QT350-22同步带轮铸件的生产工艺

The Production Technology of QT350-22 Synchronous Pulley Casting

介绍了同步带轮B264—14M55（4040）的铸件结构，详细阐述了其生产工艺：采用呋喃树脂自硬砂造型，封闭式浇注系统，浇口比为∑F内：∑F横：∑F直=1：1．25：1．36，轮缘处设置3个明顶冒口，轮缘外部放置5块随形外冷铁，轮毂底部设置外冷铁；选用低Si、低Mn、低S、低P的生铁，废钢选用45钢板及圆钢的下脚料，回炉料选用该牌号的浇、冒口及废铸件，利用1．5t中频感应电炉熔炼，采用堤坝式球化包进行球化处理，出炉温度控制在1480～1500℃，选用铁素体专用球化剂和Ba—Si—Fe孕育剂，并采取两次孕育的方法；采用高温石墨化2段退火工艺。最终生产铸件的球化等级为2级，石墨大小为6级，铁素体体积分数高于95％，力学性能符合技术要求。

The casting structure of B264-14M55 （4040）synchronous pulley was introduced and its production technology was described in detail. Self-hardening furan resin sand molding and choked running system were used. Gating ratios is ∑Flow： ∑Frunner：∑Fmouring=1 ： 1.25： 1.36. Three open top risers are designed at the rim. Five pieces of outline chill were set at external rim. External chill was also used at the bottom of rim. Pig iron contains low proportion of Si, Mn, S and P. #45 steel plate and round steel wastes were used as scrapes. Foundry returns were the riser and waste casting of this grade of steel. They were melted in a 1.5 t medium frequency furnace. The spheroidizing was performed by dam-type package and tapping temperature was between 1 480℃ and 1 500 ℃. Ferrite nodulizer and Ba-Si-Fe inoculant were used and a secondary inoculation was carried out. Graphitizing annealing was in high temperature and divided into two steps. As a result, the nodulizing grade of the final casting was the second and the size of graphite was six grade. The volume fraction of ferrite was greater than 95% and that meet the technical requirements of mechanical properties.