The testing machine shall have appropriate equipment to permit the application of the test force without slip.
The testing machine shall be able to develop a force which is sufficient to break the test pieces whilst indicating the load applied.
The accuracy of the test machine shall be in accordance with clause 9 of EN 10002-1:1990.
The tensile strength shall be calculated by dividing the force indicated at rupture by the area of the initial cross-section of the test piece. The cross-section (width and thickness) shall be measured with an accuracy of 0.1mm before the test.
The determination of tensile strength shall be carried out in accordance with ISO 185. The accuracy of testing machine shall be in accordance with clause 9 of EN 10002-1:1990.
The results of tensile tests shall be in accordance with the requirements of table 3. However the test is declared valid if the following conditions are fulfilled:
-for pipes: the average of three values taken on one day's production shall be at least 200MPa and at maximum one value may be between 180Mpa and 200Mpa.
-for fittings: all values shall be at least 150Mpa.
A test can be cancelled if the unsatisfactory results obtained are due, not to the quality of the cast iron itself, but to any of the following reasons.
-incorrect mounting of the test piece or abnormal operation of the test machine.
-fault in machining of the test piece;
-fault in the casting of the test piece appearing before or aftre fracture.
Under these conditions, a new test piece shall be taken from the same batch, and the results for the faulty test shall be cancelled.