ZwickRoell 's DWT (High Energy Drop Weight Tester) is used for testing and evaluating fracture surfaces on ferritic steels, which are frequently used for oil and gas pipelines. The test method is described as a drop weight test in the API-RP 5L3, DIN EN 10274 and ASTM-E 436 standards, among others. As it falls, the weight accelerates a standardized test specimen in the direction of the sample, which is penetrated or broken. From the type of fracture or the fracture structure of the specimen, statements can be made about the material properties. It is also possible to temper the specimen with a separate cooling unit.

The DWT large drop weight testers from ZwickRoell are used for testing and evaluating fracture surfaces on ferritic steels. © ZwickRoell

Instrumented drop weight testers also offer the option of recording complete force-displacement diagrams, from which both characteristic force points and the absorbed impact energy can be calculated. The Gövert testing laboratory in Essen has purchased a ZwickRoell DWT120 kJ drop weight tester for testing notched steel specimens from pipe cut-outs. During specimen preparation, the pipe cut-out is sawn to size, formed into a gull-wing shape and notched on a ZwickRoell 800 kN hydraulic notching press. Gövert is one of the few service providers that can produce and now also test specimens in gull-wing form. With the gull-wing shape, the original curvature is retained unchanged at the notch and test point, while the conventional specimen is tested as a machined flat specimen with a notch.

The impact tests are carried out using an instrumented fin at different temperatures. With a drop weight of approx. 3 t and a drop height of approx. 4 m, the drop weight tester generates up to 120 kJ of energy, making it one of the most powerful drop weight testers in the world. This enables tests to be carried out on large samples in accordance with test standards such as ASTM-E 436, API-RP 5L3 or DIN EN 10274.

ZwickRoell's large-scale drop weight tester particularly impressed with its reliable test results, which can be verified with a test certificate based on DAkkS, as well as the certified calibration ex works and on site at the customer's premises. The verifiable fulfillment of the high safety requirements and the comprehensive support during project planning were also important reasons for Gövert to choose the DWT 120 kJ from ZwickRoell.