JPS6152346A - Free cutting aluminum alloy tube for spacer ring and its manufacture - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to an aluminum alloy tube for spacer rings with good machinability and a method for manufacturing the same, and in particular, even by porthole extrusion, coarse crystals do not occur in welded parts, etc., and cutting is possible. The present invention relates to an aluminum alloy tube for spacer rings with good surface smoothness and surface roughness, and a method for manufacturing the same.

Prior Art and its Problems Conventionally, a spacer ring has been used as a member that is interposed between two objects to separate them. Various properties are required depending on the application. For example, when stacking computer memory disks, a spacer ring is used to create a gap into which the head is inserted and to maintain a constant distance between each disk. There are strict requirements regarding accuracy, flatness, and surface roughness. In addition, in order to withstand the clamping force for stacking each disk, it is required to be homogeneous, strong, and not subject to aging, as well as to not emit particles or foreign matter. Moreover,
The gap between the head and the disk is usually 0.2 to 0.4 μm.
Since the spacer ring is designed to operate at a certain level, extremely strict smoothness is required, and the smoothness of the end face of the spacer ring is as important as that of the disk.

By the way, such spacer rings have conventionally been made using aluminum materials, and usually there are cases where aluminum castings are used and cases where AA6061 aluminum alloy extruded tubes are used, but when the former casting is used, However, there is a problem in that pinholes and the like occur, making it impossible to sufficiently improve the smoothness and surface roughness of the spacer ring cut out from such a casting.

Also, AA6061 used for forming spacer rings.
Aluminum alloy extruded pipes are usually manufactured by porthole extrusion or mandrel extrusion, but in the case of porthole extruded pipes, as shown in Fig. 1, coarse crystal grains 2 are formed in the welded parts. , and hence Fig. 2(a).

As shown in (b), the roughness and smoothness of the cut surface become uneven in that part, so there is a problem that it is necessary to polish it after cutting or sacrifice the surface roughness etc. Ta.

On the other hand, extruded tubes for spacer rings obtained by mandrel extrusion do not have the problem of coarse crystal grains forming in the welded areas as in the above-mentioned porthole extruded tubes, and therefore the cut surface does not become uneven. Spacer rings that require particularly severe surface roughness are manufactured by cutting out the mandrel extrusion tube, but the mandrel extrusion method itself involves cutting out the billet before the extrusion process. It is necessary to make holes in the ingot (ingot), which requires special equipment, and productivity is lower than with porthole extrusion, the work is complicated and troublesome, and the manufacturing cost is high. There are problems such as, therefore, there is an inherent problem that the cost of the obtained spacer ring becomes high.

SOLUTION MEANS Here, as a result of various researches against the background of the above circumstances, the present inventors have developed an aluminum alloy tube for spacer rings with good machinability by devising various alloy components and manufacturing methods. In particular, in porthole extrusion, the present invention was achieved by discovering the fact that an extruded tube for a spacer ring in which coarsening of crystal grains at the porthole welded portion is suppressed can be advantageously obtained.

That is, in the present invention, on a weight basis, 0.4 to 1.2% Si, 0.21 to 0.55% Cu, 0.05 to 0°5
% Mn, 0.4-1.2% Mg and 0.05-0.30% Zr, and further optionally 0.04-0.
．． 35% Cr and/or 0.01-0.25% Ti
The rest, including Ai! The alloy components were adjusted so that the desired aluminum alloy tube for spacer ring could be constructed from an aluminum alloy containing unavoidable impurities.

Further, in the present invention, an ingot is produced from the A1 alloy made of such alloy components, and the ingot is subjected to a soaking treatment at a temperature of 480 to 580°C for 1 to 24 hours. After that, porthole extrusion is performed at an extrusion temperature of 400 to 550°C lower than the soaking temperature to form a predetermined extruded tube, and then the extruded tube is quenched and tempered. By performing this treatment, it has become possible to advantageously produce the desired aluminum alloy tube for spacer rings with good machinability.

Here, Si, Cu, and Mg, which are the main alloy components blended into All according to the present invention, are all effective elements for improving strength, and in order to provide sufficient strength characteristics as a spacer ring, each of them must be .4-1.2%
(on a weight basis, the same applies hereinafter), it needs to be added within the range of 0.21 to 0.55% and 0.4 to 1.2%. Furthermore, if the amount of these alloying components added is less than the lower limit, the desired strength improvement effect cannot be expected, and if they exceed the upper limit, problems such as deterioration of corrosion resistance may occur. .

Further, Mn and Zr, which are the other main alloy components in the present invention, are elements that are effective in improving strength, and only by using them together can refine the structure. In order to effectively exhibit such effects, Mn must be added in a range of 0.05 to 0.5%, and Zr must be added in a range of 0.05 to 0.30%. be. If the amount of Mn or Zr added is less than the lower limit, the above-mentioned effects can be fully achieved, while if the amount added exceeds the upper limit, giant compounds will be formed, which will cause material defects and deteriorate machinability. cause problems.

In addition, in the aluminum alloy composition according to the present invention containing the above-mentioned alloy components, if necessary, 0.04
It is possible to add -0.35% Cr and/or 0.01 to 0.25% '1'i. These C'
Similar to Mn and Zr mentioned above, Ti is an element that is effective for improving strength as well as for refining the structure, but its excessive addition also causes the generation of giant compounds. This causes problems such as material defects and deterioration of machinability.

In the present invention, such alloy components, namely Si, Cu, Mn,
Mg, Zr, and in addition to these, Cr and/or Ti are added to An (including impurities) within the above blending amount to form an A4 alloy, and this A1
By constructing the tube material for forming the intended spacer ring from the alloy, it was possible to obtain an aluminum alloy tube with good machinability.

In such alloy components and composition ranges,
After the A1 alloy molten metal is prepared, a predetermined alloy ingot is cast from the molten metal according to a known ordinary method in order to obtain the desired A1 alloy tube, and then, from the obtained ingot, The extruded tube for the intended spacer ring can be manufactured by the extrusion method described above. In particular, by adopting the above-mentioned alloy composition according to the present invention, the extruded tube for the intended spacer ring can be manufactured by the porthole extrusion method. Extruded tubes can advantageously be manufactured.

That is, first, A consisting of the alloy composition according to the present invention is prepared.
1 to 4 alloy ingots at a temperature of 480 to 580°C.
A 24 hour soaking process is applied. By such soaking treatment, Zr and Mn, or in addition to these elements, Cr and/or Ti are finely precipitated, thereby making the extruded structure finer. Note that if the soaking temperature is lower than 480°C, the precipitation of the alloy components such as Zr will not be sufficient (therefore, the extruded structure will not be sufficiently refined, and if the soaking temperature exceeds 580°C, If this temperature is used, eutectic melting occurs in the ingot, which is not preferable.

Moreover, such soaking processing is performed by a single-stage or multi-stage operation.

Next, the soaked /1 alloy ingot is subjected to normal porthole extrusion to form the intended extruded tube for spacer ring, but at this time, the extrusion temperature is 400-400℃. The temperature is set at 550°C, which is lower than the above-mentioned soaking temperature. By setting the extrusion temperature to a temperature lower than the soaking temperature, re-solid solution of precipitated alloy components such as Zr is suppressed, thereby suppressing the generation of coarse crystals.

Note that FIGS. 3(a) and 3(b) show an example of a porthole die used for porthole extrusion, and in the present invention, extrusion is performed using such a porthole die 10. That will happen.

That is, the illustrated porthole die 10 has a female die 1
A metal beleft (ingot) 16 is pressed against the back of the male mold 14, and is diverted by being guided to an entry boat 18 provided on the male mold 14, and is then separated again. By merging together and extruding from the gap 24 formed between the core metal part 22 of the male die 14 inserted into the extrusion hole 20 of the female die 12, an extruded tube having a predetermined cylindrical shape is obtained. It is.

In addition, the extruded tube obtained by such porthole extrusion is subjected to a predetermined quenching operation, but such quenching operation is performed by adding a mist of cooling liquid to the extruded tube immediately after extrusion. In addition to carrying out mist cooling by spraying water (after cooling with water), the extruded tube is cooled down to a temperature of 500 to 550°C for 1 to 3 hours. It can also be carried out by a conventional method of cooling with water after heating for a period of time.

Next, the extruded tube that has been hardened in this way is further subjected to a tempering treatment to form the intended spacer ring A.
72 alloy tube, and the tempering treatment at that time is generally performed by heating at a temperature of 150 to iso'c for 8 to 18 hours.

The thus obtained aluminum alloy tube for a spacer ring is cut into a predetermined size and used as the intended spacer ring. Even by porthole extrusion, coarse crystal grains are not generated in the welded parts, etc., and therefore the smoothness and surface roughness of the cut surface can be made to be extremely good.

Effects of the Invention As described above, when the aluminum alloy composition according to the present invention is used to manufacture an aluminum alloy tube for spacer ring, especially an extruded tube, coarse crystals are not formed in the welded portion even by porthole extrusion. No grains are generated, and the smoothness and surface roughness of the cut surface are excellent, which completely eliminates the problem that made it difficult to apply extruded porthole pipes to precision spacer ring products. I can make it happen,
The great significance of the present invention lies in its ability to improve its economic efficiency.

EXAMPLES Below, some examples of the present invention will be given in order to clarify the present invention more specifically, but it is understood that the present invention is not limited in any way by the description of such examples. It goes without saying.

Example 1 Various Affis having chemical components shown in Table 1 below
After melting an alloy ingot and subjecting it to soaking treatment at 550°C for 8 hours, porthole extrusion was performed at an extrusion temperature of 520°C, resulting in a pipe diameter of 183 mm and a pipe wall thickness of 9! A sealed porthole extruded tube was obtained.

In addition, the extruded tube immediately after porthole extrusion is subjected to mist quenching, that is, a quenching operation that combines mist cooling and water cooling, and the quenched extruded tube obtained in this manner is further
The tubes were heat-treated at a temperature of .degree. C. for 8 hours to obtain various desired extruded tubes for spacer rings.

The mechanical properties of the various extruded tubes for spacer rings thus obtained are shown in Table 2 below, and the cutting test results are shown in Table 3 below.

As is clear from the comparison of the results in Tables 1, 2, and 3, the alloy tubes of Nos. 1 to 7 according to the present invention are comparative examples outside the alloy composition range of the present invention or known AA tubes.
It is recognized that the cutting results are better than the extruded tube made of 6061 alloy, and the smoothness and surface roughness of the cut surface are excellent.

Example 2 An ingot made of alloys No. 1 and No. 5 from among the alloy compositions shown in Table 1 was soaked at 500°C for 8 hours, and then extruded through a porthole at 580°C to form a pipe. Diameter 18
An extruded tube with a length of 3 m and a tube wall thickness of 9 fi was manufactured. Next, this tube was heat treated at 520° C. for 1 hr, water quenched, and further tempered at 170° C. for 10 hr, after which various performances were investigated.

Its mechanical properties are shown in Table 4, and the cutting test results are shown in Table 5.
The results are shown together with the results obtained in Example 1 above.

As is clear from Tables 4 and 5, if the extrusion temperature is higher than the soaking temperature, Mn-Cr, Zr, etc. that were finely precipitated during soaking will re-dissolve, resulting in insufficient strength and fine structure. It is understood that it cannot be done.

[Brief explanation of the drawing]

FIG. 1 is an explanatory cross-sectional diagram showing the distribution of coarse crystal grains in an extruded porthole tube, FIG.
b) is a graph showing the surface roughness in the direction of the arrow in FIG. 2(a), FIG. 3(a) is a front view showing an example of a porthole die, and FIG. Diagram (a)
It is an AA sectional view in . 10: Porthole die 12: Female mold 14: Male mold 16: Metal billet 18: End report 20: Extrusion hole 22: Core metal part 24: Gap Applicant Sumitomo Light Metal Industries Ltd. 1st TI! J

Claims (5)

[Claims] (1) 0.4-1.2% Si, 0.21% by weight
~0.55% Cu, 0.05-0.5% Mn, 0.
4-1.2% Mg and 0.05-0.30% Zr
and further contains 0.04 to 0.35% Cr as necessary.
and/or an aluminum alloy tube for a spacer ring with good machinability, which is made of an aluminum alloy containing 0.01 to 0.25% Ti, with the remainder consisting of Al and inevitable impurities. (2) 0.4-1.2% Si, 0.21% by weight
~0.55% Cu, 0.05-0.5% Mn, 0.
4-1.2% Mg and 0.05-0.30% Zr
and further contains 0.04 to 0.35% Cr as necessary.
and/or a soaking treatment for 1 to 24 hours at a temperature of 480 to 580° C. to an aluminum alloy ingot containing 0.01 to 0.25% Ti, the remainder consisting of Al and unavoidable impurities. After that, porthole extrusion is performed at an extrusion temperature of 400 to 550°C lower than the soaking temperature to form a predetermined extruded tube, and then the extruded tube is subjected to quenching and tempering treatment. A method for manufacturing an aluminum alloy tube for a spacer ring, characterized in that: (3) The manufacturing method according to claim 2, wherein the quenching treatment is performed by cooling the extruded tube immediately after extruding the porthole with a mist and further cooling with water. (4) The quenching process heats the extruded tube to 500 to 550°C.
The manufacturing method according to claim 2, which is carried out by heating at a temperature of 1 to 3 hours and then cooling with water. (5) The tempering treatment is performed at a temperature of 150 to 180°C.
The manufacturing method according to any one of claims 2 to 4, which is carried out by heating for 18 hours.