Understanding The Practicality Of Hardness Tests In Materials Production Processes

Hardness Tests

You may have heard of hardness tests in quality control processes. Hardness tests can tell quality control officers a lot about a product. It offers insights into the flexibility, strength as well as the durability of a product. Hardness tests are performed on all types of products including raw materials and finished products. Hardness testing is easy to perform and is usually non-destructive. The test does not require major alteration to the product and advancements in technology mean that modern instruments give highly accurate readings.

How Hardness Testing Has Changed

In previous years, scratch tests were conducted to determine the hardness of a part. The testing was based on an object that had increasing hardness from one point to another. Testing was done by having the part being tested scratch various points of the bar. The level at which the part could produce a scratch on the object determined its hardness. As industries progressed, quality control officers began to use diamonds and even steel balls to determine how hard an object was. Regardless of which method, these approaches were slow and were not suited for the high-pressure demands of modern industries. For this reason, more refined instruments were developed to measure the hardness of a product.

Modern Methods of Hardness Testing

There are a variety of hardness testing approaches today. Some of these include the Rockwell Method as well as the Knoop approach. Rockwell works best with metals and alloys and is favored for the quick results that it produces. On the other hand, the Knoop approach works best for thin materials and coatings. Some hardness measuring instruments can give results very quickly and are highly portable. Modern hardness instruments leave an indentation that is so tiny that it is almost unnoticeable or does not affect the functionality of the product. For instruments that leave a much larger indentation, the indentation mark can always be sanded out so that it is not noticeable at all.

How Hardness Tests are Done

Various tests use different approaches to measure hardness. For example, the Rockwell hardness test process relies on making a small indent on the part being measured by applying a relatively small load on the indenter. This helps to establish the zero-datum position. Once this is done, a bigger indentation is made using a larger load. The difference between the first indentation (depth) and the second helps to establish the required reading. Typically, the process makes use of a diamond cone for testing metals and tungsten is used to test softer materials.

Importance of Hardness Testing

Tests done on the hardness of a material helps to determine the structural integrity of a product. This, in turn, helps manufacturers know whether the product will perform as expected in the market. We can thus say that hardness tests help consumers to use products safely and for long by helping eliminate those that are structurally unsound.

For the best in precision instruments, get in touch with Willrich Precision. We have over 45 years of experience in delivering hardness testers to customers all over the United States.

by George Chitos

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