Abstract
In the manufacture of DI can made of tinplate, macro non-metallic inclusions(NMIs) which exist on the flanging area of DI can cause cracks in flanging. It is difficult to observe NMIs on the surface of tinplate because they usually exist in the inner part of the steel sheet. The magnetic-particle testing can detect NMIs, but it is difficult to determined the size of NMIs quantitatively.
This paper describes the quantitative determination of the size of NMIs by using the magnetic leakage flux testing, and the influence of NMIs on the flanging cracks. Flanging crack ratio in continuous DI canmaking test are in proportion to numbers of NMIs obtained in this test is in good agreement with the theoretical results. Conclusively, the number of NMIs per unit area detected on the part of the coil by the magnetic leakage flux testing enable us to estimate the flanging crack ratio of the coil before DI canmaking.
