13th International Conference on the Technology of Plasticity (ICTP 2021): Poster Session
Program Organizers: Glenn Daehn, Ohio State University; Libby Culley, The Ohio State University; Anupam Vivek, Ohio State University; Jian Cao, Northwestern University; Brad Kinsey, University of New Hampshire; Erman Tekkaya, TU Dortmund; Yoshinori Yoshida, Gifu University
Monday 7:30 AM
July 26, 2021
Room: Virtual: Poster Session
Location: Virtual
Deforming Behavior in Magnetic Pressure Parallel Seam Welding: Takashi Ichimura1; Yusuke Ito1; Makoto Miyazaki1; Akira Hatta2; 1National Institute of Technology, Nagano College; 2DMG MORI CO., LTD.
Magnetic pressure welding (MPW) has attracted attention as a new joining method for aluminum thin plates. MPW is a collision welding process for producing metallic bonds of similar and dissimilar materials, utilizing electromagnetic force as the acceleration mechanism. MPW is a method of abruptly adding a high density magnetic flux around a metal material and utilizing the generated electromagnetic force to deform the thin plate at high speed and pressure welding. This paper deal with the deformation behavior of aluminum sheet with parallel coils. The sample used for this analysis is assumed to be a thin plate made of aluminum and composed of quadrilateral elements of plane strain.As the result, the collision point velocity is very high-speed at the initial collision point, but it decreases continuously during the welding. Even if the thickness was changed, the tendency of the collision point velocity and the collision angle did not changed.
Dependence of Mesoscale Structure of Drawn High Carbon Steel Wire on Wire Diameter: Shiori Gondo1; Rena Tanemura2; Ryuki Mitsui2; Satoshi Kajino1; Motoo Asakawa2; Kosuke Takemoto3; Kenichi Tashima3; Shinsuke Suzuki2; 1National Institute of Advanced Industrial Science and Technology (AIST); 2Waseda University; 3Factory Automation Electronics Inc.
For high carbon steel wire with 0.444 mm in initial diameter, our previous work clarified that mesoscale structure composed of its fiber textures is formed during wire drawing process. The mesoscale structure transitions into primary fiber texture, primary and secondary fiber textures, subprimary and secondary fiber textures with increasing drawing strain. The objectives of this study are clarifying the mesoscale structure in higher drawing strain and the dependence of mesoscale structures on the wire diameters. High carbon steel wires of 0.276, 0.444 and 0.936 mm in diameter were drawn to be as fine as possible. Crystal orientation analysis by electron backscatter diffraction pattern showed that the mesoscale structure transitioned in order as mentioned above, then the structure with only subprimary fiber texture was formed regardless of initial wire diameters. The thickness of secondary fiber texture decreased logarithmically with decreasing the drawn wire diameter at more than 1.4 of drawing strain.
Development of Antiloosening Bolts Based on Innovative Double Thread Mechanism: Teruie Takemasu1; 1Happy Science University
We developed new double-thread bolted joints based on an innovative mechanism composed of single and multiple coarse threads. The number of coarse threads of the multiple-thread was set to 3 (denoted as 3DTB-II), and its thread structure was fundamentally modified to improve rolling formability and strength as follows: (i) one of the three multiple-thread grooves was removed for 3DTB-II specimens and one of the two remaining grooves shifted downwards by a half pitch (denoted 3-1DTB-IIB) and (ii) the depth of the multiple-thread grooves was reduced by up to 50% of the thread height (denoted 3-1DTB-IIC). FEM thread rolling simulations were performed using a dedicated die. The two kinds of modified DTB-II specimens were rolled precisely and the thread heights reached the target value at all cross sections. The forming states in the thread rolling experiments well matched the FEM simulation states.
High-temperature Properties of Hot-work Tool Steel (AISI H13) Deposited via Direct Energy Deposition: Jongyoun Son1; Gwang-yong Shin1; Ki-yong Lee1; Chang-Hwan Choi2; Do-sik Shim3; 1Korea Institute of Industrial Technology; 2Stevens Institute of Technology; 3Korea Maritime and Ocean University
Conventionally, tool steels are repaired by welding; however, that of repairing is expensive, time consuming, and does not guarantee homogeneous quality. Hence, this study focused on developing an alternative repairing technique using direct energy deposition (DED) to minimize thermal effects. To simulate a repair using DED, AISI H13 powder was deposited onto heat-treated JIS SKD61. The deposited material was observed through scanning electron microscopy and its hardness and tensile properties were determined at 25, 200, 400, 600, and 800℃. The deposited material showed different hardness distributions in its cross section, revealing four representative features. The deposited region and dilution showed a hardness of 620 Hv with a dendrite structure. The hardness decreased to 490 Hv in the heat-affected zone, revealing a tempered martensite structure; however, it increased to 550 Hv in the substrate, and revealed a typical martensite structure. At all temperatures, the deposited material showed higher hardness than heat-treated SKD61. Moreover, it showed higher ultimate tensile strength and lower elongation in deposited region. Therefore, this study indicated that without heat treatment, a part repaired using DED can have better mechanical properties than heat-treated SKD61.
Strain-rate-sensitivity Calibration of Aluminum Alloy Sheet by Electromagnetic Flanging of Circular Hole: Wei Liu1; Yangzhe Lin1; Haibo Zhou1; Zhenghua Meng1; Shangyu Huang1; 1Wuhan University of Technology
The strain rate of aluminum alloy sheet reaches up to thousands per second in electromagnetic forming, and it is difficult to obtain the flow stress curve at such high speed. For the hardening law at high strain rate, the strain-hardening term was initially determined by the quasi-static uniaxial tensile test to simplify the parameter identification. Due to the delayed deformation at the central zone of circular workpiece in the electromagnetic bulge test by planar spiral coil, an inverse method of strain-rate-sensitivity calibration has been proposed by electromagnetic flanging of circular hole. The initial size of circular hole was determined as a half diameter of planar spiral coil, and the discharged energy was defined to induce reasonable deformation. A numerical model was established for electromagnetic flanging of circular hole. The experimental and simulated deformation distributions on the cross-sectional profile of workpiece were compared to calibrate the strain-rate-hardening term of Johnson-Cook model.
The Effect of Interface Cohesion on Layer Stability during Accumulative Roll Bonding of Cu/Ta Multilayers: Liya Semenchenko1; Umair Asim1; Ryan Mier2; Nancy Senabulya3; Michael Demkowicz1; 1Texas A&M University; 2Los Alamos National Lab; 3University of Michigan
We present a combined experimental and modeling investigation of composite morphology in Cu/Ta laminates processed by accumulative roll bonding. Using x-ray computed tomography, we examine numerous instances where Ta layers necked and pinched off during rolling. Maintaining layer continuity is important in the mechanical performance of multilayered metals. To understand the origin of layer instabilities, we carried out finite element simulations using an isotropic elastoplastic material model to model Cu and Ta layers in a representative volume element with different interaction properties between them. We demonstrate the plastic flow stability during rolling depends on interface cohesion and indicates that laminates with more uniform layer thickness may be processed by controlling the interface properties.
FEM Analysis on Multi-pass Wiredrawing Process of Ultra-fine Steel Wire: Investigation on Stress, Strain and Hardness: Takumi Saito1; Ken-ichi Saitoh1; 1Kansai University
Recently, there occurs an increasing demand for high precision extra fine steel wires. In order to manufacture ultrafine wires with high accuracy, it is necessary to clarify processing behavior inside the wire. The purpose is to investigate change of mechanical state inside the wire that has been drawn multiple times. However, since it is insufficient to observe experimentally, elastic-plastic finite element simulation is applied to understand the properties. Some three-dimensional models to be machined continuously multiple times are prepared and analyzed. We compare multiple models with different die shapes and discuss mainly the effects of die shapes on wire's properties. In particular, it is successful that hardness is evaluated by our newly proposed methodology using materials mechanics. It is found that the smaller the die angle per pass, the smaller the difference in strain distribution inside the wire. The same tendency is obtained as the number of processes is increased.