IMPROVEMENT OF CREEP-RUPTURE STRENGTH OF HIGH CR FERRITIC STEEL BY ADDITION OF W

被引:50
作者
TSUCHIDA, Y [1 ]
OKAMOTO, K [1 ]
TOKUNAGA, Y [1 ]
机构
[1] NIPPON STEEL CORP LTD,STEEL RES LABS,TOKAI,AICHI 476,JAPAN
关键词
9CR FERRITIC STEEL; CREEP RUPTURE STRENGTH; W ADDITION; NBN; VN; M(23)C(6); GLOBULAR LAVES PHASE; FILM-LIKE LAVES PHASE; CR2C; COHERENCY STRAIN; SUBGRAIN SIZE;
D O I
10.2355/isijinternational.35.317
中图分类号
TF [冶金工业];
学科分类号
0806 ;
摘要
The effect of W addition on creep rupture strength (CRS) of high Cr ferritic steel was evaluated with three kinds of steels; base steel of 9Cr-1Mo-V-Nb-N, 0.7%W addition to base steel, and 1.7%W addition with decreased Mo addition to 0.5%. The latter two steels have the same values of Mo+0.5W vh. Mo equivalent. Further, the reasons for the beneficial effect of W was analyzed. The CRS at 600 degrees C for 1 000 h increases with W addition at a rate of 35 MPa/%W. As the hardness remains almost constant during the creep test, the enhancement of CRS could not be attributed to the formation of precipitate or cluster during the creep test. The W addition was found to increase the partition of Nb to VN, resulting in the lattice expansion of VN and enhancing the CRS through coherency strain around VN. This effect accounts for about half of the increase of CRS by W addition. The W addition also causes the precipitation of a film-like Laves phase along the subgrain boundary. Inconsequently, Cr2C precipitates simultaneously. The Laves phase contributes to the other half of the CRS increase, possibly through suppressing the growth of subgrain during the creep test.
引用
收藏
页码:317 / 323
页数:7
相关论文
共 18 条
[1]   OPTIMUM ALLOY COMPOSITIONS IN REDUCED-ACTIVATION MARTENSITIC 9CR STEELS FOR FUSION-REACTOR [J].
ABE, F ;
NODA, T ;
OKADA, M .
JOURNAL OF NUCLEAR MATERIALS, 1992, 195 (1-2) :51-67
[2]  
DEQUIDT E, 1991, J NUCL MATER, V179, P659
[3]  
FIJITA T, 1992, ISIJ INT, V32, P175
[4]  
ISEDA A, 1991, CAMP ISIJ, V4, P1991
[5]  
ISEDA A, 1988, FOSSILE ATOMIC POWER, V39, P897
[6]  
MASUYAMA F, 1987, MITSUBISHI JUKO GIHO, V24, P491
[7]  
NAOI H, 1992, NIPPON STEEL TECH RE, P27
[8]  
NIHEI I, 1990, 133TH NISH MEM SEM T, P211
[9]  
SHERBY OD, 1977, METALL T A, V6, P843
[10]  
SIKKA VK, 1983, JUN P TOP C FERR ALL, P317