钢结构厚板的低温断裂韧性试验

针对钢结构厚板工程中脆性裂纹事故时有发生的问题,研究了钢材厚度与断裂韧性的关系.采用三点弯曲试样,利用厚板钢材Q345B在低温下对结构进行了裂纹尖端张开位移(CTOD)试验,试验选取了不同的钢板厚度、不同的试验温度和沿厚度方向不同的取样位置,分析了断裂韧性随钢板厚度、试验温度与取样位置的变化规律,并采用Boltzmann函数对断裂韧性随温度变化曲线进行了拟合,分析了各厚度钢板的韧脆转变温度.试验结果表明:厚板的断裂韧性随温度的降低而减小; 厚度较大的钢板其断裂韧性相对更差; 沿厚度方向从表面到中心位置,断裂韧性逐渐降低.

Fracture toughness tests at low temperature for thick plate in steel structures

In order to solve the problem that the brittle cracking accidents occasionally occur for the thick plates in steel structures, the relationship between the thickness and fracture toughness of steel was investigated. With adopting the three-point bending(TPB)specimens, the crack tip opening displacement(CTOD)tests for thick Q345B steel plates used for structures were carried out at low temperature. The different steel plate thickness, test temperatures and sampling locations along the thickness direction were selected in the tests. And the change rule for fracture toughness with steel plate thickness, test temperature and sampling location was analyzed. In addition, the change curves of fracture toughness with temperature were fitted with Boltzmann function, and the ductile to brittle transition temperature for the plates with various thickness was analyzed. The test results indicate that the fracture toughness of thick plates decreases with reducing the temperature, and the steel plates with larger thickness possess the relatively lower fracture toughness. Furthermore, the fracture toughness gradually reduces from surface to center position along the thickness direction.