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Kanno T.,Kimura Chuzosho Co. | Iwami Y.,Kimura Chuzosho Co. | Kang I.,Kimura Chuzosho Co.
International Journal of Metalcasting | Year: 2017

Although 3 cup thermal analysis is a good method to predict the molten metal's quality in gray cast iron, it could not be used in ductile cast iron due to several reasons. We have succeeded in investigating the graphite eutectic temperature (hereafter simply shown as TEG) and cementite eutectic temperature (hereafter simply shown as TEC) in ductile cast iron, from the chemical composition of the molten metal, as follows: TEG = 1149:1(°C) + 4:7Si mass% - 4:0[Sol:Mn mass%] - 44P mass% etc: TEC = 1142:6(°C) - 11:6Si mass% - 0:75[Sol:Mn mass% ] - 46:2P mass% etc: (hereafter, mass% is simply shown as %). We added various kinds of inoculants into the molten metals and then cast them at various fading time into 1 cup. Using the cooling curve of 1 cup and above equations, we calculated eutectic graphitization ability (hereafter simply shown as EGA). The graphite nodule count (N) of CE cup T.P. is determined by EGA(= 100 × DT1/DTE) as follows: N = 6:13 × (100 × DT1/DTE) - 126. In addition, when EGA becomes over 70 %, shrinkage tendency (θ) becomes low near 60°. Consequently, 1 cup thermal analysis is a good system to predict graphite nodule count and shrinkage tendency (θ) correctly in ductile cast iron, before pouring it. © 2016 American Foundry Society.


Patent
Kimura Chuzosho Co., Mie Prefecture, Senshu Corporation, Naniwa Roki Co., Hitachi Ltd. and Kinoshita Manufactory Co. | Date: 2011-01-24

There is provided a method for obtaining a pure melt in which the impurities Mn, Al, Ti, Pb, Zn, and B are removed from molten cast iron and depletion of useful C and Si is suppressed, the method wherein an excess oxygen flame having a theoretical combustion ratio of fuel and oxygen (amount of oxygen (volume)5/amount of fuel (volume)) of 1 to 1.5 is directly exposed to the surface of pre-melted molten cast iron, the temperature of the molten cast iron is held at 1250 C. or more and less than 1500 C. while the melt surface is superheated and an acidic slag is brought into contact with the melt, and an oxygen-containing gas is injected into the interior of the molten cast iron.


Patent
Kimura Chuzosho Co., Mie Prefecture, Kinoshita Manufactory Co., Naniwa Roki Co., Hitachi Ltd. and Senshu Corporation | Date: 2012-12-05

There is provided a method for obtaining a pure melt in which the impurities Mn, Al, Ti, Pb, Zn, and B are removed from molten cast iron and depletion of useful C and Si is suppressed, the method wherein an excess oxygen flame having a theoretical combustion ratio of fuel and oxygen (amount of oxygen (volume) x 5/amount of fuel (volume)) of 1 to 1.5 is directly exposed to the surface of pre-melted molten cast iron, the temperature of the molten cast iron is held at 1250C or more and less than 1500C while the melt surface is superheated and an acidic slag is brought into contact with the melt, and an oxygen-containing gas is injected into the interior of the molten cast iron.


Shiraki N.,Tokyo City University | Usui Y.,Tokyo City University | Kanno T.,Kimura Chuzosho Co.
Materials Transactions | Year: 2016

The purpose of this study is to investigate the effects of number of graphite nodules on fatigue limit and fracture origins in spheroidal graphite cast iron where carbon content and the number of graphite nodules are changed. As specimens, spheroidal graphite cast irons with 3.0, 3.2, 3.4, 3.6 and 3.8 mass% carbon content were produced respectively. Matrix was conducted pearlite (PDI) and ausferrite (ADI) by heat treatment (normalizing and austempering). The mean diameter of the graphite nodule decreases as the carbon content increases, and the number of graphite nodules per unit area increases. No differences were observed in tensile strength as a result of variations in the number of graphite nodules. The rotating bending fatigue test was conformed to JIS (Japanese Industrial Standards). Load frequency was 47 rpm, number of cycle to discontinue test was 1.0 × 107 cycles, and the specimen used was the 1 type of 8.00mm in diameter. All the fracture surfaces were observed with a scanning electron microscope. The relationship between the characteristics of fatigue strength and the size of fracture origins (defect size) was investigated. No differences were observed in fatigue limit as a result of variations in the number of graphite nodules. Fracture origins were microshrinkage, unspheroidizing graphite nodule and aggregate graphite nodules. The percentage of fracture origin of aggregate graphite nodules was increased by cluster of the graphite nodules. The reason of this phenomenon was due to the decrease of the graphite nodules spacing. The mean defect size in each sample was constant irrespective of the change of number of graphite nodules, which was good agreement with the results of the fatigue limit. © 2016 The Japan Institute of Metals and Materials.


Tomita Y.,Kimura chuzosho Co. | Fukuda Y.,Kimura chuzosho Co.
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

Recently, 3D printer which can create complex casting sand cores and molds is making progress in mold size and printing speed. Especially, the printing equipment using furan no-bake binder system has large advantages in product size and printing speed. But this binder system often causes veining defects in iron and steel castings. It disturbs practical using of 3D printer with this binder system in iron/steel casting area. The purpose of this study is to establish the veining-free furan no-bake 3D printing technology. It is known that veining defect does not occur in artificial sand mold because of its low thermal expansion rate. Then 65% artificial sand and 35% natural silica sand are mixed, and printing conditions are investigated. The printed sand mold has amount of thermal expansion of ambient temperature to 1273K is less than 0.9%. Casting iron and casting steel are cast into the printed mold, and no veining defects occurred.


Kanno T.,Kimura Chuzosho Co. | Kang I.,Kimura Chuzosho Co.
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

We investigated the effects of Mn and S on the mechanical properties of gray cast iron in detail, specifically, hardness, tensile strength, elongation, impact value, deflection and transverse load. With increasing Mn amount for a constant S composition, a transition point appears on each mechanical property. Hardness, tensile strength and transverse load become the smallest on this transition point. Elongation, impact value and deflection become the largest. The mechanical properties of gray cast iron are determined by the intervention of four actions such as (1) MnS nucleation action, (2) interfacial energy action of soluble S, (3) action of soluble S and soluble Mn to eutectic solidification temperature and (4) pearlitization action of soluble S (hereafter it will be abbreviated to [S].) and soluble Mn (hereafter it will be abbreviated to [Mn].). It is considered that the four actions are negated by making MnS, so the transition points exist. In addition, on the transition point composition, the graphite shape becomes the best A type. With increasing Mn amount for various S compositions, many transition points appear. When we connect these points, a new transition point appears near S0.03% and Mn0.32%. On this new transition point, excellent mechanical properties are shown. That is, hardness and tensile strength becomes the highest, and elongation and impact value which conflict with those properties also become the highest. On this new transition point (0.03%S, 0.32%Mn), MnS just starts to form or does not form ([S%]×[Mn%] = 0.01), and [S%] is the highest. Here, [S%] means soluble S amount and [Mn%] does soluble Mn amount. Consequently, in gray cast iron, the most excellent properties are obtained on S0.03% and Mn0.32%, which is just before the MnS formation. Copyright 2014 World Foundry Organization.


Kanno T.,Kimura Chuzosho Co. | Kang I.,Kimura Chuzosho Co.
Materials Transactions | Year: 2014

We investigated the effects of Mn and S on the mechanical properties of flake graphite cast iron in detail, specifically, hardness, tensile strength, elongation, impact value, deflection, and transverse load. We also investigated the cause. With increasing Mn amount for a constant S content, a transition point appears for each mechanical property. That is, hardness, tensile strength and transverse load become the smallest, and elongation, impact value and deflection become the largest. The mechanical properties of flake graphite are determined by the intervention of four actions; MnS nucleation action, interfacial energy action of soluble S, action of soluble S and soluble Mn to eutectic solidification temperature and pearlitization action of soluble S and soluble Mn. These four actions are thought to be negated by the formation MnS, resulting in the presence of the transition points. In addition, Mn and S amount showing the transition point demonstrate the best type A graphite shape. With increasing Mn amount for various S content, many transition points appear. When these points are connected, a new transition point appears near S0.03% and Mn0.32%. Excellent mechanical properties are seen at this new transition point. That is, hardness and tensile strength become the highest, and elongation and impact value which conflict with these properties also become the highest. At this new transition point (0.03%S, 0.32%Mn), MnS just starts to form ([S] × [Mn] = 0.01), and soluble S is the highest. Here, [S] means soluble S and [Mn] soluble Mn. Consequently, in flake graphite cast iron, the best excellent properties are obtained at S0.03% and Mn0.32%, which is just before MnS formation. © 2014 The Japan Institute of Metals and Materials.


Kimura H.,Kimura Chuzosho Co.
71st World Foundry Congress: Advanced Sustainable Foundry, WFC 2014 | Year: 2014

Our company introduced Full Mold Casting (FMC) in 1966, and have been innovating its technology. I will report the action contents. Although FMC was an excellent technology to produce complex castings, many defective products occurred by the residue of polystyrene pattern. Therefore, in order to prevent the residue, we developed the technology of decreasing it. Also, in order to reproduce the pattern of defective products promptly, we founded the pattern shop in 1967, the following year of FMC introduction. When the First Oil Shock occurred at the end of 1973, we promoted technological innovation of FMC with using non work hours which was caused by the recession. As a result, we developed "New Full Mold Casting (NFMC)" and started to manufacture the castings of machine tools. From 1976, we discontinued cavity mold process, and converted to FMC completely. In 1981, we founded "Japan Metal Co., Ltd. with the aim of "Clean foundry", and in 1988, we founded the foundry in Omaezaki for manufacturing large castings. The technological development of Kimura advanced greatly by construction of new plants in this way. Through the introduction of CAD/CAM, the development of coating, automatic measurement of the cut styrolfoam pattern with the laser measuring machine, and shortening the cooling time of casting production by the introduction of the water cooling system, we could started the casting series production. When amount of production decreased dramatically (2009) after Lehman shock, we developed the casting technology for engine block by FMC. Also, we developed hybrid casting process which using the integrated core manufactured with RP (Rapid Prototyping) technology, and wrapped it with the main mold of formed pattern. In addition to this, we have forwarded our human resource to develop the simulation. FMC which we have been working on was an unestablished technology, so it needed the constant development. It was lucky for us to have a task defined challenge and technological innovation for the technical establishment of FMC.


Patent
Kimura Chuzosho Co. | Date: 2012-09-10

According to the invention, by setting the linear thermal expansion amount when a mold made of a molding sand is heated from a room temperature to 1000 C. to be not more than 0.9%, and the ratio (D/d) between the diameter of a slump (D) and the diameter of a slump cone (d) in a slump test of the molding sand having a hardening agent kneaded to be not less than 1.65, a molding sand preferable for use in a mold produced using the self-hardening type of three dimensional laminate molding sand mold, having low thermal expansibility preventing occurrence of a veining defect, and capable of forming a large and complicated shape can be obtained.


Patent
Kimura Chuzosho Co. | Date: 2015-03-25

According to the invention, by setting the linear thermal expansion amount when a mold made of a molding sand is heated from a room temperature to 1000 C to be not more than 0.9 %, and the ratio (D/d) between the diameter of a slump (D) and the diameter of a slump cone (d) in a slump test of the molding sand having a hardening agent kneaded to be not less than 1.65, a molding sand preferable for use in a mold produced using the self-hardening type of three dimensional laminate molding sand mold, having low thermal expansibility preventing occurrence of a veining defect, and capable of forming a large and complicated shape can be obtained.

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