After the ductile iron test bar is taken out of the box, the angle grinder is used to cut the test bar from the inner runner, and then the burr and sand sticking on the test bar are removed. The parts of each test bar less than 40mm from the bottom of the test bar and 30mm from the top of the test bar are cut off, and the middle position is taken as the sampling part of this test.
In order to study the carbon content in high temperature austenite, it is necessary to ensure that the sample is cooled to room temperature in the process of water quenching. Therefore, the sample size of austenization + water quenching treatment sample is designed as Φ 10 mm × 1.8 mm thin sheet.
The test block and tensile test bar for austempering treatment are cut off at the outer side of each test bar by wire cutting. The size of the test block is Φ 10 mm × 10 mm, and the blank size of the tensile test bar is Φ 10 mm × 100 mm. Then it is processed into standard tensile test bar according to GB / t1348-2009, as shown in the figure.