锻造过程中钢锭内部孔洞型缺陷闭合规律研究  

THE VOID CLOSE BEHAVIOR OF LARGE INGOTS DURING HOT FORGING

作　　者：徐斌[1] 孙明月[1] 李殿中[1] 

机构地区：[1]中国科学院金属研究所沈阳材料科学国家(联合)实验室,沈阳110016

出　　处：《金属学报》2012年第10期1194-1200,共7页Acta Metallurgica Sinica

基　　金：国家自然科学基金资助项目51204157~~

摘　　要：对可能影响锻造过程中大型钢锭内部孔洞型缺陷闭合的各种因素进行了系统研究.结果表明,变形温度、应变速率、摩擦系数、试样尺寸和孔洞尺寸对锻造过程中孔洞的闭合基本没有影响,而试样高径比、孔洞位置和孔洞形状对孔洞的闭合有较大影响.其中试样高径比和孔洞位置通过影响孔洞周围的应变条件来影响孔洞闭合,是间接因素.孔洞所在位置的应变越大,孔洞越容易闭合.孔洞形状是影响孔洞闭合的直接因素,也是最本质的因素.为了描述这种现象,提出了孔洞高径比的概念.模拟结果显示,沿变形方向孔洞的高径比越大,孔洞越难闭合.基于以上研究和大钢锭的实际解剖结果,提出了全新的宽砧径向压实工艺(WRF法).该工艺可使应变集中于钢锭中心区域,并满足孔洞闭合所需的最佳高径比条件,因此,可高效愈合钢锭的中心缩孔、疏松.工业实验验证了该工艺的有效性和实用性.All the parameters that may affect void closure behavior are judged using finite element method （FEM）. The simulation results show that temperature, strain rate, friction coefficient, sample size and void size do not affect the void closure behavior. Height-diameter ratio of the sample and void position will affect the strain around the void and the void will be easier to close when the strain around it are higher. Of all the parameters, void shape is the most important one. Height-diameter ratio of the void is defined to describe the effect of void shape. The simulation results show that the larger height diameter ratio of the void, the harder it is for the void to close. Based on these results and the sectioning results of a 100 t ingot, a new forging method, wide-anvil radial forging （WRF） is proposed. WRF method can concentrate the strain on the center of the ingot; meet the optimum height-diameter ratio condition of the void closure and heal shrinkage cavities effectively. Experiments on continuous casting billets prove the effectiveness and applicability of this method.

关 键 词：孔洞闭合 孔洞高径比 宽砧径向压实法 

分 类 号：TG316[金属学及工艺—金属压力加工]