The international standard for the evaluation of spheroidal cast iron spheroidization rate, led by the team of Professor Wang Zehua of Hohai University, was recently approved by the International Organization for Standardization (ISO).
Ductile iron is a kind of high-strength cast iron material with comprehensive mechanical properties close to steel and excellent shock absorption and wear resistance. In 2017 alone, China's production of ductile iron reached 13.75 million tons, accounting for 52% of the world's production of ductile iron.
Wang Zehua introduced that the characteristic structure of ductile iron is spheroidal graphite. The shape of graphite particles directly affects the mechanical properties of ductile iron. The quality parameter is called spheroidization rate. Previously, the International Organization for Standardization, the European Union and major industrial countries have defined the spheroidization rate and stipulated the corresponding assessment methods. However, these standards are not uniform and lack of maneuverability. Human factors are large, and disputes are easy to occur, resulting in economic loss.
“Graphite particle morphology model is the basis for evaluating the spheroidization rate of nodular cast iron. The old standard only describes the shape of graphite particles qualitatively, but it is difficult to control in actual operation.” Wang Zehua said that since the ISO project was established in September 2015, the team Relying on Zhongqi Qishuyan Locomotive and Rolling Vehicle Technology Research Institute Co., Ltd., Shenyang Foundry Research Institute and Jiangsu Hengli Hydraulic Co., Ltd., a large number of experimental studies were carried out, and the area ratio of spheroidal graphite particles was finally determined, and the spheroidization rate was obtained. The model solves the contradiction between the old standard definition and the actual operation.
"The results can be made without sitting in the office. If you want to go to the production line, don't be afraid of being dirty." Wang Zehua said that the promulgation of the new standard has improved the international discourse power of China's foundry technicians and enhanced the foundry industry in China. International competitiveness.