Influence of specimen dimension on fracture toughness testing results of railway wheel steel
XIAO Feng 1， LU Lian-tao 2， ZOU Lang 2
1. Maanshan Iron and Steel Co.， Ltd.， Ma'anshan 243000， China； 2. State Key Laboratory of Traction Power， Southwest Jiaotong University，Chengdu 610031， China
Abstract：The fracture toughness of ER6 railway wheel steel was tested using CT specimens with different dimensions. The variations of both plane strain layer thickness of specimen and plastic zone size at crack tip with the specimen dimension in testing were analyzed by the finite element method. It was found that when the plane strain fracture toughness test of ER6 railway wheel steel using CT specimens with thickness of 30-50 mm could not meet the conditions of neither plane strain nor small range yield. The increase of specimen thickness could increase the plane strain layer area and reduce the small yield range zone， thereby effectively alleviate the bending of elastic segment in P-V curve. At this time， the testing results were closer to the true fracture toughness level of ER6 wheel steel.
2020, Vol. 38 
