Types of Hardness Test Methods

Updated: 7 days ago

Any material's hardness can be assessed using the Hardness Test, while toughness can be assessed using impact testing. We must first understand what hardness and toughness are before learning about the various impact testing and hardness testing procedures. Two mechanical characteristics of materials—hardness and toughness.

The file test, often known as the trial-and-error approach, is a straightforward way to determine the hardness of steel. The hardness of such a metal can be precisely measured using a variety of contemporary techniques, which are covered in more depth below. Without further ado, let's discuss the many types of hardness testing methods.

Hardness: What Is It?

Steel's hardness is described as a characteristic that prevents piercing and deformation. Steel is more resistant to piercing and deformation the harder it is.

Hardness is the property of a substance that allows it to resist being permanently indented. Instead of being a tangible feature, it is also an empirical test. There are various types of Portable Hardness Testers that can be used to define various fracture toughness for almost the same material. Each test's result should be labelled with the method utilized since it had an impact on it. Since the hardness value and number have no inherent significance and can be used directly as an ultimate tensile value. The rating is only helpful when contrasting various treatments or components.

Testing is frequently used to check and control processes, and the results are used to calculate mechanical qualities like tensile strength. Typically, testing devices equipped with an indenter are used to is gradually incorporated into the test material. Depending on the type of hardness test, the indenter can have a pyramid, ball, or cone shape. Each machine uses a separate load and force application process and records a value of hardness in kg-force according to each scale's specifications.

1. Brinell Test for Hardness

An indenter, typically a carbide ball is driven into the test model for a predetermined amount of time throughout this test, maintaining an accurately regulated force the entire time. When removed, it leaves a circumferential indentation, which is measured to determine the material's hardness in accordance with the formula.

2. Rockwell Test for Hardness

A Superficial Rockwell test is available in addition to the Rockwell Hardness Test. A small load is applied to each test individually. To establish a zero-reference point, pressure is applied either to a steel ball as well a diamond cone force is applied and placed on the test material's surface. The major load is then applied for a predetermined amount of time, and the minor load is applied upon release. The difference in depth between the shift caused by a significant load and also the away from the reference position is called the hardness number. The characteristics of the test sample influence the indenter choice. Although all tests provide three major load possibilities, the Rockwell Requirement applies higher load values than the Superficial Rockwell Test. Due to varied combinations and selections of principal loads, indenters, and scales, more than 30 various plans are used among Superficial Rockwell & Rockwell testing.

3. Test for Knoop Hardness

Utilized on tiny material features that cannot be tested using conventional techniques is the microhardness test. It employs a testing capacity of no more than 1 kg. Similar to the Brinell hardness value, the Knoop is carried out by exerting stress on a rhombus-shaped indenter over time. The imprint is measured with great care, and the test load is used to determine the weight's value.

4. Test for Vickers Hardness

The Modulus of Rigidity could be run on both macro & micro-hardness scales with a measured maximum load of 50 kg. This kind of metal hardness tester is carried out by gradually applying regulated force to an indenter, which is a diamond with a square shape. The necessary formula is used along with the test load & impression measurement to determine Vickers hardness value. This test features an all-inclusive scale, just like Knoop and Brinell.

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