Hot-tearing cracks usually form near the solidus temperature. It is caused by a combination of tensile stress and metallurgical embrittlement. In order to quantify embrittlement and to incorporate it in the thermal-st...Hot-tearing cracks usually form near the solidus temperature. It is caused by a combination of tensile stress and metallurgical embrittlement. In order to quantify embrittlement and to incorporate it in the thermal-stress analysis, many different criteria have been developed. Among them,the submerged split-chill tensile （SSCT） test is an efficient one. This paper tries to use SSCT to estimate the critical strain of hot tearing for some steels.展开更多
A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API （American Petroleum Institute） X80 strip steel was investigated in this work. Microstructural analysis showed that th...A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API （American Petroleum Institute） X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. acicular ferrite in thick-walled X80 pipeline steel in order Some methods were proposed to obtain fine and homogeneous to minimize the occurrence of separation.展开更多
In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and...In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and each plane of the grains. Smaller θ means easier to crack. It gave a good explanation of the crack propagation throughout the grains. It also revealed that propagation path is along with the plane. This finding will give a prediction of tear properties and help us understanding the cracking mechanism and the behavior of tearing.展开更多
文摘Hot-tearing cracks usually form near the solidus temperature. It is caused by a combination of tensile stress and metallurgical embrittlement. In order to quantify embrittlement and to incorporate it in the thermal-stress analysis, many different criteria have been developed. Among them,the submerged split-chill tensile （SSCT） test is an efficient one. This paper tries to use SSCT to estimate the critical strain of hot tearing for some steels.
文摘A separation phenomenon occurring during the drop weight tear test of commercial thick-walled API （American Petroleum Institute） X80 strip steel was investigated in this work. Microstructural analysis showed that the band structure of bainite elongated along the rolling direction works as the initiation sites of separation. The propagation of separation can be promoted not only by the occurrence of the band structure of martensite/austenite constituent, prior austenite grain boundaries, and elongated bainite, but also by fine acicular ferrite and bainite. Wide separation formed in the former case, while the narrow one appeared in the latter case. acicular ferrite in thick-walled X80 pipeline steel in order Some methods were proposed to obtain fine and homogeneous to minimize the occurrence of separation.
文摘In this paper, the orientation of grains which adjacent to a developed opening crack was investigated by EBSD. A definition of θ has been came up with which represents the angle between the principal stress plane and each plane of the grains. Smaller θ means easier to crack. It gave a good explanation of the crack propagation throughout the grains. It also revealed that propagation path is along with the plane. This finding will give a prediction of tear properties and help us understanding the cracking mechanism and the behavior of tearing.
