While metal casting might be the best process to manufacture a wide range of components, depending on your needs, a forging could be the best option. Or vice-versa. Here are 5 things to consider when deciding if a casting or forging is right for your component, application, and overall needs.
Which casting process should you use to manufacture your metal part? This is a common question when customers develop a new component or are considering making a switch to metal castings from a fabrication or forging. Partnering with a supplier that brings a full range of metalworking processes lets you be confident that you are getting the best metalworking advice and not just being sold on an idea because it is the only answer a supplier has.
In this article, we will cover various casting processes you might select based on your product design and needs in a simple, bullet point format.
NOTE: This article assumes you have a basic understanding of various casting methods. More specifically, sand casting, investment casting, and centrifugal casting.
Investment Casting (Lost Wax Casting)
Factors such as design requirements, cost, and feasibility to manufacture dictate which casting process is most suitable to manufacture a product. This article describing investment casting is intended to help you make an informed casting decision.
Investment casting produces precise components while minimizing material waste, energy, and subsequent machining. It can also ensure the production of very intricate parts. This makes the investment casting process quite useful to design engineers.
The goal is to understand what is meant by investment casting. So, What exactly is the investment in “investment” casting? The term “invested” historically carries the meaning of “clothed” or “surrounded.” Investment casting employs a shell made of ceramic, plaster, or plastic that is formed around a wax pattern. The wax pattern is melted and removed in a furnace and metal is poured into the shell to create the casting.
What is investment casting used for? Let's break down the investment casting production process for a greater understanding:
The days when manufacturers had a host of technical experts on staff are past in many industries. And this at a time when material choices are broader and product performance demands are higher than they have ever been. So the situation will not get any easier. Here are just four real life examples where MetalTek International helped a customer's heat, wear, or corrosion problem.
If you have a question about alloy selection, if you manufacture products that operate in harsh corrosive, high wear, or extreme temperature environments, or if you are simply looking to improve product performance, contact MetalTek.
#1.) Bearium Solves Load and Friction Problems in Mobile Crawler
From the days of Apollo program through the Space Shuttle a heavy duty crawler has carried the enormous weight of space vehicles down the one-mile path to the launch pad. Early designs used to carry this load were subject to sudden catastrophic failures of the roller bearings, jeopardizing timing of the launches. The crawler went through an emergency redesign to replace the roller bearings with sleeve bearings manufactured using Bearium B-10, a high-lead bronze that is only available from MetalTek International. Designs using Bearium delivered acceptable performance in an application that would then feature much higher friction. Bearium is used in the space craft crawler application to this day.
#2.) Creating a “Memorial to Last a Lifetime”
Working with architects to create a “Memorial to Last a Lifetime” is no small task. Every step of program management is critical—from materials and engineering, to budget compliance, to execution. Initially, the Pentagon Memorial team approached MetalTek International about choosing the “right” alloy to last 150 years; as various materials were trialed and budgeted, the ultimate selection came down to a restricted-range 316LN (CF3MN-Mod) alloy that would meet the design requirements and still be producible to tolerances such that 184 Memorial Units, each weighing over half a ton and measuring over 12’ (4m) in length, would seem to be “identical.” Specialized tooling, processing and fixtures were developed, trialed, and modified against an aggressive timeline. In the end, MetalTek met the Vision, the Budget, and the Schedule.
Partnering with a supplier that brings a full range of metalworking processes lets you be confident that you are getting the best metalworking advice – and not just being sold on an idea because it is the only answer a supplier has. The replacement of multi-piece weldments or highly-machined hogouts by single piece castings has been proven time and again to be one of the most effective ways to reduce real product cost. Here are just five real-life examples of when the casting process was a better choice for the customer than a fabrication or forging.
#1.) Centrifugal Casting Replaced Complex Fabrication
Controllable pitch propulsion (CPP) systems provide the ability to alter the angle of the ship’s propeller while in use, allowing for different performance during cruising and maneuvering. A centrifugal hub provides the strength and size needed to transfer up to 50,000 shaft horsepower to five attached propeller blades. The hub and 15 other accessories that MetalTek produces for the CPP must perform in corrosive environments for the life of the vessel. Fabrications previously used were very intricate, with multiple pieces and welds, and much machining. The single piece nickel aluminum bronze hub that MetalTek has supplied for 35 years is the largest, most complex centrifugal casting ever produced. The use of a single piece part in this application eliminates welded joints and defects in those fabrications that are only discovered after finished machining.
#2.) Fabrication Could Not Achieve Dimensional Stability
International research, including that done in conjunction with the DOE, strives to create conditions in the lab necessary to support nuclear fusion. Huge machinery, such as the “Z-Machine”, can create temperatures of 2.9 million °F (1.6 million °C) for fractions of a second. Integral components must have the ability to conduct electricity and perform in the machine’s water cooling system. Attempts to use fabrications in those applications were abandoned because dimensional stability could not be achieved. The customer came to MetalTek for a casting solution, a particularly challenging one because of the product’s large size. MetalTek specializes in large investment castings, and now supplies products with better dimensional consistency than was available with a fabrication.