“Hardness” is a concept we use every day to compare objects: fresh bread vs. stale bread, a baseball vs. a softball. In manufacturing the definition is a bit more specific: hardness is a measure of a material’s ability to resist localized scratching or deformation by indentation at a specific loading location.
Our understanding of hardness and relative hardness between materials is key to manufacturing metal products. The correlation of hardness with other mechanical properties also makes it possible for us to predict, with a high degree of accuracy, the strength and ductility of a material without submitting it to destructive testing.
Past civilizations had practical reasons for caring about metal properties. They asked questions like “Can I break my enemy’s sword before he breaks mine?” or “How thick does my armor need to be to provide enough protection?” These warriors had a vested interest in material strength.
In previous installments of our series on Metal Properties, we’ve discussed characteristics that set metals apart from one another, as well as those that distinguish them from other nonmetallic elements. Conductivity represents an array of essential features that go to the very heart of what defines a metal. In this article we will be asking: what are the factors affecting the conductivity of metals? What are the most thermally and electrically conductive metals, and why does conductivity matter for manufacturers?
All materials possess some degree of conductivity. One of the main characteristics of metals is their ability to conduct heat and electricity, so metals are all relatively conductive compared to non-metals. However, even within metals you’ll find a broad range in levels of conductivity. A sound knowledge of where various metals fall on the spectrum helps manufacturers choose the right alloy for each product.
Corrosion is a common challenge affecting the surface of most metal parts. While corrosion often only affects the aesthetics of a metal part, severe corrosion can affect performance and can even lead to equipment failure. Corrosion is such a widespread challenge that the global cost of corrosion is estimated to be $2.5 trillion annually, according to a study by the National Association of Corrosion Engineers (NACE).
Here we explore many of the ways corrosion can manifest in a material, and the techniques manufacturers use to prevent corrosion from affecting part performance.
In the metal manufacturing industry, mechanical properties play a huge role when choosing the right alloy for each job. Throughout casting and machining processes, as well as during the product's useful life, the chosen material will be subject to many external forces. It’s up to the manufacturers to create products that perform as needed every step of the way. By understanding mechanical properties, manufacturing professionals can make the right choices for materials and processes.
Physical properties are an important way of distinguishing one material from another. In the study and application of metallurgy, physical properties are often considered a broader category than mechanical properties, but not all properties overlap. Physical properties are most easily distinguished from mechanical properties by the method of testing. While mechanical properties require forces to be applied to obtain a measurement, physical properties can be measured without changing the material.
Metals are all around us, in the things we use to cook, drive, work, and live. When choosing a metal for a cast product or other specific application, it’s important to make sure that its properties will be suitable for the expected operating conditions.
There’s a big difference between the kind of metal used in a skyscraper and the kind of metal used in a gate valve. Some metals are pure elements, like iron (Fe) and aluminum (Al), but most products are made from alloys, or mixtures of metals. Manufacturers must consider many variables before deciding which alloy to use for a particular product.