The influence of the secondary thermal cycle on the microstructure of coarse grain heat-affected zone in an XIO0 pipeline steel was investigated by means of a thermal simulation technique and microscopic analysis meth...The influence of the secondary thermal cycle on the microstructure of coarse grain heat-affected zone in an XIO0 pipeline steel was investigated by means of a thermal simulation technique and microscopic analysis method. The property of coarse grain heat-affected zone was characterized by Charpy V-Notch impact properties testing. The results indicated that the experimental steel exhibited local brittleness of intercritically reheated coarse-grained heat-affected zone when the peak tempera- ture of secondary thermal cycle was in the range of two phases region （ ~ and 3/）. There were two main reasons for the local brittleness. The first was that the microstructures of intercritically reheated coarse-grained heat-affected zone were not fined although partial grain recrystallization occurred. The second was that M-A islands, which had the higher content, larger size and higher hardness, existed in intercritically reheated coarse-grained heat-affected zone.展开更多
This paper deals with structure and impact energy of weld HAZ of 10CrNi3MoV steel after secondary weld thermal cycle (t_ 8/5 =8 s ～120 s ; peak temperature T_ m =750 ℃ ～1 300 ℃ ). It is demonstrated that the c...This paper deals with structure and impact energy of weld HAZ of 10CrNi3MoV steel after secondary weld thermal cycle (t_ 8/5 =8 s ～120 s ; peak temperature T_ m =750 ℃ ～1 300 ℃ ). It is demonstrated that the coarse grain and structure produced by first thermal cycle keep unchanged after secondary thermal cycle above Ac_ 1 critical temperature but below 1 050 ℃ . At the same time the low temperature impact energy decreases obviously with increasing t_ 8/5 . By metallurgical microscope and transmission electron microscope(TEM) , it is revealed that the effect of coarse grain and structure caused by secondary thermal cycle on low temperature impact energy.展开更多
基金This work was supported by the National Natural Science Foundation of China（ No. 50874090）.
文摘The influence of the secondary thermal cycle on the microstructure of coarse grain heat-affected zone in an XIO0 pipeline steel was investigated by means of a thermal simulation technique and microscopic analysis method. The property of coarse grain heat-affected zone was characterized by Charpy V-Notch impact properties testing. The results indicated that the experimental steel exhibited local brittleness of intercritically reheated coarse-grained heat-affected zone when the peak tempera- ture of secondary thermal cycle was in the range of two phases region （ ~ and 3/）. There were two main reasons for the local brittleness. The first was that the microstructures of intercritically reheated coarse-grained heat-affected zone were not fined although partial grain recrystallization occurred. The second was that M-A islands, which had the higher content, larger size and higher hardness, existed in intercritically reheated coarse-grained heat-affected zone.
文摘This paper deals with structure and impact energy of weld HAZ of 10CrNi3MoV steel after secondary weld thermal cycle (t_ 8/5 =8 s ～120 s ; peak temperature T_ m =750 ℃ ～1 300 ℃ ). It is demonstrated that the coarse grain and structure produced by first thermal cycle keep unchanged after secondary thermal cycle above Ac_ 1 critical temperature but below 1 050 ℃ . At the same time the low temperature impact energy decreases obviously with increasing t_ 8/5 . By metallurgical microscope and transmission electron microscope(TEM) , it is revealed that the effect of coarse grain and structure caused by secondary thermal cycle on low temperature impact energy.
