Specimen preparation for metals
Nowadays test pieces from steel sheet and metal foils are economically and accurately produced using specimen blanking machines. The standards, e.g. EN 10002, ASTM A 370, BS 18 (replaced by EN 10002) stipulate that the test results must not be influenced by any material change caused by strain-hardening at the test piece edge zone.
Unlike cutting techniques with eccentric cutting presses, in which the strain-hardening zone can comprise up to 35% of test piece thickness, Zwick RZ specimen blanking machines give significantly better cutting. Numerous structural examinations of steel sheet have shown that the strain-hardening zone along the cutting line is generally a maximum 10 % of test piece thickness.
This is achieved by a low cutting speed and special blanking tool design and offers substantial economic advantages in the event of subsequent grinding.
C-shape specimen blanking machines RZ 50 and RZ 65
The open shape of specimen blanking machines and blanking tools (C-shape) also allows specimens to be taken from panels. If several blanking tools are used the roller table version of the table extension is recommended: So blanking tools not being used at that time can be put aside.
The stamping presses RZ 50 and RZ 65 (with a compressive force of 500 / 650 kN) are suitable for the following thicknesses of material: 0.2 to 1.2 mm; 1.2 to 3 mm; 3 to 6 mm.
O-shape specimen blanking machines RZ 100 and RZ 150
The closed shape (O-shape) requires pre-cut strips 70 ... 80 mm wide. These specimen blanking machines are already equipped with a table extension.
The RZ 150 specimen blanking machine (with compressive force up to 1500 kN) can also take 6 ... 8 mm blanking tools.
Specimen grinders 7120
Test piece cold-hardening zones can be removed economically and quickly by grinding with Zwick 7120 specimen grinding machine.
No other procedure allows good test piece quality to be obtained at very low cost. Guaranteed parallelism is better than 0.07 mm in accordance with IDDRG recommendations. Work is carried out in the direction of tension, so ghost lines have no effect on the test result.
