Segregation and homogenization treatment of 5%Si high silicon austenitic stainless steel
HU Yong1,2, WANG Li-hua1,2, LIN Hong-ze1,2, OUYANG Ming-hui3, CHU Cheng1, HU Yong-qi1
1. State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology, Lanzhou 730050, Gansu, China; 2. Wenzhou Pump and Valve Engineering Research Institute, Lanzhou University of Technology, Yongjia 325105, Zhejiang, China; 3. Corrosion-resistant Special Metal Materials Research Institute, Zhejiang Xuanda Group, Yongjia 325105, Zhejiang, China
Abstract:High-silicon austenitic stainless steel has excellent high-temperature corrosion resistance properties and low cost due to the addition of high content silicon,and it has potential application value in the acid industry. However, the addition of high content Si will promote the redistribution of solute during solidification process, which will cause significant element segregation,and ultimately lead to the formation of dendritic structure and numerous harmful phases in the alloy. Homogenizing the ingot structure can effectively eliminate dendrites and element segregation,promote precipitation phase re-dissolution and dendrite ablation,thereby improving the thermoplasticity of material,and effectively coping with the problems of thermal deformation and cracking. Therefore,the work studied the microstructure and element distribution of 5%Si high-silicon austenitic stainless steel ingots prepared under laboratory conditions through metallographic microscope (OM), scanning electron microscope/energy spectrum analysis (SEM/EDS), Electronic probe (EPMA), JMatPro software calculation and other methods. Finally,a reasonable homogenization treatment process for 5%Si high-silicon austenitic stainless steel was confirmed using the calculation of residual segregation index and diffusion kinetics,combined with homogenization treatment experiments. The results show that Mo is the most serious segregation element during the solidification of 5%Si high-silicon austenitic stainless steel,the homogenization kinetic equation calculated by residual segregation index model can be used to guide the homogenization treatment process of this alloy. After homogenizing at 1 150 ℃×12 h,the dendrites in 5%Si high-silicon austenitic stainless steel ingot are ablated and element segregation is eliminated,the precipitated phase and ferrite are re-dissolved into the matrix,the alloy is transformed into full austenite structure and thermoplasticity is improved. When the temperature is increased to 1 250 ℃,the alloy is overheated and grain boundaries begin to melt.
胡勇, 王力华, 林鸿泽, 欧阳明辉, 褚成, 胡永淇. 5%Si高硅奥氏体不锈钢元素偏析及均匀化处理[J]. 钢铁, 2022, 57(4): 114-122.
HU Yong, WANG Li-hua, LIN Hong-ze, OUYANG Ming-hui, CHU Cheng, HU Yong-qi. Segregation and homogenization treatment of 5%Si high silicon austenitic stainless steel[J]. Iron and Steel, 2022, 57(4): 114-122.
[1] 刘焕安,邱德良,赵成永. 高温浓硫酸用DS-1高硅不锈钢板材的研制[J]. 硫酸工业,2003(1):18.(LIU Huan-an,QIU De-liang,ZHAO Cheng-yong. Development of DS-1 high-silicon stainless steel sheet for high-temperature concentrated sulfuric acid[J]. Sulfuric Acid Industry,2003(1):18.) [2] 张亚彬, 任建斌, 王锦永, 等. S31254超级奥氏体不锈钢析出相演变及微观表征[J]. 中国冶金, 2021, 31(12): 61. (ZHANG Ya-bin, REN Jian-bin, WANG Jin-yong, et al. Evolution and microstructure characterization of precipitate phases in S31254 super austenitic stainless steel[J]. China Metallurgy, 2021, 31(12): 61.) [3] 曾莉,张威,王琦,等. 超级奥氏体不锈钢的高温变形行为[J]. 钢铁, 2017, 52(10): 72. (ZENG Li, ZHANG Wei,WANG Qi,et al. Hot deformation behavior of super austenitic stainless steel[J]. Iron and Steel, 2017, 52(10): 72.) [4] 李勇华,邵远敬,贺立红. 热轧奥氏体不锈钢带钢酸洗工艺机理分析[J]. 钢铁, 2014, 49(10): 58. (LI Yong-hua, SHAO Yuan-jing, HE Li-hong. Analysis of pickling process mechanism of hot-rolled austenitic stainless steel strip[J]. Iron and Steel, 2014, 49(10): 58.) [5] 欧阳明辉,刘焕安,叶际宣. 不锈钢在浓硫酸中的腐蚀探讨[J]. 全面腐蚀控制,2015,29(8):39.(OUYANG Ming-hui,LIU Huan-an,YE Ji-xuan. Discussion on the corrosion of stainless steel in concentrated sulfuric acid[J]. Total Corrosion Control,2015,29(8):39.) [6] Robin R,MiserqueF,Spagnol V. Correlation between composition of passive layer and corrosion behavior of high Si-containing austenitic stainless steels in nitric acid[J]. J Nucl Mater,2008,375(1):65. [7] 王玮,罗明,张启富. 硅对含强氧化性离子沸腾硝酸中奥氏体不锈钢耐蚀性的影响[J]. 钢铁研究学报,2009,21(8):41.(WANG Wei,LUO Ming,ZHANG Qi-fu. The effect of silicon on the corrosion resistance of austenitic stainless steel in boiling nitric acid containing strong oxidizing ions[J]. Journal of Iron and Steel Research,2009,21(8):41.) [8] 谢霞,乔军,贺立红. 热轧奥氏体不锈钢无硝酸酸洗工艺机理分析[J]. 轧钢, 2020, 37(2): 64.(XIE Xia, QIAO Jun,HE Li-hong. Analysis of mechanism in pickling process without HNO3 for hot rolled austenitic stainless steel[J]. China Rolling, 2020, 37(2): 64.) [9] 侯向东, 李彦鑫, 史学红, 等. 固溶处理对冷轧Cr-Mn-N奥氏体不锈钢组织性能的影响[J]. 中国冶金, 2020, 30(12): 59. (HOU Xiang-dong, LI Yan-xin, SHI Xue-hong, et al. Effect of solution treatment on microstructure and properties of a cold-rolled Cr-Mn-N austenitic stainless steel[J]. China Metallurgy, 2020, 30(12): 59.) [10] 翁建寅,彭伟,鲍贤勇,等.无镍高氮奥氏体不锈钢软化工艺研究[J].上海金属,2020,42(6):99.(WENG Jian-yin,PENG Wei, BAO Xian-yong, et al. Study on softening process for nickel-free high-nitrogen austenitic stainless steel[J]. Shanghai Metal, 2020,42(6):99.) [11] 宁小智,邢长军,雍歧龙,等. 氮含量对无镍奥氏体不锈钢理化性能的影响[J]. 中国冶金, 2019, 29(6): 34. (NING Xiao-zhi, XING Chang-jun, YONG Qi-long, et al. Effects of nitrogen content on physical and chemical properties of nickel free austenitic stainless steels[J]. China Metallurgy, 2019, 29(6): 34.) [12] 陈思含,梁田,张龙,等. 6%Si高硅奥氏体不锈钢固溶处理过程中 bcc 相的演变机制研究[J]. 金属学报,2017,53(4):397.(CHEN Si-han,LIANG Tian,ZHANG Long,et al. Study on the evolution mechanism of bcc phase during solution treatment of 6%Si high silicon austenitic stainless steel[J]. Acta Metallurgica Sinica,2017,53(4):397.) [13] 高建兵,范思鹏,张树才,等. 新型超级奥氏体不锈钢654SMO偏析行为及均匀化工艺[J]. 钢铁,2018,53(8):83.(GAO Jian-bing,FAN Si-peng,ZHANG Shu-cai,et al. Segregation behavior and homogenization process of new super austenitic stainless steel 654SMO[J]. Iron and Steel,2018,53(8):83.) [14] 赵朋, 杨树峰, 杨曙磊, 等. 镍基高温合金均质化冶炼研究进展[J]. 中国冶金, 2021, 31(4): 1. (ZHAO Peng, YANG Shu-feng, YANG Shu-lei, et al. Research process in homogenized smelting of nickle-based superalloy[J]. China Metallurgy, 2021, 31(4): 1.) [15] 李文才,吴浩,崔恩强,等.一种新型Er、Zr微合金化Al-Zn-Mg-Cu合金的均匀化处理[J].上海金属,2021,43(1):67.(LI Wen-cai,WU Hao, CUI En-qiang, et al.Homogenizing treatment of a new Al-Zn-Mg-Cu alloy microalloyed with Er and Zr[J]. Shanghai Metal, 2021,43(1):67.) [16] 龙正东,马培立,仲增墉. IN706合金锭的均匀化处理[J]. 钢铁研究学报,1997,9(1):25.(LONG Zheng-dong,MA Pei-li,ZHONG Zeng-yong. Homogenization of IN706 alloy ingot[J]. Journal of Iron and Steel Research,1997,9(1):25.) [17] 李海峰. 铸态GH3625合金均匀化处理及热变形行为研究[D]. 兰州:兰州理工大学,2016.(LI Hai-feng. Homogenization Treatment and Hot Deformation Behavior of As-cast GH3625 Alloy[D]. Lanzhou:Lanzhou University of Technology,2016.) [18] 曾莉,张威,王岩. 超级奥氏体不锈钢偏析行为及元素再分配规律[J]. 材料热处理学报,2015,36(4):232.(ZENG Li,ZHANG Wei,WANG Yan. Segregation behavior and element redistribution law of super austenitic stainless steel[J]. Transactions of Materials and Heat Treatment,2015,36(4):232.) [19] 周荣青,孙维连,贾玉挺. 铸造316L不锈钢偏析及其均匀化处理研究[J]. 材料热处理学报,2017,38(4):106.(ZHOU Rong-qing,SUN Wei-lian,JIA Yu-ting. Research on segregation and homogenization of cast 316L stainless steel[J]. Transactions of Materials and Heat Treatment,2017,38(4):106.) [20] 李红梅,聂义宏,张鑫,等. 均匀化处理对铸态GH625合金组织的影响[J]. 材料热处理学报,2019,40(3):75.(LI Hong-mei,NIE Yi-hong,ZHANG Xin,et al. The effect of homogenization treatment on the structure of as-cast GH625 alloy[J]. Transactions of Materials and Heat Treatment,2019,40(3):75.) [21] Di Schino A,Mecozzi M G,Barteri M,et al. Solidification mode and residual ferrite in low-Ni austenitic stainless steels[J]. Journal of Materials Science,2000,35(2):375. [22] 彭志方,任遥遥,梅青松,等.镍基单晶高温合金CMSX-2原始树枝状晶中γ'相的定向粗化[J]. 金属学报,1999(9):902.(PENG Zhi-fang,REN Yao-yao,MEI Qing-song,et al. Directional coarsening of γ' phase in primary dendrites of nickel-based single crystal superalloy CMSX-2[J]. Acta Metallurgica Sinica,1999(9):902.) [23] 朱冠妮,毕中南,董建新,等. 镍基耐蚀合金C-276铸锭元素偏析和均匀化工艺[J]. 北京科技大学学报,2010,32(5):628.(ZHU Guan-ni,BI Zhong-nan,DONG Jian-xin,et al. Elemental segregation and homogenization process of nickel-based corrosion resistant alloy C-276 ingot[J]. Journal of University of Science and Technology Beijing,2010,32(5):628.) [24] 田玉亮,王玲,董建新,等. GH742铸锭偏析及均匀化过程中元素分布规律[J]. 稀有金属材料与工程,2006(8):1315.(TIAN Yu-liang,WANG Ling,DONG Jian-xin,et al. Element distribution law during segregation and homogenization of GH742 ingot[J]. Rare Metal Materials and Engineering,2006(8),1315.) [25] 李阳,李莎,曾莉,等. GH4700合金偏析行为及均匀化过程中元素分配的规律[J]. 材料热处理学报,2013,34(6):52.(LI Yang,LI Sha,ZENG Li,et al. Segregation behavior of GH4700 alloy and the law of element distribution in the homogenization process[J]. Transactions of Materials and Heat Treatment,2013,34(6):52) [26] 李科敏,杨玉军,王志刚,等. GH350合金铸锭元素偏析及其均匀化热处理[J]. 钢铁研究学报,2012,24(7):54.(LI Ke-min,YANG Yu-jun,WANG Zhi-gang,et al. Elemental segregation and homogenization heat treatment of GH350 alloy in-gots[J]. Journal of Iron and Steel Research,2012,24(7):54.) [27] 彭坤,杨弋涛,张洪奎,等. 合金钢锭铬元素高温均质化过程的动力学分析[J]. 材料热处理学报,2010,31(5):87.(PENG Kun,YANG Yi-tao,ZHANG Hong-kui,et al. Kinetic analysis of high temperature homogenization process of chromium in alloy steel ingots[J]. Transactions of Materials and Heat Treatment,2010,31(5):87.) [28] Paul S. Diffusion in Solids[M]. Berlin: Springer,2016. [29] LIU X G,MENG D N,WANG Y H,et al. Influences of high-temperature diffusion on the homogenization and high-temperature fracture behavior of 30Cr1Mo1V[J]. Journal of Materials engineering and Performance,2015,24(2):1079. [30] 梅声勇,郑磊,蒙肇斌,等. GH105合金铸锭元素偏析和均匀化工艺[J]. 北京科技大学学报,2009,31(6):714.(MEI Sheng-yong,ZHENG Lei,MENG Zhao-bin,et al. Elemental segregation and homogenization process of GH105 alloy ingot[J]. Journal of University of Science and Technology Beijing,2009,31(6):714.) [31] Le Claire A D. Solute diffusion in dilute alloys[J]. Journal of Nuclear Materials,1978,69/70:70. [32] Askill J. Empirical and Semi-Empirical Diffusion Relations[M]. Boston: Springer,1970. [33] Campbell C E,Boettinger W J,Kattner U R. Development of a diffusion mobility database for Ni-base superalloys[J]. Acta Mater,2002,50(4):775. [34] Dinsdale A T. SGTE data for pure elements[J]. Calphad,1991,15(4):317.