IMPACT TESTING

CHARPY V NOTCH TEST

To assess the ability of a material to resist fracture under impact, metal materials are subject to Impact Testing, which measures the amount of energy absorbed during fracture. Testing is typically performed at varying temperatures to gauge the impact energy's sensitivity to temperature changes. By evaluating test results, materials can be assessed for their suitability in specific applications and for predicting their expected lifespan.

IMPACT TEST METHODS OFFERED BY CCT

CCT provides charpy impact testing services for metallic materials, which includes both the charpy V-notch and weld charpy tests. These tests can be conducted within a wide temperature range, from -196℃ to 100℃, with a maximum impact energy of 450J.

The charpy test method is used to evaluate the toughness or impact strength of materials under fast loading conditions, particularly in the presence of a flaw or notch. In this destructive test, notched impact test specimens are fractured at various temperatures using a swinging pendulum, and the energy absorbed by the material during fracture is measured. The charpy V-notch or U-notch test specimens are typically used for this purpose.

SPECIMENS FOR IMPACT TESTING

CCT has extensive in-house machining capabilities enabling us to quickly prepare precision specimens for our impact testing lab. Our full-service Machine Shop prepares all types of metal impact specimens with the latest CNC equipment.

TEST METHODS/SPECIFICATIONS

· ASTM A370

· ASTM E23

· ASTM E208

· ISO 148

· GB/T229

Let us know your requirements for impact testing of metals, and we will provide a fast quote.

THE IMPACT TEST PROCESSES

Iron and all other body-centered cubic metals undergo a transition from ductile behavior at higher temperatures to brittle behavior at lower temperatures. Impact Testing is required by many industries to evaluate the toughness of materials used in manufacturing products, including steel hull plate for ships, nuclear plant pressure vessels and forgings for electric power plant generator rotors.

CHARPY TESTING

The Charpy Impact Test assesses the impact strength of a material by striking a notched specimen with a swinging pendulum or weight. The material fractures at its notched section, and the upward swing of the pendulum is used to measure the amount of energy absorbed during fracture, which indicates the material's notch toughness. The test can reveal the material's brittleness, which is directly related to the amount of energy absorbed. To show the relationship between ductile and brittle transition in absorbed energy, the Charpy test is performed at a range of temperatures.

To perform some methods of Charpy testing, multiple machined bar specimens, sized at 1cm x 1cm x 5.5cm with a 2mm deep U-shaped notch at the center of a specified flat surface, are needed. Another commonly used method, the Charpy V-notch impact test, requires a specimen with a V-shaped notch.

The impact specimens are tested at specified temperatures, ranging from -196℃ to 100℃, such as -20ºC, -10ºC, 0ºC, +10ºC, and +20ºC. For low-temperature Charpy testing, the test specimen is immersed in a liquid nitrogen chamber until a calibrated thermocouple records the temperature required for the test.

Once the specimen reaches the required temperature, it is quickly placed into a holder in the test machine. The Charpy specimen is positioned horizontally, with the notch facing away from the pendulum or striker, and is supported on two sides.

CCT CAPABILITIES

· Types of Testing:  charpy impact (including V notch, U notch and weld charpy test)

· Temperatures:  -196℃ to100℃

· Impact Energy:  up to 450J.

· Materials Tested: metals

· Specimen Machining:  in-house machine shop prepares charpy test specimens;