National Engineering Research Center for Equipment and Technology of Cold Strip Rolling, Yanshan University, Qinhuangdao 066004, China
Cite this article:
XIAO Hong,XU Pengpeng,QI Zichen,WU Zonghe,ZHAO Yunpeng. Preparation of Steel/Aluminum Laminated Composites by Differential Temperature Rolling with Induction Heating. Acta Metall Sin, 2020, 56(2): 231-239.
Both cold-rolled and hot-rolled steel/aluminum laminated composites exhibited obvious strain-hardening of steel layer because the rolling temperature, limited by the melting point of aluminum (about 660 ℃), was lower than dynamic recrystallization temperature of steel (about 710 ℃). This led to poor deformation ability of composite plates and subsequent processing cracks. And the initial bonding of cold-rolled steel/aluminum composite plates usually required more than 50% highly first pass reduction, which resulted in high requirement for rolling mill capacity, especially for medium or thick size composite plates. To solve above two problems simultaneously, in this study, the steel/aluminum composite plates were prepared by differential temperature rolling (DTR) with induction heating in an argon atmosphere. The bonding properties and microstructure of the steel/aluminum laminated composites were studied, and the effect of DTR process on the bonding properties was analyzed compared with the cold rolling process. The results show that dynamic recovery and recrystallization occurred with equiaxed grains appearing in the structure of the rolled carbon steel due to the higher heating temperature of the steel layer, and an equiaxed fine grain zone with an average grain size of approximately 5 μm was formed near the interface of the steel side, which greatly reduced the hardening phenomenon of the laminated composites compared with the cold rolled clad plate. The micro-interface of DTR steel/aluminum clad plate was tightly bonded without holes and gaps. The diffusion width of Al and Fe elements across the interface reached 2.4 μm, indicating the clad plate achieved a good metallurgical bonding state, and the fine grained zone near the interface improved the properties of the sheet. The combined effect made the shear strength of the DTR clad plates much higher than that of the cold-rolled plate. At 45% reduction, the shear strength of DTR composite plate reached 85 MPa, which was 7 times of cold-rolled composite plate with the same reduction (12 MPa). The fracture of cold-rolled composite plate occurred at the steel/aluminum interface, showing brittle fracture, while the fracture of DTR clad plates occurred in the aluminum alloy matrix with a large number of dimples in the shear section, showing the characteristics of plastic fracture.
Table 1 Chemical compositions of commercial Q235 sheet and 6061 Al alloy sheet (mass fraction / %)
Material
Ultimate tensile strength
MPa
Yield strength
MPa
Shear strength
MPa
Fracture elongation
%
Q235
351±5
235±4
197±4
36.5±1.5
6061
215±4
141±3
124±3
24.7±0.8
Table 2 Mechanical properties of the used materials in the experiment
Fig.1 Schematic for the structure of billet plate
Fig.2 Schematic of differential temperature rolling (DTR) process with induction heating
Fig.3 Temperature variations in individual laminated plates under different induction currents and clearances between Q235 and 6061 (?Tmax—maximum temperature difference)(a) 300 A, 0.5 mm (b) 300 A,1 mm (c) 1800 A, 0.5 mm (d) 1800 A, 1 mm
Fig.4 Tensile-shear test and interface observation of the laminated composites(a) schematic of the sample (h0—total thickness, h1—Al thickness)(b) real image of tensile-shear sample (F—maximum shear stress)(c) fractured specimen(d) polished interface
Fig.5 Shear strengths of the laminated composites prepared by DTR and cold rolling (CR) under different reductions
Fig.6 SEM images showing bonding interfaces of laminated composites under different processes(a) CR, 45% reduction (b) CR, 55% reduction (c) CR, 67.5% reduction (d) DTR, 45% reduction
Fig.7 Low (a) and locally high (b) magnified metallographic structures of steel layer of the DTR composite plate
Fig.8 Interface element diffusion curves of the DTR composite plate
Fig.9 Element diffusion widths of the DTR and cold-rolled composite plates
Fig.10 Tensile-shear fracture morphologies and EDS maps (insets) of the laminated composites with 45% reduction(a) CR, steel side (b) CR, Al side (c) DTR, steel side (d) DTR, Al side
Position
Fe
Al
C
1
95.9
2.9
1.2
2
95.8
3.4
0.8
3
0.6
99.0
0.4
4
0.8
98.7
0.5
5
2.3
97.5
0.2
6
0.2
99.7
0.1
Table 3 EDS analysis of points 1~6 in Fig.10 (mass fraction / %)
[1]
Liu G. Applications of steel-aluminum compound track in construction of line Daxing in Beijing urban mass transit [J]. Rail. Stand. Des., 2011, (1): 119
Wang C, Wang L Y, Zhao H Q, et al. Application of steel-aluminum composite plate-beam structure in car body [J]. Sci. Technol. Inform., 2012, (35): 140
Han H D, Zhang P, Du Y H, et al. Research on manufacture for steel-backed aluminum-matrix bearing material [J]. Intern. Combust. Eng. Parts, 2008, (3): 18
Shiran M K G, Khalaj G, Pouraliakbar H, et al. Effects of heat treatment on the intermetallic compounds and mechanical properties of the stainless steel 321-aluminum 1230 explosive-welding interface [J]. Int. J. Min. Met. Mater., 2017, 24: 1267
[6]
Song L, Sun B Y, Cui P P. Study on steel/aluminum solid-liquid composite casting and rolling [J]. Hot Work. Technol, 2018, 47(4): 126
Grydin O, Gerstein G, Nürnberger F, et al. Twin-roll casting of aluminum-steel clad strips [J]. J. Manuf. Process., 2013, 15: 501
[8]
Movahedi M, Kokabi A H, Seyed Reihani S M. Investigation on the bond strength of Al-1100/St-12 roll bonded sheets, optimization and characterization [J]. Mater. Des., 2011, 32: 3143
[9]
Manesh H D, Taheri A K. Study of mechanisms of cold roll welding of aluminium alloy to steel strip [J]. Mater. Sci. Technol., 2004, 20: 1064
[10]
Manesh H D, Shahabi H S. Effective parameters on bonding strength of roll bonded Al/St/Al multilayer strips [J]. J. Alloys Compd., 2009, 476: 292
[11]
Wang C Y, Jiang Y B, Xi J X, et al. Interface formation and bonding mechanism of embedded aluminum-steel composite sheet during cold roll bonding [J]. Mater. Sci. Eng., 2017, A708: 50
[12]
Wang C Y, Jiang Y B, Xie J X, et al. Effect of the steel sheet surface hardening state on interfacial bonding strength of embedded aluminum-steel composite sheet produced by cold roll bonding process [J]. Mater. Sci. Eng., 2016, A652: 51
[13]
Wu B, Li L, Xia C D, et al. Effect of surface nitriding treatment in a steel plate on the interfacial bonding strength of the aluminum/steel clad sheets by the cold roll bonding process [J]. Mater. Sci. Eng., 2017, A682: 270
[14]
Gao C, Li L, Chen X, et al. The effect of surface preparation on the bond strength of Al-St strips in CRB process [J]. Mater. Des., 2016, 107: 205
[15]
Wang C Y, Liu X H, Jiang Y B, et al. Effects of annealing and cold roll-bonded interface on the microstructure and mechanical properties of the embedded aluminum-steel composite sheet [J]. Sci. Bull., 2018, 63: 1448
[16]
Chen X, Li L, Zhou D J. Review on the formation and inhibition mechanism of Fe-Al intermetallic compound [J]. Mater. Rev., 2016, 30(13): 125
Tang C L, Xu Q P, Weng H, et al. Influence of the surface treatment process on bonding properties of Al/steel(4A60/08AL) clad sheets by cold roll bonding [J]. Light Alloy Fabric. Technol., 2016, 44(6): 25
Li M Q, Jiang F L, Zhang H, et al. Deformation rule of steel/aluminum metal-laminate material during hot roll bonding [J]. Chin. J. Nonferrous Met., 2009, 19: 644
Xiao H, Qi Z C, Yu C, et al. Preparation and properties for Ti/Al clad plates generated by differential temperature rolling [J]. J. Mater. Process. Technol., 2017, 249: 285
[22]
Qi Z C, Yu C, Xiao H. Microstructure and bonding properties of magnesium alloy AZ31/CP-Ti clad plates fabricated by rolling bonding [J]. J. Manuf. Processes., 2018, 32: 175
[23]
Jiao H, Zhang M, Yan Z J. Study on binding property of steel/aluminum laminated sheets fabricated by two-pass hot rolling [J]. New Technol. New Processes, 2015, (8): 95
Li L, Zeng X Y, Chen X, et al. Influence of heat treatment on microstructure and mechanical properties of 4A60 Al/08Al steel clad strip by cold roll bonding [J]. Heat Treat. Met., 2015, 40(7): 28
Manesh H D, Taheri A K. Bond strength and formability of an aluminum-clad steel sheet [J]. J. Alloys Compd., 2003, 361: 138
[26]
Sauvage X, Dinda G P, Wilde G. Non-equilibrium intermixing and phase transformation in severely deformed Al/Ni multilayers [J]. Scr. Mater., 2007, 56: 181
[27]
Chung C Y, Zhu M, Man C H. Effect of mechanical alloying on the solid state reaction processing of Ni-36.5 at.% Al alloy [J]. Intermetallics, 2002, 10: 865
[28]
Valiev R Z, Islamgaliev R K, Alexandrov I V. Bulk nanostructured materials from severe plastic deformation [J]. Prog. Mater. Sci., 2000, 45: 103
[29]
Sauvage X, Wetscher F, Pareige P. Mechanical alloying of Cu and Fe induced by severe plastic deformation of a Cu-Fe composite [J]. Acta Mater., 2005, 53: 2127
[30]
Sato K, Yoshiie T, Satoh Y, et al. Simulation of vacancy migration energy in Cu under high strain [J]. Mater. Sci. Eng., 2003, A350: 220
