Durometer: uses, prices, characteristics, types …

November 2, 2021

Among the many materials that we find in laboratories we have the Dosimeter , Desiccator and in this case the Durometer . The latter being the one we will focus on below.

History of the Durometer

The first Durometer that was invented was by Albert Shore, a metallurgical engineer of American origin who was born in 1876. His invention received the name of the scleroscope, which by means of a hammer with a diamond peak inside a glass tube, which falls 10 inches from the material to be tested.

This process produced a rebound in the hammer, which could be measured by means of the Shore scale. In 1900 the first Durometer as we know it today was created. This creation was by the hand of the metallurgical engineer Johan August Brinell .

However, in the 18th century scratch tests were started to determine hardness. This allowed the development of tests in which the width of the mark left by a diamond was measured. Being Brinell the one that would create a first instrument of a measurement of the hardness.

It is important to mention that with the industrial revolution it became necessary to create an instrument that will allow to measure the hardness of materials. Due to this, new tests such as the one developed by Robert Smith and George Sandland in the British company Vickers began to be created .

For the year 1912 the brothers Hugh and Stanley Rockwell, took as a base the indentation test of Paul Ludwik , to devise the Rockwell hardness tester. Thanks to this experiment, the use of this was made much easier, since it gave much more direct measurements. To all this it is important to mention that the patent for this product was obtained in 1919 and another in 1924 for another tester with improvements.

With the passage of time, reaching 1939, another durometer was created for much more fragile materials based on the vickers scale. Thanks to this, Fredrick Knoop modified the shape of the diamond using an elongated shape, which had a shallower depth, which allowed the Knoop scale to be established.

Then by 1950 Instron included the closed loop system as a way to measure electronics. Specifically, an electronic form is used to measure the force that could be applied in tensile tests. But also to forward this information to later adjust the production equipment.

It is important to mention that since its inception this instrument has been undergoing modifications. Even today these arrangements and advances in these equipment are increasingly necessary. So the changes and improvements to continue automating the process are very important.

What is the Durometer?

In simple terms, a Durometer is a measuring instrument, which indicates the hardness of a material , all in order to know how resistant it is. It can be used on a wide variety of materials, from soft to those that are harder.

To this it is important to add that there is not a single type of Durometer, but there are several types which will depend on the material that is going to be used. However, the function of each of them remains the same, which is to determine the hardness of a material.

It is important to add that this instrument was originally designed to work on the MOHS scale . However, by the nineteenth century such a scale of measurement would not be very useful.

Durometer Parts

This laboratory instrument is composed of two parts, which is the body and the penetrating element or indenter . Being the body the one that generates the force that will be applied in the material to be tested. In the case of the indenter or penetration element, it works to leave a mark or mark on the object to be tested.

It is important to add that the element used to penetrate will depend on the marking method that you decide to use. We can say that the parts of this instrument can be divided as follows;

  • Rotating body.
  • Hardness dial indicator.
  • Analog scale indicator.
  • Hard and rigid steel flat support.
  • Scale adjusting device or screw.
  • Side lever to manage the main load.
  • Rotating or winch handle to raise the stand and also manage initial load.

To all this we must add that the parts of this instrument will depend on the model and the advances that have been made to it. For example, there are some more advanced ones that have a digital display or screen , electrolytes and other parts.

What is the Durometer for?

As we have been mentioning, this instrument is used to measure the hardness of a material . Which is achieved by means of an element that allows the penetration of the same, which leaves a mark of depth.

With this in mind we can say that this apparatus is used in fields such as the pharmaceutical industry and the construction industry . In the first one, it is used to calculate the resistance of the processed material. This is done in order to verify that they can support the process for which they will be intended.

If we talk about the construction industry, to determine the hardness of materials for the construction of a structure, building, electronic device, ceramics, and a wide range of other materials.

To all this it is important to add that the materials most subject to this test are metal and those materials used in the construction process . This is important, as it allows you to verify that they meet the necessary safety and quality standards.

How does the Durometer work?

The function or use of this instrument is not complicated at all, since it only consists of selecting a material. Then the force that will be applied by means of the penetrating element must be standardized .

Once this is done, the result of the depth or size of the hardness will be determined, taking some of the hardness numbers. It is important to note that these instruments can work with different scales, for example the Mohs hardness scale , where the determined values ​​are made from 1 to 10.

Being by means of the footprint and the previous scale that the resistance or not of the cut of the surface of the material to be analyzed can be determined. In this sense, the softer the material, the deeper the footprint will be.

To use this instrument correctly, it must be placed in a vertical position on the material to be measured. The specimen is then located where the test will take place. It is important to bear in mind that the disposition of the material to be measured must have a diameter greater than 6mm.

After this we must exert pressure on it without letting it collide with the sample. We must observe the material steadily until the contact surface is applied on it. Finally we must read the result and if necessary we can use the resistance indicator .

Types of Durometers

Specifically, we can say that there are three main types of Durometers, however we can also find many more. In more detail we can say that the different types of hardness meter that exist are;

Durómetro Shore

In this case we are talking about an instrument defined by Albert Shore in 1920. As we mentioned before there are several scales and in this particular case we have that the most common for this device is A and D. With A being used for white plastics and D for harder samples.

Leeb Durometer

This type of hardness meter is characterized by leaving a smaller footprint than the rest of the durometers. Because of this it is mostly used to read the energy loss on a defined impact after hitting the sample.

Basically the device generates an initial impact, and then when the material is struck, impact energy is lost. Being this loss of energy the one that is measured, to later convert it into a hardness measurement.

Durómetros Rockwell

In this case we are talking about an instrument designed to measure any metal or alloy. The latter can be both hard and soft materials . It works by exerting a small load. Which will increase the accuracy of the measurement and then exert a much higher load.

It is important to mention that at present this machine has the ability to automatically calculate the hardness of the material.

Durómetros Vickers

The main principle is to observe the resistance that the material has to deformation. When we have the resulting fingerprint, it is measured by means of a built-in microscope and the HV or DPH hardness is transformed using a formula.

We should mention that this type of hardness tester has an image analyzer through a computer. Thanks to this, it is possible to analyze the location of the footprint, carry out the operations of the hardness values ​​and graph the information obtained.

Brinell Durometer

The Brinell Durometer is the one that uses a hard spherical indenter, together with a constant load. In this way, it is possible to measure the diameter of the fingerprint with a microscope and it is converted to a specific HB number using a formula.

Durómetros Button

In this case we are talking about an instrument very similar to that of Vickers. Only this needs a much smaller sample in the material to determine the hardness of it.

Dr. Loony Davis5
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Born and raised in Brussels in an English family, I have always lived in a multicultural environment. After several work experiences in marketing and communication, I came to Smart Water Magazine, which I describe as the most exciting challenge of my career.
I am a person with great restlessness and curiosity to learn, discover what I do not know, as well as reinvent myself daily, someone who is curious about life and wants to know. I enjoy sharing knowledge.
This is my personal project but I also collaborate in other blogs, it is the case, the most important web on water currently exists in the US, if you are interested you can read my articles here.

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