Effects of W on Creep Behaviors of Novel Nb-Bearing Austenitic Heat-Resistant Cast Steels at 1000 ℃
Received date: 2017-01-03
Online published: 2017-05-16
Supported by
Supported by Ford China University Research Program and Fundamental Research Funds for the Central Universities (No.FRF-IC-16-005)
In order to comply with more stringent emissions and fuel economy regulations worldwide, the operation temperature of exhaust components for automotive gasoline engines is now reaching to as high as 1000 ℃, about 200 ℃ higher than the conventional standard. As a result, the incumbent materials for exhaust manifolds and turbine housings are being pushed beyond their high-temperature strength and oxidation limitations. Therefore, there is an urgent demand from automotive industries to develop novel and cost-effective alloys those durable against these increased temperatures. In this work, the effect of W additions on the creep behavior of a series of Nb-bearing austenitic heat-resistant cast steels is investigated at 1000 ℃ and 50 MPa. Microstructures before and after creep rupture tests are carefully characterized to investigate the microstructural evolution during creep deformation. The minimum creep rate of these alloys shows a trend from decline to rise as the W addition is increased. Microstructural analyses reveal that the W addition does not affect the formation of primary Nb(C, N), whereas significantly improves the precipitation of Cr-rich carbides, as well as accelerating the phase transformation from (Cr, Fe, W)7C3 to (Cr, Fe, W)23C6. Moreover, the excessive addition of W leads to the formation of the interme tallic χ-phase. During creep deformation, the secondary precipitation of nano-scale Nb(C, N) also aids in the strengthening of the creep resistance through pinning the dislocations. However, the cellular Cr-rich phase that contains χ-phase significantly accelerates the nucleation and propagation of creep cracks, thereby increasing the creep rate and decreasing the creep life.
Yinhui ZHANG , Qiang FENG . Effects of W on Creep Behaviors of Novel Nb-Bearing Austenitic Heat-Resistant Cast Steels at 1000 ℃[J]. Acta Metall Sin, 2017 , 53(9) : 1025 -1037 . DOI: 10.11900/0412.1961.2017.00002
| [1] | Matsumoto K, Tojo M, Jinnai Y, et al.Development of compact and high performance turbocharger for 1050 ℃ exhaust gas[J]. Mitsubishi Heavy Ind. Tech. Rev., 2008, 45(3): 1 |
| [2] | Kunanoppadon J.Thermal efficiency of a combined turbocharger set with gasoline engine[J]. Am. J. Engg. Applied Sci., 2010, 3: 342 |
| [3] | Ebisu M, Terakawa Y, Ibaraki S.Mitsubishi turbocharger for lower pollution cars[J]. Mitsubishi Heavy Ind. Tech. Rev., 2004, 41(1): 40 |
| [4] | An B, Shiraishi T.Development of variable two-stage turbocharger for passenger car diesel engines[J]. Mitsubishi Heavy Ind. Tech. Rev., 2010, 47(4): 7 |
| [5] | Itoh K, Hayashi K, Souda T.Development of HERCUNITE?-S NSHR?-A5N for high performance gasoline engines[J]. Hitachi Metals Tech. Rev., 2006, 22: 51 |
| [6] | Shingledecker J P, Maziasz P J, Evans N D, et al.Creep behavior of a new cast austenitic alloy[J]. Int. J. Pres. Ves. Pip., 2007, 84: 21 |
| [7] | Takabayashi H, Ueta S, Shimizu T, et al.Development of thermal fatigue resistant ferritic cast steel for turbine housing of diesel engine automobile[J]. SAE Int. J. Mater. Manuf., 2009, 2: 147 |
| [8] | Perron A, Toffolon-Masclet C, Ledoux X, et al.Understanding sigma-phase precipitation in a stabilized austenitic stainless steel (316Nb) through complementary CALPHAD-based and experimental investigations[J]. Acta Mater., 2014, 79: 16 |
| [9] | Erneman J, Schwind M, Liu P, et al.Precipitation reactions caused by nitrogen uptake during service at high temperatures of a niobium stabilised austenitic stainless steel[J]. Acta Mater., 2004, 52: 4337 |
| [10] | Erneman J, Schwind M, Andrén H O, et al.The evolution of primary and secondary niobium carbonitrides in AISI 347 stainless steel during manufacturing and long-term ageing[J]. Acta Mater., 2006, 54: 67 |
| [11] | Yamamoto Y, Brady M P, Santella M L, et al.Overview of strategies for high-temperature creep and oxidation resistance of alumina-forming austenitic stainless steels[J]. Metall. Mater. Trans., 2011, 42A: 922 |
| [12] | Pickering F B.Physical Metallurgy and the Design of Steels[M]. London: Applied Science Publishers Ltd, 1978: 12 |
| [13] | Medvedeva N I, Van Aken D C, Medvedeva J E. Stability of binary and ternary M23C6 carbides from first principles[J]. Comp. Mater. Sci., 2015, 96: 159 |
| [14] | Yamamoto Y, Santella M L, Brady M P, et al.Effect of alloying additions on phase equilibria and creep resistance of alumina-forming austenitic stainless steels[J]. Metall. Mater. Trans., 2009, 40A: 1868 |
| [15] | Jung S, Sohn S S, Jo Y H, et al.Effects of Cr and Nb addition on high-temperature tensile properties in austenitic cast steels used for turbo-charger application[J]. Mater. Sci. Eng., 2016, A677: 316 |
| [16] | Jung S, Jeon C, Jo Y H, et al.Effects of tungsten and molybdenum on high-temperature tensile properties of five heat-resistant austenitic stainless steels[J]. Mater. Sci. Eng., 2016, A656: 190 |
| [17] | Kim Y J, Lee D G, Jeong H K, et al.High temperature mechanical properties of HK40-type heat-resistant cast austenitic stainless steels[J]. J. Mater. Eng. Perform., 2010, 19: 700 |
| [18] | Taneike M, Abe F, Sawada K.Creep-strengthening of steel at high temperatures using nano-sized carbonitride dispersions[J]. Nature, 2003, 424: 294 |
| [19] | Sherby O D, Burke P M.Mechanical behavior of crystalline solids at elevated temperature[J]. Prog. Mater. Sci., 1968, 13: 323 |
| [20] | Rieth M, Falkenstein A, Graf P, et al.Creep of the austenitic steel AISI 316 L(N): Experiments and models [R]. Wissenschaftliche Berichte FZKA 7065, 2004: 1 |
| [21] | Zhang Y H, Li M, Godlewski L A, et al.Effects of N/C ratio on solidification behaviors of novel Nb-bearing austenitic heat-resistant cast steels for exhaust components of gasoline engines[J]. Metall. Mater. Trans., 2017, 48A: 1151 |
| [22] | Buchanan K, Kral M.Crystallography and morphology of niobium carbide in as-cast HP-niobium reformer tubes[J]. Metall. Mater. Trans., 2012, 43A: 1760 |
| [23] | Qiao G W, Wang D H, Cao Z B.An EM study of carbide precipitates in HK40 refractory steel[J]. Acta Metall. Sin., 1986, 22: 67(乔桂文, 王德和, 曹智本. HK40耐热钢碳化物析出的电镜研究[J]. 金属学报, 1986, 22: 67) |
| [24] | Ozbayraktar S, Koursaris A.Effect of superheat on the solidification structures of AISI 310S austenitic stainless steel[J]. Metall. Mater. Trans., 1996, 27B: 287 |
| [25] | Zhang Y H, Li M, Godlewski L A, et al.Effective design of new austenitic cast steels for ultra-high temperature automotive exhaust components through combined CALPHAD and experimental approaches[J]. Mater. Sci. Eng., 2017, A683: 195 |
| [26] | Zhang Y H, Li M, Godlewski L A, et al.Effects of N on creep properties of austeni-tic heat-resistant cast steels developed for exhaust component applications at 1000 ℃[J]. Acta Metall. Sin., 2016, 52: 661(张银辉, Li M, Godlewski L A等. N对汽车发动机用新型奥氏体耐热铸钢1000 ℃蠕变性能的影响[J]. 金属学报, 2016, 52: 661) |
| [27] | Lo K H, Shek C H, Lai J K L. Recent developments in stainless steels[J]. Mater. Sci. Eng., 2009, R65: 39 |
| [28] | Ribeiro E A A G, Papaléo R, Guimar?es J R C. Microstructure and creep behavior of a niobium alloyed cast heat-resistant 26 pct Cr steel[J]. Metall. Trans., 1986, 17A: 691 |
| [29] | Zhang Y H, Li M, Godlewski L A, et al.Creep behavior at 1273 K (1000 ℃) in Nb-bearing austenitic heat-resistant cast steels developed for exhaust component applications[J]. Metall. Mater. Trans., 2016, 47A: 3289 |
| [30] | Zhang J S.High Temperature Deformation and Fracture of Materials [M]. Beijing: Science Press, 2007: 3(张俊善. 材料的高温变形与断裂 [M]. 北京: 科学出版社, 2007: 3) |
| [31] | Michalska J, Sozańska M.Qualitative and quantitative analysis of σ and χ phases in 2205 duplex stainless steel[J]. Mater. Charact., 2006, 56: 355 |
/
| 〈 |
|
〉 |
