Bend Tests are conducted to determine the ductility or strength of a material. Bend tests are divided into two categories.
Bending Ductility Tests
This type of bend testing determines the smallest radius around which a specimen can be bent without cracks forming on the outer radius. This bend test is often used to test the ductility of welds.
Bending Strength Tests
Bending strength test offer a means of determining the modulus of elasticity in bending and the bending strength of flat metallic samples in the form of strip, sheet or plate.
Charpy Impact Testing
Charpy Impact Testing is the application of a sudden applied load confined to a localized area of a material to determine its notch toughness or impact strength.
Charpy impact tests are frequently performed as a means of determining the toughness of a material. A Charpy test sample has a V-notch, keyhole, or U-notch machined on one side, is supported at both ends, and struck from behind the notch by a swinging pendulum of fixed mass. The energy that is absorbed by producing the fracture is referred to as the material’s impact energy. The more impact energy that a material is able to absorb, the tougher the material.
This test is often performed to determine the toughness of roll-over protection systems for farm equipment and automobiles. It is also critical to determine the ‘Ductile to Brittle Transition Temperature’ of materials. This is essential in the failure analysis of structures at subzero temperatures. This is also an essential material property for structural members such as bridge girders.
Tension testing is a routinely used method of determining material strength. A material’s yield strength, ultimate tensile strength and percent elongation (ductility) may be determined from a tension test.
Testlabs International Ltd. machines tensile test specimens, and is capable of performing tension tests at lowered, room or elevated temperatures.
Hardness of a material is defined as a measure of the resistance of a material to surface indentation or abrasion. The hardness of materials is a routinely measured and specified parameter, which is an indication of the strength and heat treatment of the material.
During a hardness test, a ball, diamond cone, or pyramid is forced into the material being tested. The total test force to the area or depth of indentation provides the measure of hardness.
The hardness tests available include:
(a) Rockwell A, B and C Scale
Rockwell hardness testing is the most widely used method for determining hardness. It can determine the hardness of most metals and alloys, ranging from the softest materials to the hardest steels.
(b) Micro Vickers
Vickers hardness testing is a form of Micro-hardness testing, where a Vickers indenter (square-based pyramidal diamond) is forced upon the test surface of the material using loads ranging from 1 to 1000g.
(c) Macro Vickers
Macro-hardness testing utilizes an applied force much greater than a micro-hardness test. Similar to Micro Vickers hardness testing, a pyramidal diamond indenter is forced upon the test surface using loads ranging from 1 to 100 kilograms.
(d) Onsite Hardness Testing (Portable Krautramer)
Onsite hardness testing is performed on components and structures that cannot be removed from service for laboratory testing. Hardness measurements are calculated based on the rebound of the indenter from the test surface. For this reason, this test method has limitations with relation to the mass and thickness of the test sample.
Cyclic and Constant Pressure Hydraulic and Pneumatic Pressure Testing
Pressure testing is used to validate that a pipe, tube, fitting, or component is able to withstand a designed internal pressure with a margin of safety. Pressure testing can consist of non-destructively charging the test sample to a specified, constant pressure, and held for a pre-determined duration. At this pressure the test sample is observed for leaks, or other indications of failure.
Pressure testing can also consist of cyclic fatigue testing to determine if the sample can withstand repeated pressure variations without fatigue and failure. This is a valuable test method as an accelerated test to simulate the life cycle of the test component.