Effect of Applied Electricity on Springback During Bending and Flattening of 304/316 Stainless Steel, Titanium AMS-T-9046 and Magnesium AZ31B

2016 ◽  
Author(s):  
Jacklyn Niebauer ◽  
Tyler Grimm ◽  
Derek Shaffer ◽  
Ian Sweeney ◽  
Ihab Ragai ◽  
...  
Keyword(s):  
Stainless Steel ◽  
High Strength ◽  
Electrical Current ◽  
Applied Loading ◽  
Stainless Steel 304 ◽  
Additional Testing ◽  
Specialized Equipment ◽  
Current Densities ◽  
Time And Energy ◽  
Electrically Assisted Manufacturing

One of the major issues with forming sheet metal is the tendency for parts to spring back towards their original shape when the applied loading is released. Springback is a form of geometric inaccuracy and is the result of residual stresses, which are created as the part deforms. As a result, forming intricate parts require specialized equipment and calculations to compensate for springback. Transportation industries that rely on forming high strength parts currently use complicated machinery that takes up time and energy to meet specifications. This research investigates the effects of electrically assisted manufacturing (EAM), a process in which electrical current is applied while a material is being manufactured, on springback. Bending and flattening testing will be performed on 4 metals: stainless steel 304 and 316, ASM-T-9046 titanium, and AZ31B magnesium. Additional testing will be performed on stainless steel, observing the effect of changing thicknesses, pulse durations, and current densities on springback. It was observed that an increase in pulse durations results in decreased springback for all the materials. Applying electricity to decrease springback was more effective for bending than flattening procedures in stainless steel and titanium, though it was equally effective for magnesium. For the additional testing on stainless steel, a change in thickness affected results when comparing it to current density, but not when observing similar applied current.

scholarly journals Experimental and Numerical Investigations on Microcoining of Stainless Steel 304

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Gap-Yong Kim ◽  
Muammer Koç ◽  
Jun Ni
Keyword(s):  
Grain Size ◽  
Stainless Steel ◽  
Bulk Material ◽  
High Strength ◽  
304 Stainless Steel ◽  
Feature Size ◽  
Stainless Steel 304 ◽  
Metallic Parts ◽  
Type 304 ◽  
Type 304 Stainless Steel

Increasing demands for miniature metallic parts have driven the application of microforming in various industries. Only a limited amount of research is, however, available on the forming of miniature features in high strength materials. This study investigated the forming of microfeatures in Type 304 stainless steel by using the coining process. Experimental work was performed to study the effects of workpiece thickness, preform shape, grain size, and feature size on the formation of features ranging from 320μmto800μm. It was found that certain preform shapes enhance feature formation by allowing a favorable flow of the bulk material. In addition, a flow stress model for Type 304 stainless steel that took into consideration the effects of the grain and feature sizes was developed to accurately model and better understand the coining process. Weakening of the material, as the grain size increased at the miniature scale, was explained by the Hall–Petch relationship and the feature size effect.

Influence of Continuous Direct Current on the Microtube Hydroforming Process

2016 ◽  
Vol 139 (3) ◽  
Author(s):  
Scott W. Wagner ◽  
Kenny Ng ◽  
William J. Emblom ◽  
Jaime A. Camelio
Keyword(s):  
High Pressures ◽  
Tube Hydroforming ◽  
Electrical Current ◽  
Deformation Energy ◽  
Recrystallization Temperature ◽  
Machining Processes ◽  
Electrically Assisted ◽  
Stainless Steel 304 ◽  
Hydroforming Process ◽  
Electrically Assisted Manufacturing

Research of the microtube hydroforming (MTHF) process is being investigated for potential medical and fuel cell applications. This is largely due to the fact that at the macroscale the tube hydroforming (THF) process, like most metal forming processes, has realized many advantages, especially when comparing products made using traditional machining processes. Unfortunately, relatively large forces compared to part size and high pressures are required to form the parts so the potential exists to create failed or defective parts. One method to reduce the forces and pressures during MTHF is to incorporate electrically assisted manufacturing (EAM) and electrically assisted forming (EAF) into the MTHF. The intent of both EAM and EAF is to use electrical current to lower the required deformation energy and increase the metal's formability. To reduce the required deformation energy, the applied electricity produces localized heating in the material in order to lower the material's yield stress. In many cases, the previous work has shown that EAF and EAM have resulted in metals being formed further than conventional forming methods alone without sacrificing the strength or ductility. Tests were performed using “as received” and annealed stainless steel 304 tubing. Results shown in this paper indicate that the ultimate tensile strength and bust pressures decrease with increased current while using EAM during MTHF. It was also shown that at high currents the microtubes experienced higher temperatures but were still well below the recrystallization temperature.

Sensitivities When Modeling Electrically-Assisted Forming

2012 ◽  
Author(s):  
Cristina J. Bunget ◽  
Wesley A. Salandro ◽  
Laine Mears
Keyword(s):  
Heat Transfer ◽  
Stainless Steel ◽  
Electrical Power ◽  
Transfer Model ◽  
Modeling And Analysis ◽  
Factors Affecting ◽  
Electrically Assisted ◽  
Stainless Steel 304 ◽  
Analysis Strategy ◽  
Electrically Assisted Manufacturing

Recent research by the authors has resulted in the conception of several methods of accounting for direct electrical effects during an Electrically-Assisted Manufacturing (EAM) process, where electricity is applied to a conductive workpiece to enhance its formability characteristics. The modeling and analysis strategy accounts for both mechanical effects and heat transfer effects due to the applied electrical power. This work presents a sensitivity analysis and explanation of several key material and process inputs during an Electrically-Assisted Forming (EAF) test on Stainless Steel 304 and Titanium Grades 2 and 5 specimens. First, the effect that the specific heat (Cp) value has on the model will be discussed and compared with another lightweight material. Second, the significance of all three heat transfer modes (conduction, convection, and radiation) will be noted, and any possible simplifications to the existing heat transfer model will be highlighted. Third, the general electroplastic effect coefficient (EEC) profile shape for the Stainless Steel 304 material will be compared to that of Titanium alloys. Fourth, a frequency analysis will be done on the data taken during the experiments, by way of a Fast Fourier Transform (FFT), and the variation of frequency response with the electric input is studied. Overall, this work provides insight into several factors affecting a material’s EEC profile, and also compares resulting EEC profiles of various materials.

A TEM microscopical investigation of the magnetic domain structure of a metastable austenitic stainless steel

1994 ◽  
Vol 52 ◽  
pp. 696-697
Author(s):  
G. Fourlaris ◽  
T. Gladman
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cold Rolling ◽  
Solution Treatment ◽  
Magnetic Domain ◽  
High Strength ◽  
Medium Carbon Steel ◽  
Magnetic Characteristics ◽  
Metastable Austenitic Stainless Steel

Stainless steels have widespread applications due to their good corrosion resistance, but for certain types of large naval constructions, other requirements are imposed such as high strength and toughness , and modified magnetic characteristics.The magnetic characteristics of a 302 type metastable austenitic stainless steel has been assessed after various cold rolling treatments designed to increase strength by strain inducement of martensite. A grade 817M40 low alloy medium carbon steel was used as a reference material.The metastable austenitic stainless steel after solution treatment possesses a fully austenitic microstructure. However its tensile strength , in the solution treated condition , is low.Cold rolling results in the strain induced transformation to α’- martensite in austenitic matrix and enhances the tensile strength. However , α’-martensite is ferromagnetic , and its introduction to an otherwise fully paramagnetic matrix alters the magnetic response of the material. An example of the mixed martensitic-retained austenitic microstructure obtained after the cold rolling experiment is provided in the SEM micrograph of Figure 1.

METGLAS MBF-30/30A

Alloy Digest ◽  
1981 ◽  
Vol 30 (12) ◽  
Keyword(s):  
Stainless Steel ◽  
Metallic Glass ◽  
Physical Properties ◽  
Flow Characteristics ◽  
High Strength ◽  
Thin Foil ◽  
Heat Treating

Abstract METGLAS MBF-30A is a brazing foil in ductile, flexible metallic-glass form (a similar grade, MBF-30, is identical except that it has larger dimensional tolerances). This foil provides an alloy with high strength at both elevated and room temperatures. It can be used to join highly stressed stainless steel and heat-resisting alloy components. The excellent flow characteristics of this alloy recommend it for assemblies with good fit-up and tight-tolerance joints. It works well on thin-foil, honeycomb designs and on fairly heavy components. This datasheet provides information on composition, physical properties, and microstructure. It also includes information on heat treating. Filing Code: Ni-273. Producer or source: Allied Corporation.

AISI No. 633

Alloy Digest ◽  
1981 ◽  
Vol 30 (7) ◽  
Keyword(s):  
Heat Treatment ◽  
Stainless Steel ◽  
Stainless Steels ◽  
High Strength ◽  
Heat Treating ◽  
Corrosion Resistant ◽  
Martensitic Stainless Steels ◽  
Steel Mills ◽  
Temperature Performance ◽  
Structural Applications

Abstract AISI No. 633 is a chromium-nickel-molybdenum stainless steel whose properties can be changed by heat treatment. It bridges the gap between the austenitic and martensitic stainless steels; that is, it has some of the properties of each. Its uses include high-strength structural applications, corrosion-resistant springs and knife blades. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on high temperature performance and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-389. Producer or source: Stainless steel mills.

ARMCO 21-6-9

Alloy Digest ◽  
1961 ◽  
Vol 10 (12) ◽  
Keyword(s):  
Fracture Toughness ◽  
Stainless Steel ◽  
Corrosion Resistance ◽  
High Temperature ◽  
Austenitic Stainless Steel ◽  
Physical Properties ◽  
High Strength ◽  
Heat Treating ◽  
Steel Alloy ◽  
Temperature Performance

Abstract Armco 21-6-9 is an austenitic stainless steel alloy designed for use in applications where a combination of high strength and corrosion resistance is desired. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties as well as fracture toughness. It also includes information on low and high temperature performance, and corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: SS-125. Producer or source: Armco Inc., Eastern Steel Division.

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