July 26th, 2023

Unlocking the Power of Alloys: Enhancing Materials for High-Temperature Applications

In the quest for materials that can withstand extreme conditions, engineers and scientists have turned to the fascinating world of alloys. From stainless steel's corrosion resistance to brass's malleability, alloys have become indispensable in various industries.

For high-temperature environments, refractory anchors are essential in supporting and stabilizing refractory materials. Choosing the right alloy for these anchors ensures their longevity and effectiveness in harsh conditions.

Join us as we explore the key considerations when selecting the best alloy and delve into the world of heat-resistant materials to optimize refractory anchor performance for your specific needs.

What is an Alloy?

An alloy is a mixture of two or more elements, with at least one of them being metal. Some well-known examples include stainless steel, which contains chromium to resist corrosion, and brass, an alloy of copper and zinc known for its malleability.

Alloys are created to enhance the properties of the individual elements, making them more useful for specific applications. The properties of an alloy differ from those of its constituent elements. The resulting material often exhibits a combination of desirable characteristics that the pure elements don't possess on their own. By mixing metals, it's possible to obtain alloys with improved strength, hardness, ductility, corrosion resistance, and other desirable attributes.

Refractory Anchor Alloys

Refractory anchors are used to hold refractory materials in place, providing stability and support in high-temperature environments. The choice of the best alloy for refractory anchors depends on the specific conditions and requirements of the application.

Choosing the best alloy for refractory anchors will depend on factors such as operating temperature, chemical environment, mechanical stress, and other specific requirements.

It's essential to select the most appropriate alloy to ensure the refractory anchors can withstand the conditions they will be exposed to during their service life. Additionally, proper design and installation of refractory anchors are crucial to maintaining the integrity of refractory linings in high-temperature applications. With 42 years of experience in the refractory anchor industry, we can help you choose the best alloy for your application.

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Choosing the Right Alloy: 5 Things to Consider

1. Environment
Select a group of alloys that offer adequate stability and resistance to the environment, at the maximum expected temperature.

Never select an alloy using temperature as the only guide!

Rule of thumb for alloys with resistance to oxidation:

  • Minimum chromium content 20 percent

  • Addition of silicon and rare earth elements

Rule of thumb for alloys with resistance to sulfidation:

  • Minimum chromium content 20 percent

  • Maximum nickel content 14 percent

2. Cyclic Conditions
For cyclic conditions, select a group of alloys having low coefficients of expansion and good oxide adherence. Many heat-resistant alloys have relatively high coefficients of expansion. Repeated expansion and contraction increase oxidation due to flaking of the normally protective oxide coating, and shortens the fatigue life because of thermal stresses created.

Rule of thumb for alloys with resistance to spalling and severe thermal cycling:

  • Fine-grained structure

  • Minimum chromium content 18 percent

  • Minimum nickel content 30 percent

3. Strength
Select those alloys offering the required strength and ductility at the maximum temperature to be encountered.

Various heat-resistant alloys offer different characteristics of strength and ductility at high temperatures. The strength and ductility required will depend upon the amount of creep or deformation under load that may be tolerated, the life expectancy desired, and the loss in physical properties that are expected due to changes created by the environment. Also, alloys that creep freely will flake off the protective oxide and become susceptible to further oxidation.

Rule of thumb for high-strength alloys:

  • Minimum nickel content 30 percent

  • Course-grained structure or alloy with C, Nb, W, Co, Mo

  • Small additions of rare earth elements

4. Melting Point
Select a group of alloys that will not melt at the maximum expected temperature and allow possible changes in chemical composition caused by the environment.

Heat-resistant alloys have a difference in melting temperatures of 150°C or more. Published melting points are the liquid temperatures, and incipient grain boundary melting may occur at 40-80°C less. Absorbed contaminants may decrease the solidus temperature by 75-125°C.

Rule of thumb for high-melting points alloys:

  • Maximum nickel content 40 percent

  • Minimum chromium content 25 percent

  • Maximum carbon content 0,06 percent

  • Minimize alloying with strengthening elements

5. Testing
The given data should not be considered as guaranteed maximums or minimums. We recommend that the material be tested under actual service conditions to determine its suitability for a particular application.

From the group of alloys that have been selected so far, the final choice of one or two can be made based on cost, availability, ease of fabrication, and the expected service life.

It may be desirable to use a more costly alloy if its increased strength permits a reduction in cross-section to minimize thermal stresses, or if its resistance to the environment is greater so that less metal is needed for loss due to corrosion.

In comparing final costs, the labor of fabrication should be included and not only the metal cost. The more costly, alloys seldom require more labor than the lower-priced materials. An increase of 100 percent in the raw material may result in an increase of only 60 percent in the fabricated item.

Technical data illustrating the properties of heat-resisting alloys are very helpful guides in selecting a suitable alloy for a given application. However, the behavior of alloys during long exposure to the many environments and temperatures that may be encountered cannot be completely documented nor charted. Experience obtained from actual installations is most helpful.

Good to Know
SILICON can supply a wide range of high-temperature alloys such as 310, 330, 800, 601, and 625, which are available in various shapes, including round bars, flat bars, plates, and round wire. We also provide metallurgical consultancy to help you choose the best solution for your industry. These alloys work perfectly with our Rapid Arc Welding (RAW) machines and guns, the fastest, safest, and highest quality alternative to stud welding technology. We do our own Positive Material Identification (PMI) testing in-house to determine the chemical composition of a metal or alloy. This means that we are able to check all the stainless steel materials used in our manufacturing from arrival at the warehouse as raw materials to dispatch as end products.

In addition, we supply conformance certificates 3.1 which contain the chemical and mechanical composition of the material used to manufacture the anchors.

Our quality standards ensure that you will receive what you ordered.

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