How are the materials are tested as per ASTM standards?

ASTM (American Society for Testing and Materials) International publishes a vast range of material testing standards that are used around the globe to improve product quality, enhance safety, and market access and trade. Materials testing encompasses a diverse range of substances, including metals, polymers, ceramics, composites, and biomaterials. The exact method employed depends on the specific ASTM standard being followed and the type of material.

Let me guide you through a general process of how materials are commonly tested per ASTM standards.

1. **Identify the applicable ASTM Standard**: Identify the specific ASTM standard that applies to the testing you need to perform. The standard would indicate the specific requirements for test sample selection and preparation, including the size and shape of the test pieces.

2. **Test preparation**: Depending on the test, you will need to accurately prepare your test specimen. This may involve machining, molding, conditioning, or other forms of preparation.

3. **Carry out the test**: The ASTM standards will contain detailed instructions about how to perform the test, including what equipment to use, the environment of the test (temperature, humidity etc.), how to apply the load or perform the measurement, and the duration of the test.

4. **Record and analyze the data**: The ASTM standard will typically offer specific procedures for how to interpret the results of the test, allowing for consistency when comparing results from different sources or repeated tests.

Some examples of specific ASTM test methods include:

- **Tensile Testing (ASTM D638)**: This test method is used to measure the force required to break a plastic sample and the extent to which the sample stretches before breaking. The material is formed into a standard "dumbbell" shape and stretched at a consistent speed until it breaks.

- **Charpy Impact Test (ASTM E23)**: This test determines the amount of energy absorbed by a material during fracture. A notched sample is hit by a pendulum, and the energy absorbed by the sample is measured.

- **Density Testing (ASTM D792)**: This test method covers procedures for determining the mass per unit volume (density) of plastic materials in the form of void-free molded geometric shapes, cut from molded bodies, or cut from extruded or cast sheet, rod and tubing.

- **Flammability Testing (ASTM E84)**: This test method measures the flame spread and smoke development of materials used in interior surfaces of buildings.

Remember, ASTM isn't just a sealed catalogue of methods, but rather a continuous working standard that is updated to reflect changes in technology and industry needs.

Please ask specifically for a particular ASTM standard if you want to dig deeper into the procedure.