Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Sn heat treatmentNakajima, Hideo; Hamada, Kazuya; Takano, Katsutoshi*; Okuno, Kiyoshi; Fujitsuna, Nobuyuki*
IEEE Transactions on Applied Superconductivity, 14(2), p.1145 - 1148, 2004/06
Times Cited Count：36 Percentile：78.60(Engineering, Electrical & Electronic)In ITER, the conductor for the Central Solenoid (CS) uses Incoloy 908, which requires special environment control to prevent cracks caused by Stress Accelerated Grain Boundary Oxidation (SAGBO) during Nb3Sn heat treatment. Use of a stainless steel jacket can simplify the design and fabrication because the special caution is not required for SAGBO. JAERI has already developed high manganese, JK2, whose thermal contraction from 300K to 4 K is almost the same as that of Incoloy: thus no change in the mechanical design of the CS is necessary. However, during the heat treatment, phosphorus enhances embrittlement of JK2. Carbon reduction and boron addition was considered to be a possible solution to mitigate the phosphorus effect. Jackets of low carbon and boron added JK2(JK2LB) were produced and tensile properties, fracture toughness, and crack propagation rate were measured at 4K. Elongation and fracture toughness at 4K after the heat treatment are 33% and 91 MPam
for the final jacket, which satisfy the ITER targets. JK2LB can be applied to the ITER CS.
Kato, Teruo; Maeta, Hiroshi
Teion Kogaku, 30(3), p.143 - 149, 1995/00
no abstracts in English
Jiang, L.*; Wang, H. H.*; Xu, P. G.; Su, Y. H.; Shinohara, Takenao; Wang, Y. W.*
no journal, ,
High manganese austenitic steels as a cryogenic structural material are widely applied in the pressurized storage infrastructures for storing and transporting liquefied natural gas (LNG), liquefied hydrogen (LH). Considering that cryogenic impact toughness is important in predicting the service performance of high manganese austenitic steel, it is critical for analyzing residual strain and plastic deformation evolution in impacted fractures and for deeply understanding the deformation and fracture mechanisms. Here, the strain and plastic deformation evolution of impacted fractures in high manganese steel (24Mn-4Cr-0.4C-0.3Cu) were comparably investigated by neutron Bragg-edge transmission (BET) imaging and electron back scattering diffraction (EBSD) at various cryogenic temperatures. The BET results show that the residual strain 
111 is negative and 200 is positive in the region with large plastic deformation near the fracture. However, 111 and 200 in the region far away from the fracture show similar distribution in the V-notched impact sample at the same temperature. With the decrease of impact temperature, the high broadening area of Bragg-edge width near the fracture gradually decreased, revealing that the local plastic strain during cryogenic impact deformation in the corresponding area decreased, which is primarily consistent in the change trend of impact toughness value obtained at various temperatures. EBSD results show evident difference in the local distribution density of 
111
and 200-oriented grains in the region near the fracture after cryogenic impacting. It is suggested that the steel texture is a primary reason for clarifying the different distribution features of 111 and 200 in the region near the cryogenic impact fracture.
