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FROM THE DESK OF THE METALS EXPERTS

Welcome to the MetalTek Blog.

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.

What Are Ferrous Alloys?

Posted by Dave Olsen on 12/27/19 9:23 AM

Ferrous metals or alloys are metals that consist mostly of iron (Fe). Steel is an iron-based alloy containing typically less than 1% carbon, where iron frequently contains 2% or more carbon. Iron and steel are widely available, strong, cheap, and can be shaped by casting.  Their mechanical properties can be improved by heat treating and, in the case of steels, by working (i.e. rolling or forging). Stainless steels were developed to resist corrosion and generally contain 12% or more chromium, and may contain nickel in any amount up to or even exceeding the chromium content based upon the mechanical properties desired and application.

There are several types of stainless steel. When considering these alloys for use in a corrosive environment, the most widely used method for initial selection is to compare PREn ratings (pitting resistance equivalent number) across materials.  This is calculated using the weight % of key alloying elements present in any particular grade of stainless steel. The formula is:

                                                                PREn = % Cr + (3.3 x % Mo) + (16 x % N)

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Topics: Ferrous Alloys

Copper Based Alloys - An Overview

Posted by Dave Olsen on 12/26/19 10:39 AM

Depending on which copper alloy you chose, you can achieve the strength of steel, superior corrosion resistance and/or durability in applications that require wear and galling resistance. But first, let’s differentiate between brass and bronze, because in some quarters of industry, the terms are used interchangeably.

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Topics: Copper Based Alloys, Non-Ferrous, Bronze

What Is Aluminum Bronze?

Posted by Dave Olsen on 12/19/19 10:12 AM

Aluminum Bronzes are a family of copper-based alloys that use iron and nickel in their chemistry - but rely on aluminum as the principle alloying element. Aluminum significantly adds to the strength to the point that it is similar to that of medium carbon steel. The additional advantage is that aluminum bronze also possesses excellent corrosion resistance.  It is that strength and corrosion resistance that gave rise to the early use of aluminum bronze.

A small adjustment in metallurgy causes significant changes in performance. This recognition of other properties has led to the use of Aluminum Bronzes for a variety of parts requiring strength, hardness, resistance to wear and galling, low magnetic permeability, resistance to cavitation, erosion, softening and oxidation at elevated temperatures.  These properties, together with ease of weldability, have greatly extended the fields of application for Aluminum Bronze.

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Topics: Copper Based Alloys, Non-Ferrous, Bronze, Aluminum Bronze

4 Real Life Examples Of Solving A Heat, Wear, Or Corrosion Problem

Posted by Dave Olsen on 12/16/19 2:32 PM

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.
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Topics: Alloy Selection, Corrosion Resistance, Wear, Casting Process, Conversion, High Heat

5 Examples When Castings Were Better Option vs. Fabrication or Forging

Posted by Dave Olsen on 12/10/19 4:36 PM

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.

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Topics: Investment Casting, Sand Casting, Centrifugal Casting, Continuous Casting, Process Selection, Casting Process, Lost Wax Casting, Conversion

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