Browse Topic: Hardening

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Sliding-Window Matrix Pencil Method for Whirl Flutter Bifurcation AnalysisF-0080-2024-12715/7/2024
This paper investigates a sliding-window matrix pencil method for predicting flutter points and limit-cycle oscillation amplitudes of nonlinear aeroelastic systems that experience whirl flutter. The approach applies the matrix pencil method to a short time window that slides along the free decay of a quantity of interest, quantifying the variation in the system's recovery rate to equilibrium with amplitude. The recovery rates at each amplitude and various forward speeds are extrapolated to predict the critical forward speed of zero recovery rate at those amplitudes. This process yields a set of limit-cycle oscillation solutions that can be visualized as a bifurcation diagram. The approach is demonstrated using output data from transient simulations of a propeller-nacelle test case with hardening structural nonlinearities. The impact of each parameter in the sliding-window matrix pencil method is first characterized via sensitivity analyses. Next, the bifurcation diagram is predicted using the recovery rates for the optimal parameter values. The results are compared with direct time marching and with the extrapolation of recovery rates estimated from envelope functions. The proposed method accurately captures the bifurcation diagram using two pre-flutter transient simulations with no need for envelope functions. This approach shows promise for output-based bifurcation analysis of nonlinear aeroelastic systems exhibiting limit-cycle oscillations associated with whirl flutter.
Warren, Theodore, Riso, Cristina
Cast Aluminum Alloy Composite 4.6Cu - 3.4Ti - 1.4B - 0.75Ag - 0.27Mg (205.0/TiB2/3p-T7P) Investment Cast, Solution and Precipitation Heat TreatedAMS4471B (Historical)4/22/2021
This specification covers a dilute aluminum/TiB2 metal matrix composite in the form of investment castings.
AMS D Nonferrous Alloys Committee
Bake Hardening Behavior of DP, TBF, and PHS Steels with Ultimate Tensile Strengths Exceeding 1 GPa2020-01-05364/14/2020
Third generation advanced high strength steels (AHSS) have been developed combining high strength and formability, allowing for lightweighting of vehicle structural components. These AHSS components are exposed to paint baking operations ranging in time and temperature to cure the applied paint. The paint baking treatment, combined with straining induced from part forming, may lead to increased in-service component performance due to a strengthening mechanism known as bake hardening. This study aims to quantify the bake hardening behavior of select AHSS grades. Materials investigated were press hardenable steels (PHS) 1500 and 2000; transformation induced plasticity (TRIP) aided bainitic ferrite (TBF) 1000 and 1200; and dual phase (DP) 1000. The number designations of these grades refer to minimum as-received ultimate tensile strengths in MPa. Paint baking was simulated using industrially relevant times and temperatures from 15 to 60 min and 120 to 200 °C, respectively. Samples were prestrained 0, 2, or 5 pct to replicate part forming. Bake hardening values ranging from 90 to 140 MPa were observed for DP and TBF grades that were prestrained 2 pct and baked at 170 °C for 20 min. However, ductility diminished for these steels when subjected to 5 pct prestrain with uniform elongations after baking decreasing to 1 pct in some instances. PHS steels, on the other hand, showed substantial increases in yield strength without prestrain. Increases of 122 and 175 MPa were recorded for PHS 1500 and PHS 2000, respectively, following baking at 160 °C for 60 min. However, ultimate tensile strengths decreased due to reduced strain hardening, while total elongations decreased slightly.
Blesi, Brandon W., Smith, Charles, Matlock, David K., De Moor, Emmanuel
Study on Effect of Laser Peening on Inconel 718 Produced by DMLS Technique *CSP Meta Testing 2*2019-28-014610/11/2019
In Additive manufacturing, Direct Metal Laser Sintering (DMLS) is a rapid manufacturing technique used for manufacturing of functional component. Finely powered metal is melted by using high-energy fiber laser, by Island principle strategy that produces mechanically and thermally stable metallic component with reduced stresses, thermal gradients and at high precision. Inconel is an austenitic chromium nickel-based superalloy often used in the applications which require high strength and temperature resistant. It can retain its properties at high temperature. An attempt is made to examine the effect of laser shot peening (LSP) on DMLS Inconel 718 sample. Microstructure shows elliptical shaped structure and formation of new grain boundaries. The surface roughness of the material has been increased due to the effect of laser shock pulse and ablative nature. Macro hardness increased to 13% on the surface. Depth wise microhardness was investigated, found to be 17% increase on the sub-layer of the material due to the effect of a hardened matrix formed by precipitation hardening and grain size refinement attributed by laser shock peening. SEM analysis shows larger grains are being refined into smaller grains. The residual stress analysis result shows compressive residual stress values have increased.
Navin Kumar, Nattudurai, Yadav, Aditya Chandrakant, Raja, Kumar, Prabhakaran, Subramanian, Naiju, Chooriyaparambil Damodaran, Kalainathan, Sivaperuman
Gaseous NitrocarburizingAMS2757C (Current)3/15/2019
This specification covers the engineering requirements for producing a continuous thin epsilon-iron-carbonitride compound layer on parts by means of a gaseous, low temperature process, and properties of the case.
AMS B Finishes Processes and Fluids Committee
Steel, Bars and Forgings 3.1Cr - 11.5Ni - 13.5Co - 1.2Mo (0.21 - 0.25C) Vacuum Melted, Normalized and Overaged Precipitation HardenableAMS6532G (Historical)6/11/2018
This specification covers a premium aircraft-quality alloy steel in the form of bars, forgings, and forging stock.
AMS E Carbon and Low Alloy Steels Committee
Minimizing Distortion During High Pressure Gas Quenching ProcessesF-0074-2018-128015/14/2018
ABSTRACT Steel components, such as gears for rotorcraft transmissions, are quench hardened to improve the hardness, strength, and fatigue performance. During a quench hardening process, components are heated to form austenite, followed by quenching (either gas or liquid) to transform to hard martensite. With High Pressure Gas Quenching (HPGQ), parts are rapidly cooled by using a pressurized gas such as Nitrogen or Helium. Hardening is a highly nonlinear process due to the plastic deformation caused by thermal stresses and phase transformations, both of which lead to distortion. Reducing distortion caused by hardening has always been pursued by heat treaters for the purposes of improving part quality and reducing cost. A new gas quenching method to minimize distortion of Ferrium C64 gear steel was developed by DANTE Solutions as part of an effort with the US Army's Aviation Development Directorate (ADD). This method utilizes a new state-of-the-art gas quench chamber to control the temperature uniformity of parts using a recipe developed through computer modeling.
Li, Zhichao, Fetty, Jason, Sims, Justin, Ferguson, B., Baker, Treven
Effect of E-Modulus Variation on Springbackand a Practical Solution2018-01-06304/3/2018
Springback affects the dimensional accuracy and final shape of stamped parts. Accurate prediction of springback is necessary to design dies that produce the desired part geometry and tolerances. Springback occurs after stamping and ejection of the part because the state of the stresses and strains in the deformed material has changed. To accurately predict springback through finite element analysis, the material model should be well defined for accurate simulation and prediction of stresses and strains after unloading. Despite the development of several advanced material models that comprehensively describe the Bauschinger effect, transient behavior, permanent softening of the blank material, and unloading elastic modulus degradation, the prediction of springback is still not satisfactory for production parts. Dies are often recut several times, after the first tryouts, to compensate for springback and achieve the required part geometry. In this study, the effect of Young’s modulus (E-modulus) on springback is investigated. Current challenges in determination of E-modulus through tensile test are discussed and a practical method is proposed which has the potential to improve springback prediction after the first die tryout. In this method, the unloading elastic modulus is adjusted by measuring the springback of the part produced during the first tryout and comparing it with finite element (FE) simulation results. The unloading elastic modulus obtained from this method is called the “apparent E-modulus”. This method is applied to three bending cases: a wipe bending, a U-drawing, and a 3-D crash forming of an actual production part. Results show that the springback can be predicted fairly accurate using the apparent E-modulus and a simple isotropic hardening model.
Fallahiarezoodar, Ali, Goertemiller, Cliff, Katre, Aanandita, Altan, Taylan
Definitions of Heat Treating TermsJ415_201801 (Current)1/9/2018
(These definitions were prepared by the Joint Committee on Definitions of Terms Relating to Heat Treatment appointed by the American Society for Testing and Materials, The American Society for Metals, the American Foundrymen's Association, and the SAE.) This SAE revision emphasizes the terms used in heat treating ferrous alloys, but also includes for reference some non-ferrous definitions at the end of the document. This glossary is not intended to be a specification, and it should not be interpreted as such. Since this is intended to be strictly a set of definitions, temperatures have been omitted purposely.
Metals Technical Committee
Multifunctional Structural Composite with Integrated Electromagnetic ShieldingF-0073-2017-121745/9/2017
ABSTRACT The ability to construct a multifunctional material that provides electromagnetic (EM) hardening on an aircraft structure integral to the material form has been demonstrated. The material's key attribute is the integration of a high level of EM shielding directly into a structural fiber-reinforced graphite composite in a manner that has minimal to no impact on the mechanical characteristics of the host composite. The material form has demonstrated the EM shielding equivalency of an aluminum electronics enclosure structure on a composite alternative for 25% of the weight without impacting structural characteristics. This material form provides a lightweight alternative to traditional means of providing aircraft EM protection from existing and emerging threats, such as high-power microwaves (HPMs) and EM pulse (EMP)/high-altitude EMP (HEMP), without incurring parasitic weight penalties. Its multifunctionality provides a weight-efficient means to address EM shielding in a composite while taking advantage of its strength-to-weight properties.
Luzetsky, Harry, Ostrander, Graham, Klein, Martha
Fatigue Life Prediction of Induction Hardened Case Depth Specimens Made From 38MnVS6 Micro Alloyed Steel2017-01-03573/28/2017
The application of induction hardening treatment plays a vital role for enhancing fatigue life of various automotive components. This will incorporate compressive residual stresses in the component at significant extent. In this paper, wide range of experiments have been carried out on Rotating Bending Fatigue (RBF) specimens made from 38MnVS6 micro alloyed steel with induction hardening up to three different case depths. The set of specimens are fatigue tested at fully reverse loading condition using rotating bending fatigue testing machine. Based on this study a surface treatment factor is evaluated. This surface treatment factor is used as an input for evaluating precise fatigue life of the specimen using FEA packages. The fatigue life evaluated using FEA is showing good agreement with the results obtained through tests on the actual specimens.
Lomate, Dattaprasad, Tewari, Asim, Date, Prashant, Ukhande, Manoj R, Shegavi, Girish M, Singh, Raj Kumar Prasad
Study of Influence of Electron Beam Treatment on Surface Properties of the Material Produced by Selective Laser Melting2016-01-21429/27/2016
The treatment of solid surface by powerful streams of charged particles accelerated with power density ≥106 W/cm2 widely used for modification of different materials properties. The fast enter of electron beam power in the material of target causes the flow intense thermal and deformation processes. The changing of the structure, the phase composition, the microrelief of treated surface consequently happens. It is often accompanied by the hardening and increase of the wearing properties. The work proposed of using low-energy high-current electron beam as finish treatment of product obtained by selective laser melting of heat-resistant nickel alloy EP648. The subject of research was the surface properties of the product.
Lykov PhD, Pavel, Leyvi, Artem, Baytimerov, Rustam M., Doikin, Aleksei, Safonov, Evgeny
Alkali-Activated Inorganic Based Brake Pads: Realization and Performances of Alternative Friction Materials for a Concrete Industrial Application2016-01-19139/18/2016
Organic brake pads for automotive can be defined as brake linings with bonding matrix constituted of high-temperature thermosetting resins. Bonded together inside the polymeric binder are a mix of components (e.g. abrasives, lubricants, reinforcements, fillers, modifiers…), each playing a distinctive role in determining the tribology and friction activity of the final friction material. The herein reported work presents inorganic “alkali-activated”-based materials suitable for the production of alternative brake linings (i.e. brake pads), by means of an unconventional low-temperature wet process. Exploiting the hydraulic activity of specific components when exposed to an alkaline environment, such peculiar inorganic materials are capable of coming to a complete hardening without the need of traditional high-temperature energivorous procedures. The main advantages of these materials resides in: the decreased embodied energy of the employed raw materials, the reduction of process costs, a potential drop of the emitted pollutants coming from the high-temperature degradation of organic resins. In the present work the results of our investigation in the field are illustrated, our prototype inorganic material is indeed compared to the original resin-based OE and to another traditional phenolic alternative. Brake pads were tested on a full-scale automotive brake dynamometer, following SAE J2522 (AK Master) procedure. In order to prove the excellent performance of such inorganic materials even under high-demanding conditions, brake pads were also tested by means of an internal fading procedure. The results obtained so far are promising and pave the way to further developments toward a concrete industrialization of these unconventional class of friction materials.
Sanguineti, Alessandro, Tosi, Federico, Bonfanti, Andrea, Rampinelli, Flavio
Fatigue Life Prediction of an Automotive Chassis System with Combined Hardening Material Model2016-01-03784/5/2016
The choice of an appropriate material model with parameters derived from testing and proper modeling of stress-strain response during cyclic loading are the critical steps for accurate fatigue-life prediction of complex automotive subsystems. Most materials used in an automotive substructure, like a chassis system, exhibit combined hardening behavior and it is essential to capture this behavior in the CAE model in order to accurately predict the fatigue life. This study illustrates, with examples, the strain-controlled testing of material coupons, and the calculations of material parameters from test data for the combined hardening material model used in the Abaqus solver. Stress-strain response curves and fatigue results from other simpler material models like the isotropic hardening model and the linear material model with Neuber correction are also discussed in light of the respective fatigue theories. A prediction of number of cycles for crack initiation of an automotive chassis system under a braking load cycle are compared to the results of physical tests in order to understand the merits and limitations of each model.
George, John, Gross, Daniel, Jahed, Hamid, Roostaei, Ali
Experimental Study of the Plasticity Responses of TRIP780 Steel Subjected to Strain-Path Changes2016-01-03634/5/2016
The work-hardening response of TRIP780 steel subjected to strain-path changes was investigated using two-stage tension experiments. Large specimens were prestrained and then sub-sized samples were subjected to tension along various directions. The influence of strain-path changes on flow stress and work hardening performance was discussed in detail. The specific plastic work was calculated to compare the kinematic hardening behaviour after strain-path changes. The results showed that transient hardening was observed for TRIP780 sheets subjected to orthogonal strain-path change. The strain-hardening exponent (n-value) was influenced by prestraining levels and the strain path. The n-value exhibited a greater decrease under an orthogonal strain-path change. Prestraining can delay the onset of high work hardenability of TRIP steels. It is meaningful for the safety design of vehicles.
Yu, HaiYan, He, ZeZhen, Shen, JiaYi
Application of Local Mechanical Tensioning and Laser Processing to Modify the Residual Stress State and Microstructural Features of Multi-Pass HSLA Steel2015-01-06044/14/2015
In a multi-pass weld, the development of residual stress to a large extent depends on the response of the weld metal, heat affected zone and parent material to complex thermo-mechanical cycles during welding. Previous investigations on this subject mostly focused on mechanical tensioning or heat treatment to modify the residual stress distribution in and around the weld. In this research, microstructural refinement with modification of residual stress state was attempted by applying post weld cold rolling followed by laser processing. The hardening of the weld metal was evaluated after welding, post weld cold rolling and post weld cold rolling followed by laser processing. The residual stress was determined non-destructively by using neutron diffraction. Hardness results showed evidence of plastic deformation up to 4 mm below the weld surface. In residual stress analysis, the result indicated that, up to 4 mm below the weld surface, post weld cold rolling was effective in changing the longitudinal residual stress distribution, modifying the stress state from tensile to compressive across the weld center line. Post weld cold rolling followed by laser processing was carried out to induce recrystallization of the cold rolled grains. Microstructural characterization indicates some grain refinement near the capping pass, however, laser processing reinstated the as-welded residual stress distribution and profile. The stress variation in as-welded state, showed diminishing longitudinal peak stress magnitude through the thickness from cap to root pass.
Sule, Jibrin, Ganguly, Supriyo
Effect of Surface Heat Treatment on Corrosion-Related Failure of the Suspension Spring2015-01-05184/14/2015
In this research, a new wire material made using surface-reforming heat treatment was developed in order to enhance the corrosion fatigue resistance of suspension springs. The aim of surface reforming is to improve hydrogen embrittlement characteristics through grain refinement and to improve crack propagation resistance by partial softening of hardness. The grain refinement method used an α'→γ reversed transformation by rapid short-term heating in repeated induction heating and quenching (R-IHQ) to refine the crystal grain size of SAE 9254 steel spring wire to 4 μm or less. In order to simultaneously improve the fatigue crack propagation characteristics, the possibility of reducing the hardness immediately below the spring surface layer was also examined. By applying contour hardening in the second IHQ cycle, a heat affected zone (HAZ) is obtained immediately below the surface. Hardness immediately below the surface was reduced a maximum of 25% by making use of the tempering effect of this HAZ. The corrosion durability life for springs made of wire material produced by the above method was approximately 50% higher than for those made by the conventional method. Greater compactness and lower weight were then successfully achieved by means of high-stress design.
Fuchigami, Hirokuni
Study of Impact of Shot Size Ratio in the Process of Shot Peening on Fatigue Life of Suspension Coil Spring2014-01-09744/1/2014
Hardened steel is the majorly used raw material for automotive components. In spite of its abundance, its application is limited due to low fatigue life in dynamic loading. Shot peening is one of the identified processes to improve the fatigue life of the ductile steel by inducing the work hardening & surface improvement. The process of shot peening involves the bombardment of shots on the component surface. As the process & technique, the shot size selection plays very important role in the fatigue life improvement as it alters the results substantially. Also during the process, shot size decreases due to the normal wear of the shots after hitting the component surface. As a result, there is always a ratio of various sizes of the shots involved in the process. Therefore it becomes imperative to control the shot size ratio for obtaining the required work hardening & possible fatigue life improvement. This paper explains the effects of shot size ratio on the durability life of a component & the process of shot size ratio selection.
Tiwari, Deepak, Bhope, Anand, Hegde, Akshay
An Indirect Method to Determine Friction Coefficient in the OSU Punch Stretch Test2014-01-09874/1/2014
An indirect method to determine friction coefficient under punch stretching conditions has been developed. The methodology involves correlation of experimental draw-in measurements to FEA predictions for a range of assumed friction coefficients. Initial evaluation with a ferritic stainless steel (SS 439) shows that the proposed indirect method to determine the effective friction coefficient during punch stretching is feasible. Friction coefficient (μ) estimate based on the indirect method was 0.15 for the sample with residual mill oil (dry), 0.12 with excess mill oil (wet), and 0.03 with polyethylene sheets between the sample blank and tooling. The importance of prescribing accurate material hardening behavior beyond uniform elongation to obtain good correlation between simulation and experimental punch loads and to better tune the model is highlighted in the paper.
Raghavan, K.S., Comstock, R.J., Hance, B.M.
New Trends of Material & Heat Treatment in Automotive Transmission Shaft2013-01-24469/24/2013
This paper deals with new trends in materials & heat treatment in automotive transmission shafting. The material is S48C a low carbon alloy steel and material for automotive shaft special significance as it reduces overall cost in vehicle transmission shafts. Conventional method of shaft heat heat-treatment is case hardening for 20MnCr5. S48C is low-carbon alloy steel. This is an alternate proposal to 20MnCr5.There are lot of advantages in induction hardening over case hardening. Also induction hardening process with S48C material becomes cheaper than case-hardening with 20MnCr5.Strength and resistance to stress must therefore be carefully considered during the material selection and heat-treatment process. We have done Static torsion test for 20MnCr5 (case hardened steel) and S48C (induction hardened shaft). Test results were comparable with 20MnCr5 (case hardened steel). Also after test a metallurgical inspection was done on an S48C (induction hardened shaft). Significant cost saving occur in the induction hardening process with S48C material. This will reduce overall cost of the transmission.
Bhat, Muralidhar Suryanarayan, G, Magendran
Heat Treatment of Wrought Copper-Beryllium Alloys, Process for (Copper Alloys: Numbers C17000, C17200, C17300, C17500, and C17510)AMSH7199A (Current)4/19/2013
This specification presents requirements for the heat treatment of parts and components fabricated from wrought (plate, sheet, strip, bar, rod, wire extrusions and tube and forgings) copper alloys, numbers C17000, C17200, C17300, C17500, and C17510 (see 6.7). This specification also covers “bright hardening”.
AMS D Nonferrous Alloys Committee
Numerical Investigation of Dynamic Impact between Cellular Shear Band Based Non-Pneumatic Tire and Sand with Obstacle2013-01-06314/8/2013
In this paper, dynamic impact between cellular shear-band-based non-pneumatic tire and sand with obstacle is investigated by using the Finite Element Method (FEM) for the NASA's new Moon mission. In this research, the shear band with cellular geometry of (cell angle θ = -65°, cell height h = 21) is used. The Lebanon sand found in New Hampshire is used in this research and Drucker-Prager/Cap plasticity constitutive law with hardening is employed to describe the behavior of the sand. The obstacle is represented as an elastic body. Penalty contact algorithm is used to model the tangential behavior of the contact between the tire and sand. Coulomb's law is considered for the friction between tire and sand. Numerical results show the deformation of sand and tire. The effects of the running speed on the deformation of tire and sand, stresses and strains of the tire and sand, vertical accelerations of the hub center, horizontal reaction forces of the hub center are presented.
Ma, Jianfeng
Radiation-Tolerant DC-DC ConvertersTBMG-1487410/1/2012
A document discusses power converters suitable for space use that meet the DSCC MIL-PRF-38534 Appendix G radiation hardness level P classification. A method for qualifying commercially produced electronic parts for DC-DC converters per the Defense Supply Center Columbus (DSCC) radiation hardened assurance requirements was developed.
Effects of Titanates in Low Steel Formulation: Prevention of Metal Pick Up Growth2012-01-17859/17/2012
Titanates are currently used in friction materials worldwide. This study investigates the effects of titanates in friction materials with Low Steel (LS) formulations. A kind of titanate compound is examined with a LS formulation. Test pieces both with and without the titanate are examined using small rotors of gray cast iron. The frictional performance tests use a 1/7 scale dynamometer. The surfaces and the cross-sections are closely observed using a Scanning Electron Microscopic analyzer. Results of the testing on samples without the titanate suggest that frictional effectiveness is sensitive to the load value especially in high speed braking conditions. A Metal Pick Up (MPU) phenomenon, which is one of the significant problems of friction materials, also occurs. The millimeter-sized picked-up metals consist of micron-sized wear debris of iron. The crystalline transformation of the steel fibers around the picked up metals is investigated. Results show that the crystalline structure of the steel fibers changes from ferrite to martensite. This results in hardening of the steel fibers. The frictional effectiveness may become unstable due to these changes. On the other hand, frictional effectiveness in high speed braking conditions is stabilized in the samples containing the titanate. The MPU phenomenon and the hardening of steel fibers are not found. Titanates seem to have the effect of stabilizing frictional effectiveness by preventing the MPU phenomenon in high speed braking conditions. There is a reason to suggest that titanates might be better classified as “modifiers” rather than lubricants or abrasives in LS formulations.
Kamada, Shogo, Inada, Kousuke
3D Printer With Nano-PrecisionTBMG-136075/1/2012
Metal Matrix Composite Hardfacing of MIC-6(R) Al Castings by Friction Stir Fabrication2012-01-04734/16/2012
MIC-6(R) and other Al alloys are relatively soft in comparison to other materials used for wear surfaces such as hardened steels and other iron-based materials. However, if the wear resistance of Al castings can be improved by local surface modification then significant weight reductions could be realized by replacing iron-based castings with Al. Deposition of Al-50 vol% SiC coating onto a MIC-6(R) substrate was demonstrated using friction stir fabrication (FSF). While fundamentally a coating process, FSF can be used to successively build-up layers and thus enables true wrought-metal fabrication. The metal matrix composite (MMC) coatings produced in this effort show much promise for the application of FSF to deposit wear resistant coatings onto Al substrates. Microstructural characterization shows a banded structure that is free of defects. Hardness testing showed that the deposited MMC coating is approximately twice as hard the base metal. The MMC coated surface showed an almost three-fold improvement in the reciprocal wear rate as compared to the base casting when tested under ASTM G65 abrasion testing.
Schultz, Jeff
Equivalent Sections of Certain Shapes to Round BarsAS1260 (Historical)10/28/2010
Primarily to provide the aerospace industry with approximate standards for comparing various shaped sections to round bars, in determining the response to hardening characteristics when heat treating low-alloy and martensitic corrosion-resistant steels.
AMS E Carbon and Low Alloy Steels Committee
Formula for the Removal and Remediation of Polychlorinated Biphenyls in Painted StructuresTBMG-80716/4/2010
An activated metal treatment system (AMTS) removes and destroys polychlorinated biphenyls (PCBs) found in painted structures or within the binding or caulking material on structures. It may be applied using a “paint-on and wipe-off” process that leaves the structure PCB-free and virtually unaltered in physical form. AMTS is used in conjunction with a solvent solution capable of donating hydrogen atoms. AMTS as a treatment technology has two functions: first, to extract PCBs from the material, and second, to degrade the extracted PCBs.
Drawbead Restraining Force Modeling with Anisotropic Hardening2010-01-09834/12/2010
A detailed investigation of the influence of anisotropic hardening models on drawbead restraining force is presented in this paper. The recently modified Yoshida model is adopted to characterize the anisotropic hardening behavior for steels. A two-dimensional drawbead model is used and the restraining forces corresponding to several different bead penetrations are obtained and compared against experimental results. The comparison of the predicted results for the Modified Yoshida Model with isotropic hardening models indicates that the anisotropic hardening gives lower drawbead restraining forces in general. The impact of hardening models on springback is also presented, and it's demonstrated that the springback amount predicted by the modified Yoshida model is much closer to the experimental data than that predicted by conventional isotropic hardening model.
Sun, Jixian, Zhu, Xinhai, Zeng, Danielle, Xia, Z. Cedric
Mechanical Properties and Crash Worthiness of Ultrafine Grained Multi-Phase Steel Sheets for Automotive Body Applications2010-01-04384/12/2010
Mechanical properties, formability and crash worthiness of a new sheet steel having an ultrafine grained (UFG) multi-phase (MP) microstructure are shown. The fabricated UFG-MP steel showed significant work hardening caused by deformation induced martensitic transformation of retained austenite, which resulted in a combination of high strength and large tensile elongation. It was confirmed by dynamic collapse test and FEM simulation that the large work hardenability of the UFG-MP steel promoted compact mode collapse that improved the absorbed energy.
Okitsu, Yoshitaka, Naito, Tadashi, Takaki, Naoki, Sugiura, Tomoaki, Tsuji, Nobuhiro
A Generalized Anisotropic Hardening Rule Based on the Mroz Multi-Yield-Surface Model and Various Classical Yield Functions2009-01-13924/20/2009
In this paper, a generalized anisotropic hardening rule based on the Mroz multi-yield-surface model is derived. The evolution equation for the active yield surface is obtained by considering the continuous expansion of the active yield surface during the unloading/reloading process. The incremental constitutive relation based on the associated flow rule is then derived for a general yield function. Detailed incremental constitutive relations for materials based on the Mises yield function, the Hill quadratic anisotropic yield function and the Drucker-Prager yield function are derived as the special cases. The closed-form solutions for one-dimensional stress-plastic strain curves are plotted for materials under cyclic loading conditions based on the three yield functions. For materials based on the Mises and the Hill anisotropic yield functions, the stress-plastic strain curves show closed hysteresis loops under uniaxial cyclic loading conditions and the Masing hypothesis is applicable. For materials based on the Drucker-Prager yield function, the stress-plastic strain curves do not close and show the ratcheting effect under uniaxial cyclic loading conditions. The ratcheting effect is due to different strain ranges for a given stress range for the unloading and reloading processes. A user material subroutine based on the Mises yield function, the anisotropic hardening rule and the constitutive relation was written and implemented into ABAQUS. Computations were conducted for a simple plane strain finite element model under uniaxial monotonic and cyclic loading conditions based on the anisotropic hardening rule, the isotropic and nonlinear kinematic hardening rules of ABAQUS. The results indicate that the plastic response of the material follows the intended input stress-strain data for the anisotropic hardening rule whereas the plastic response depends upon the input strain ranges of the stress-strain data for the nonlinear kinematic hardening rule.
Choi, K. S., Pan, J.
Development of Hardening Depth Evaluation Technique using Eddy Current – Establishment and Introduction of In-line Hardening Depth Inspection System –2009-01-08674/20/2009
A hardening depth evaluation technique using eddy current has been developed, which can be applied to a mass production line for destructive (cutting) inspections. Using this technique, changes in the hardness of the induction-hardened structure can be detected based on the changes in magnetic permeability. This technique reduces the thermal effect and improves measurement accuracy through a multi-frequency exciting method and a difference method algorithm.
Yamamoto, Takanari, Yamaguchi, Tetsuya
Residual Stresses and Dimensional Changes in Ferritic Nitrocarburized Navy C-rings and Prototype Stamped Parts Made from SAE 1010 Steel2009-01-04254/20/2009
Nitrocarburizing is an economical surface hardening process and is proposed as an alternative heat treatment method to carbonitriding. The focus of this study is to compare the size and shape distortion and residual stresses resulting from the ferritic nitrocarburizing and gas carbonitriding processes for SAE 1010 plain carbon steel. Gas, ion and vacuum nitrocarburizing processes utilizing different heat treatment temperatures and times were performed to compare the different ferritic nitrocarburizing processes. Navy C-Ring specimens and prototype stamped parts were used to evaluate size and shape distortion. X-ray diffraction techniques were used to determine the residual stresses in the specimens. Overall, the test results indicate that the nitrocarburizing process gives rise to smaller dimensional changes than carbonitriding, and that the size and shape distortion can be considerably reduced by applying appropriate ferritic nitrocarburizing procedures.
Nan, Chunyan, Northwood, Derek O., Bowers, Randy J., Sun, Xichen, Bauerle, Peter
Weight Reduction from High Strength Aluminum Die-Castings2009-01-05534/20/2009
High pressure die-casting (HPDC) is extensively used as a cost effective way to mass produce metal components that are required to have close dimensional tolerances and smooth surface finishes. Recently, novel heat treatment technologies have been developed that enable the yield stress, wear resistance, fatigue resistance, fracture toughness and thermal conductivity of conventional HPDC’s to be substantially improved. These technologies have been evaluated for parts ranging from small structural castings weighing around 1kg up to large components weighing over 30kg. Opportunities now exist to achieve cost savings and weight reductions by utilizing this new technology through re-design of existing aluminum alloy HPDC’s, the replacement of more expensive wrought and cast aluminum products, or replacing iron and steel components or subassemblies. This paper gives an overview of the new technology and presents cost analyses for three cases where substantial cost savings and weight reductions appear to be possible.
Lumley, Roger N.
The Potential for use of Heat Treated Aluminum High Pressure Die-Castings in Engine Applications2008-32-00589/9/2008
Aluminum alloys used for most high pressure die-castings manufactured worldwide are based on the Al-Si-Cu-(Fe) system, examples being the alloys (AA)380, (JIS) ADC10, (JIS) ADC12, and EN-AC-AlSi8Cu3(Fe). These alloys are used for a wide range of applications including engines and drivetrains for which they are usually heat treated to a stabilized T5 temper. Such a treatment does not, however, provide a significant improvement to the as-cast mechanical properties. The reason why conventionally produced HPDC components are not heat treated to the higher strength T6 or T7 tempers is that a standard solution treatment cycle (e.g. 8h at 540°C) causes internal pores to expand resulting in unacceptable surface blistering and dimensional instability. Recently a modified heat treatment regime has been developed which avoids these problems and allows large improvements (e.g. around 100%) to be achieved in some tensile properties. Fatigue resistance and thermal conductivity are also improved. The potential for using age hardened, high pressure diecast alloys for engine and drivetrain applications can now be evaluated in light of this discovery. In the current paper, a summary of results to date are presented, and brief consideration is given to possible changes in the design of future engine and drivetrain components.
Lumley, Roger N.
Gas Nitriding of Steel PartsAMS2756B (Current)6/3/2008
This specification covers a process for surface-hardening parts, made from appropriate low-alloy steels (See 8.4), by the introduction of nitrogen from ammonia.
AMS B Finishes Processes and Fluids Committee
Innovative Press Hardened Steel Based Laser Welded Blanks Solutions for Weight Savings and Crash Safety Improvements2008-01-10764/14/2008
This paper summarizes our latest developments in the field of Press Hardened Steel (PHS) based Laser Welded Blanks (LWB). New PHS steel named Ductibor 500P has been developed to enlarge the range of LWB applications in combination with Coated Boron Steel (CBS). Laser welding of these materials is presented through static and dynamic test results of laser welded specimens. Mass analysis and crash simulations results for three different applications are presented and analyzed. For these applications weight savings ranging from 4.1 to 5.4 kg/veh were achieved.
Duque Múnera, Daniel, Pic, Aurélien, Abou-Khalil, Damien, Shmit, Francis, Pinard, Fabrice
Distortion and Residual Stresses in Nitrocarburized and Carbonitrided SAE 1010 Plain Carbon Steel2008-01-14214/14/2008
The focus of this study was to determine the residual stress and retained austenite profiles for carbonitrided and nitrocarburized SAE 1010 plain carbon steel and to relate these profiles to one another and to the distortion resulting from heat treatment. Navy C-ring specimens were used for the purpose of this study and X-ray diffraction techniques were used to measure both residual stress and retained austenite. The findings from this research are then applied to a manufacturing application involving the surface hardening of a thin shelled, plain carbon steel automotive component.
Campagna, Victoria, Bowers, Randy, Northwood, Derek O., Sun, Xichen, Bauerle, Peter
Heat Treatment of Wrought Copper-Beryllium Alloys, Process for (Copper Alloys: Numbers C17000, C17200, C17300, C17500, and C17510)AMSH7199 (Historical)4/24/2007
This specification presents requirements for the heat treatment of parts and components fabricated from wrought (plate, sheet, strip, bar, rod, wire extrusions and tube and forgings) copper alloys, numbers C17000, C17200, C17300, C17500, and C17510 (see 6.7). This specification also covers “bright hardening”.
AMS D Nonferrous Alloys Committee
Forming Limit Diagram Prediction of Stainless Steels Sheets2007-01-03384/16/2007
The development of adapted design tools, such as Forming Limit Diagrams (FLD), participates to the increasing use of stainless steels in automotive applications notably. FLD are now in widespread use, but still present the major drawback of a test-intensive determination procedure. The paper presents a Cayssials-type predictive model, which describes FLD as a strain instability during biaxial loading and permits to evaluate it from strain hardening properties. Ultimately, tensile tests results and thickness of the sheet are simply required for an accurate FLD prediction. At Ugine & Alz, the model has been adapted with a common formalism for both ferritic and austenitic stainless steel grades.
Chinouilh, G., Toscan, F., Santacreu, P.O., Leseux, J.
Steel Carburizing and Nitriding, Processes forAMSS6090B (Current)5/15/2006
This specification presents requirements for the carburizing and nitriding of carbon and alloy steels to produce the mechanical properties specified by drawings, detail metal specifications, or other applicable specifications (see 6.3).
AMS E Carbon and Low Alloy Steels Committee
Paint Bake Response on the Vehicle2006-01-09854/3/2006
The average weight of a car has increased significantly in recent years due to higher crash requirements and demands in standard equipment. Therefore, BMW has decided to use aluminium for the body front end of the new BMW 5-series. During the paint process, the 6XXX-alloys currently adopted for the body front end exhibit a considerable increase in yield strength in the E-coat dryer. The increase of strength, the so-called paint bake response of 6XXX-alloys, needs to be fully exploited to meet the increasing demand of future passive safety concepts.
van Tol, R. T., Pfestorf, M.
Cryogenic High-Sensitivity MagnetometerTBMG-2986/1/2005
A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10-16 Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10-10 Tesla).
Dusty-Plasma Particle AcceleratorTBMG-5676/1/2005
A dusty-plasma apparatus is being investigated as means of accelerating nanometer- and micrometer-sized particles. Applications for the dusty-plasma particle accelerators fall into two classes:
Cryogenic High-Sensitivity MagnetometerTBMG-5816/1/2005
A proposed magnetometer for use in a cryogenic environment would be sensitive enough to measure a magnetic-flux density as small as a picogauss (10-16 Tesla). In contrast, a typical conventional flux-gate magnetometer cannot measure a magnetic-flux density smaller that about 1 microgauss (10-10 Tesla).
Improved Ion-Channel BiosensorsTBMG-156410/1/2004
An effort is underway to develop improved biosensors of a type based on ion channels in biomimetic membranes. These sensors are microfabricated from silicon and other materials compatible with silicon. As described below, these sensors offer a number of advantages over prior sensors of this type.
Deformation and Texture Behaviors of Al-3mass%Mg Alloy at High Temperatures2003-01-278610/27/2003
Uniaxial compression tests were conducted on Al-3mass%Mg alloy under various temperatures and true strain rates. High temperature yielding was observed at the temperatures higher than 623K. Texture examination elucidated that fiber textures are constructed in all the deformation conditions examined in this study. It was found that the kinds and the intensities of texture components varied depending on deformation temperature, strain rate and the amount of strain. It was concluded that orientation stability against the lattice rotation by slip deformation as well as the rapid recovery during the deformation of the grains close to {001} orientation made it possible to grow by consuming the other deformed grains with the orientations such as {011}, resulting in the development of {001} texture.
Okayasu, Kazuto, Fukutomi, Hiroshi
Explicit Pore Pressure Material Model in Carbon-Cloth PhenolicTBMG-11997/1/2003
An explicit material model that uses predicted pressure in the pores of a carbon-cloth phenolic (CCP) composite has been developed. This model is intended to be used within a finite-element model to predict phenomena specific to CCP components of solid-fuel-rocket nozzles subjected to high operating temperatures and to mechanical stresses that can be great enough to cause structural failures. Phenomena that can be predicted with the help of this model include failures of specimens in restrained-thermal-growth (RTG) tests, pocketing erosion, and ply lifting.
Steel, Maraging, Bars, Forgings, Tubing, and Rings 18.5ni 9.0co 4.9mo 0.65ti 0.10al Consumable Electrode Vacuum Melted, AnnealedAMS6514E (Historical)6/16/2003
This specification covers a premium aircraft-quality steel in the form of bars, forgings, mechanical tubing, flash welded rings, and stock for forging or flash welded rings. These products have been used typically for parts requiring through hardening, without quenching, to a yield strength of 270 psi (1862 MPa) and higher and where such parts may require welding during fabrication, but usage is not limited to such applications.
AMS E Carbon and Low Alloy Steels Committee
Steel Carburizing and Nitriding, Processes forAMSS6090A (Historical)11/21/2002
This specification presents requirements for the carburizing and nitriding of carbon and alloy steels to produce the mechanical properties specified by drawings, detail metal specifications, or other applicable specifications (see 6.3).
AMS E Carbon and Low Alloy Steels Committee
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