INDUSTRIAL TESTING.
Piece of material is placed into a Tensometer machine and held in clamps at each end. One of these moves on a 'worm' drive gear putting the piece under constant tension. The yield or stretch is measured before the piece ‘necks’.
Izod impact test: a piece of material is held vertically in the vice of the machine. The energy absorbed is calculated from the height the pendulum (маятник) swings to after it hits the piece. The material that absorbs the most impact is the toughest.
HARDNESS TEST.
In the Rockwell test, a small force is first used to press a diamond into the material's surface. Then, a heavier force is added and kept there for a while. After that, we measure the distance between the two forces.
In the Brinell test, we press a steel ball into the material's surface using a certain amount of force. Then, we measure how big the dent made by the ball is. If the dent is smaller, it means the material is harder.
The Vickers pyramid test is for really tough materials. It uses a diamond pyramid to make a dent in the material's surface. We use diamond because it doesn't change shape under pressure. Small dent - hard material.
MALLEABILITY AND DUCTILITY TESTING.
A bend test checks how well a material can handle bending without cracking. If a material can bend a lot before breaking, it's ductile. First, we put the material in a machine that bends it in the middle. Then, we check for cracks. If there are cracks on the outside bend, it shows how ductile the material is. If there are cracks on the inside bend, it shows how malleable the material is.
NON-DESTRUCTIVE TESTING (NDT).
Non-destructive testing (NDT) is used to check big items like large castings for hidden flaws or problems that might not show up with other tests. There are two main ways to do NDT.
ULTRASONIC TESTING:
A device called a transducer sends sound waves into the material being tested. These waves bounce back, and their strength is shown on a screen. This helps find hidden cracks or problems inside different materials.
X-RAY TESTING: a special beam goes through the material and creates a picture on a screen. This method helps look inside things like computer chips and circuit boards, and even finds tiny holes in materials used in things like race cars. It can also find problems in parts of engines like airplane turbines.
ELECTRICAL CONDUCTIVITY: To find out how well materials conduct electricity, we use a method called the four-point probe. Four thin wires are placed in a row on a plastic block. By using Ohm's law, we can figure out how much the material resists electricity flow.
THERMAL CONDUCTIVITY: using a heat flow meter, a square-shaped material test piece is placed between two temperature -controlled plates. The temperature is increased at a controlled rate and the heat flow through the material is measured.
WORKSHOP TESTING.
TENSILE TESTING: it is like stretching a piece of material. We put a weight on one end of the material, which is held in place. This pulls the material, stretching it out. It feels like it's being pulled from one side and pushed from the other.
TOUGHNESS TESTING: It is done by placing the test material in a vice then hitting it with a hammer. The more impact it can withstand, the tougher the material. Brittle materials will withstand less force or even shatter completely. The problem with this test is maintaining a consistent level of force with each blow.
HARDNESS TESTING: To test how tough something is, we can do hardness testing. One way is to rub a file on the surface to see how many scratches it makes. The material with fewer scratches is tougher.
Another way is using a dot punch—a tool you hit with a hammer. The bigger the mark it makes on the material, the softer it is. But it's tricky to hit with the same force each time, so the results might not be consistent.
MALLEABILITY AND DUCTILLITY TESTING: To check how easily something bends and stretches, we can do malleability and ductility testing together. We hold a piece of the material in place and try to bend it to 90 degrees using a hammer or mallet.
If we see cracks or damage on the outside of the bend, it means the material isn't very stretchy.
If there are cracks on the inside, it means the material isn't very bendable.
CORROSION TESTING: To see how well a material holds up against rust or other damage from the weather, we do corrosion testing. We put the material outside where it can get rained on or exposed to sunlight. Then, we check it to see if there are any signs of rust or damage on the surface.
If we see any problems, we might do more tests to see if the material has gotten weaker or less tough because of the corrosion.
ELECTRICAL CONDUCTIVITY -To check how well something conducts electricity, we can use a tool called a multimeter. We attach the probes of the multimeter at a certain distance from each other. If the material has high resistance, it means it doesn't conduct electricity very well.
THERMAL CONDUCTIVITY - To see how well something lets heat move through it, we use a thermometer. We put the thermometer a certain distance from one end of the material. Then, we heat up that end with a Bunsen burner for a while. If the thermometer gets to a certain temperature quickly, it means the material lets heat move through it fast.