Metal treatment – Process of modifying or maintaining internal physical... – With casting or solidifying from melt
Patent
1995-06-14
2000-08-29
Yee, Deborah
Metal treatment
Process of modifying or maintaining internal physical...
With casting or solidifying from melt
148543, C21D 1000
Patent
active
061103055
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention concerns a low-expansion cast iron having a high Ni content and relates to a method for the production of a high-strength low-expansion cast iron which is allowed to acquire exalted strength without a sacrifice of the low-expansion property inherent therein.
BACKGROUND ART
As known to date, cast iron has been in popular use as the basic material for industry. This is because the cast iron has such advantages as excelling in castability, allowing formation of multiple kinds of complicatedly shaped articles, readily yielding to cutting and similar machining works, incurring rather low expenses in procurement of raw materials and execution of melting work, and enjoying ease of manufacture even at a factory of a small scale.
Recently, the electronic industry and the optical industry have advanced to a point where the machine tool, measuring devices, molding dies, and other manufacturing machines which are associated with these industries demand materials of increasingly high accuracy and function. For the purpose of answering this demand, the necessity for materials which are capable of lowering thermal expansion coefficient and repressing thermal deformation to the fullest possible extent besides keeping the characteristic properties of the conventional materials intact is growing all the more in profundity. As metallic materials of low thermal expansion coefficients, an about 36%Ni--Fe alloy (Invar alloy) and an about 30%Ni--5%Co--Fe alloy (Super Invar alloy) which are shown in Table 1-1 and Table 1-2 are known. They have not yet been fully tamed for the utmost use. This is because they are unfortunately deficient in cutting workability, and castability. In recent years, the materials which are obtained by treating the Invar and the Super Invar alloy so as to impart the quality of cast iron thereto and vest them with improved cutting workability and enhanced castability and which, therefore, are relieved of the drawback mentioned above have been attracting growing attention. Table 1-1 and Table 1-2 also show the low-expansion cast iron which has been known as Niresist D5 for a long time, Nobinite cast iron as one example of the low-expansion cast irons developed in the last several years, and the cast iron disclosed in JP-A-62-268,249.
The materials shown in Table 1-1 and Table 1-2, however, are either alloys which have not induced separation of graphite by crystallization or nodular graphite cast irons and mainly have an austenitic structure as a base matrix and, therefore, have tensile strength in the range of from 40 to 55 kgf/mm.sup.2 and Brinell hardness in the neighborhood of HB 120. Where the graphitic structure is formed of graphite flakes or pseudonodular graphite particles, the tensile strength is still lower in the approximate range of from 25 to 35 kgf/mm.sup.2 and the Brinell hardness in the neighborhood of HB 100. When they are applied to such parts as are required to have high accuracy, therefore, the produced parts often pose problems of deformations of various sorts due to insufficient strength. Owing to the softness, they find only limited applications to such sliding parts as are in need of resistance to abrasion.
Besides the materials cited above, JP-A-61-177,356 discloses a low thermal expansion high-nickel content austenite graphite cast iron of the shape of vermicular, JP-A-02-298,236 an alloy having low thermal expansion at a relatively high temperature, JP-A-64-55,364 a low thermal expansion cast iron endowed with improved strength by a heat treatment, JP-B-01-36,548 a low thermal expansion alloy incorporating Ni, Co, V, and Nb therein, JP-A-02-70,040 a low thermal expansion alloy endowed with improved strength by a solid solution treatment, and JP-A-63-433 a graphite cast iron of the shape of vermicular. None of them satisfies both high strength and low expansion; some of them are deficient in strength and others in low expansion.
It is further known that low expansion cast irons having a graphite structure generally incur conspicuous Ni segregatio
REFERENCES:
patent: 5264050 (1993-11-01), Nakashima et al.
Kamohara Hisato
Nishimura Takanobu
Suzuki Motoo
Kabushiki Kaisha Toshiba
Yee Deborah
LandOfFree
Method for production of high-strength low-expansion cast iron does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Method for production of high-strength low-expansion cast iron, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Method for production of high-strength low-expansion cast iron will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1245587