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Deep drawing and redrawing of solution-treated Cu-Cr-Zr-Ti alloy sheets and post-forming characterization of the redrawn cup wall

Behera Dibya Ranjan, Katiyar Bhupesh Singh, Das Sayan, Panda Sushanta Kumar, Kar Sujoy Kumar, Murty S. V. S. Narayana

Archives of Civil and Mechanical Engineering

2023

Vol. 23, no. 3

art. no. e217, 2023

Recently, space research organizations are interested in investigating multistage deep drawing of Cu-Cr-Zr-Ti alloy sheets for the fabrication of large-depth thrust chamber liners used in cryogenic engine of satellite launch vehicles. Hence, an attempt was made for the first time to design and develop a laboratory scale two-stage deep drawing setup to successfully draw cylindrical cups of solution-treated Cu-0.5Cr-0.05Zr-0.05Ti (wt. %) sheets of 1.7 mm thickness. The finite element (FE) model with Marciniak–Kuczynski forming limit diagram (MK-FLD) was implemented to design the above two-stage deep drawing setup, and two different anisotropic models, namely Hill48 and Barlat89, along with solid and shell element formulations were used to capture the deformation behavior. After setup design, the two-stage deep drawing experiments were conducted, and successful redrawn cups with overall drawing ratio of 2.94 with maximum cup depth of 58.5 mm was achieved. The strain evolution during deformation was analyzed in polar effective plastic strain (PEPS) locus, and it was also observed that the surface roughness of cup wall and corner was significantly increased to 2.73 μm and 3.16 μm, respectively, due to accumulation of plastic strain and evolution of texture. Further, the orientation gradient inside the grains at both cup wall and corner regions was observed, and evolution of Copper {112} < 111> and Y{111} <112> texture components were identified in the cup wall. However, the marginal increase in roughness of cup corner as compared to that of the cup wall might be due to the development of Brass {110} < 112 > texture. Finally, the aging behavior of redrawn cup wall was analyzed, and it was found that the peak aging occurred at 500 °C for 2 h. with a hardness of 98 ± 4 VHN due to the formation of fine Cr-rich precipitates.

Experimental and numerical analyses on crushing behaviour of drawn cups of laser welded tailored blanks under axial loading

Katiyar Bhupesh Singh, Panda Sushanta Kumar, Saha Partha

Archives of Civil and Mechanical Engineering

2022

Vol. 22, no. 4

art. no. e211, 2022

It is imperative to characterize the crushing behaviour of deep drawn components of tailor welded blanks for their wide applications in different autobody structures. In the present work, extra deep drawing steel sheets were laser welded to produce welded blanks of similar thickness and dissimilar thickness (LWTBs), and these were deformed using a two stage deep drawing setup to fabricate geometrically similar drawn cups consisting of both hemispherical and cylindrical segments. Subsequently, these drawn cups were axially crushed between two flat platens to study collapse modes, load–displacement responses and energy absorption capabilities. The collapse of the drawn cups was found to onset with an inward dimpling of the hemispherical segment. As deformation progressed, the folding of cylindrical section occurred either axisymmetrically or unevenly based on the extent of non-uniform thickness variations across the weld zone (WZ). It was also found that the load–displacement response and energy absorption of the cups were enhanced because of the presence of WZ and thickness difference in LWTBs. Also, finite element-based numerical models were developed to collate the prediction capabilities of three different anisotropic material models viz. Hill48, YLD89, and Stoughton non-associated flow rule (S-NAFR)-based model. All these material models were successfully calibrated to predict the collapse modes, but the S-NAFR model was found to closely predict the load–displacement curves and energy absorption. Furthermore, the assessment of specific energy absorption and crushing force efficiency suggested that lightweight LWTB components can be fabricated with improved crashworthiness performance using sheet materials of different thickness.