness distribution of formed workpieces, and achieve the effect of large friction, practical production technology, and low friction

Inactive Publication Date: 2008-08-06
HARBIN INST OF TECH
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0003] The purpose of the present invention is to solve the problem of uneven thickness distribution of the formed workpiece in the existing superplastic bulging method, and to provide a forward and reverse superplastic bulging method with variable friction conditions

Method used

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Examples

Experimental program
Comparison scheme
Effect test

specific Embodiment approach 1

[0007] Specific embodiment one: the forward and reverse superplastic bulging method of a kind of variable friction condition of this embodiment is finished like this: a, mold processing: first carry out the processing of reverse bulging mould, in the opposite direction that shape has been completed A series of grooves perpendicular to the reverse bulging direction of the slab are processed on the surface of the bulging mold to increase the friction between the slab and the upper mold; The method of surface spraying on the surface of the bulging mold is used to reduce the friction between the slab and the lower mold. First, the BN ceramic powder solution is prepared, the lower mold is heated, and then the BN ceramic powder solution is sprayed on the lower mold with a high-pressure spray gun. On the surface of the cavity, a thin lubricating layer is formed; b, the mold is loaded into the furnace; c, the slab enters the mold; d, the mold is closed; e, the temperature is raised, an...

specific Embodiment approach 2

[0008] Specific embodiment 2: The difference between this embodiment and specific embodiment 1 is: in this embodiment, in the mold processing step a, the sections of the series of grooves perpendicular to the reverse bulging direction of the slab are U-shaped structure. It can generate a large friction force, which makes it difficult for the slab to continue to flow after the mold is pasted, and the pre-thinning effect is obviously increased.

specific Embodiment approach 3

[0009] Embodiment 3: The difference between this embodiment and Embodiment 1 is that in the mold processing step a of this embodiment, the series of grooves perpendicular to the reverse bulging direction of the slab are reverse bulging The position and density of the surface of the mold are determined according to the thickness of the slab, and the depth and width of the groove are not more than 500 μm. Grooves with different density and different depths are processed on the reverse model surface, so that different regions have different friction forces, so that the different degrees of thinning in different regions of the reverse bulging of the slab can be controlled to achieve effective pre-thinning Effect.

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PUM

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Abstract

The invention provides a forward and reverse superplastic bulging method for altering friction condition, relating to a forward and reverse superplastic bulging method. The method of the invention solves the problem of the existing superplastic bulging method that the thickness distribution of the formed workpiece is uneven, which is completed as follows: a. die processing: a series of grooves are processed on moulding surface of a reverse bulging die, and surface spray coating method is adopted on moulding surface of a forward bulging die; a lower die is heated, a high pressure spray gun is used for spraying and coating BN ceramic powder solution on the surface of a lower die cavity; b. die charging; c. die entering of plate blank; d. die assembly; e. heating up and heat preservation; f. reverse bulging; g. pressure maintaining after die pressing; h. reverse pressure unloading; j. forward bulging; k. pressure maintaining after die pressing; L. furnace cooling; m. workpiece withdrawing. The forward and reverse superplastic bulging method for altering friction condition provides an economic, efficient and practical manufacturing technique for solving the problem of controlling the uniform thickness of the workpiece in forward and reverse superplastic bulging.

Description

technical field [0001] The invention relates to a forward and reverse superplastic bulging method, which belongs to the field of superplastic bulging processing technology. Background technique [0002] Under the condition of superplastic deformation, the structural superplastic alloy has low deformation stress, high elongation, and almost no elastic composite strain hardening effect. It can stamp and form workpieces with very complex shapes on low-tonnage equipment without precision. Whole processing. Therefore, superplastic forming technology has been paid much attention in modern industry. However, in the existing superplastic bulging method, during the bulging process, since the surrounding material of the slab is pressed by the mold and does not participate in the deformation, the increase in the area of ​​the part is completely realized by the thinning of the slab, and the unevenness of the stress and strain field distribution The obvious difference in the wall thick...

Claims

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Application Information

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IPC IPC(8): B21D26/02B21D37/10B21D37/18B21D37/16
Inventor 张凯锋蒋少松
Owner HARBIN INST OF TECH