Cupping attempt

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The cupping test is a test method in metal processing and is used to determine the cupping ability of sheet metal and strips.

method

High demands are made on sheets and strips for stretch forming purposes with regard to their cold formability . When they are machined, they have to withstand a high degree of plastic deformation without cracks occurring. In the cupping test, this deformability is checked by pressing a ball punch against the test sheet and continuously increasing the applied force until a crack forms. The indentation depth before crack formation is considered a characteristic value.

One test method that has developed over time is the Erichsen cupping test, which is standardized in DIN EN ISO 20482. The sample is assessed based on the maximum indentation, the force that occurs and the surface.

Experimental setup and procedure

There are special testing machines for the Erichsen cupping test, in which the sheet to be tested is inserted and held on the die by a hold-down force . A hardened ball with a diameter of about 20 mm then presses against the sheet metal from below, causing cold deformation. The current cupping (this corresponds to the punch travel) and the force that occurs can be read off on two dial gauges . The test is carried out in the event of a load drop, i.e. H. when a crack forms, terminated.

The Erichsen index, standardized according to DIN 50101, is derived from the cupping and the drawing force as a measure of the cupping ability of the material. In addition, the deformed sheet is visually assessed. To scatter to detect several measurements are required.

Current standards

  • DIN EN ISO 20482 (2003-12) Metallic materials - Sheets and strips - Erichsen cupping test
  • DIN 50101-1 (1979-09) testing of metallic materials; Cupping test on sheets and strips with a width of at least 90 mm (according to Erichsen), thickness range: 0.2 mm to 2 mm
  • DIN 50102 (1979-09) testing of metallic materials; Cupping test on narrow strips (according to Erichsen), width range: 30 mm to less than 90 mm

Web links

Individual evidence

  1. ↑ Archived copy ( Memento of the original from October 4, 2005 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. . @1@ 2Template: Webachiv / IABot / mitarbeiter.fh-heilbronn.de

literature

  • Macherauch: internship in materials science; Vieweg-Verlag, 10th edition 1992
  • Domke: Materials science and material testing; Giradet publishing house
  • Schlinke: Material testing for metals, VDI-Verlag