应用仪器化DWTT试验评价管线钢的动态韧断行为  

TO EVALUATE THE DYNAMIC DUCTILE FRACTURE OF PIPELINE STEELS BY USING INSTRUMENTED DROP WEIGHT TEAR TEST

作　　者：方健[1,2] 沈巍[2] 王磊[1] 

机构地区：[1]东北大学材料与冶金学院,沈阳110819 [2]宝山钢铁股份有限公司研究院,上海201900

出　　处：《机械强度》2015年第1期39-44,共6页Journal of Mechanical Strength

基　　金：宝山钢铁股份有限公司科研基金资助项目(Y12ECEC03Y)

摘　　要：基于三点弯曲试样韧断铰链模型,建立了根据加载点位移与韧带宽度关系定量评价材料裂纹尖端张开角度(CTOA)值的单试样方法。使用能量高达40k J的摆锤冲击机对压制缺口落锤撕裂试样(DWTT)试样实施仪器化冲击,采用关键曲线法验证了韧断过程中试样极限载荷与韧带宽度平方值的线性关系,进而提供了一种评测材料参数A*σf的试验方法。针对全板厚与减薄试样的试验结果表明,尽管由于初始韧带截面积的不同导致试样在承载耗能上存在显著差异,但在裂纹扩展阶段两组试样的CTOA值与变化趋势近似一致。所设定的对应裂纹长度25 mm^40 mm的稳态阶段,临界CTOA值,即CTOAC作为材料止裂性能的本征参数,其结果不受试样厚度影响而基本保持基本恒定。Derived from the hinge model for a single-edge notched bend specimen, a single specimen method to estimate CTOAc of high strength and toughness pipeline steels has been established, by regression of load line displacement against the logarithmic ligament during crack extension. As to monitor the crack behavior after crack initiation directly from an instrument load-displacement curve, the linear correlation between the limit load and the square of remaining ligament width has been confirmed by applying a huge 40kJ instrumented pendulum machine onto standard pressed-notch API X80 DWTT specimens and employing key curve method, which also provides an experimental way to determine the material based parameter of A ＊ o＇f, required by other CTOAc estimation algorithm. As a result, in spite of the difference in the dynamic load endurance and energy consumption between full-scale and thickness-reduction sample plates, the evolution tendency of CTOA during ductile cracking are similar to each other. Moreover, CTOAc values of both plates were determined to be constant over a given range of crack length from 25 to 40mm within steady-state stage, independent of specimen geometry.

关 键 词：落锤撕裂试验(DWTT) 仪器化冲击试验 裂纹尖端张开角度(CTOA) 管线钢 

分 类 号：TG115.5[金属学及工艺—物理冶金]