Material testing has become very important for a wide range of industries. The tested materials are reliable and perform better in real-world conditions. However, there are different types of material testing. Each of these types differs in terms of the procedure and effectiveness. Some tests involve breaking and damaging the materials during testing.
However, some other tests examine materials without damaging them. In addition, various types of testing machines are used for these tests. Understanding material testing is crucial if you want to make strong and reliable products. In this article, I will discuss all types of material testing and provide details on each. So, let’s get started.
Importance of Material Testing
Material testing is equally important across all industries. In fact, engineers don’t use materials in the construction sector unless they are tested and approved. That’s because tested materials are always more reliable and trustworthy. Let’s explore important material testing.
- Engineers determine a material’s maximum pressure-bearing capacity by testing it. So they use the materials appropriately. When a material is stressed within its limits, it remains reliable and strong for a longer period.
- The selection of materials becomes easier when they are tested for different parameters. For example, different projects need different levels of flexibility or hardness. Material testing provides precise measurements of flexibility, hardness, and other parameters. So you know the true value of materials and choose the right ones for your needs.
- Tested materials are less likely to break or fail. This is very important when engineers choose materials for bridges and other such projects. As a result, bridges and other buildings remain stable even in the face of earthquakes or other disasters. Not only for construction, but also for all types of products made from tested materials.
- Material testing helps identify defects in various materials. When such material is used to make products, it ensures consistent quality. Such high-quality products deliver excellent performance over extended periods. Customers also trust brands that use tested materials in their products.
Types of Material Testing
As I said above, there are different types of material testing available. Each of these tests checks the quality of different materials. In the section below, I will discuss these tests and their key specifications.
1- Mechanical Testing
Mechanical testing is a broad term for all tests that use force to evaluate materials. This means the material under the test is exposed to different types of forces. The type of force depends on the test type. These forces put stress on the materials and check their capabilities. Some examples of mechanical testing are as follows:
- Tensile Testing
- Impact Testing
- Fatigue Testing
- Hardness Testing
- Compression Testing
- Flexural (Bending) Testing
These mechanical tests check some key parameters of the materials. These include strength, brittleness, flexibility, and so on. In tensile tests, the material is exposed to a pulling force. This checks how much pulling force a material can withstand before deforming completely. Similarly, an impact test measures the force a material can withstand before breaking.
Compression tests involve compressing materials to assess their load-bearing capacity. It is worth noting that mechanical testing is not confined to any specific materials. Instead, you can use it to check the quality of a wide range of materials. These include metals, plastics, elastomers, composites, and more. This testing is widely used across industries where material strength is essential.
2- Chemical Testing
Chemical testing involves checking materials against different chemicals. These include alkalis, acids, gases, and more. The purpose of chemical testing is to check how well the material resists different chemicals. If a material remains stable when exposed to chemicals, it is considered reliable and safe for use in various applications.
In contrast, if it deteriorates when it comes into contact with chemicals, it is of low quality. Various tests fall under chemical testing. Some of these include:
- pH Testing
- Toxicity Testing
- Corrosion Testing
- Spectroscopy Testing
- Chromatography Testing
As you know, corrosion is a common problem that metals face, right? This is even more prevalent if metal parts are being used in moist conditions. So materials used to make marine parts are tested for corrosion resistance. This test uses a specialized chamber in which the material is exposed to moisture and salty water.
This controlled environment exposes materials to harsh conditions. If the material is strong, it does not corrode, indicating its better quality. Such materials are widely used in making corrosion-resistant parts and products. Similarly, pH testing ensures materials are not too acidic and checks their composition so they can be used safely.
Remember, chemical testing is most crucial in the food industry. Packaging materials used for different foods can leach chemicals into the food. So these materials are tested to ensure they are safe (stable) and don’t react with food. As a result, this testing helps the material comply with food safety regulations. Not just the food section, chemical testing is used for a wide range of industries.
3- Thermal Testing
Thermal testing involves checking the behavior of materials under heat. As you know, some materials are thermally stable. They don’t lose their stability when exposed to high or low temperatures. On the other hand, other materials start to expand and contract at high and low temperatures, respectively. That’s where thermal testing proves particularly helpful.
These methods expose materials to controlled heat depending on the type of thermal test. There are different types of thermal testing, each with its own working and operation. Some thermal tests are as follows:
- Melting Point Testing
- Heat Deflection Testing
- Thermal Cycling Testing
- Thermal Expansion Testing
- Thermal Conductivity Testing
Some thermal testing checks materials by exposing them to both very low and high temperatures. This is called thermal shock testing. It helps identify the behavior of materials when exposed to sudden high-to-low temperature changes. Generally, thermal testing chambers are used for this type of testing. Materials with higher thermal resistance are preferred for most applications.
4- Electrical Testing
As the name suggests, electrical testing is used to check a material’s ability to conduct electricity. If a material allows an electric current to pass through, it is a conductor. Examples of such materials include copper and aluminum. On the other hand, some materials do not allow current to pass through, such as rubber.
Electrical testing checks the ability of the material and determines whether it is a good or poor conductor of current. This type of testing is crucial for the electronics industry. Remember, copper is used to make wires because of its electrical conductivity. Similarly, manufacturers use rubber to make buttons because it is an insulator. Electrical testing includes some tests:
- Resistance Testing
- Conductivity Testing
- Dielectric Strength Testing
- Insulation Resistance Testing
The resistance test measures the resistance of the material when current flows through it. Each electrical test ensures that materials are checked against different parameters. Tested materials can be used in electronics and are very reliable. Manufacturers use tested materials to ensure the safety and reliability of electrical products.
5- Destructive Testing (DT) vs Non-Destructive Testing (NDT)
Destructive and non-destructive testing are two important types of material evaluation. However, both techniques differ in how they work. Destructive testing involves testing materials and damaging them. During testing, the material is tested until it reaches its breaking point. In other words, testing is conducted beyond the material’s maximum limit.
This gives the materials their maximum capacity; however, it also damages them. Operators note the limit at which materials begin to break or deteriorate. Examples of destructive testing include tensile testing, impact testing, compression testing, and more. All these testing methods damage the materials during testing.
In contrast, non-destructive testing is essential for inspecting materials without damaging them. In other words, the material to be tested is exposed to controlled conditions. Examples of this type include Ultrasonic Testing, X-ray Testing, and Eddy Current Testing. This type of testing does not expose the materials to the maximum limit.
Operators inspect the material even before the force reaches the maximum limit. After non-destructive testing, materials can be used as they are not damaged. Non-destructive testing can be performed even if the material is already used to make products. However, destructive testing cannot be done on the finished product. Instead, it applies to raw materials before making products from them.
Advantages and Disadvantages of DT & NDT
| Pros of DT | Cons of DT |
| Accurate strength results | Material is destroyed |
| Shows failure point clearly | High material wastage |
| Useful for R&D | Not usable on finished products |
| Pros of NDT | Cons of NDT |
| No damage to material | May miss internal defects |
| Can test finished products | Requires skilled operators |
| Fast inspection process | Limited detailed analysis compared to DT |
How to Choose the Right Material Testing?
As I said, material testing is very important for different industries. However, there is a wide range of tests available for checking the quality of materials. How will you know which type of test is best for you? That can be confusing, especially if you’re new to material testing. In the section below, I will discuss key factors to help you choose the right material testing method.
-
Type of Material
Different materials have different testing requirements. For example, you’ll need to test for hardness when dealing with metal or solid materials. In contrast, you’ll need a flexibility test when working with rubber or plastics. You should analyze your material type before finalizing any material test.
-
Purpose of Testing
Your purpose defines what type of material testing you need. For example, if you want to test a material for impact resistance, I recommend using a mechanical testing method. Similarly, you should use chemical testing when evaluating materials for chemical compatibility. Before choosing any test, you must consider the purpose of your test.
-
Accuracy & Precision Level
Material testing selection comes down to the precision and accuracy you require. Some tests are more precise than others due to their better testing equipment. If you’re working on a sensitive project, accuracy should be a top priority. It is key to choose a testing method that is both accurate and precise.
-
Stage of Product Development
Do you have raw materials or finished products? That’s another important aspect to decide on when determining the material testing you need. If you have raw materials, you should perform destructive testing to obtain accurate results. On the other hand, non-destructive testing is suitable for finalized products or parts. This may not be ideal for precision, but it still works fine for finished products.
-
Cost and Time Limitations
Interestingly, different tests come with different costs and time limitations. Some tests require expensive testing equipment, making it costly. If you have a tight budget, I recommend choosing a less expensive test. Additionally, you should not ignore the time it takes for a test to give you the final reading or outcomes. Considering both cost and time is essential when you’re choosing any material testing method.
Conclusion
There is no doubt that material testing has become a must in modern industries. Manufacturers use tested materials in making their products. This ensures their products are reliable and long-lasting when used in real-world conditions. As you know, competition among manufacturers is also fierce.
Every brand wants to outperform its competitors. This increases the importance of testing materials before use. In this article, I have discussed different testing methods. Each of these methods offers unique pros and cons. These test methods indicate a broad category where many smaller tests can be used. In the last section, you’ll also find a selection guide to help you choose the right test for your specific material.