Nippon Piston Ring Co., Ltd.

Fuji Jukogyo Kabushiki Kaisha

Jtekt Corporation

Hiroshi Takiguchi

Teruyuki Oda

Takeshi Takahashi

Kazushi Numazaki

Yoshikatsu Nakamura

Tetsuo Masuyama

Natsuki Iwamoto

Takao Omiya

Yudai Watanabe

Atsuya Aoki

A fusible plug for a high pressure gas cylinder includes a communication hole filled with a low melting point alloy, a porous metal sintered body is press-fitted in at least a part of the communication hole in a length direction, all or a part of the porous metal sintered body is impregnated with the low melting point alloy to solidify and composite the low melting point alloy. It is preferable that: the low melting point alloy has a melting point of 110° C.; the porous metal sintered body to be press-fitted is a porous metal sintered body having pores with an area ratio of 30% or more and 50% or less and having pores with a diameter exceeding 5 μm among the pores of 80% or more in terms of area ratio to all the pores; and the porous metal sintered body is a porous austenitic stainless steel sintered body.

Fusible plug

A preform main body of an iron species preform for forming a metal matrix composite inserted in an aluminum species alloy base material to be cast-in is bored with a first to fourth through holes communicating an inner peripheral face and an outer peripheral face. In a cast-in step, shrinkage in a peripheral direction of the inner peripheral face and the outer peripheral face of the iron species preform in accordance with solidification of the melted aluminum species alloy is uniformly received by shrinkage in accordance with solidification of the melted aluminum species alloy invading the through holes, movement thereof in the peripheral direction is restrained, a clearance can be prevented from being brought about at an interface, a cast-in performance is excellent and a stable bonding strength of the interface is achieved.

Iron species preform

An iron species preform for forming a metal matrix composite is inserted in an aluminum species alloy member to be cast-in. The aluminum species alloy member has bearing faces having a section in a semicircular arc shape. An inner peripheral face of the iron species preform is provided with a plurality of inner side grooves. The inner side groove includes flat portions and groove bottom portions continuous to two end edges continuous to the inner peripheral face and opposed to each other. In a cast-in step, shrinkage in a peripheral direction accompanied by solidifying a melted aluminum species alloy is uniformly received by the respective inner side grooves, movement in the peripheral direction is restrained, a clearance at an interface can be prevented from being brought about, so that a cast-in performance is excellent, and stable bonding strength and close contact of the interface can be ensured.

The object of the invention is to provide a porous metal structure body suitable for reinforcing a light metal alloy member such as an aluminum alloy member. A mixed powder containing a metallic powder is filled in a mold, and is molded into a shape having a single cavity or plural cavities in the inner portion while having a maximum thickness of 6 mm or less at the surface portion side. The molded powder body is sintered to form into the porous metal structure body having a porosity of 20 to 50% by volume at the portions except the cavities. It is preferable that the metallic powder sintered body having a porosity of exceeding 50% by volume is formed into the cavities by being monolithically integrated with the porous metal structure body. Consequently, a structure being lightweight, having a high mechanical strength and being excellent in handling performance while being excellent in impregnability can be obtained.

Porous metal structure body and method for manufacturing the same

The object of the invention is to provide an iron based sintered body suitable for being enveloped in light metal alloy such as an aluminum alloy by casting, and a method for producing the same. A mixed powder is prepared by mixing an iron based powder, a copper powder and a graphite powder blended so that the Cu content and the C content are 5 to 40% by mass and 0.5 to 2.5% by mass, respectively, in the mixed powder. A lubricant powder and a fine particle powder for improving machinability may be further added in the mixed powder. Then, the mixed powder is filled into a mold formed to a green compact, and is sintered into a sintered body so that the sintered body has a desired average thermal expansion coefficient. The surface of the sintered body may be adjusted to have a surface roughness Rz of 10 to 100 &#x3bc;m optionally by applying a shot blast treatment or by a shot blast treatment and an additional steam treatment. This process permits the sintered body to be enhanced in an adhesive property and bonding strength while being improved in enveloping casting property when the sintered body is enveloped in the light metal alloy by casting. A martesitic stainless steel powder or ferritic stainless steel powder may be used instead of the pure iron powder, or Cr, Mo and W powders may be further blended.

Iron based sintered body excellent in enveloped casting property in light metal alloy and method for producing the same

The present invention provides a synchronizer ring excellent in strength and abrasion resisting property, used in a speed change gear. This synchronizer ring according to the invention is consisted of, by weight, C:0.2&tilde;1.0%, Ni:1.0&tilde;6.0%, Mo:0.6&tilde;3.0%, Cu:1.0&tilde;4.0% and the reminder Fe and inevitable impurities, and is made of Fe sintered alloy of which base composition comprises of mainly martonsite and bainite. And the base composition is preferably consisted of, by volume, martensite: 57&tilde;80%, bainite: 17&tilde;40%, austenite: 8% or less.

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Tochigi, Japan

Hiroshi Takiguchi