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Green Sand Metalcasting Foundry News

Intro to Green Sand Casting Foundries

Posted by Hill and Griffith Company on Feb 18, 2020 8:00:00 AM

Article excerpt from the TheMetalCasting.com.

Foundry sand is used for making castings, and is primarily generated by the automotive industry and its part suppliers. It consists of clean silica sand, which is of high quality; or lake sand, which is bonded to make molds for ferrous (iron and steel) and non-ferrous (copper, aluminum, brass) metal castings. The following types of sands are used for making molds in the foundry industry: Green Sand, Resin Coated Sand, Molasses, Cold Box Sand, Hot Box Sand, and CO2 Sand.

These types of sand can be obtained directly from the foundries located in the Midwest states such as Illinois, Wisconsin, Michigan, Ohio, and Pennsylvania.
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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Green Sand Foundry Supplies, TheMetalCasting.com

Cast in Place: Integrating Non-Cast Components into Castings

Posted by Hill and Griffith Company on Feb 11, 2020 8:00:00 AM

Article excerpt from the August 2017 issue of Modern Casting by Geoffrey D. Korff and Travis B. Stewart.

Steam turbines are built using a variety of castings ranging from standard class 25 gray iron to 400 series stainless steels. A typical single-stage turbine can contain up to 21 castings of different variations for the base design, while a typical multi-stage turbine can contain 30 castings or more. This does not include any castings that would be used for add-on equipment, such as trip and throttle valves and aftermarket governors or for other equipment on the equipment train.

The casting material is determined based on the temperature, pressure, environment, and steam conditions for the turbine application. In many cases, casting materials are interchangeable depending on these factors. For example, iron castings may be used in some applications for their thermal properties and ductility/dampening, while stainless steels may be used in other applications where it is needed for corrosion resistance. Material selection is important not only for the operation of the unit, but also for servicing the unit. Depending on the operating temperatures, there may be requirements for J-Factor calculations to avoid embrittlement in the time vs. temperature designs. Charpy impact testing may be required for low temperature service. For turbines, this is mostly environment-based and not dependent on operating temperatures.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Modern Casting Magazine

Large Format Additive Technology Reinvigorates Green Sand Casting

Posted by Hill and Griffith Company on Feb 4, 2020 8:00:00 AM

One of today’s newest technologies helps re-invent one of the oldest industrial techniques in the manufacturing of heavy machinery and tools.

Article excerpt from the Design World January 2020 issue by Leslie Langnau.

At JC Steele (a global leader in stiff extrusion machinery and solutions for customers in heavy clay, iron and steel, ferro alloys, and gypsum/wallboard) large-format Additive Manufacturing (AM) has been paired with traditional sand casting. The company uses a BigRep ONE 3D printer to develop, test and create the patterns needed for sand casting molds.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Design World

Predicting, Preventing Core Gas Defects in Steel Castings

Posted by Hill and Griffith Company on Jan 28, 2020 8:00:00 AM

Modeling and analyzing core gas evolution and metal solidification behavior can aid in the prediction and prevention of porosity caused by core gas.

Article excerpt from the Modern Casting September 2014 issue by L. Xue, M. Carter, A. Catalina, Z. Lin, C. Qiu and C. Li.

Porosity is a common but serious casting defect. One type of porosity is a result of core gas that has evolved and become trapped in the casting during solidification. Detailed information is needed to reduce or eliminate core gas-related defects regarding the core gas generation, flow and venting in the core, and the metal flow and solidification behavior in the mold. In a recent study, numerical simulations were conducted based on a prototype design for a steel casting for Caterpillar. Core gas and porosity defects calculated in the simulations were analyzed and compared with the real casting results.

The gases dissolved during solidification can be caused by hydrogen or nitrogen in the initial liquid or core gas decomposed from the sand core and vented to the liquid, and they play a major role in porosity formation in castings. For all the analytical models developed to predict porosity defects in castings, most are based on tracking the evolution of dissolved gases in the initial liquid. Due to the complicated physics involved, modeling the core gas evolution in castings is difficult. However, without the consideration of core gas, predictions of porosity defects are insufficient.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Modern Casting Magazine

Printing Long, Thin Cores for Aluminum Sand Casting

Posted by Hill and Griffith Company on Jan 21, 2020 8:00:00 AM

While the use of printed sand molds and cores has become increasingly common, two researchers investigated whether longer, thinner cores could hold up during the metalcasting process.

Article excerpt from the Casting Source November 2015 issue by Tom Mueller and Larry Andre.

One of metalcasting’s major advantages, when compared to other methods of manufacturing, is its ability to produce geometrically complex components. Metalcasting allows designers to put metal only where it’s needed because liquid metal can flow into the open mold cavity. Often, cores are placed into a mold to form an interior part of a casting. These inserts, often made of sand, prevent the molten metal from filling the entire mold, so interior cavities can be included in the casting design.

In recent years, the growth of 3-D printing capabilities has become a topic of interest for every manufacturing industry. In metalcasting, the process offers the potential of producing complex molds and cores with desirable mechanical and physical properties. Printed cores and molds allow for immediate evaluation of design iterations without the additional costs and lead time associated with tooling, which speed the development of cast components for end users.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Casting Source Magazine

Optimizing New Sand and Core Sand Additions in Foundry Green Sand Systems

Posted by Hill and Griffith Company on Jan 14, 2020 8:00:00 AM

The old rule for new/core sand additions is 300 lbs. per ton of metal poured, but that approach needs to be re-evaluated (and made more exact) for current molding methods and materials.

Article from the Foundry Management & Technology August 2005 issue by Mark Ziegler.

In order to understand the effect of core sand and the various binder systems on green sand properties and castings, the new sand's contribution to the dilution must be established. The objective of this research is to create a model where different amounts of new sand and core sand are added to system sand so that the green sand's properties and casting results can be evaluated. Initial work by the Green Sand Committee of CISA has shown that certain levels of new sand can be added, along with new clay/additives, to maintain consistent green sand properties. The study also found that there are critical levels where major changes in the green sand properties occur.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metal Casting Design & Purchasing

Nobake: The Basics

Posted by Hill and Griffith Company on Jan 7, 2020 8:00:00 AM

Dozens of chemically bonded sand molding methods exist, but they can be divided into three main categories: coldbox, heat-activated and nobake.

Excerpt from the Metal Casting Design & Purchasing January/February 2018 issue.

The basic principle is that a binder and catalyst are mixed with the sand to help form the mold into a “brick-like” product when cured. The differences in the process focus on the sand resin binder and catalyst used and how the mold or core is cured.

Coldbox—with this method, sand is coated with one of several binders, such as liquid sodium silicate or phenolic urethane, and catalyzed by a gas (such as carbon dioxide or sulfur dioxide) passing through the sand. This causes the resin binder to harden (cure) and lock the sand grains in place to maintain a solid mold wall.

Heat-Activated/Shell (also called hotbox and warmbox)—heat is used as the curing means in shell molding. Plastic resin-coated sand is compacted around a pattern and allowed to rest until a “shell” forms. The mold then is heated to temperatures higher than 500F (260C) to cure the mold.    

Nobake (also called airset, dry sand and precision sand)—like coldbox, several binders are optional. However, a liquid catalyst is used. The sand is processed in a continuous mixer and then formed around the pattern until it is fully cured.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metal Casting Design & Purchasing

Selecting the Right Green Sand Heater

Posted by Hill and Griffith Company on Dec 31, 2019 11:28:39 AM

For foundries that prepare chemically bonded sand for molds and cores, optimizing the process means understanding and evaluating the primary features and options for water-based and electric-resistance systems.

Excerpt from the Foundry Management & Technology Magazine February 2019 issue by Jack Palmer

In general, there are two types of sand heaters used to prepare chemically bonded sand for molding and coremaking, and both are designed as fluid bed processes — meaning the sand is moved around the heating/cooling elements with compressed air or blower air. The more popular style is the electric-resistance fluid bed with compressed air fluidization, followed by water-pipe units in which hot or cold water is passed through piping, with fluidized sand moving around them with blower air.

The popularity of the electric-resistance type heater is due primarily to cost (compared with water-pipe designs) and size. The electric-resistance units are much smaller than the water pipe-based designs, though both offer advantages.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Foundry Management & Technology magazine

Smooth Moves: Sand's Impact on Surface Finish

Posted by Hill and Griffith Company on Dec 24, 2019 8:00:00 AM

Different Types of Sand Molds and Cores Used by Your Supplier Will Impact the Surface Finish of Your Castings.

Excerpt from Casting Source Magazine Jan/Feb 2016 issue

For many casting buyers, a smooth, uniform surface finish is more than a visually appealing bonus. It can be a sign that the casting supplier has produced a high-quality component. Perhaps more importantly for the casting buyer, a proper surface finish can lead to eventual cost savings in the cleaning, finishing and machining of the part.

Castings produced in sand molds can have relatively smooth surfaces, but if need be, the baseline surface finish can be improved through various means, though such gains will come with additional costs. Discussions with casting suppliers can help buyers understand potential solutions and associated costs.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Casting Source Magazine

Semi-Permanent Release Agents for Cold Box Core Production

Posted by Hill and Griffith Company on Dec 17, 2019 4:42:37 PM

Posted to Metalworking World Magazine Jan. 16, 2017

There are several different types and formulations for release agents used in the cold box process. In highly stressed areas of the core box, traditional release agents do not function well. A new resistant release coating based on novel technology that adheres to the core box has been developed and introduced into foundry production to combat resin wipe-off. Trials were run, monitoring the number of cycles before the release coating needed to be re-applied. Data is presented from the trials. The testing shows the coating to be effective up to several hundred or even thousands of cycles between applications.

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Tags: Green Sand Casting Products, Green Sand Foundry Supply, Foundry Supply, Green Sand Release Agents, Foundry Supplies, Metalworking World Magazine

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