Aluminum alloy billet for magnetic disk and aluminum alloy substrate for magnetic disk

A technology of aluminum alloy and billet, applied in the base layer of the recording layer, magnetic recording, magnetic recording layer, etc., can solve the problems of performance degradation, micro ripples cannot be removed, etc., and achieve excellent impact strength, surface smoothness, and excellent yield The effect of intensity

Inactive Publication Date: 2018-06-08
KOBE STEEL LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, micromoires cannot be sufficiently removed with a soft polishing cloth because the occurrence of micromoirés is caused by irregularities generated during plating pretreatment due to differences in etching performance according to differences in grain orientations
Microripples appear remarkably, especially when the grain size is large or non-uniform, and performance deteriorates as a magnetic disk

Method used

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  • Aluminum alloy billet for magnetic disk and aluminum alloy substrate for magnetic disk
  • Aluminum alloy billet for magnetic disk and aluminum alloy substrate for magnetic disk
  • Aluminum alloy billet for magnetic disk and aluminum alloy substrate for magnetic disk

Examples

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Embodiment approach

[0039] First, an embodiment of a blank will be described.

[0040] The raw material in this embodiment includes Mg: 4.5 mass % or more and 6.0 mass % or less, Mn: 0.10 mass % or more and 0.55 mass % or less, Si: 0.025 mass % or less and Fe: 0.025 mass % or less, and the balance is Al and unavoidable impurities.

[0041] The blank in the present invention has the following characteristics: the average grain size on the surface is 27 μm or less, the aspect ratio of the average grain size on the surface is 1.2 or less, and the yield strength is 140 MPa or more.

[0042] The ingredient composition of the blank in this embodiment is described below, and then, the state of the recrystallized structure and the mechanical properties are described.

[0043]

[0044] (Mg)

[0045] Mg is an element effective for improving the yield strength of a billet. When the amount of Mg is less than 4.5% by mass, sufficient yield strength may not be obtained and the impact strength of the bille...

Embodiment

[0136] The contents of the present invention will be specifically described below with reference to Examples exhibiting the advantageous effects of the present invention and Comparative Examples not exhibiting the advantageous effects of the present invention.

[0137] First, the material was melted at 700° C., the composition was adjusted to have the component compositions shown in Nos. 1 to 43 of Table 1, and an ingot was cast.

[0138] Next, peeling for removing the segregation layer on the surface of each ingot was performed, and the ingot was kept at 530 to 560° C. for 4 hours. After that, heat treatment for homogenization is performed by maintaining it at 510 to 530° C. for 0.5 to 12 hours.

[0139] Immediately after the heat treatment for homogenization, hot rolling was started to prepare a hot-rolled sheet having a thickness calculated from a predetermined cold-rolling reduction ratio and a processed sheet thickness. Hot rolling was performed to complete within 10 min...

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Abstract

The invention provides an aluminium alloy blank for a magnetic disk and an aluminium alloy substrate for a magnetic disk, the aluminium alloy blank and the aluminium alloy substate have sufficient impact strength to avoid deformation due to impact in the falling process when they are thinned, microwavy lines are impossible to appear on the plating surface after electroplating, and surface defects are few. The aluminium alloy blank for the magnetic disk comprises Mg of above 4.5 mass% and below 6.0 mass%, Mn of above 0.10 mass% and below 0.55 mass%, Si of below 0.025 mass%, Fe of below 0.025 mass%, and the rest of Al and unavoidable impurities. The average grain size on the surface of the aluminium alloy blank is below 27 [mu]m, the aspect ratio of the average grain size on the surface of the aluminium alloy blank is below 1.2, and the yield strength of the aluminium alloy blank is above 140 MPa.

Description

technical field [0001] The invention relates to an aluminum alloy blank for a magnetic disk and an aluminum alloy substrate for a magnetic disk. Background technique [0002] With the digitization of information and the spread of the Internet, a large amount of digital data has been generated, and increased capacity of hard disk drives (HDDs) has been required, mainly in data centers. In order to achieve an increase in the capacity of HDDs, increasing the number of magnetic disks to be mounted per HDD has been studied. Then, in order to increase the number of magnetic disks to be mounted, thinning of the magnetic disks has been studied. In research into thinning, it has been proposed to reduce the thickness of a magnetic disk to be mounted in a 3.5-inch HDD from about 1.3 mm in the conventional case to less than 0.8 mm. [0003] Here, as a problem when the thickness becomes thin, examples thereof include deformation of the magnetic disk due to impact (about 300G) when drop...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C22C21/06C22C21/08C22F1/047G11B5/73
CPCC22C21/06C22C21/08C22F1/047G11B5/7315
Inventor 梅田秀俊寺田佳织山本胜久林雄一广桥正博
Owner KOBE STEEL LTD
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