The hot deformation behavior of 316H stainless steel used in the 4th-generation nuclear systems was investigated by thermal compression tests at 1000–1150 C and 0.01–10 s^(-1).It was found that true stress firstly i...The hot deformation behavior of 316H stainless steel used in the 4th-generation nuclear systems was investigated by thermal compression tests at 1000–1150 C and 0.01–10 s^(-1).It was found that true stress firstly increased and then decreased with the increasing strain rate with a threshold of 1 s^(-1).Electron backscatter diffraction was used to analyze the microstructure evolution.Discontinuous dynamic recrystallization(DDRX)was the dominant dynamic recrystallization(DRX)mechanism,while continuous dynamic recrystallization(CDRX)was the supplementary one.DDRX happened before CDRX and provided additional nucleation sites for the latter.Twin grain boundaries(R3)appeared in DRX grains due to growth accidents.As the length fraction of R3 increased,the coincidence site lattice(CSL)boundary transition began to occur,forming R9 and R27.After the occurrence of full DRX,the growth and annexation of DRX grains were easy to be promoted,in which progress both equiaxed grains and CSL boundaries disappeared.The ideal deformation microstructure with fine and uniform DRX grains,which was accompanied by a high length fraction of CSL boundaries,appeared at 1000℃–0.01 s^(-1),1050℃–0.01–0.1 s^(-1),1100℃–0.1–1 s^(-1) and 1150℃–1–10 s^(-1).That is,the deformation conditions mentioned above were the preferable thermal forming parameters for 316H stainless steel in actual productions.展开更多
通过对成分计算、熔炼工艺和电渣渣系分析、均质化退火工艺试验等方法,对20 t EAF-A0D-LF-VD-φ430 mm电极-φ590 mm ESR锭-均质处理-φ310 mm锻材流程生产的核电用钢超纯316H工艺进行研究。当成分(/%)满足0.042~0.047C,≤0.55Si,1.60~1...通过对成分计算、熔炼工艺和电渣渣系分析、均质化退火工艺试验等方法,对20 t EAF-A0D-LF-VD-φ430 mm电极-φ590 mm ESR锭-均质处理-φ310 mm锻材流程生产的核电用钢超纯316H工艺进行研究。当成分(/%)满足0.042~0.047C,≤0.55Si,1.60~1.80Mn,17.00~17.30Cr,12.20~12.40Ni,2.50~2.60Mo,≤5×10^(-6)H,≤30×10^(-6)O,0.055~0.070N时,将φ430 mm电极采用CaF_(2):Al_(2)O_(3):CaO=60%:30%:10%渣系电渣成φ590mm锭,在1200~1250℃经过30h均质化处理后,能够生产出符合标准的产品,实物夹杂物级别为A,C0级,B_(细)0.5级,B_(粗)0级,D_(细)1.0级,D_(粗)0~0.5级,D_(s)(0~0.5)级;铁素体含量≤0.5%。展开更多
基金This work was supported by China Postdoctoral Science Foundation(No.2019M661738)Opening Project of Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology(No.ASMA202002)Postgraduate Research and Practice Innovation Program of Jiangsu Province(No.SJCX21_1703).
文摘The hot deformation behavior of 316H stainless steel used in the 4th-generation nuclear systems was investigated by thermal compression tests at 1000–1150 C and 0.01–10 s^(-1).It was found that true stress firstly increased and then decreased with the increasing strain rate with a threshold of 1 s^(-1).Electron backscatter diffraction was used to analyze the microstructure evolution.Discontinuous dynamic recrystallization(DDRX)was the dominant dynamic recrystallization(DRX)mechanism,while continuous dynamic recrystallization(CDRX)was the supplementary one.DDRX happened before CDRX and provided additional nucleation sites for the latter.Twin grain boundaries(R3)appeared in DRX grains due to growth accidents.As the length fraction of R3 increased,the coincidence site lattice(CSL)boundary transition began to occur,forming R9 and R27.After the occurrence of full DRX,the growth and annexation of DRX grains were easy to be promoted,in which progress both equiaxed grains and CSL boundaries disappeared.The ideal deformation microstructure with fine and uniform DRX grains,which was accompanied by a high length fraction of CSL boundaries,appeared at 1000℃–0.01 s^(-1),1050℃–0.01–0.1 s^(-1),1100℃–0.1–1 s^(-1) and 1150℃–1–10 s^(-1).That is,the deformation conditions mentioned above were the preferable thermal forming parameters for 316H stainless steel in actual productions.
文摘通过对成分计算、熔炼工艺和电渣渣系分析、均质化退火工艺试验等方法,对20 t EAF-A0D-LF-VD-φ430 mm电极-φ590 mm ESR锭-均质处理-φ310 mm锻材流程生产的核电用钢超纯316H工艺进行研究。当成分(/%)满足0.042~0.047C,≤0.55Si,1.60~1.80Mn,17.00~17.30Cr,12.20~12.40Ni,2.50~2.60Mo,≤5×10^(-6)H,≤30×10^(-6)O,0.055~0.070N时,将φ430 mm电极采用CaF_(2):Al_(2)O_(3):CaO=60%:30%:10%渣系电渣成φ590mm锭,在1200~1250℃经过30h均质化处理后,能够生产出符合标准的产品,实物夹杂物级别为A,C0级,B_(细)0.5级,B_(粗)0级,D_(细)1.0级,D_(粗)0~0.5级,D_(s)(0~0.5)级;铁素体含量≤0.5%。
