Against this background Zwick has enlarged its product program for metals testing and introduced a new DWT line of large drop impact testers from 20 to 100 kJ.
The drop weight test helps Engineers to evaluate the fractured surfaces of Ferritic steels, as the relative proportions of deformation and brittle fracture surfaces are diagnosed by visual determination. Ferritic steels are usually used for pipeline tubes or for sheet metals used in the manufacturing of such tubes.
The recommended practice 5L3 issued by the American Petroleum Institute (API) describes the testing procedure to be used on large-drop impact testers. A specimen supported at both ends is impacted with a cold-press-fitted notch, with the point of impact opposite the notch. Since the specimen thicknesses are very large sections of actual pipeline tubes, high impact energies of up to 100,000 Joule are necessary to break the specimen.
Zwick’s DWT large-drop impact testers are differentiated by their sophisticated integral safety concept that does not allow any access to the test area while in test mode. Furthermore, for drop impact tests, high rates of testing are required, so Zwick has developed a pneumatic feeding system to simplify the loading of the specimens into the testing machine.
Technical data of the Zwick DWT 60-2,5
• Maximum energy 60,000 Joule
• Drop weight ca. 2450 kg, depending on the drop energy
• To be able to vary the drop energy, the drop weight is separated into single weights
• Overall height 6160 mm
• Drop height of 715 mm to 2,500 mm continuously adjustable
• To be used for specimens according to API RP 5L3
• Modular system with two sizes, two drop heights and six energy ranges
• Pneumatic specimen infeed and mounting outside the test room
• Electrical and mechanical test room protection
• Touchscreen operation with display for drop height, drop weight, drop energy and fall velocity
• Four high-performance shock absorbers with compensation tank for the safe absorbing of the drop weight