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PAPERS LIST
P-1A Study of the Consistency of Zircon Flour, Manuel Guerra, July 1991
Proper control of slurries used in investment casting is critical in producing a high quality finished part. The flour component is by far the largest part (by weight) of the slurry, yet its effect on rheology and overall life is one of the least understood aspects in slurry control. It is well known that the type of flour used and its particle size distribution greatly affect the resulting slurry viscosity and coating properties. This is especially important on the prime layer.
Zircon flour, a naturally occurring mineral, is one of the most commonly used flours for prime slurries. It combines the desirable characteristics of high refractoriness, good chemical inertness, and relatively high abundance. Yet, when the investment caster receives his zircon flour, he is at the mercy of the supplying company's ability to produce a consistent grind. Can a consistent product be produced without the added expense of blending? The answer appears to be a conditional yes.
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P-2 Alumina and Zirconia Binders, R. Chester Feagin, Presented at the 29th Annual Meeting of the Investment Casting Institute, October 1981
This paper discusses the chemical properties and bonding characteristics of new commercially available binders of aqueous colloidal alumina monohydrate and zirconium oxide.
Potential applications are indicated together with some physical property data derived from bonded refractory systems.
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P-3 Avoid Shell Cracking by Controlling Your Process, Craig T. Lanham, March 1995
A discussion focused on shell formulation, control and process to prevent stress on the ceramic shell, which can cause shell cracking.
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P-4 Casting of Reactive Alloys: An Update of Current Technology, Charles H. Matzek, June 19, 1997. Presented at the Cannon-Muskegon Technology Conference in Conjunction with The Paris Air Show (Same as P-39)
Casting quality is an important issue to all foundries. The quality of the casting is, at best, only as good as that of the wax pattern. Nothing used in the investment casting process stands by itself from the standpoint of affecting the final quality. Every component used in the process – the wax, the pattern cleaner, the face coat binder and refractories, the backup binders and refractories, the metal, the crucibles and transfer ladles – interacts with and is affected by the other components. Process controls or, more often, the lack of proper controls has additional impact on quality. Everything the foundryman does in his selection of process conditions, processing controls and raw material selection is directed towards keeping the quality of the finished casting as high as possible. These issues are especially important to those foundries casting reactive alloys. Reactive alloys add another dimension to the problem because the foundry must now have face coats, cores and crucibles/transfer ladles which will not react with the metal during melting, transfer, pouring and cooling.
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P-5 Casting of Reactive Metals into Ceramic Molds, R. Chester Feagin, Presented at the 6th World Conference on Investment Casting, October 1984
This paper describes the results of casting titanium and other reactive metals into experimental ceramic mold systems under controlled conditions. Photomicrographs of metalographic sections show relative degrees of reactivity. Certain specific mold systems are recommended for further study.
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P-6 The Ceramic Molding Process, Glenn W. Schiefelbein, February 1984
There are two processes used in PIC, i. e. , Solid Mold and Ceramic Shell. Although the solid mold process remains in use today, the shell process is more popular. The main reason for its popularity is overall economics. For this reason, we will emphasize the ceramic shell process.
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P-7 Ceramic Shell Production for Controlled Shell Cracking, Glenn W. Schiefelbein, June 1987
Shell cracking is the product of stresses applied during the shell building process. Factors that contribute to the stresses are identified. Practical methods to produce maximum green strength of shells are described. These include the process control of slurries and stucco, mechanics of shell building and drying. Twelve guidelines are given to ensure optimum shell strength to resist stresses that cause cracking.
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P-8 Characteristics of Some Aluminosilicates - Colloidal Silica Shell Systems, R. Chester Feagin, Presented at the 26th Annual Meeting of the Investment Casting Institute, October 1978 and at the EICF Conference, June 1978
This paper is a report on some continued work on alumino-silicate shell systems which have been bonded with colloidal silica. The main purpose of this study is to give some various compositional differences in shell systems, using alumino-silicates, the types of which are currently in use today in the U. S. ; also to show the influence of some materials differences, such as small versus large particle colloidal silica, stucco variations, particle size distributions of the slurry refractory, and the addition of fused silica flour to slurries, and their effect on modulus at rupture of test specimens prepared with such slurries. A group of thermal expansion curves on these systems is also included.
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P-9 Colloidal Silica in the Precision Casting Industry, Glenn W. Schiefelbein, March 1987
Colloidal silica is the most popular binder used in the precision casting industry today. It is safe, economical, easy to use and performs well. All of these desirable attributes tend to lull us into a sense of well being when we use colloidal silica. We frequently forget that this workhorse of the industry is sensitive and needs some attention to keep it working at its best. This paper describes colloidal silica, its properties and those things that will affect its performance.
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P-10 Controlling Core Related Casting Defects, by Glenn W. Schiefelbein, November 1992
Slide show in conjunction with Dipcoat Nucleation paper by R. Chester Feagin.
This paper will give a brief summary of the generally accepted principles of nucleation, along with a brief review of the technical and patent literature relating to dipcoat nucleation. In addition, a description will be given of various experiments that have been carried out employing different nucleating agents. Several specific examples of grain size controlled castings produced in molds having nucleants on the mold surface will be shown as described.
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P-11 Dipcoat Nucleation, R. Chester Feagin, 1967
This paper will give a brief summary of the generally accepted principles of nucleation, along with a brief review of the technical and patent literature relating to dipcoat nucleation. In addition, a description will be given of various experiments that have been carried out employing different nucleating agents. Several specific examples of grain size controlled castings produced in molds having nucleants on the mold surface will be shown as described.
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P-12 Effect of Dilution on REMASOL® ADBOND® BV Binder, Manuel Guerra, Presented at Investment Casting Institute Meeting, October 1993.
Since its market introduction in late 1992, REMASOL® ADBOND® BV binder has successfully replaced both ethyl silicate and other colloidal silica binders in foundries where fast processing times are required. Because of its good green strength, a reduction in autoclave cracking can also be realized.
Due to the variety of use conditions, additional work has been done with REMASOL ADBOND BV binder to determine the effect of dilution with respect to shell properties and improved cost performance. This paper updates that work.
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P-13 The Effect of Dry Time on Shell Strength, Manuel Guerra, Presented at AFS Meeting, October 3, 1991
This paper looks at the effects of drying on shell modulus of rupture strength. Dry time between dips was varied and two different final dry times were also evaluated. MOR strips were chosen as the test configuration and results showed that the amount of dry time between dips can have a significant impact on MOR strength. A longer final dry did not make up for insufficient bonding caused by very short dry times between dips.
Because one particular set of drying parameters was chosen for this study, the numbers in this report should not be regarded as absolute. However, for actual production, the results reported here should give foundrymen some idea as to how much strength is lost by insufficient drying.
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P-14 Enhanced Binder Systems for the Investment Casting Industry, Jeffrey C. Niles, March 1995
The development of enhanced binder systems has been an ongoing process which has been accelerated with increasingly restrictive limits on alcohol emissions. Ethyl silicate based ceramic shell systems were ideal because of their fast processing capabilities and resulting strength. The bonds in an ethyl silicate system could be chemically set with ammonia and the alcohol would evaporate rapidly because of its relatively high vapor pressure. Work has been done on chemically setting water based systems, but the results have been poor, with low strength compared to alcohol systems. The direction is now to modify existing colloidal silica binders to allow them to produce similar processing times and strengths as ethyl silicate binders. These types of binders have been termed "enhanced binders".
The first enhanced binder systems were developed for primary applications. The primary binder has different requirements versus the backup. It should have longer term stability because of its slower turnover rate and should provide excellent coating characteristics. The goal of an enhanced primary binder is to reduce surface defects such as buckle, cracking and lifting and promote adhesion to the wax pattern.
Various types of materials such as latexes, polyvinyl alcohols, methylcellulose, acrylic resins, etc. , have been evaluated in colloidal silica to develop enhanced primary and backup binders. The results of this work have been varied because of the wide number of materials that must be evaluated and incomplete understanding of the process. In the last 8 to 10 years, a great deal of work has been done by various companies to produce significant advances in enhanced binder systems. These new generation products, such as REMASOL ADBOND BV and LUDOX® SK have opened the door for even more research into these binder types. In the last five years, many enhanced binder products have been introduced. The enhanced primary binders have been shown to reduce typical primary type drying defects, while the backup binders have provided faster processing and higher strengths versus standard colloidal silicas.
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P-15 Enhanced Binders for the Production of Ceramic Shells, Craig T. Lanham, November 1994
The limits of any foundry’s casting capabilities are governed by the ceramic mold it produces. These constraints effect both casting quality and foundry responsiveness. As in the past, current and future binder developments will continue to define and constrain how the demands of casting buyers are met.
The ceramic shell process and the binders the Investment Caster use are relatively young, only 50 to 60 years old. The desire and need to pour high temperature ferrous alloys led to the development of ethyl silicate binders in the mid 1930’s. Colloidal silica was introduced as a binder in ceramic molds a decade later. During the mid to late 1940’s the industry began to move away from the solid mold process to improve casting surfaces. By the mid 1950’s the development of the ceramic shell process was well underway.
As most in our industry know, environmental concerns and ever increasing material costs are inducing foundries to convert from ethyl silicate binders to colloidal silica binders. As we move away from the alcohol based binders we have had to deal with the traditional problems associated with the use of water based binders; high viscosity slurries that wet poorly, process slowly, and produce lower green strength shells.
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P-16 Ethyl Silicate Shell Systems, R. Chester Feagin, Presented at 27 Annual Meeting of the Investment Casting Institute, October 1979
This paper reports on the continuation of some work on aluminosilicate shell systems in which ethyl silicate binders are used. Some work on aluminosilicate shell systems has previously been reported. (1) (2) Modulus of Rupture (MOR) data were presented on aluminosilicate shell systems using colloidal silica binders showing the influences of slurry refractory particle size, colloidal silica particle size, and silica concentration, type of aluminosilicate, and fused silica additions to aluminosilicate shells on MOR and thermal expansion.
This paper is a continuation of work on aluminosilicates in shell systems. A fused silica shell system is used as a base with substitutions of zircon and aluminosilicates as slurry and stucco refractories. Commercially available prehydrolyzed ethyl silicate and hybrid ethyl silicate binders at ten and twenty weight percent silica were used in the slurries. Some MOR data at room and 1750°F temperatures, and thermal expansion data to 1832°F (1000°C) are presented. Although this study is primarily a continuation of work on REMASIL 60, a highly refractory material, for shell application, these data have particular significance in view of recent shortages of fused silica. Much work still has to be done such as more data on binder silica contents and types, hot MOR and thermal expansion. However, we have determined some areas of interest by laboratory test specimens, which will require practical castings confirmation.
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P-17 Factors Affecting Shell Strength and The Effect of Dry Time on Shell Strength, By Manuel Guerra & W. O. Roberts (DuPont), Presented by Albert T. Bozzo at the 22nd EICF Conference, Paris, April 1992.
The factors influencing the flexural strength of ceramic shell molds made of refractory particles bonded with air dried colloidal silica have been identified. The bonding mechanism appears to be completely different for the unfired than for the fired shell mold.
Before firing, shell strength was found to be mostly a function of binder silica sol characteristics and to be independent of the chemical composition of the bonded particles. In general, the strength of the unfired shell is a function of the
After firing, the strength of the shell was found to be highly dependent on the refractoriness of the bonded particles and the binder solids. In general, the strength of the fired shell is a function of firing time and temperature
In addition, this paper looks at the effects of drying on shell modules of rupture strength. Dry time between dips was varied, and two different final dry times were also evaluated. MOR strips were chosen as the test configuration, and results showed that the amount of dry time between dips can have a significant impact on MOR strength. A longer final dry did not make up for insufficient bonding caused by very short dry times between dips. Because one particular set of drying parameters was chosen for this study, the numbers in this report should not be regarded as absolute. However, for actual production, the results reported here should give foundrymen some idea as to how much strength is lost by insufficient drying.
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P-18 Factors Effecting Slurry Rheology, Glenn W. Schiefelbein & Manuel Guerra, February 11, 1991
Today foundrymen are interested in controlling casting quality. This includes the control of surface finish, internal shrink and metal grain size. Shell and metal controls work synergistically to create conditions that produce a quality product on a consistent basis. This paper will address factors that effect shell uniformity, namely slurry control.
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P-19 Hot Modulus of Rupture Measurements on Some Aluminosilicate Shell Systems, R. Chester Feagin, Presented at 28th Annual Meeting of the Investment Casting Institute, October 1980 and at the 5th World Conference on Investment Casting, June 1980
For the past three years we have been involved in the evaluation of aluminosilicate refractories in various shell systems. This work involves the preparation of shell test specimens in which the first two coats utilize zircon refractory, which is common practice for many shell systems, and the remainder of the shell being totally aluminosilicate refractory both in the slurry and stuccos. Colloidal silica was the major binder evaluated using a prehydrolyzed hybrid REMET A-1 binder containing 20% SiO2. These shell systems were evaluated for modulus of rupture at room temperature in the unfired state after drying, and after firing to temperatures of 649°C, 927°C and 1093°C and then cooling to room temperature. Thermal expansion measurements were run on three shell systems, and hot modulus of rupture measurements at 1371°C were determined on most of the shell series. Results of the room temperature and hot modulus of rupture measurements and thermal expansions are presented with discussion.
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P-20 The Influence of Refractory Particle Size of Slurries and Shells, R. Chester Feagin, Presented at 25th Annual Meeting of the Investment Casting Institute, October 1977
Some work carried out in the REMET Corporation laboratory relative to certain projects has produced some data which is related to the general subject of particle size of refractories and to its influence on slurry characteristics and strength of shell molds. This work was not carried out specifically to determine the particular influence of particle size distribution on slurries and shells but provided some interesting information on certain systems.
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P-21 Investment Casting 1930-1950, R. Chester Feagin, Presented at 39th Annual Meeting of the Investment Casting Institute, September 1991
This paper will describe the early beginnings of commercial investment casting in the United States at Austenal Company where the first turbine bucket for airplane superchargers was cast. A summary of the processes used and a list of the main casters are noted. A list is given of the patents issued at that time and a description of the principal ones, some of which are still in use today.
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P-22 MOR, Who Needs It?, Craig T. Lanham, October 1993.
Do we really need MOR testing? Under continual pressure to reduce overhead costs this is a typical question at most foundries. ased on a traditional understanding of Modulus of Rupture or MOR testing and past evaluation techniques, I think the question is justified. In order to find value in MOR testing, today’s foundryman needs to advance his understanding of this test. This paper will describe proper MOR testing and offer a new perspective on the uses for this valuable investigative tool. Perhaps you will then be able to answer the question; “MOR, Who Needs It?”
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P-23 Particle Size Determination of Refractories, R. Chester Feagin
Presented at 25th Annual Meeting of the Investment Casting Institute, October 1977
Every investment caster is concerned with particle size distribution of refractories. Particles of various types of material are used in slurries, stuccos, finishing materials, abrasives, and even binders, etc. , yet many casters have very little idea of the best means for measuring particle size and relatively few do any control testing on refractory materials. The purpose of this discussion, therefore, is to review a few of the recommended methods for particle size determination for refractories and similar materials along with some of the pros and cons of each method. This discussion will not review methods for particle size of silica in colloidal silica.
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P-24 Proper Techniques to be Followed in Preparing and Maintaining a Slurry, Theodore R. Owens, June 1987
An overview of slurry mixing procedures, wetting agents and antifoams, slurry maintenance procedures, and quality control checks.
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P-25Refractories Used for Investment Casting of High-Temperature Alloys, Manuel Guerra
Alumina refractories play a key role in contemporary precision investment casting. As one of the main constituents in shell molds for high-temperature alloys, alumina is favored because of its chemical inertness and high-temperature capability. This chapter summarizes the principal physical and chemical characteristics of alumina in relation to the requirements for its use in both the slurry and stucco components of typical shell molds. Particular attention is given to factors affecting slurry stability and shell strength. Other applications for alumina in investment casting, including crucibles, alloy filters and mold insulating warp are briefly reviewed. The current trend to increasing process temperatures dictated by advances in directional solidification technology, points to expanded use of alumina refractories in the investment casting of high-temperature alloys.
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P-26 Refractory Selection for Primary Shell Coat, Glenn W. Schiefelbein, Presented at Cannon-Muskegon Seminar, May 1994 and September 1994 Investment Casting Institute Meeting.
A discussion of two major considerations when selecting a primary coat refractory.
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P-27 REMASIL 60: A Refractory for Casting Parts Under High Thermal Stress Conditions, Charles H. Matzek, June 1988
In an effort to meet the needs of their customers and to be more competitive and more profitable, ferrous investment casters are casting larger and thicker sectioned parts and are pouring more metal into each shell due to increased part density on the assembly. All of these can cause temperature build ups which exceed the refractoriness of the shell. Deformation occurs, scrap and rework costs increase and profitability is reduced. The high temperature properties of REMASIL 60 and MOLOCHITE™ are compared in both colloidal silica and ethyl silicate bonded systems. Conclusions are drawn and recommendations made regarding a shell system that will allow investment casters to extend their ability to cast larger castings.
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P-28 REMASOL® ADBOND® B and REMASOL® ADBOND® BV Binders, Manuel Guerra, Presented at the 40th Annual Meeting of the Investment Casting Institute, October 1992
The ethyl silicate bonded shell process is under environmental and cost pressure worldwide. Alternative polymer containing binder systems, which claim to approach the speed of ethyl silicate, require expensive, specially sized fused silica refractories. Frequently, fused silica cannot be used because of shell expansion and other considerations versus the refractory system currently in place.
REMASOL ADBOND B and REMASOL ADBOND BV binders allows the investment casting foundry to achieve drying rates comparable to ethyl silicate while using any standard refractory.
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P-29 REMASOL ADBOND BV Binder - An Update, Manuel Guerra, Presented at the 8th World Conference on Investment Casting, June 1993
REMASOL ADBOND BV binder was introduced to the Precision Investment Casting industry in October 1992 as a backup binder. The product has now been used in production and many foundries have discovered that REMASOL ADBOND BV does provide for significantly faster shell processing time versus standard colloidal silica, to the point where it can equal alcohol-based binder systems.
This paper is an update to the original paper presented in 1992 at the 40th ICI Conference in Las Vegas, Nevada. Additional information on MOLOCHITE™ refractory with a REMASOL ADBOND BV system, and the effect of diluting the binder percent silica of a REMASOL ADBOND BV system are shown.
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P-30 REMASOL® ADBOND® BV: A Practical Update, Charles H. Matzek, Presented to Verein Deutscher Gießereifachleute (VDG), February 1994.
The REMASOL ADBOND BV system was introduced to the U. S. market in late 1992. It was developed with the goal of replacing Ethyl Silicate as a binder. Several key goals were established at the outset of the program. These include:
Initially, REMET's direction was to look at only ethyl silicate replacement situations. The market opened our eyes to the productivity improvement needs of foundries which were using non-latex modified Colloidal Silica bonded shell systems. Very simply, the REMASOL ADBOND BV systems offered improvements to foundries regardless of which binder system they were currently using. The purpose of this paper is to provide some practical foundry experiences based upon the more than 30 foundries who have already converted to the REMASOL ADBOND BV system so that you can better judge the potential value which it can provide to you in your particular production situation.
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P-31 REMASOL® ADBOND® BV: A Practical Update, James R. Pyne, Presented to the E. I. C. F. Conference, Prague, June 1994
The REMASOL ADBOND BV system was introduced to the U. S. market in late 1992. It was developed with the goal of replacing Ethyl Silicate as a binder. Several key objectives were established at the outset of the program. These included:
Initially, REMET's direction was to look at only ethyl silicate replacement situations. The market opened our eyes to the productivity improvement needs of foundries which were using non-polymer modified Colloidal Silica bonded shell systems. Very simply, the REMASOL ADBOND BV systems offered improvements to foundries regardless of which binder system they were currently using.
The purpose of this paper is to provide you with some practical foundry experiences based upon the more than 35 foundries who have already converted to the REMASOL ADBOND BV system so that you can better judge the potential value which it can provide to you in your particular production situation.
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P-32 Review of Shell Components, Manuel Guerra, Presented at Cannon-Muskegon Metallurgical Seminar, May 1994 and September 1994 Investment Casting Institute Meeting.
The selection of the proper refractories for producing an investment cast, shell-mold many times involves making some compromises. Since the slurries contain an active binder, only a handful of refractories have enough stability to provide useful slurry life. In addition, the properties of the refractory (thermal expansion, refractoriness, etc. ) must be considered, as well as the cost.
The major constituents of a shell-mold are the binder and the refractory flour. The other components, which are usually in relatively small quantities, are nonetheless very important. This is so because they can not only influence slurry stability, but also overall shell integrity.
A brief review of the components necessary to build a shell can be helpful. The shell can be broken down into five areas:1) binder; 2) refractory; 3) surfactant; 4) antifoam; and 5) polymers. While there are some other additives, their usage is relatively small, and the above five areas will be concentrated on here.
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P-33 Surfactants, Wetting and Foams, Albert T. Bozzo, September 1989
Wetting agents have traditionally been added to aqueous based prime slurries to help wet out the refractory flours and to enable the slurry to wet the wax patterns. Antifoams are only necessary to negate the foaming effect of the wetting agent. The minimum effective concentration of wetting agent and antifoam is considered the best (do not overtreat).
The current generation of latex modified binders, special new wax formulations and restrictions on pattern cleaning compounds puts added pressure on the proper selection of a wetting agent and antifoam.
What are these products you have been working with? How effective are they for their intended use? Do they promote stability in the slurry system? This paper is a guide to your better understanding of the products available to the PIC foundry.
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P-34 Titanium Investment Casting, R. Chester Feagin, Presented at the EICF Conference, May 1986
This paper briefly reviews the U. S. patent literature on refractory metal casting, with particular reference to titanium. This paper also describes the preliminary work of the author in the casting of Ti6Al4V alloy into shell molds with casting surfaces having compositions between approximately 100% ZrO2 and 100% Y2O3. It also describes results of casting the same alloy in shell molds embedded in bonded sand and having casting surfaces approximately 100% Y5O, having been formed by various techniques.
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P-35 Understanding the Shell Room Process, Craig T. Lanham, November 1994
Producers of metal products, whether cast, fabricated, forged, or machined, spend more time than they would like analyzing the cause of defects in their products. The characterization of these defects is considered to be a critical step in lowering scrap rates and improving practices, processes, and the foundry’s bottom line.
A discussion of pattern production and preparation, shell room production environments, shell room process control, and offers suggestions, recommendations and references.
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P-36 Using Stucco More Effectively, Charles H. Matzek, February 1988, Modern Casting
A proper stucco program is essential in order to successfully make a shell which will yield a high quality investment casting. The stucco program involves the choice of the proper stucco size for each coat, using stucco materials which have a tightly controlled particle size distribution and proper maintenance of the stucco application equipment.
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P-37 Water Quality and Colloidal Silica Slurries, Craig T. Lanham, August 1992
As the foundryman’s interest in reducing manufacturing costs through improved shellroom process control has increased the subject of water quality has become increasingly important. All too often there are unanswered questions about the level of water quality needed to properly make and control water based shellroom slurries. Once water quality is defined the foundry is then confronted with the question of how to meet this need in the most convenient and cost effective way.
No water source is completely pure. Every source, whether industrial, commercial, or natural, contains dissolved solids or contaminant salts. These dissolved solids conduct electricity. This conductivity allows us to measure the concentration of these contaminants. The measurement, in parts per million, is referred to as a measurement of Total Dissolved Solids (TDS) and is measured by Specific Conductance in Micromhos or Specific Resistance in Ohms.
There are three major water treatment processes in use today to produce high purity water; Distillation, Reverse Osmosis and Deionization. Depending on the water volume and the level of quality required these systems may be used separately or in conjunction with each other.
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P-38 Cobalt Aluminate Levels in Primary Slurries, Manuel Guerra and Jeffrey C. Niles, presented at the Investment Casting Institute/World Conference, San Francisco, CA, 10/14/96 by Manuel Guerra, Technical Manager
Cobalt aluminate from Shepherd Color Company was evaluated for its effectiveness as an inoculant for investment cast alloys. Various levels of cobalt content (of the cobalt aluminate) and percent cobalt aluminate in the primary slurry were tested. The results are presented in this paper.
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P-39 Casting of Reactive Alloys: An Update of Current Technology, Charles H. Matzek, June 19, 1997. Presented at the Cannon-Muskegon Technology Conference in Conjunction with The Paris Air Show (Same as P-4)
Casting quality is an important issue to all foundries. The quality of the casting is, at best, only as good as that of the wax pattern. Nothing used in the investment casting process stands by itself from the standpoint of affecting the final quality. Eery component used in the process – the wax, the pattern cleaner, the face coat binder and refractories, the backup binders and refractories, the metal, the crucibles and transfer ladles – interacts with and is affected by the other components. Process controls or, more often, the lack of proper controls has additional impact on quality. Everything the foundryman does in his selection of process conditions, processing controls and raw material selection is directed towards keeping the quality of the finished casting as high as possible. These issues are especially important to those foundries casting reactive alloys. Reactive alloys add another dimension to the problem because the foundry must now have face coats, cores and crucibles/transfer ladles which will not react with the metal during melting, transfer, pouring and cooling.
REMET CORPORATION has had a long term interest and involvement in the development of face coats for use with reactive alloys. Research in this has resulted in numerous papers and Patents. This area of research continues to be actively pursued by REMET CORPORATION today. The purpose of this Paper is to provide a summary of what has been done as well as to provide an overview of those areas in which REMET CORPORATION continues to be active. This presentation is not meant to provide a “recipe” which a foundry can follow. Conditions vary too much for that to be a practical goal. Rather it is most important that each of you in the audience realize that this is an active area and that there are resources available to you to help you be successful.
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P-40 Slurry Development and Control, Julian G. Kovacs, August 1997
Most foundries' success is dependent on the foundry men's intelligent choice of materials to their shell development and on the particular control of the variables in the process that they have established in their operation.
This paper attempts to provide some guidelines to the foundry men about the material selection available for making reliable slurries and to assist them in setting up control parameters for the slurry process. Some practical suggestions about mixing slurries and drying shells will also be included.
The selection of binders, refractories and other components of slurries will be discussed. Slurry preparation, mixing, maintenance and testing will also be reviewed.
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P-41 The Effect of Particle Size of Fused Silica Flour on Shell Properties, Jeffrey C. Niles, September 1997
Presented at the ICI 45th Annual Technical Meeting, Atlanta GA, September, 1997
This study evaluated the effect that particle size of fused silica flour has on shell properties. Three different flour sizings were tested (-120, -200 and –270 mesh sizings) with REMASOL SP-30 colloidal silica (diluted to 26% silica solids) and both fused silica stucco (30 x 50 mesh) and aluminosilicate stucco (20 x 40 mesh). The test results include green, hot and fired MOR, hot permeability, thermal expansion and high temperature creep.
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P-42 Comparison Of Properties Of Zircon/Alumino-Silicate Shells With Water-Based And Ethyl Silicate-Based Binders, Manuel Guerra, Jr. , Presented at the 24th EICF Conference in Rome, Italy, May 1998
Two polymer-enhanced, colloidal silica binders (both large and small particle sols) were compared against an alcohol hybrid binder system. The three binders were used with a Zircon and 60% alumina, alumino-silicate flour blend, with Molochite stucco. All of the systems were tested for:green MOR, hot MOR, fired MOR, high temperature creep, and thermal expansion. The hybrid binder had the highest overall MOR strength, but some of this difference could be due to the processing conditions (50-55% RH), which were somewhat more favorable to an alcohol system. There were only minor differences in the creep and thermal expansion results.
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P-43 Investment Casting Analysis Past, Present and Future, A. Barker, M. Sc, Dussek Campbell Ltd. , Crayford, Kent, U. K.
Investment casting analysis has expanded from the use of the human eye and evaluation of waxes by ashing, to the use of light microscopy and, now, electron microscopy (for photography and e