Using a prefabricated porous ferroboron lump, a surface composite layer was made on gray cast iron matrix, with a common casting method.是什么意思_Using a prefabricated porous ferroboron lump, a surface composite layer was made on gray cast iron matrix, with a common casting method.在線(xiàn)翻譯_英語(yǔ)_讀音_用法_例句