- December 14, 2020
- Posted by: AQI Service
- Category: Product Testing
Physical and mechanical testing determine the physical, mechanical, and metallographic properties of materials, especially metals and alloys. By testing the materials, one can distinguish the material from other materials.
Mechanical testing is an inevitable part of the design and manufacturing process. Because it unveils the mechanical properties of any item which helps the designer to develop a plan perfectly. The safety, quality, and durability of any product depend on its mechanical qualities to a great extent.
Type of Testing
Broadly, there are two types of material testing
A. Destructive Testing/ Mechanical Test
Materials are usually tested for the identification of mechanical properties such as hardness, toughness, strength, etc.
B. Non-destructive Testing
Sample or finished products are tested before usage or routine checkup of materials.
The testing has two major purposes such as product-endurance analysis and product-safety assurance. Given these purposes, the following physical And mechanical testing on materials are usually performed.
- Tensile strength
- Shear strength
- Hardness (Brinell, Knoop, Rockwell, Shore, Vickers)
- Stress rupture
- Bend testing
- Thermomechanical Fatigue
- Charpy impact
- Coating bond strength
- Gardner impact
- Peel testing
- Flexural strength
Either your organization must have the in-house testing capability to conduct aforesaid tests, Or you will need to contact an accredited lab to perform the test.
Type of Material Testing
However, let’s discuss these tests.
a. Tensile Testing:
Tensile testing is usually performed to determine the amount of force a material can withstand before being broken. Whether raw materials that are provided by your supplier meet minimum requirements or not must be ensured before awarding any supplier. Because final products that are made of raw materials with low tensile strength will not bring reputation as well as customer satisfaction.
Universal Testing Machine is usually used for testing tensile strength. This machine usually uses a hydraulic cylinder to create the required force. However, the following properties can be identified by tensile testing.
- Modulus Of Resilience
- Modulus Of Toughness
b. Hardness Testing:
It is one of the easiest approaches to defining certain mechanical properties of the material. It is the ability to withstand scratches. The hardness test also checks how materials will respond to heat treatment. Therefore, when heat treatment is required, the material will need to be tested to verify conformance. There are three types of hardness measurement
- Scratch Hardness
- Indentation Hardness
- Rebound Hardness
Indentation hardness can be measured by following three types of test
|Brinell Hardness Test (BHN)||Rockwell Hardness Tests (HRC)||Vickers Hardness Test (HV)|
|Uses spherical shaped indentor||Gives direct reading||Measures Small Samples|
|Used for large components||Flexible, quick, and easy||Uses square-shaped pyramid indenter|
|The surface area of indentation is measured||Rockwell B (ball) used for soft materials||Usually used on very hard materials and for surface hardness measurement|
|Cannot be used for thin materials||Rockwell C (cone) uses a diamond cone for hard materials.||Accurate results|
When selecting a hardness test method, important considerations include:
- Accuracy of the result
- Type of material
- Size of the part
- Number of samples
- Whether compliance with a standard is required or not
- The approximate hardness of the material
- Homogeneity or heterogeneity of the material
c. Impacts Test:
The Impact test determines material toughness as well as the ability to resist high rate loading. There are two types of impact tests:
- Charpy Test
- Izod Test
d. Fatigue Testing:
Fatigue testing is mechanical testing that determines the ability materially to withstand applied cyclic loading. This cycle of loading and/or unloading is being continued until the end of the test. Fatigue tests are normally loaded in tension or compression.
A fatigue test is usually performed to determine the expected lifespan of materials and the maximum load that a sample can absorb for a period of time against the specified number of cyclic loading.
There are two types of fatigue tests:
- load controlled high cycle
- strain controlled low cycle fatigue
Typical Applications of Mechanical Testing:
- Determining the strength of materials
- Determining the lifespan of materials
- Replacement of materials
- Selecting materials for usage
- Verifying the change in raw material supplier.
- Design/construction of the new mechanical element
- Controlling of established processes
- Physical Properties
Properties that define the nature of materials in response to physical forces. These properties can be observed without changing the identity of the material.
a. Thermal Properties:
Properties that are determined by temperature are usually called the thermal properties of materials. These properties are related to the storage as well as the flow of heat within a substance.
- Thermal conductivity: Thermal conductivity is the ability of a material to transfer within a material from molecule to molecule or conduct heat in a per unit area in unit time.
- Thermal expansion: Material tends to change its shape in response to a change in temperature.
b. Electrical Properties:
Properties of materials that exhibit the nature of the material in response to electrical fields.
- Conductivity: It identifies the flow electrical charge through the material
- Resistivity: It defines a material’s capability to resist current flow
c. Volumetric and Melting Properties
Properties related to the volume of solids and reaction to temperature:
- Density: It implies the mass of material per unit volume. Generally, higher density rates imply heavier materials. Typical units are g/cm3 (lb/in3)
- Melting/Boiling Point: the minimum temperature for a solid material to change into liquid
d. Elastic Properties:
The elasticity of Materials represents how it regains its original dimensions upon the removal of the force
It requires a range of physical testing under different environmental conditions
- Stability tests
- Strength tests
- Durability testing
- Weather conditioning
To conclude, both physical and mechanical properties are intrinsic properties of raw materials that have a substantial impact on final products. You must build a robust quality department with high-quality lab equipment and experts, or you have to contact a third-party quality control company. There are many agencies like AQI Service that are equipped with a range of the latest instruments and machinery for the inspection of any type of material. AQI is committed to delivering the most accurate report within the shortest possible time at an affordable price.
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Author: AQI Service as a professional quality control service company in China specialized in providing a complete range of quality inspection and testing certification services in China & Asia for global importers, buyers, retailers, and sellers.
Happy Chinese New Year Please kindly be informed that our office will be closed from Jan. 27h to Feb. 8th for Chinese New Year holidays and our operation will be resumed on Feb. 8th. The inspections and audits in other Southeast Asian countries are not affected and can be arranged. We are sorry for anyJanuary 27, 2022