The mechanical test is one of a sequence of tests that are used in the process of designing products and part manufacturing to identify the material characterization, selection and verification of products.
This article will present the tests conducted and their application in the design of products and parts manufacturing.
What is Mechanical Testing?
The mechanical test is a sequence of standard tests used to evaluate the mechanical and physical properties and the suitability of its applications. It is necessary to design products and manufacture parts due to the need to meet the standards of organizations like ISO. These tests enable manufacturers to identify poor-quality materials and select the best product.
Five Types of Mechanical Testing – Measure Material’s Strength
There are a variety of mechanical engineering tests that can be used to determine the strength of a material that is found in various resins, plastics, and metal strength charts. Each test is unique in its method and difficulty, which can reveal information on several parameters related to strength. Please find out about the commonly used tests and what they cover.
Testing for Torsion is a different type of testing in mechanical that examines the material’s behaviour when exposed to stress through an angle of displacement. It provides information on the material’s shear modulus of elastic and shear yield strength.
It also includes information about shear strength and the shear modulus of fracture and ductility. Contrary to tensile tests, Torsion testing is applied to products and materials. In addition, various types of torsion testing are discussed below.
- Torsion only: Applying only torsional force to the material.
- Testing for failures: Testing for failure involves bending the product or material until it is broken or there is a noticeable defect.
- Testing for proof: applying a torsional force to the material and holding that tension for a specific period.
- Functional testing: Testing to determine the behaviour of a material under the torsional force and load.
As per ISO, the standard tests for torsional are ISO 7800 (Torsion Testing of Metallic Wire).
The test for mechanical fatigue tests determines how a substance behaves in the face of varying loads that are applied axially, through flexure or Torsion. The process involves exposing materials to a minimum load and alternating one. In the end, the material is likely to fatigue (i.e., it will break when the material fails).
The results will be presented during the test as an S-N diagram, which is an illustration that shows the frequency of cycles that fail in the strength of the stress cyclical (which can refer to stress amplify, max stress, or minimum stress).
Fracture Mechanics Testing
Testing for fracture mechanics allows manufacturers to know how small the amount of energy is required to split a material with a crack in two. In addition, it will enable manufacturers to assess the material’s resistance to fracture through intrinsic stress.
Based on the information, manufacturers can examine the brittle fracture and determine the grain size, case depth, etc.
Compressive testing is a different fundamental mechanical engineering test that determines a material’s behaviour when exposed to crushing forces. It is crucial in part manufacturing as materials undergo various stages.
Creep testing, also known as stress-relaxation tests, exposes the material’s continuous stress at high temperatures while recording deformation over the specified time interval. Then, the operators chart the creep about duration on graphs to determine the rate of creep (slope of graph).
This test permits manufacturers to identify a material’s capacity to shrink under constant tension in constant temperatures (to include the effects of thermal shrinkage or expansion). This is crucial for specific materials like springs, metal workings, and soldered joints.
Tests to Measure Material’s Mechanical Properties
The various types of tests for mechanical strength above allow manufacturers to determine the properties of a material’s strength. But these tests do not reveal how to select specific properties like hardness, stiffness, and resistance to corrosion.
Take a look at four commonly used mechanical properties tests.
The hardness test lets manufacturers assess the hardness of a material, i.e., the ability of the product to withstand indentation. The test is performed only for the materials. Thus, there is no requirement to test the final product. There are a variety of tests of hardness in metal.
But the most commonly used tests are:
Brinell Hardness Test
This is the most straightforward testing for hardness to carry out. It is done by indenting the substance by placing a steel ball on the material and then putting an object onto it.
The operator then measures the indentation created by the steel ball and loads at a set time by calibrating an instrument. Then, they calculate an estimate of the Brinell the Hardness Number (BHN) by dividing bags by the surface of the indentation area.
The benefit of using the Brinell hardness test is that the user doesn’t need to be concerned about the roughness of the surface. In addition, it’s also ideal for bulk metal hardness measurement.
Vickers Hardness Test
Vickers steel hardness test is similar in concept to the Brinell test. However, in contrast to it, the ball made of steel employs diamonds as an indenter. Additionally, it’s better since the indentation’s depth is not a factor in the accuracy, as the diamond indenter cannot be deformed.
The operator positions an indenter over the surface and then puts the weight on it.
Corrosion tests accelerate to evaluate the coating and non-coated metals’ reactions in non-saline and saline environments. There are a variety of difficulties that conform to international standards.
Salt Spray Testing is the most common and widely used method to test coated and uncoated materials’ resistance to corrosion. This involves spraying material using a saltwater solution and checking what the colour of the oxide looks like.
Exposure Testing for CASS This is a severe corrosion testing procedure for aluminium alloys and chrome plating on steel and zinc alloys. The test may be cosmetic or functional and determine the duration of exposure (not longer than 48 hours).
Immersion Corrosion Testing The process of testing for corrosion in the presence of an immersion involves placing a substance in an aggressive, aqueous atmosphere. Then, analytical techniques are used to identify the weight loss caused by corrosion.
- Non-destructive Tests
Non-destructive tests (NDT) (also known as non-destructive examination, are a collection of procedures that allow you to test the properties of a material without causing damage to the material. The most common NDT techniques used in part manufacturing include:
- Acoustic Emission Testing
This test is a passive mechanical inspection for the industrial sector. It allows you to identify active cracks in the product and material. It is done by sending short pulses that emit ultrasound throughout the development and material.
- Electromagnetic Testing
The process involves passing either an electrical current or magnetic force through the material to identify flaws, measure the thickness or detect materials.
- Internal Audit
Internal audits in the design of the product and, in part, manufacturing permit manufacturers to gain access to their manufacturing processes, materials, and products, as well as ensure compliance with the international standards required.
A thorough internal audit will reveal whether the materials used in the process pass the internationally-standardized tests. If they don’t, then the manufacturers must find an alternative. But any solution will take time and energy.
- External Audit
The external audit is an audit process wherein an individual or a company exposes another company’s product to various tests. In the end, they can determine conformance to international standards.
Products not subjected to mechanical tests can result in products that do not pass an audit from outside. In addition, it could cause an erosion of confidence in the product.
- Increased Cost
The use of inferior materials could cause wastage and a lack of authenticity of products. In addition, it can result in manufacturing processes that could be simpler and lead to an increase in the price of production.
Part manufacturers can decrease or even optimize production costs using materials that meet international standards.
- Product Failure
This is the costliest result of not investing in mechanical testing for industrial use. Failure can destroy the product and cause loss of life and exposure to legal action.
Failure of products is typically due to internal and external audits. However, there could be an oversight during auditing. Therefore, careful investment in the test is crucial.
- Possibility of a Future Failure
If a product is damaged during testing or service, Failure analysis may help to determine the likelihood of a failure in the future.
Failure analysis is a method that uses deep investigation to discover the reason for the failure of the product and employs analytical methods to analyse the component that has failed. This is why manufacturers rely on the results of failure analysis and can decide the best way to prevent future failures of their products.
Is Industrial Mechanical Testing Important?
Structural integrity is a crucial component of manufacturing parts to maintain safety and economic feasibility. The set of tests will determine the part’s structural integrity.
To ensure quality testing, mechanical engineering tests are essential for every manufacturer. They also allow companies to keep their name and reputation intact, reduce production costs, and prevent products from failing.
Only a few manufacturing companies do not have the equipment required to conduct these tests. So, ensuring you contract with a company with the necessary equipment is essential.
- Material Dealers
Dealers of materials must ensure that they adhere to international standards since they are the most critical aspect of material acquisition. This is a way to establish credibility for the dealers.
Every client and customer associated with the manufacturing process should make sure that there is a mechanical test on products and materials before, during, and following production. In the end, they can enhance the quality of products and decrease failure.
Mechanical testing is a set of testing methods used for testing materials and products to ensure safety in production, the proper use of materials, and efficiency. It is an integral component of every design and manufacturing industry. This article discussed several mechanics engineering test procedures and their significance in manufacturing.
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