湿型砂力学本质特征曲线的研究

Study on Characteristic Curves of Green Sand

用自制的型砂多项性能测试仪,获得了型砂抗压、松弛、抗剪和抗拉测试过程中的应力 应变本质特征曲线,并对它们进行了深入研究,在特征曲线上确定了反映型砂本质性能的8项性能参数,考察了膨润土含量和紧实率对型砂本质特征曲线和型砂性能参数的影响。型砂力学本质特征曲线决定于型砂的内部微观组织结构,反映出型砂的粘弹性和粘塑性等本质性能,体现出型砂在受力变形过程中的微变形本质特征。

During the courses of compression,relaxation,shear and tensile tests,characteristic curves of green sand were obtained with the self-made molding sand multi-property tester.These characteristic curves were intensively studied, and eight parameters which reflect the essential properties of green sand were defined.Effects of bentonite percentage and compactibility on the characteristic curves and eight parameters were investigated.It is concluded that mechanical characteristic curves are determined by the microstructure of green sand,reflecting the essential properties of green sand such as visco-elasticity and visco-plasticity,and representing the nature of green sand microdeformation during the process of loading.