Determination of continuous constitutive relationship of weld zone of high?strength steel rectangular welded tube
Hai‑long Liu1,2, Yu‑li Liu1,2, Zhong Yang2, Kun Wang2, Meng‑meng Liu1,2
1 Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, Guangdong, China 2 State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China
Determination of continuous constitutive relationship of weld zone of high?strength steel rectangular welded tube
Hai‑long Liu1,2, Yu‑li Liu1,2, Zhong Yang2, Kun Wang2, Meng‑meng Liu1,2
1 Research and Development Institute of Northwestern Polytechnical University in Shenzhen, Shenzhen 518057, Guangdong, China 2 State Key Laboratory of Solidification Processing, School of Materials Science and Engineering, Northwestern Polytechnical University, Xi’an 710072, Shaanxi, China
For QSTE700 high-strength steel rectangular welded tube, the mechanical properties of the weld zone vary with the distance from the centerline of the weld. Therefore, the accurate description of constitutive relationship of the weld zone is of great significance for the study of formability of QSTE700 rectangular welded tube. Firstly, the mechanical properties of parent and mixed specimens containing weld zone and parent zone were obtained by uniaxial tensile test. And based on the microhardness test, the width and the microhardness distribution of the weld zone were determined. Secondly, by subdividing the weld zone into several small areas, and combining with the rule of mixtures and nanoindentation test, the continuous functional relationships of strength coefficient K, hardening coeffecient n and elastic modulus E were obtained, and then, the continuous constitutive relationship of QSTE700 rectangular welded tube was established. Finally, the validity and reliability of the continuous constitutive relationship of welded tube were verified by nanoindentation test and rotary draw bending of rectangular welded tube. Besides, it was found that the finite element model of rotary draw bending of QSTE700 rectangular welded tube established by using the continuous constitutive relationship can well simulate the cross section deformation and wall thickness variation.
For QSTE700 high-strength steel rectangular welded tube, the mechanical properties of the weld zone vary with the distance from the centerline of the weld. Therefore, the accurate description of constitutive relationship of the weld zone is of great significance for the study of formability of QSTE700 rectangular welded tube. Firstly, the mechanical properties of parent and mixed specimens containing weld zone and parent zone were obtained by uniaxial tensile test. And based on the microhardness test, the width and the microhardness distribution of the weld zone were determined. Secondly, by subdividing the weld zone into several small areas, and combining with the rule of mixtures and nanoindentation test, the continuous functional relationships of strength coefficient K, hardening coeffecient n and elastic modulus E were obtained, and then, the continuous constitutive relationship of QSTE700 rectangular welded tube was established. Finally, the validity and reliability of the continuous constitutive relationship of welded tube were verified by nanoindentation test and rotary draw bending of rectangular welded tube. Besides, it was found that the finite element model of rotary draw bending of QSTE700 rectangular welded tube established by using the continuous constitutive relationship can well simulate the cross section deformation and wall thickness variation.
Hai‑long Liu,Yu‑li Liu,Zhong Yang, et al. Determination of continuous constitutive relationship of weld zone of high?strength steel rectangular welded tube[J]. Journal of Iron and Steel Research International, 2020, 27(10): 1212-1225.
2020, Vol. 27 
