JPH1058107A - Centrifugal casting metallic mold for producing long size ti and ti alloy casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a casting having little dispersion in the quality in the longitudinal direction by constituting a centrifugal casting mold for Ti casting with an upper and lower mating type annular metallic mold unit and forming long cavities extended as radiating state on the mating surfaces. SOLUTION: On the mating surfaces at the upper and the lower parts of the annular metallic mold unit 1, 1', plural long cavities 1b extended as the radiating state from the center hole 1a are formed. The annular metallic mold units 1, 1' are composed of a fitting body of Cu alloy-made inside ring pieces 1A, 1A' for forming the inside part of the cavity 1b and alloy tool steel for hot metallic mold-made outside ring pieces 1B, 1B' for forming the outside part. Two sets of the annular metallic mold units 1, 1' are piled through a spacer 3 on a bottom plate 2 and fixed with bolts 4. This metallic mold is set to a centrifugal casting machine so that the center hole 1a of the metallic mold becomes a rotating axis. The long size material of the Ti or the Ti alloy is cast while utilizing the center hole 1a of the metallic mold as a feeder head.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a centrifugal casting mold for producing long-sized Ti and Ti alloy castings, which has very little material variation in the longitudinal direction.

[0002]

2. Description of the Related Art Conventionally, long cast Ti and Ti alloys such as engine valves and connecting rods of automobiles have been centrifugally cast using a graphite mold, a lost wax mold, and an alloy tool steel mold for a hot mold. It is widely known that it is manufactured by a method.

[0003]

On the other hand, in recent years, the performance of various driving devices has been remarkably improved, and accordingly, long Ti and Ti alloy castings such as engine valves and connecting rods used as structural members for the driving devices have been remarkably improved. Although there is a strong demand for improvement in material properties, Ti produced by the centrifugal casting method described above is also required.
And, in the case of using a metal mold for the production of a Ti alloy casting, there is a problem in terms of reliability because the material variation between the side of the casting runner and the tip of the casting becomes large due to a local difference in the cooling rate, especially when a mold is used. There is a current situation.

[0004]

Means for Solving the Problems Accordingly, the present inventors have
From the viewpoints described above, in order to produce long Ti and Ti alloy castings having no material variation in the length direction, focusing on a centrifugal casting mold used for the production thereof, and as a result of conducting research, The centrifugal casting mold is constituted by a stacked body of a ring-shaped mold unit of a top-to-bottom type, and a plurality of long cavities radially extending from a center hole are formed on a top-to-bottom surface of the ring-shaped mold unit, Further, the ring-shaped mold unit is constituted by a fitting body of an outer ring piece made of alloy tool steel for a hot mold that forms the outer part of the cavity similarly to an inner ring piece made of Cu alloy that forms the inner part of the cavity. , And the center hole of the ring-shaped mold unit becomes a rotation axis,
In addition, assuming that it has a structure that becomes a hot water, the elongated Ti and Ti alloy castings manufactured using this centrifugal casting mold are cooled by the Cu alloy inner ring pieces constituting the mold. Is promoted, so that the cooling of the side of the casting feeder to be cast later and the tip of the casting to be cast earlier are equalized, so that the material variation in the length direction is extremely small. That's the research result.

The present invention has been made on the basis of the above research results, and a centrifugal casting mold for producing a long-sized Ti and Ti alloy casting comprises: (B) a plurality of elongated cavities extending radially from a center hole of the ring-shaped mold unit are formed on the upper and lower mating surfaces of the ring-shaped mold unit;
(C) The ring-shaped mold unit is a fitted body of an alloy tool steel outer ring piece for a hot mold that forms the outer part in the same manner as the Cu alloy inner ring piece forming the inner part of the cavity. (D) The center hole of the ring-shaped mold unit serves as a rotation axis and serves as a hot water, and has the above-described structures (a) to (d).

The Cu alloy constituting the Cu alloy inner ring piece is (a) Be: 1.5 to
2.2%, Co: 0.1 to 0.5%, the balance being C
a Cu alloy having a composition consisting of u and unavoidable impurities,
(B) Be: 1.8 to 3%, Co: 0.1 to 1%, S
i: It is desirable to be composed of a Cu alloy containing 0.1 to 0.5% and the remainder having a composition of Cu and unavoidable impurities. Further, it is preferable that the outer ring piece made of the alloy tool steel for a hot mold is made of an alloy tool steel material for a hot mold defined in SJIS4404 as SKD4 to SKT4.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a centrifugal casting mold according to the present invention will be described in detail with reference to the drawings.
FIG. 1 is a vertical sectional view of a centrifugal casting mold of the present invention. FIG. 2 is a plan view of a half of the lower mold (right and left mold) 1 of the upper and lower mold dies 1 and 1 'constituting the centrifugal casting mold of the present invention. As shown in the figure, a plurality of elongated cavities 1b extending radially from a central hole 1a are formed in the upper and lower mating surfaces of the ring-shaped mold units 1, 1 '.
b has a size of 14 mm in diameter × 170 mm in length. In addition, the ring-shaped mold unit 1,
1 'is a fitting of an inner ring part 1A made of a Cu alloy forming the inner part of the cavity 1b, and an outer ring part 1B, 1B' made of an alloy tool steel for hot die forming the same outer part as the 1A '. Consists of a body. Cu alloy inner ring piece 1A
, 1A ', by weight%, Be: 1.9%, Co:
0.25%, Cu and inevitable impurities: Forging and rolling a Cu alloy ingot having a composition consisting of the remainder, and cutting to form a central hole diameter: 300 mm × upper surface outer diameter: 420 mm
× Lower surface outer diameter: 380 mm × Thickness: Finished to dimensions of 25 mm (hereinafter referred to as inner ring member A-1), Be: 2.6%, Co: 0.6%, Si: 0.3 %, And the rest was finished to the same dimensions as the above dimensions by cutting from a Cu alloy ingot having a composition consisting of Cu and inevitable impurities (hereinafter referred to as inner ring piece a-2). As the outer ring pieces 1B and 1B 'made of the alloy tool steel for the hot mold, C: 0.38% by weight%,
Si: 1.09%, Cr: 5.16%, Mo: 1.35
%, V: 1.07%, and the rest has a composition consisting of Fe and unavoidable impurities, and is cut from an alloy tool steel ingot equivalent to SKD-61, and has a top hole diameter of 420 mm ×
Lower surface hole diameter: 380 mm x outer diameter: 700 mm x thickness: 25
mm (hereinafter referred to as an external ring member A). Next, as shown in FIG. 1, two sets of these ring-shaped mold units 1 and 1 'are placed on a pure copper bottom plate (made of Cu alloy or steel) 2 and a spacer 3 made of Cu alloy (made of steel). , And fixed to the bottom plate 2 with steel bolts 4 to assemble the centrifugal casting molds 1 and 2 of the present invention (hereinafter referred to as the molds of the present invention). For the purpose of comparison, half of the lower mold (right-and-left mold) 1 is shown in FIG. 3 as a top-down type ring-shaped mold unit 1, 1 ′. The dimensions and number of the plurality of elongated cavities 1b radially extending from the central hole 1a by cutting from an alloy tool steel ingot equivalent to SKD-61 having the same central hole diameter of 300 mm × Outer diameter: 700mm ×
Thickness: A comparative centrifugal casting mold (hereinafter, referred to as a comparative mold) was assembled under the same conditions except that an integrally finished one having a dimension of 25 mm (dimensions in a left-right state) was used.

Next, each of these dies is set in a centrifugal casting machine so that the center hole of the dies becomes the rotation axis 1a, and the rotation speed of the dies is set to 500 rpm. p. m. Ti, Ti-6% Al-4% V alloy (hereinafter referred to as Ti
Alloy 1) and a Ti-34% alloy (hereinafter referred to as Ti
Alloy 2) is cast at a casting temperature of 1850 ° C. for pure Ti and Ti alloy 1 and 1700 ° C. for Ti alloy 2 with the center hole of the mold as a pusher. A number of Ti and Ti alloy castings having dimensions of diameter: 14 mm x length: 170 mm were produced.

[0009] The long cast Ti and Ti alloys obtained as a result are measured at 10 mm, 60 mm, 110 mm, and 160 mm from the feeder side for the purpose of evaluating material variation.
The Vickers hardness and the crystal grain size at the position of mm were measured. Table 1 shows the results of these measurements. The crystal grain size was shown as an average value of 10 arbitrary crystals.

[0010]

[Table 1]

[0011]

From the results shown in Table 1, it can be seen that the Ti and Ti alloy castings manufactured by the dies 1 and 2 of the present invention were manufactured by the comparative dies even though they were long. It is apparent that the material variation in the length direction is extremely small. In this way, the centrifugal casting mold of the present invention having a stacked structure in which the upper and lower mating ring-shaped mold unit is divided into an inner ring piece made of Cu alloy and an outer ring piece made of alloy tool steel for hot mold. According to this, it is possible to manufacture a long-sized Ti and Ti alloy casting which is materially uniform in the length direction and therefore extremely reliable.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view illustrating a centrifugal casting mold of the present invention.

FIG. 2 is a plan view exemplifying a half of a lower die (left-right alignment die) of a vertically aligned ring-shaped die unit constituting the centrifugal casting die of the present invention.

FIG. 3 is a plan view exemplifying a half of a lower mold (right-to-left mold) of a vertically aligned ring-shaped mold unit constituting a comparative centrifugal casting mold.

[Explanation of symbols]

 1, 1 'top-to-bottom type ring-shaped mold unit 1a center hole 1b long cavity 1A, 1A' inner ring part piece made of Cu alloy 1B, 1B 'outer ring part made of alloy tool steel for hot die 2 bottom plate 3 Spacer 4 Bolt

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[Procedure amendment]

[Submission date] October 1, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0008

[Correction method] Change

[Correction contents]

Next, each of these dies is set in a centrifugal casting machine so that the center hole of the dies becomes the rotation axis 1a, and the rotation speed of the dies is set to 500 rpm. p. m. Ti, Ti-6% Al-4% V alloy (hereinafter referred to as Ti
Alloy 1) and a Ti-34% Al alloy (hereinafter, referred to as alloy 1).
The molten alloy of Ti alloy 2) is cast at a casting temperature of 1850 ° C. for pure Ti and Ti alloy 1 and 1700 ° C. for Ti alloy 2 with the center hole of the mold as a pusher. A number of Ti and Ti alloy castings having dimensions of diameter: 14 mm × length: 170 mm were produced.

Claims (1)

[Claims] (A) A stack of a ring-shaped mold unit of a top-to-bottom alignment type, and (b) a plurality of ring-shaped mold units arranged on a top-bottom surface of the ring-shaped mold unit radially extending from a center hole thereof. An elongated cavity is formed, and (c) the ring-shaped mold unit is made of an alloy tool steel for a hot mold that forms an outer portion as well as a Cu alloy inner ring piece that forms an inner portion of the cavity. (D) a center hole of the ring-shaped mold unit serves as a rotating shaft and a hot water;
Elongated Ti and Ti characterized by comprising (d)
Centrifugal casting mold for alloy casting production.