Recent development of ductile cast iron production technology. Ductile iron is a type of cast iron known for its impact and fatigue resistance, elongation, and wear resistance due to the spherical round graphite structures in the metal. Metal technologies currently has the capacity to produce 110,000 tons of ductile iron each year. Nodular cast iron hereafter called nci is an engineering material displaying high ductility, elastic modulus, mechanical strength and corrosion resistance. Ductile iron is not a single material but part of a group of materials which can be produced with a wide range of properties through control of their microstructure. While dipra member companies have different names and locations, they all have one thing in common. Research programs aimed at improving production technology, solving long standing production problems, and providing better manufacturing. Solution strengthened ferritic ductile irons ssf ssf cast iron is a high strength ductile cast iron quality alloyed with silicon between 3.
Ductile iron is also called ductile cast iron, spheroidal graphite cast iron, or nodular cast iron. Production of ductile iron castings without feeders. Ductile cast irons are materials having strength, impact toughness and ductility comparable to those of many grades of steel while exceeding by far those of standard gray irons. Ductile iron castings foundry and supplier carson castings. The production of ductile iron is 3035% cheaper than steel and 34% times cheaper than nonferrous alloys and only 2030% more costly than normal grey iron. Improving ductile iron production using ultralow additions of magnesium. Durabar ductile iron is a costsaving alternative to lowmedium carbon steels and has similar strengths with excellent free machining properties. This study was undertaken to evaluate the wear resistance of different grades of ductile iron as alternatives to high tensile strength alloyed and inoculated gray irons and bronzes for machine tool and highpressure hydraulic components. Thermal analysis of ductile iron casting intechopen. At that time, there were various infectious diseases spread within japan. Ductile iron microstructure by thermal analysis one promising new technology is the rapid classification of microstructure by thermo analysis. Consequently, if ductile iron flanges are desired, that option must be so stated in the specifications and on the purchase order. Both of the production process needs to be controlled closely. Magnesiumsulfur relationships in ductile and compacted.
This change in graphite form is accomplished by adding an inoculant, usually magnesium, to molten iron of appropriate composition during manufacture. Insufficient amount of feed metal available at early stages of the solidification. It reacts with the sulfur and oxygen in the molten iron and changes the way the graphite is formed. A galvanic series showing less noble anodic metals to the left and more noble cathodic metals to the right. Production ductile iron castings cnc machining foundry. This video takes you inside the casting process and allows you to see step by step what it takes to make a ductile iron pipe. Ductile iron, also known as ductile cast iron, nodular cast iron, spheroidal graphite iron, spheroidal graphite cast iron and sg iron, is a type of graphiterich cast iron discovered in 1943 by keith millis. While ductile iron can be produced from steel or iron scrap, pig iron is the primary source of infeed for most modern ductile iron foundries. The ductile iron used to manufacture the pipe is characterized by the spheroidal or nodular nature of the graphite within the iron. Typical failures of cast iron pipes are characterized by leaks in pipe wall along the graphite flakeferrite interface.
This alloying level of silicon is constant per ssfgrade, unlike. Wo2004022791a1 method for production of ductile iron. When used in place of grey iron, the design of the casting is. This versatility is especially evident in the area of mechanical properties where ductile iron offers the designer the option of choosing high ductility, with grades guarantee. Low s grey irons and ductile irons treated with high re fsm reduce effectiveness. Its strength, toughness and ductility duplicate many grades of steel and far exceed those of standard gray irons. Section 15060 other requirements nsf61ansi for potable water applications applications water and sewer preapproved manufacturer issue date. Corrosion is the manifestation of the second law of thermodynamics, entropy, the inexorable march toward disorder. Back to awwa c11012 ductileiron and gray iron fittings pdf this standard describes 3 to 48in. Since then, our long technical experience realized ductile iron pipes with excellent strength, durability and. Ductile iron in china dandong foundry gray iron, ductile. In addition, ductile iron provides a unique combination of strength, wear resistance, fatigue resistance, and toughness. Inoculation of cast irons an overview 357 combination with 0. This form of graphite favours the elasticity of the cast iron and increases its inherent strength.
Continuous testing and field experience have brought the production and use of ductile iron pipe to maturity. A comprehensive study was carried out to design a production route for thin wall ductile iron castings free of eutectic carbides. The title describes both the contents and the objective of this book. Effect of processing parameters on the mechanical properties. Product specifications ductile iron mechanical joint. Fluidity and temperature profile of ductile iron in thin.
Ductile iron s ease of maching and economy of production are almost equal to gray iron. Deteriorating buried infrastructure management challenges. Production ductile iron castings are another type of casting produced here at cpm industries. Processing techniques and productions of ductile iron. Ductile iron data for design engineers revised edition. In addition, they have the same advantages of design flexibility and low. Production and properties of thinwall ductile iron castings article in international journal of cast metals research 16. Ductile iron what ductile iron is ductile iron is a family of cast graphitic irons which possess high strength, ductility and resistance to shock. Iacoviello et alii, frattura ed integr ita strutturale, 2010 316. Austempered ductileiron castings advantages, production. Ductile iron also offers flexibility in casting a wide range of sizes, with sections ranging from very thin to very thick. It has been accepted for inclusion in masters theses by an authorized administrator of trace.
Oluwasegun abstractductile cast irons are materials having strength, impact toughness and ductility comparable to those of many grades of steel while exceeding by far those of standard gray irons. Special test methods were employed to simulate typical conditions of reciprocating sliding wear with and without abrasive contaminated lubricant for. Pure metals solidify with a solidification front that is very well defined and a clearly delineated solidliquid interface. Ecob customer services manager, elkem as, foundry products division abstract the objective of this paper is to provide an overview of some of the most common metallurgical defects found in the production of ductile cast iron today. A recent development is to use an austempering heattreatment process to obtain improved combi nations of mechanical properties. This article discusses the raw materials that are used for ductile iron production and outlines the most common and important requirements for. Willmans ductile iron foundry produces a family of cast graphitic irons that are high strength, resistant to shock, and with high ductility greatly exceeding standard grey irons and with properties similar to many high grades of steel, plus resistant to fracture even when bent, twisted or deformed. The delavaud casting process incorporates a metal mold which has a peen pattern on its inside diameter. Ductile iron structure, properties and applications. We produce all standard grades of ductile iron including 654512, 805506, and 1007003 as well as austempered ductile iron, and customer specific grades.
The inoculation of grey and ductile iron is realized by the addition of small amounts of materials known as inoculants. Production process of ductile iron pipesxinxing pipes xinxing pipes. Ductile iron usually hypereutectic is produced by treatment with magnesium immediately prior to pouring castings see fig. Ferrosilicons with higher silicon content are made in electric arc furnaces. Magnesium is added to the melt in the form of a master alloy. Chemical composition of molten iron should be high carbon, low silicon, low sulfur, and low phosphorus. However, dipra recommends the use of ductile iron flanges on ductile iron pipe because of their superior strength and impactresistance. When compared to forged steel and conventional ductile iron, both with equal or inferior mechanical properties, adi exhibits unnotched charpy impact values at room temperature that are less than those of forged steel, but three times higher than conventional ductile iron table 4.
Ductile iron mechanical joint restraints minimum standards ansiawwa. In order to be able to produce ductile iron castings in green sand mould without feeders it is essential that feed metal can be supplied from the pouring cup through the gating system during the. Ferrosilicon is produced by reduction of silica or sand with coke in the presence of iron. En 1563 new generation ductile irons solid solution. Us20040042925a1 method for production of ductile iron. Ductile iron finds application as a substitute for steel, malleable iron and nonferrous alloys. Other bainitic and martensitic structures may be formed by heat treatment processes such as quenching and tempering and austempering. The present invention relates to a method for nodularizing treatment of ductile iron using a ladle treatment method for nodularizing of a magnesium ferrosilicon alloy, where a magnesium ferrosilicon nodularizing alloy consisting essentially of 40 to 80% by weight of silicon, 2 to 15% by weight of magnesium, 0. The use of ductile iron has grown rapidly in the past 40 years, mainly through conversions from gray and malleable iron castings, steel castings, forgings and fabrications, and also through its use in new components designed with ductile iron. Other resources such as agma 939a07 austempered ductile iron for gears 8, ductile iron data for design engineers 9 and the afs strainlife fatigue properties database for cast iron 10 include informative charts, tables, appendices and fea coefficients and exponents. Ductile iron is primarily used for pipes, tubes, and fittings, and for.
Welding of ductile iron with nifemn filler metal a new filler metal system can be used with several welding processes to produce joints in ductile iron that match or exceed base metal properties up to 80,000 psi 552 mpa by t. An inoculant is a ferrosilicon based alloy added to the molten metal either just before or during the pouring of the liquid iron. Dilution of magnesium reduces the violence of the subsequent. Effect of magnesium and calcium as spheroidizers on the. Pdf analysis of ductile iron production on steel scrap base. The matrix may be ferritic, pearlitic or a mixture of the two. The present invention relates to a method for nodularizing treatment of ductile iron using a ladle treatment method for nodularizing of a magnesium ferrosilicon alloy, where a magnesium ferrosilicon nodularizing alloy consisting essentially of 40 to 80% by weight of silicon, 2 to 15 % by weight of magnesium, 0,3 to 5 % by weight of lanthanum, 0 to 6 % by weight of calcium, 0 to 5 % by weight. Current technology consists of either pouring a sample with two ears on it for micro analysis or creating a micro lug in the runner system of a mold and digging the lug out for grinding and polishing. Production and properties of thinwall ductile iron. Analysis of ductile iron production on steel scrap base article pdf available in international journal of cast metals research 274. Use of high purity pig iron for foundries producing ductile iron castings high purity pig iron hppi is differentiated from other types of pig iron by its low manganese, phosphorus and sulphur contents. They are commonly used for potable water distribution and the pumping of slurries, sewage and process chemicals.
Annealed cast ductile iron can be bent, twisted or deformed without fracturing. In ductile iron the free graphite is in the form of discrete nodules or spheroids. Ductile iron society research committee report compiled by. Thus, to fully utilize the potential of ductile iron castings, the designer should be aware of the wide range of heat treatments available for ductile iron, and its response to these heat treatments. Products cast using ductile iron include valves, impellers, winch drums, separator body liners, etc.
The results described in this paper show that unalloyed ductile iron. Ductile iron pipes and cast iron pipes, however, corrode at about the same rate in soil. Mechanical and microstructural characterization of nodular. Radzikowska, the foundry research institute, krako. Ductile iron production practices karsay, stephen i on. Ferrosilicons with silicon content up to about 15% are made in blast furnaces lined with acid fire bricks. For the same pressure design, ductile iron pipe will have a. Production of ductile iron castings1 cast iron science. It will be held at the hilton garden inn chicago ohare airport in des plaines, il. Ductile iron is also known as nodular cast iron, spheroidal graphite iron, spherulitic iron. The term pig iron arose from the oldfashioned method of casting blast furnace iron into molds arranged in sand beds in such a manner that. Ductile iron pipe is typically manufactured with larger inside diameters than steel pipe, resulting in lower pumping costsand an average 21% savings in energy costs. Production process of ductile iron pipesxinxing pipes. Member companies ductile iron pipe research association.
Ductile iron pipe is designed according to rigorous and prudent awwa standards. Recent development of ductile cast iron production. January 24, 2018 mcwane ductile utah, embracing the mcwane way from start to finish. The reasonable control of the sulfur content is an important condition in the production of ductile iron. Solution strengthened ferritic ductile iron iso 1083js500. The common defining characteristic of this group of materials is the shape of the graphite. Ductile iron differs from cast iron in that its graphite form is spheroidal, or nodular, instead of the flake form found in cast iron. The globalization and inoculation processes effectively improved the mechanical properties, particularly increased plasticity and toughness, which is higher than the strength of carbon steel. This form of graphite favours the elasticity of the cast iron and increases its. Ductile iron is a high strength, tough material used in water and wastewater systems in all 50 states of the united states and in many other areas of the world.
Ductile iron solidifies and crystallises into hexagonal close packed hcp structure. Some problems in the production of ductile irons by. The history of wrought and cast iron shawn van dyke university of tennessee knoxville this thesis is brought to you for free and open access by the graduate school at trace. The highest fluidity for ductile iron poured into a mould made of chemically bonded silica sand was obtained for melt no. Gagne, ductile iron for heavy section windmill castings, in proceedings of the keith millis symposium on ductile cast iron, pp. Cpm can complete castings from start to finish, producing a turnkey product that will meet or exceed our customers expectations. Ductile iron is a growth metal in the casting industry to the point of approaching gray iron production levels. Offsetting shrinkage in ductile iron ver 2 meltlab.
During the last years the industrial use of ncis iron has been. Pig iron refers to the primary iron production of a blast furnace that contains over ninety percent iron. Ductile iron casting refers to a process in which magnesium cerium as an alloy of magnesium cerium is added to cast iron. Ductile iron pipe is centrifugally cast by pouring molten iron against the inside wall of an externally cooled rotating metal mold.
Austempered ductile iron castings advantages, production, properties and specifications abstract ductile irons, having a spheroidal or nodular graphite structure, are wellestablished engineering materials. While most varieties of cast iron are weak in tension and brittle, ductile iron has much more impact and fatigue resistance, due to its nodular graphite inclusions. Unlike gray iron, which contains graphite flakes, ductile iron has an ascast structure containing graphite particles in the form of small, rounded, spheroidal nodules in a ductile metallic matrix. Typical sources of iron are scrap iron or millscale. The new development of ductile iron production techniques, such as coredwire injection wirefeeding nodularization process, tundish cover ladle nodularizing process, horizontal continuous casting, and epc process lost foam for ductile iron castings, etc. Metallography and microstructures of cast iron janina m. Dipra is a nonprofit association supported by all of the ductile iron pressure pipe manufacturers in north america.
Cast iron flanges, like cast iron pipe, have a long and successful service history. Microstructure influence on fatigue crack propagation resistance. Ductile iron pipe and fittings manual of water supply practices m41 third edition awwa manual m41. The outer skin is formed being very thin in ductile iron. The top and bottom plane of the hex agon are called basal plane and the six sides are the prismatic planes. Ductile iron is a kind of spherical graphite cast iron. In addition to panels on gatingrisering, solving casting defect problems, manganese mn and mnsulfur s ratios in gray irons, the division featured afs research reports on fractal methods for assessing ductile iron nodularity, age strengthening of gray iron, status of the astm a48 b test bar mold and. In ductile irons, graphite is in the form of nodules rather than flakes as in grey iron.
Process control in the production of ductile iron castings. Almost every foundry that uses batch type treatments to produce ductile iron adds a constant amount of magnesium to each ladle. The main objective of the ductile iron society is to advance the technology, art, science of ductile iron production and to disseminate all such information to the members. The origin of kubota s ductile iron pipes goes way back to 1890s.
Use of high purity pig iron for foundries producing. This triggered gonshiro kubota, our founder, to produce the first iron pipes in japan. Hppi is manufactured from the smelting of ilmenite sand in electric furnaces to produce titanium dioxide slag and pig iron. It is a comprehensive summary of data describing the engineering properties of ductile iron. Ductile cast iron solidification is characterised by a very thin solidified skin and appearance of different phases. The ratio of mechanical failure between the cast iron and ductile iron pipes is 2. This peen pattern is transferred to the pipe during the casting process. The youngest but most successful member of a truly ancient family, ductile iron has suffered from an abundance of myths and a lack. Pdf processing techniques and productions of ductile. Ductile cast iron also called as spheroidal graphite cast iron or nodular cast iron has been widely used as a main industrial material in place of highgrade cast iron. In this study, a test casting assembly with section thicknesses from 3 to 10 mm representative of actual castings was designed using computer modeling technique.
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