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As your Metals Partner, it is our goal to educate you on various casting processes. Feel free to browse around to learn more but if you have questions or need to submit an RFQ, please contact us. MetalTek International. Because You Demand More Than Metal.

Centrifugal Casting Process: Advantages and Limitations

Posted by Dave Olsen on 7/17/18 10:25 AM

Advantages

Centrifugal Casting Eliminates Mid-wall Defects

  • The centrifugal process does not rely on discrete risers or feed points to ensure the absence of trapped porosity. Rather, the inner diameter remains fully liquid during the solidification process, resulting in a continuous supply of metal to feed areas of contraction.
  • Unlike conventional gravity or static castings that chill from both the inside and outside surfaces and risk trapping mid-wall shrinkage, centrifugal castings solidify from the outside surface inward. The result is a part consistently free of shrinkage cavities, gas pockets, and blowholes.

Centrifugal Casting Controls Impurities

  • Unique to the centrifugal process is the high force that effectively isolates less dense substances in the casting’s bore area. These impurities are later machined away, leaving a defect free part. Molten metal is fed into a rotating mold where a centrifugal force of up to 100Gs is applied to the metal. Centrifugal force is critical for this process. The Gs produced are dependent on the RPM and diameter of the die.
  • The centrifugal force pushes high density metal against the mold sidewall while lower density components migrate or "float" toward the I.D. These lower density items include metal oxides, sulfides, gas, and other impurities that would otherwise have been inclusions in the casting. This phenomenon is termed “secondary refining”.
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Topics: Centrifugal Casting, Horizontal Casting, Vertical Casting, Casting Process

Casting Processes: When To Use Which Method

Posted by Dave Olsen on 7/17/18 10:10 AM

 

There is more than one way to bake a cake. Ingredients, temperature, bake time, and how many you are serving dictate your approach. Making brownies for the third grade class is not the same as baking an elaborate wedding cake for 350 degrees.  The same is true when it comes to selecting a right metal casting process to manufacture any component.  Which process offers the best all-in cost, considering requirements for features, material, quality, and quantity?  

The list of methods to produce metal parts is long, and includes machining/hogouts, forging, fabrication, and more. In this article, we will just discuss various casting processes you might select to make an important component.

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Topics: Investment Casting, Sand Casting, Centrifugal Casting, Continuous Casting, Process Selection

What is Centrifugal Casting and How Does It Work?

Posted by Dave Olsen on 7/17/18 9:46 AM

Overview

Centrifugal casting is a process that delivers components of high material soundness. As a result, it is the technology of choice for applications like jet engine compressor cases, hydro wear rings, many military products, and other high-reliability applications. It has also proven to be a cost-effective means of providing complex shapes with reduced machining requirements and lower manufacturing costs as compared to forgings and fabrications.

In the centrifugal casting process, molten metal is poured into a preheated, spinning die. The die may be oriented either on a vertical or horizontal axis depending on the configuration of the desired part.

By spinning a mold while molten metal is poured into it, centrifugal force acts to distribute the molten metal in the mold at pressures approaching 100 times the force of gravity. The combination of this applied pressure and the engineering mechanics of controlled solidification and secondary refining produces components of superior quality.

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Topics: Centrifugal Casting, Horizontal Casting, Vertical Casting, Vacuum Casting, Solidification, Casting Process

Sand Casting Process: Advantages and Limitations

Posted by Dave Olsen on 7/17/18 9:31 AM

Advantages of Using Sand Casting

Nearly any alloy:  Sand castings can be readily produced in nearly any ferrous or non-ferrous alloy.  Some other casting processes will melt and pour super-alloys in vacuum, but that is not typically done as a sand casting. Some materials cannot be “worked”, and must be produced as a casting.

Low tooling cost:  The relatively low cost of tooling makes sand casting a process of choice for lower volume needs.  Patterns do wear so the material selected for the pattern (typically wood, plastic, or metal) will depend on the expected usage quantity of the part being produced. Though not necessarily cheaper in the short run, the use of machined (or “patternless”) molds may be a cost effective option for components with expected lower usage over a longer period of time.

Versatile – Size, Weight, Shape:  Sand castings can be produced in weights from ounces to 200+ tons.  Through the use of cores, internal structures can be cast in place.  Shaped parts rely mainly on the imagination of the designer.  Most sand castings, however, will need at least some machined surfaces, either because of innate tolerance limits of the process, or the need to mate with other components.

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Topics: Sand Casting, Casting Process

What is Investment Casting and How Does It Work?

Posted by Dave Olsen on 7/16/18 4:30 PM

Investment Casting

Design requirements, cost, and feasibility to manufacture, dictate which metalworking processes (including which casting processes) are most suitable when choosing how to manufacture a product. This article describing investment casting is designed to assist you in making an informed manufacturing process decision.  

Investment casting employs techniques that produce precision engineered components that minimize material waste, energy, and subsequent machining. No other casting method, perhaps other than die casting, can ensure production of very intricate parts. That makes this process quite useful to design engineers.

So what is the investment in “Investment” casting? The term “invested” is not often used this way today, but carries the historical meaning of “clothed” or “surrounded”.  Investment casting employs a ceramic, plaster, or plastic shell that is formed around a wax pattern, into which metal is poured.  

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Topics: Investment Casting, Casting Process, Lost Wax Casting

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