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Process for reducing coarse grain layer at free end of profile for rail

A free-end, profile technology, applied in the field of aluminum alloy extrusion, can solve the problems of high scrap rate, coarse-grained layer cannot meet customer requirements, etc., to prevent grain growth, reduce stress corrosion cracking sensitivity, and reduce thickness. Effect

Active Publication Date: 2021-03-09
CHINA ZHONGWANG
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0004] In view of this, the present invention provides a solution to the problem that existing profiles for rails with a wall thickness of 2-4 mm have symmetrical or isolated free end profiles, causing the coarse crystal layer at the free end to fail to meet customer requirements and high reject rate. The process of reducing the coarse-grained layer at the free end of the rail profile, by adjusting the composition, optimizing the mold structure, adopting short-sized ingots, adjusting the extrusion process and quenching, meets the control requirements of the free-end coarse-grained layer, and improves the yield

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0022] A process for reducing the coarse-grained layer at the free end of a section bar for a track, comprising the steps of:

[0023] A. Ingredients: The mass percentage ratio of each element of the aluminum alloy profile is as follows:

[0024] element Si Fe Cu mn Mg Ti Cr Zn Impurities Al content 0.65 0.25 0.11 0.20 0.50 0.05 0.15 0.10 0.10 margin

[0025] B. Melting and casting: Add the prepared aluminum alloy raw materials into the smelting furnace and mix them evenly to melt them into liquid aluminum alloys. The aluminum alloy is fused and cast into an aluminum alloy cast rod with a length of 800mm and surfaced;

[0026] C. Extrusion: After preheating, the aluminum alloy casting rod after melting and casting is sent to the aluminum alloy extruder for extrusion molding to obtain aluminum alloy profiles. The temperature is 480-510°C, the temperature of the aluminum alloy casting rod is controlled at 470-490°C, and the extrus...

Embodiment 2

[0031] The difference between embodiment 2 and embodiment 1 is that the mass percentage ratio of each element of the aluminum alloy profile in step A is as follows:

[0032] element Si Fe Cu mn Mg Ti Cr Zn Impurities Al content 0.70 0.25 0.16 0.30 0.60 0.05 0.20 0.10 0.10 margin

[0033] In step F, aging heat treatment is performed on the aluminum alloy profile after sawing to length, the aging temperature is 190° C., and the aging time is 7 hours.

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Abstract

The invention belongs to the field of aluminum alloy extrusion, and relates to a process for reducing a coarse grain layer at the free end of a profile for a rail. An aluminum alloy raw material comprises components of 0.65-0.70% of Si, less than or equal to 0.25% of Fe, 0.11-0.16% of Cu, 0.20-0.30% of Mn, 0.50-0.60% of Mg, less than or equal to 0.05% of Ti, 0.15-0.20% of Cr, less than or equal to0.10% of Zn and the balance Al, a single impurity is less than or equal to 0.05%, the total is less than or equal to 0.15%, and the balance is Al. By adjusting the components, a mold structure is optimized, a short cast ingot is adopted, the extrusion process and quenching are adjusted, the requirement for free-end coarse grain control is met, and the yield is increased.

Description

technical field [0001] The invention belongs to the field of aluminum alloy extrusion, and relates to a process for reducing the coarse-grained layer at the free end of a rail profile. Background technique [0002] Rail transit floors, side walls, or air-conditioning flat roofs and other profiles have symmetrical free ends or isolated free ends due to welding. During production, 6005A alloy is used for extrusion. During the extrusion process, the free end is subject to friction and occurs Dynamic recrystallization, grain growth, resulting in a large coarse-grained layer at the free end; moreover, the mold structure at the free end hinders the flow of metal, resulting in excessive metal energy storage, the growth of the coarse-grained layer is obvious, and the isolated free end is more serious, resulting in The coarse-grained layer at the free end cannot meet customer requirements, and the reject rate is high. [0003] According to the actual production, adjust the coarse gr...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): B21C37/00B21C23/00B21C25/02B21C29/00B21C29/04B21C31/00C22C21/02C22F1/00C22F1/043
CPCB21C37/00B21C23/002B21C25/02B21C29/003B21C29/04B21C31/00C22C21/02C22F1/043C22F1/002
Inventor 刘勇凯何强王志永赵明然韩启强关明政王志博董军贺付学丹远继才王爽
Owner CHINA ZHONGWANG
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