Title: Metal member to be cast-wrapped
Abstract: A metal member to be cast-wrapped by a metal cast article, a manufacturing method thereof and a metal cast article including the metal member cast-wrapped are provided. A hollow cylindrical metal member having an outer surface with projections to be cast-wrapped by a metal cast article is manufactured in such a manner that a hollow cylindrical metal raw material 13 is inserted in a die 17 having a inner peripheral surface with longitudinal grooves of a depth H and a width W, and the hollow cylindrical metal raw material 13 is subjected to hot-extrusion.
Patent Number: 7,014,924 Issued on 03/21/2006 to Koyama, et al.
| Inventors:
|
Koyama; Yoshiaki (Wako, JP);
Arimura; Mitsunori (Wako, JP);
Mitsuuchi; Kaoru (Wako, JP);
Shibasaki; Toshiyuki (Wako, JP);
Itou; Yoshiaki (Itami, JP);
Shiga; Ryuji (Itami, JP);
Yamada; Kouji (Itami, JP)
|
| Assignee:
|
Honda Giken Kogyo Kabushiki Kaisha (Tokyo, JP)
|
| Appl. No.:
|
069976 |
| Filed:
|
June 15, 2001 |
| PCT Filed:
|
June 15, 2001
|
| PCT NO:
|
PCT/JP01/05141
|
| 371 Date:
|
March 12, 2002
|
| 102(e) Date:
|
March 12, 2002
|
| PCT PUB.NO.:
|
WO02/04150 |
| PCT PUB. Date:
|
January 17, 2002 |
Foreign Application Priority Data
| Jul 12, 2000[JP] | 2000-211747 |
| Current U.S. Class: |
428/687; 428/609; 428/573; 428/577; 428/582; 164/111 |
| Current Intern'l Class: |
B32B 3/00 (20060101); B32B 15/00 (20060101); B21C 37/00 (20060101); B21C 37/06 (20060101) |
| Field of Search: |
403/265,267
164/111
428/609,573,574,577,580,582,583,586,687,612,654
|
References Cited [Referenced By]
U.S. Patent Documents
| 4154900 | May., 1979 | Kaku et al.
| |
| 4576875 | Mar., 1986 | Olsson et al.
| |
| 6050323 | Apr., 2000 | Soell et al.
| |
| 6074763 | Jun., 2000 | Rueckert et al.
| |
| Foreign Patent Documents |
| 49-44857 | Nov., 1974 | JP.
| |
| 49-044857 | Nov., 1974 | JP.
| |
| 53-099040 | Aug., 1978 | JP.
| |
| 01-317679 | Dec., 1988 | JP.
| |
| 1-317679 | Dec., 1989 | JP.
| |
| 08-290255 | Nov., 1996 | JP.
| |
| 10-94867 | Apr., 1998 | JP.
| |
Primary Examiner: Lavilla; Michael E.
Attorney, Agent or Firm: Armstrong, Kratz, Quintos, Hanson & Brooks, LLP
Claims
The invention claimed is:
1. A metal member to be cast-wrapped by a metal cast article, wherein said metal
member to be cast-wrapped has an extruded roughened surface portion resulting from
tearing of a surface portion of a metal material by hot extrusion through a die
to produce a plurality of irregularly formed projections which extend outwardly
from said surface, and wherein a maximum width of said projections at a tip end
portion thereof is wider than a maximum width of the projections at a base portion thereof.
2. A metal member to be cast-wrapped as claimed in claim 1, wherein at least
a part of said tip end portion of each of said projections is formed in a tapering
sharp sectional shape.
3. A metal member to be cast-wrapped as claimed in 2, wherein said extruded,
roughened surface is arranged as elongated mutually spaced surface portions extending
parallel to a direction of extruding of the member and wherein elongated smooth,
unroughened surface portions are disposed between, and extend parallel to, said
roughened surface portions.
4. A metal member to be cast-wrapped as claimed in claim 3, wherein a side of
each of said irregularly formed projections facing an extrusion starting end is
wide and high, and a side of each of said irregularly formed projections facing
an extrusion completing end is narrow and low.
5. A metal member to be cast-wrapped as claimed in 2, wherein said metal member
to be cast-wrapped is a hollow cylindrical body.
6. A metal member to be cast-wrapped by a metal cast article as claimed in claim
1, wherein said metal member is a cylindrical member that has an outer surface
having at least one extruded roughened surface portion resulting from tearing of
at least one surface portion of the cylindrical metal material by hot extrusion
through a die to produce said irregularly formed projections extending outwardly
from said surface, said projections of a roughened surface portion being arranged
in a row extending parallel to an axis of the cylindrical member and at intervals
spaced circumferentially about the cylindrical member.
7. A metal member to be cast-wrapped by a metal cast article as claimed in claim
6, wherein each of said projection-defining tears has a tip end portion bent laterally.
8. A metal member to be cast-wrapped by a metal cast article as claimed in claim
6, wherein unroughened grooves are provided between circumferentially adjacent
rows of projection-defining tears.
9. A metal member to be cast-wrapped by a metal cast article as claimed in claim
6, wherein said roughened surface contains rows of projections resulting from said
tearing, said rows being arranged at regular intervals about the circumference
of said cylindrical member.
10. A metal member to be cast-wrapped by a metal cast article as claimed in claim
6, wherein said projection-defining tears are arranged at irregular intervals in
said rows and generally out of circumferential alignment.
11. A metal member to be cast-wrapped by a metal cast article as claimed in claim
6, wherein said cylindrical member is hollow.
Description
TECHNICAL FIELD
The present invention relates to a metal member to be cast-wrapped by a metal
cast article, a method for manufacturing the metal member to be cast-wrapped and
a metal cast article including the metal member to be cast-wrapped.
BACKGROUND ART
A light metal member to be cast-wrapped by a light metal cast article, which
has
a rough uneven outer surface formed by shot-blast blowing hard coarse pyramidal
or sharp grains against the outer surface, has been known (Japanese Laid-open Patent
Publication Hei 10-94867).
In the above-mentioned light metal member to be cast-wrapped, an outer surface
of the hard coarse grain is required to have a sharp edge, in order to make the
outer surface of the light metal member rough.
When the outer surface of the light metal member to be cast-wrapped is made
rough using the hard grains, bottoms of the rough surface are formed in sharp ravines
by sharp edges of the hard coarse grains, but tops of the rough surface are not
necessarily formed in a sharp peaks. Further, it is required that mean grain size
of the hard grains is 70 μm and distribution of the grain sizes is a nearly
a predetermined normal distribution. If velocity of an air jet for blowing the
hard coarse grains and ratio of amount of the air jet and amount of the hard coarse
grain are not appropriate, a desired rough surface can not be obtained.
Since the above-mentioned hard coarse grain is a high-class corundum particle
which is a fragile hard material with broken sharp edge, it is inevitable that
the hard coarse grain becomes fine by the shot-blast. Therefore, in order to use
the hard coarse grains after the shot-blast repeatedly, it is necessary that the
hard coarse grains made fine by the shot-blast are separated and removed continuously
to maintain a predetermined distribution of the grain size. This administration
of the grain size is complicated.
Projections of a rough surface formed on the light metal member to be
cast-wrapped may be melted by large heat capacity of the cast-wrapping light metal
and metallurgically combined with the cast-wrapping light metal. However, the metallurgically
combined portion is a part of the surface of the light metal member to be cast-wrapped
and the projection of the rough surface is tapered, so that mechanical combining
force between the light metal member to be cast-wrapped and the cast-wrapping light
metal is low. Therefore, when a force for mutually separating the light metal member
to be cast-wrapped and the cast-wrapping light metal acts owing to difference of
thermal expansion of them, a crack is apt to be produced at a boundary portion
between them to remarkably lower heat transfer between them.
DISCLOSURE OF INVENTION
The present invention relates to an improvement of the customary metal member
to be cast-wrapped overcoming the above difficulties. The present invention provides
a metal member to be cast-wrapped by a metal cast article, wherein the metal member
to be cast-wrapped has an irregular uneven surface, a projection is projected from
the surface, and a maximum width of the projection at a tip end portion is wider
than a maximum width of the projection at a base portion.
When a molten metal is poured to cast-wrap the metal member to be cast-wrapped,
the cast wrapping molten metal surrounds the projection of the metal member to
be cast-wrapped covering a wide area and the surface of the projection is sufficiently
heated by heat of the molten metal to be metallurgically combined with the cast-wrapping
metal surely.
Since the maximum width of the projection at the tip end portion is wider than
the maximum width of the projection at the base portion, the projection is combined
with the cast-wrapping metal mechanically strongly by hook effect, so that a crack
is hardly produced at a boundary portion between them and a high heat transfer
is obtained.
Since the metal member to be cast-wrapped has an irregular uneven surface,
surface area of the projection of the metal member to be cast-wrapped is increased
to promote the metallurgical combination and the metal member to be cast-wrapped
is combined with the cast-wrapping metal more strongly.
At least a part of the tip end portion of the projection may be formed in a tapering
sharp shape. Since the tip end portion of the projection is sharp, heat mass is
little and the projection can be metallurgically combined with the cast-wrapping
metal perfectly.
The metal member to be cast-wrapped may be an extruded member having smooth grooves
directed in a direction of extruding and irregular projections disposed between
the grooves, and the irregular projections may be formed when the metal member
is extruded. The metal member to be cast-wrapped having projections can be mass-produced
efficiently and at a low cost.
And, mechanical combination by a hook effect of the club-shaped portion and
metallurgical combination by molten metal storing effect of the undercut shape
are promoted.
A side of the irregular projection near an extrusion starting end may be wide
and
high and a side of the irregular projection near an extrusion completing end may
be narrow and low. Drag resistance of the metal member to be cast-wrapped against
the cast-wrapping metal in the extruding direction becomes larger remarkably.
The metal member to be cast-wrapped may be a hollow cylindrical body. A sleeve
of an internal combustion engine, for example, can be manufactured easily and very
strong tight combination of a block and the sleeve can be obtained.
The present invention provides a cylindrical metal member to be cast-wrapped,
wherein the cylindrical metal member has an outer surface formed with projections,
the projections are arranged axially in rows and arranged circumferentially at
regular intervals through grooves, and tip end portions of the projections are
bent laterally.
The tapered tip end of the projection of the cylindrical metal member to be cast-wrapped
is metallurgically combined with the cast-wrapping metal sufficiently, and the
whole projection is heated by molten metal storage effect of the undercut portion
to promote the metallurgical combination. Further, movement of the cast-wrapping
metal in radial and circumferential directions is restrained by a bent portion
having the undercut portion to strengthen combining force and adhering force owing
to mechanical combination.
Further, the present invention provides a cylindrical metal member to be
cast-wrapped, wherein the cylindrical metal member has an outer surface formed
with projections, the projections are arranged axially in rows and arranged circumferentially
at regular intervals through grooves, and tip end portions of the projections are
bent in axial direction.
Adhesion and combining forces in an axial direction of the cylinder are
improved to restrain mutual slipping in the axial direction between the cylindrical
metal member to be cast-wrapped and the cast-wrapping metal and fix them to each
other firmly. Owing to improvement of adhesion, heat transfer, cooling performance
and knocking resistance are improved.
Since the projections formed on the outer surface of the cylindrical metal
member to be cast-wrapped are arranged axially in rows and arranged circumferentially
at regular intervals through grooves, adhesion and combining forces in an axial
direction of the cylinder are improved by the rows of the projections and the grooves
intervening between the rows of the projections, mutual slipping in the axial direction
between the cylindrical metal member to be cast-wrapped and the cast-wrapping metal
is restrained, and they are fixed to each other firmly. Therefore, owing to improvement
of adhesion, heat transfer, cooling performance and knocking resistance are improved.
The groove between the rows of projections improves running of molten metal so
that quality of the cast product is improved.
The projections formed on the outer surface of the metal member to be cast-wrapped
may be arranged axially at irregular intervals and may not be aligned circumferentially.
Mutual slipping between the cylindrical metal to be cast-wrapped and the cast-wrapping
metal in circumferential direction, as well as in an axial direction, is restrained,
adhesion and combining forces between the cylindrical metal to be cast-wrapped
and the cast-wrapping metal are improved more, and cooling performance and knocking
resistance are further improved.
The present invention provides further, a method for manufacturing a cylindrical
metal member to be cast-wrapped by a metal cast article having an outer surface
with projections, comprising: preparing a die having an inner peripheral surface
formed with longitudinal grooves of depth H and width W, wherein the relation between
a maximum depth H
MAX and a minimum width W
MIN of the groove
being set as H
MAX/W
MIN≧1.5; inserting a cylindrical
metal material in the die; and hot-extruding the cylindrical metal material to
obtain the cylindrical metal member to be cast-wrapped having an outer surface
with projections.
According to this method, projections can be formed on the outer surface
of the cylindrical metal member to be cast-wrapped simultaneously with extrusion
of the cylindrical metal member, and a working step such as a shot blast is unnecessary,
therefore cost-reduction is possible.
By setting the relation between the maximum depth H
MAX and the minimum
width W
MIN of the groove as H
MAX/W
MIN≧1.5,
the aforementioned cylindrical metal member to be cast-wrapped having high adhesion
and combining force can be manufactured easily.
The minimum width W
MIN of the groove may be set as W
MIN≦1.3
mm. Many more portions bent in an axial direction can be produced on the outer
surface of the cylindrical metal member to be cast-wrapped.
The relation between a minimum inner diameter d and a total inner peripheral
length L of a cross-section of the die may be set as L/d·π≧1.5.
The portions bent in an axial direction can be produced on the outer surface of
the cylindrical metal member to be cast-wrapped more surely.
The metal member to be cast-wrapped may be made in a hollow cylindrical body.
When the metal member to be cast-wrapped is applied to a sleeve of an internal
combustion engine, combination and adhesion between a block and the sleeve and
cooling nature are improved so that an internal combustion engine of high reliability
can be obtained.
BRIEF DESCRIPTION OF DRAWINGS
FIGS. 1
a to 1
g are explanatory views showing an outline
of a method for manufacturing a metal member to be cast-wrapped according to the
present invention;
FIG. 2 is an enlarged front view of an essential part of a die used in the manufacturing method;
FIG. 3 is a further enlarged front view of an essential part of FIG. 2;
FIG. 4 is a partial enlarged front view of an other die;
FIG. 5 is a table showing data of samples in various embodiments;
FIG. 6 is a perspective view of a sleeve in which only rugged lines formed on
the outer surface is shown schematically and in magnification;
FIG. 7 is a partial enlarged plan view of the rugged lines formed on the outer
surface of the sleeve;
FIG. 8 is a partial enlarged perspective view of the rugged lines formed on
the outer surface of the sleeve;
FIG. 9 is an enlarged longitudinal sectional view of an essential part of FIG. 9;
FIG. 10 is a perspective view of the sleeve showing only one of the rugged lines
formed on the outer surface schematically and in magnification;
FIG. 11 is an enlarged plan view of the rugged line of FIG. 10;
FIG. 12 is a longitudinal sectional view taken along the line XII—XII
of FIG. 11;
FIG. 13 is a cross-sectional view taken along the line XIII—XIII of FIG. 12;
FIG. 14 is a cross-sectional view taken along the line XIV—XIV of FIG. 12;
FIG. 15 is a figure of an essential part of the sleeve shown in FIG. 6; and
FIG. 16 is a figure of an essential part of the sleeve shown in FIG. 7.
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described
with reference to FIGS. 1 to 16.
As shown in FIG. 1
a, molten light alloy
1 containing Al-73%, Si-17%,
Fe-5%, Cu-3.5%, Mg-1% and Mn-0.5% (weight %) is charged in a crucible
3
from a pot
2. The molten light alloy drops through an opening provided at
a bottom of the crucible. At that time, the molten light alloy becomes fine particles
and is rapidly cooled by air or inert gas blown at a high speed from nozzles
4
surrounding the opening, and matrix sub-/per-eutectic aluminum silicon alloy powder
5 is formed (atomizing process).
The matrix sub-/per-eutectic aluminum silicon alloy powder
5 is charged
into a mixing vessel
6 together with alumina powder giving abrasion resistance
and graphite powder giving self-lubricating nature (FIG. 1
b). Then, the
mixing vessel
6 is closed tight and rotated about a horizontal axis
7
so that the powder is mixed uniformly and billet raw material powder
8 is obtained.
As shown in FIG. 1
c, the billet raw material powder
8 is charged
into a cylindrical rubber bag
10 in which a core
9 having a diameter
corresponding to a diameter of a cylinder bore of an internal combustion engine
is disposed. The cylindrical rubber bag
10 is housed in a cylindrical pressure
vessel
12 having upper and lower lids
11. A liquid such as water
is charged in the cylindrical pressure vessel
12 and given pressure of 1.6
GPa to preparatively form a hollow cylindrical billet
13 (FIG. 1
d)
having a uniform density distribution and a density ratio of about 70% (cold hydrostatic
pressure forming process).
The hollow cylindrical billet
3 is put in a heating furnace (not shown)
and preheated and degassed under nitrogen atmospheric gas (FIG. 1
e). Then,
the hollow cylindrical billet
13 is charged in a container
15 of
a hot extrusion apparatus
14 shown in FIG. 1
f. In the container
15,
a mandrel
16 is inserted in a central hole of the hollow cylindrical billet
13. The mandrel
16 is fixed so that a front end of the mandrel
16
is positioned on an extrusion side of a die
17 fixed to the container
15.
A front end of a main ram
18 is touched to a back side of the hollow cylindrical
billet
13 so that the hollow cylindrical billet
13 is extruded when
the main ram
18 moves in a extruding direction X. The extruded hollow cylindrical
billet
13 is cut by mechanical work to obtain sleeves
19 of predetermined
length (FIG. 1
g).
As shown in FIGS. 2 and 3, the die
17 has a circular opening
17a
having an inner diameter of 94.3 mm, and on the peripheral surface of the opening
17a are formed grooves
17b of width W and depth H arranged
circumferentially uniformly.
As shown in FIG. 5, in an embodiment
1 including samples
1 to
5,
all samples have the same groove width W of 0.38 mm and the same groove span (center
angle) of 1.50 but have different respective groove heights of 1 mm, 0.7 mm, 0.5
mm, 0.3 mm and 0.2 mm. In the samples
1 and
2 having H/W more than
1.5, tears are produced on projecting lines of the sleeve
19 and irregular
rugged lines
20 are formed as shown in FIGS. 5 to 9,
10 to
14
and
15 to
16.
If peripheral length of the groove
17b is long, the hollow cylindrical
billet
13 is subjected to a large resistance owing to contact with the grooves
17b of the die
17 when the billet
13 passes through
the grooves
17b, so that the above-mentioned tears are produced.
The "tear producing rate" in FIG. 5 means a ratio of a number of the projecting
line on which irregular rugged lines are formed by the tear to the total number
of the projecting lines on the sleeve
19. In the samples
1 and
2,
the tear producing rate is more than 70% and good, therefore H/W more than 1.9
is desirable.
In the rugged line
20 shown in FIGS. 6 to 9, wide and high portions
20a
and narrow and low portions
20h are arranged irregularly in direction
of extrusion, and in the wide and high portion
20a, a tip end portion
is wider than a base portion near a surface of a groove
21 of the sleeve
19 (the base portion is constricted as shown in FIGS. 10 and 11). Further,
the surface of the wide and high portions
20a is formed in an irregular
rugged surface. Therefore, the sleeve
19 and a cylinder block cast-wrapping
the sleeve
19 are mechanically combined strongly.
Since at least a part of the tip end of the wide and high portion
20a
of the rugged line
20 is formed in a sharp shape, heat of the cast-wrapping
molten metal for the cylinder block is added to the sharp tip end of the portion
20a concentrically to melt an oxidized film on the portion
20a,
so that a sure metallurgical combination cian be obtained.
Each of the wide and high portion
20a of the rugged line
20
has a side near an extrusion starting end that is wider and higher and another
side near an extrusion completing end that is narrower and lower, and ar end surface
of the wide and high portion
20a at the extrusion starting end is
inclined in the extrusion direction from the base portion toward the tip end portion
(FIG. 9 and FIG. 12). Therefore, when the sleeve
19 cast-wrapped by the
cylinder block is forced in the extrusion direction, a large resistance is exhibited.
In the samples
1,
2, since the sleeve
19 has the irregular
rugged lines
20 on the outer surface, heat of molten metal for the cylinder
block cast-wrapping the sleeve
19 is rapidly transferred to an irregular
rugged surface of the rugged line
20, so that the rugged surface is melted
at a sufficiently high temperature for metallurgical combination. Moreover, since
the tip end of the wide and high portion
20a of the rugged line
20
is bent like a hook and the bottom part of the portion
20a is made
wide (see FIG. 12), the sleeve
19 and the cylinder block is strongly combined
mechanically, so that the sleeve
19, which comes into sliding contact with
a piston and is subjected to various forces, can be held by the cylinder block
stably and firmly.
Even it a thermal stress is generated so as to separate the sleeve
19
and the cylinder block owing to a difference of thermal expansion between the sleeve
19 and the cylinder block, the sleeve
19 and the cylinder block is
kept in a strongly combined state and there is no fear that a gap is generated
between them.
Since the sleeve
19 and the cylinder block are combined tight without
a gap, heat of the sleeve
19, which is contacted with a combustion chamber
and heated, escapes through the cylinder block having a high heat transfer coefficient,
and the sleeve
19 is kept at a suitable temperature. Therefore, knocking
performance is improved, load of the cooling system is lowered, and space between
neighboring sleeves
19 can be shortened to miniaturize the internal combustion engine.
In case that the sub-/per-eutecticaluminumsilicon alloy sleeve
19 having
projections of undercut shapes formed on the outer peripheral surface during extrusion
of the sleeve
19 is cast-wrapped by a cylinder block (not shown) produced
by high pressure die casting, following features can be obtained.
When the outer peripheral surface of the sleeve
19 is cast-wrapped by
the cylinder block, molten metal for the cylinder block surrounds entirely the
projecting portion
20a of undercut shape by injection pressure of
the die casting. At that time, a strong oxidized film on the tip end of the projecting
portion
20a having small heat-mass is locally melted by thermal energy
of the molten metal. Thus, both a mechanical combination and a metallurgical combination
are carried out and high adhesion combining force can be obtained.
Since different kinds of combinations can be carried out simultaneously in
the injection process of the cylinder block, gaps produced between the cylinder
block and the outer peripheral surface of the sleeve are few. Therefore, the piston
is cooled effectively, knocking performance is improved, and heat generated in
the combustion chamber can be led to cooling system effectively. Since the sleeve
is fixed to the cylinder block firmly, oil-up is reduced and exhaust emission (hydrocarbon)
can be reduced.
If the cylinder block is subjected to age heat treatment in consideration of
thermal
history, gaps between the sleeve and the cylinder block are very few and therefore
combination of the sleeve and the cylinder, block is strong, so that deformation
of an inner peripheral surface of the bore in course of operation is reduced, and
as the result, oil consumption and blow-by performance are improved.
In the samples
3,
4,
5 of the table shown in FIG. 5, H/W
are less than 1.5 and as tear result, the tear producing rates are low.
In an embodiment
2 in the table of FIG. 5, the same hollow cylindrical
billet
13 as the billet in the embodiment
1 is used, and H and W
of the samples
6-
10 are selected so that H/W of all of the samples
are 2.7 (more than 1.5). In the samples
6,
7,
8 and
9,
since the width of the groove
17b of the die
17 is smaller
than 1.3 mm, the tear producing rate is more than 70%. Accordingly, the samples
6,
7,
8 and
9 can be put to practical use.
But, in the sample
10, since the width of the groove,
17b of
the die
17 is 1.5 mm more than 1.3 mm, the tear is not produced. Accordingly
the sleeve
19 extruded from the die
17 has the same cross-section
as that of the die
17 and the sleeve
19 cannot be put to practical use.
In an embodiment
3 in the table of FIG. 5, powder having a composition
(Al-58.5%, Si-25%, Cu-4.5%, Mg-1.5%, Al
2O
3-10% and Gr (graphite
particle)-0.5%) other than that in the embodiment
1 is shaped at a pressure
of 1.6 GPa by cold hydrostatic pressure press to obtain the hollow cylindrical
billet
13. The hollow cylindrical billet
13 is hot extruded at a
state heated to 450° C. The above powder is made in such a manner that after
matrix sub-/per-eutectic aluminum silicon alloy powder is shaped by atomizing process
similarly to the embodiment
1, Al
2O
3 and Gr are added.
In the samples
11,
12 of the embodiment
3, since H/W is
more
than 1.5, width W of the groove
17b of the die
17 is less
than 1.3 and peripheral length ratio L/d ·π is more than 1.5, tear producing
rate is 92% or 87% and good rugged line
20 is formed.
However, in the samples
13,
14, since the peripheral length
ratio L/d·π is less than 1.5, tear producing rate is low though tear
is produced partly, so that these samples can not be put to practical use.
In an embodiment
4 in the table of FIG. 5, the same hollow cylindrical
billet
13 as that in the embodiment
3 is used. In each of the samples
15,
16, the groove
17b of the die
17 is formed
in T-shape as shown in FIG. 4, inner peripheral length of the die
17 is
necessarily long, correspondingly the peripheral length ratio L/d·π
is remarkably larger than 1.5 and therefore tear producing rate is 100%.
In the samples
17,
16, peripheral length ratio is more than 1.5
but smaller compared with the samples
15,
16, therefore tear producing
rate is high but does not reach 100%.
In the above-mentioned embodiments, the metal member to be cast-wrapped is a
sinter-extruded
article (sleeve
19), but it may be an ordinary extruded article, a forged
article or a cast article.
INDUSTRIAL APPLICABILITY
The present invention can be applied to a metal member to be cast-wrapped by
a metal cast article such as a sleeve of an internal combustion engine to be cast-wrapped
by a cylinder block or the like.
*
