Criteria

Text:
Display:

Results

Viewing 1 to 30 of 7535
2017-05-15 ...
  • May 15-16, 2017 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
  • October 10-11, 2017 (8:30 a.m. - 4:30 p.m.) - Troy, Michigan
Training / Education Classroom Seminars
Advanced High Strength Steels (AHSS) are now commonly used in automotive body structural applications. The high strength of this grade classification is attractive to help reduce mass in the automotive body through reduction in thickness. Strength also supports improvements in safety requirements so that mass increases are minimized. In some specific grades of AHSS, energy absorption is possible in addition to the high strength. This course will review the definition and properties of AHSS and cover several common applications in automotive body structures.
2017-04-06
Event
This symposium provides a forum for researchers and application engineers to disseminate the knowledge and information gained in the area of advanced high-strength and press-hardening steel development and applications in automotive structures, enabling light-weight and durable vehicles with improved safety.
2017-04-06
Event
This symposium provides a forum for researchers and application engineers to disseminate the knowledge and information gained in the area of advanced high-strength and press-hardening steel development and applications in automotive structures, enabling light-weight and durable vehicles with improved safety.
2017-03-28
Technical Paper
2017-01-1704
D.J. Branagan, A.E. Frerichs, B.E. Meacham, S. Cheng, A.V. Sergueeva
Demand is growing for advanced high strength steels (AHSS) in the automotive industry driven by a desire for lightweighting solutions to meet increasingly stringent fuel economy standards. Formability is a critical factor for producing reduced gauge steel parts with the complex geometries required to maintain stiffness. Global formability represents the ability of a sheet material to be deformed under various stress conditions and to be formed into a part without failure. It can be estimated using forming-limit diagrams or ductility measurements from conventional uniaxial tensile tests. However, these tests cannot reliably assess the local formability at the edges or at the internal holes of the blanks during stamping. Numerous correlations have been previously developed to predict local formability such as yield strength to tensile ratio, true strain at fracture, and post uniform elongation but they are often inaccurate – particularly for AHSS grades.
2017-03-28
Technical Paper
2017-01-1707
C. Matthew Enloe, Jason Coryell, Jeff Wang
Retained austenite stability to both mechanically induced transformation and athermal transformation is of great importance to the fabrication and in-vehicle performance of automotive advanced high strength steels. Selected cold-rolled advanced high strength steels containing retained austenite with minimum tensile strengths of 980 MPa and 1180 MPa were pre-strained to pre-determined levels under uniaxial tension in the rolling direction and subsequently cooled to temperatures as low as 77 K. Room temperature uniaxial tensile results of pre-strained and cooled steels indicate that retained austenite is stable to athermal transformation to martensite at all tested temperatures and pre-strain levels. To evaluate the combined effects of temperature and pre-strain on impact behavior, stacked Charpy impact testing was conducted on the same steels following similar pre-straining in uniaxial tension.
2017-03-28
Technical Paper
2017-01-1708
Saeid Nasheralahkami, Collin Malek, Erika Rugh, Weitian Zhou, Daniel Kowalsky, Sergey Golovashchenko
In recent years, dual phase (DP) Advanced High Strength Steels (AHSS) and Ultra High Strength Steels (UHSS) are considered as prominent materials in the automotive industry due to superior structural performance and vehicle weight reduction capabilities. However, these materials are often sensitive to trimmed edge cracking if stretching along sheared edge occurs in such processes as stretch flanging. Another major issue in the trimming of UHSS is tool wear because of higher contact pressures at the interface between cutting tools and sheet metal blank caused by UHSS’s higher flow stresses and the presence of a hard martensitic in the microstructure. The objective of the current paper is to study the influence of trimming conditions and tool wear on the quality of trimmed edge of DP980 steel sheet. For this purpose, mechanically trimmed edges were characterized for DP980 steel and compared with other steels such as HSLA350 and BH210.
2017-03-28
Technical Paper
2017-01-1703
Ryan A. Howell, Richard Gerth
FeMnAl is in a class of steels called Hadfield steel. This paper will present details, including ballistic performance, Johnson Cook coefficients, and other previously published and unpublished data for the specific alloy: Fe-30Mn-9Al-1Si-.9C-.5Mo. This particular alloy exhibits improved performance over Rolled Homogenous Armor (RHA) at equivalent aerial density. It has tunable ductility (>40% ductility) and corrosion resistance similar to 340 stainless steel. Because it has the equivalent volumetric ballistic properties to RHA at a reduced density, it can be introduced into current vehicles for any RHA component without changing part thickness or geometry. This allows current interfaces with other components to be maintained and achieve a 10% weight reduction without any change in ballistic performance. This makes introduction of this material as a weight reduction technology less costly than using a material that requires a different thickness to meet ballistic requirements.
2017-03-28
Technical Paper
2017-01-0351
Guofei Chen, Mingchao Guo
Advanced high strength steels (AHSS) have been extensively used in the automotive industry for vehicle weight reduction. Although AHSS show better parental metal fatigue performance, the influence of material strength on spot weld fatigue is insignificant. To overcome this drawback, structural adhesive was used along with spot weld to form weld-bond joints, which greatly improved spot weld fatigue performance and joint stiffness of the downgaged AHSS structures. In this study, the formulation of cohesive element based on Cohesive Zone Model (CZM) was employed to predict the onset and propagation of failure in the adhesively bonded joints in lap-shear and coach-peel specimens under quasi-static loadings. The predicted responses were compared with experimental results with good agreement.
2017-03-28
Technical Paper
2017-01-0506
Xueyuan Nie, Jimi Tjong
Ultra-high strength steel (UHSS) and magnesium (Mg) alloy have found their importance in response to automotive strategy of light weighting. UHSS to be metal-formed by hot stamping usually has a hot-dipped aluminum-silicon alloy layer on its surface to prevent the high temperature scaling during the hot stamping and corrosion during applications. In this paper, a plasma electrolytic oxidation (PEO) process was used to produce ceramic oxide coatings on aluminized UHSS and Mg with intention to further improve their corrosion resistances. A potentiodynamic polarization corrosion test was employed to evaluate general corrosion properties of the individual alloys. Galvanic corrosion of the aluminized UHSS and magnesium alloy coupling with and without PEO coatings was studied by a zero resistance ammeter (ZRA) test. It was found that the heating-cooling process simulating the hot stamping would reduce anti-corrosion properties of aluminized UHSS due to the outward iron diffusion.
2017-03-28
Technical Paper
2017-01-1705
Hua-Chu Shih, Dajun Zhou, Bruce Konopinski
The hole piercing is a simple but important task in manufacturing processes. The quality requirement of the pierced hole varies between different applications. It can be either the size or the edge quality of the hole. Furthermore, the pierced hole is often subject to a secondary forming process, in which the edge stretchability is of a main concern. The lately developed advanced high strength steels (AHSS) and ultra high strength steels (UHSS) have been widely used for vehicle weight reduction and safety performance improvements. Due to the higher strength nature of these specially developed sheet steels, the hole piercing conditions are more extreme and challenging, and the quality of the pieced hole can be critical due to their relatively lower edge stretching limits than those for the conventional low and medium strength steels. The stretchability of the as-sheared edge inside the hole can be influenced by the material property, die condition and processing parameters.
2017-03-28
Technical Paper
2017-01-0283
Mohammad Alam, Navid Nazemi, Syed Saqib, Ruth Jill Urbanic, Afsaneh Edrisy
Laser cladding is a novel process of surface coating, and researchers in both academia and industry are developing additive manufacturing solutions for large, metallic components using this process. There are many interlinked process parameters (e.g. laser power, laser speed and powder feed rate) associated with laser cladding. These process parameters have a direct impact on the resultant bead geometry and the microhardness profile throughout the bead zone, dilution zone and heat affected zone (HAZ). A set of single bead laser cladding experiments were done using a 4 kW fibre laser coupled with a 6-axis robotic arm for 420 martensitic stainless steel. A design of experiments approach was taken to explore a wide range of process parameter settings.
2017-03-28
Technical Paper
2017-01-0285
Navid Nazemi, Mohammad Alam, Syed Saqib, Ruth Jill Urbanic, Afsaneh Edrisy
Laser cladding is used to coat a surface of a metal to enhance the metallurgical properties of a substrate such as corrosion and wear resistance. For a surface cladding operations, overlapping bead geometry is required. Single bead analyses do not provide a complete representation of essential properties. The research scope targets the coaxial laser cladding process specifically for P420 stainless steel clad powder using a fiber optic laser with a 4.3 mm spot size on a low/medium carbon structural steel plate (AISI 1018). Many process parameters influence the bead geometrical shape, and the bead characteristics are varying for different overlap bead conditions. The complex temperature distributions in the process could cause subsequent large variations in hardness values. The bead overlap configurations experiments performed with 40%, 50% and 60% bead overlaps for a three pass bead formation.
2017-03-28
Technical Paper
2017-01-0453
Zane Yang
Considered in this study by the use of finite element model is a unit of assembled stator and one-way clutch (OWC) whose inner chamber is maintained at a given temperature of 150 degree C while its exterior housing surfaces are exposed to the room temperature. Two key components of dissimilar metals are assembled, as usual, at the room temperature, through the conventional interface fitting, to form a secured joint by the means of internal friction forces so that torque loads are capable to be transmitted. Due to the dissimilar materials and resulting difference in their thermal expansion coefficients, an outer component of aluminum from this joint tends to expand more than the inner component of steel when the temperature rises. This work is indented to demonstrate that using a combined thermal and structural FEA can play a pivoting role in designing not only a robust product, but also a vital test procedure that can really captures how the product functions.
2017-03-28
Technical Paper
2017-01-0372
Guang Cheng, Kyoo Sil Choi, Xiaohua Hu, Xin Sun
Advanced High Strength Steels (AHSS) represent an important technology in efforts to lightweight vehicles for improved fuel-efficiency and occupant safety. Main difference between AHSS and conventional high strength steels is their microstructures. Conventional steels are single phase materials whereas AHSS are primarily multiphase materials having several different phases in it, depending on its chemical composition and heating process. For this reason, the microstructure-based modeling methods have been usually adopted for study of AHSS. It is well known that, along with the microstructure itself, the constituent phase properties (i.e., stress-strain curves) also play a crucial role in the microstructure-based modeling. Therefore, it is important to accurately measure/estimate the phase properties of constituent phases of AHSS.
2017-03-28
Technical Paper
2017-01-0394
Junrui Li, Ruiyan Yang, Zhen Li, Changqing Du, Dajun Zhou, Lianxiang Yang
Advanced high-strength steel (AHSS) is gaining popularity in the automotive industry due to its higher final part strength with the better formability compares to the conventional steel. However, the edge fracture occurs during the forming procedure for the pre-strained part. To avoid the edge fracture happens during the manufacturing, the effect of pre-strain on edge cracking limit need to be studied. In this paper, digital image correlation (DIC), as a high accuracy optical method, is adopted in the strain measurement for the edge cracking limit determination. Sets of the wide coupons are pre-strained to obtain the samples at different pre-strain level. The pre-strain of each sample is precisely measured during this procedure using DIC. After pre-straining, the half dog bone samples are cut from these wide coupons. The edge of the notch in the half dog bone samples is created by different methods for the distinct edge condition.
2017-03-28
Technical Paper
2017-01-0478
Pai-Chen Lin, WeiNing Chen
ABSTRACT Fatigue analysis of swept friction stir clinch (Swept-FSC) joints between 6061-T6 aluminum (Al) and S45C steel (Fe) sheets was conducted through experimental approaches. Before fatigue tests, the welding tool was first modified to eliminate the hook structure inside the Swept-FSC joint. A parameter study for the indentation depth and re-indentation depth was conducted to obtain appropriate process parameters and improve the mechanical properties of Swept-FSC joints. After the lap-shear (LP) and cross-tension (CT) specimens were made, a series of quasi-static and fatigue tests were conducted. The fatigue data of Swept-FSC joints were recorded. The fatigue behavior of Swept-FSC joints in LP and CT specimens were examined through optical and scanning electron microscopes. Experimental results indicated that LP specimens have three failure modes, while CT specimens have only one failure mode.
2017-03-28
Technical Paper
2017-01-1706
Sandeep Bhattacharya, Daniel Green, Raj Sohmshetty, Ahmet Alpas
Automobile body panels made from advanced high strength steel (AHSS) provide high strength-to-mass ratio and thus AHSS are important for automotive light-weighting strategy. However, in order to increase their use, the significant wear damage that AHSS sheets cause to the trim dies should be reduced. The wear of dies has undesirable consequences including deterioration of trimmed parts' edges. In this research, die wear measurement techniques that consisted of white-light optical interferometry methods supported by large depth-of-field optical microscopy were developed. 1.4 mm-thick DP980-type AHSS sheets were trimmed using dies made from AISI D2 steel. A clearance of 10% of the thickness of the sheets was maintained between the upper and lower dies. The wear of the upper and lower dies was evaluated and material abrasion and chipping were identified as the main damage features at the trim edges.
2017-03-28
Technical Paper
2017-01-0353
Matilde Scurria, Sinem Emre, Benjamin Möller, Rainer wagener, Tobias Melz
Manganese sulfides (MnS) are nonmetallic, ductile inclusions with high melting temperature (1610 °C) which improve the machinability and retard the grain growth in steels, in addition to contributing to avoid cracking during hot working. In this paper, the effect of manganese sulfides on the fatigue life of forged steel is discussed. As the initial state a wrought product of rolled steel with a high sulfur content of 0.073% is used. Orthogonal to the direction of rolling, a cylinder is extracted and forged in the axial direction, decreasing the height by a factor corresponding to an upset (logarithmic) strain of -1.35 at a temperature of 1200°C. Due to this upset forging process, the MnS are compressed to thin and long particles.
2017-03-28
Technical Paper
2017-01-0342
Benjamin Möller, Alessio Tomasella, Rainer wagener, Tobias Melz
In case of highly loaded welded structures, the fatigue strength of critical sections is dominated by plastic strains in the low cycle fatigue (LCF) regime. Regarding fatigue, the transition from the weld seam to the base material, which additionally is affected by the heat input due to welding, is the most critical region. Fatigue life assessment by the notch strain concept is based on the evaluation of the local strain at the weld toe or weld root and includes the cyclic material behavior. The choice of the stress-strain relation is connected to the cyclic stress-strain curve and a hardening model. Stress-controlled fatigue test results of butt joints and transverse attachments show a linear extension (in the log-log scale) of the S-N line into the LCF regime. Therefore, the nominal and notch stress concept can be applied up to at least 5,000 cycles to failure.
2017-03-28
Technical Paper
2017-01-0310
Wei Wu, Dajun Zhou, Donald Adamski, Darryl Young, Yu-Wei Wang
The die wear properties were investigated in real production condition using a prog-die with up to 70,000 hits using DP1180 steel. In total, 14 die inserts with the combination of 6 die materials and 5 coating methods of surface treatment were evaluated. The analytical results of die service life for each insert were provided by examining the surface condition of formed (flanged) part. The moments of appearance of die defects, propagation of die defects, and catastrophic failure were determined. Moreover, the surface roughness of the formed parts for each die insert after 70,000 hits were characterized using Wyko NT110 machine. The current study provides the guidance for the die material and coating selections in successful stamping production using next generation AHSSs. Keywords: Die wear; Roughness; AHSS; Stamping, Die Surface Treatment, Die Steel
2017-03-28
Technical Paper
2017-01-0376
Jianyong Liang, Jonathan Powers, Scott Stevens, Behrooz Shahidi
While Advanced High Strength Steels (AHSS) and next generation steel grades offer improved crash safety and reduced weight for vehicles, the global stiffness and NVH performance are often compromised due to reduced material thickness. This paper discusses an advanced method of evaluating the joint effectiveness on contribution to global stiffness and NVH performance of vehicles. A stiffness contribution ratio is proposed initiatively in this research, which evaluates the current contribution of the joints to the global stiffness and NVH performance of vehicles. Another parameter, joint effectiveness factor, has been used by Ford Motor Company to study the potential of each joint on enhancing the global stiffness. The critical joints to enhance the vehicle stiffness and NVH performance can be identified based on above two parameters, and design changes be made to those critical joints to improve the vehicle performance.
2017-03-28
Technical Paper
2017-01-0471
Yasuo Kadoya, Yuki Oshino
By implementation of core technology of Capacitor-resistance welding, RingMash technology, metallic bonding, is developed to manufacture svarious components, the best suited for powertrain components such as transmission gears, at low cost. Components made by RingMash are attributed to smaller and lighter transmission. The technology is recommended to manufacture co-axle male-female work pieces bonding, male side diameter is slightly larger than female side hole. RingMashing is a solid state bonding without melting work piece. The actual RingMashing process is done in ambient atmosphere and does not use filler. RingMashing bonding process itself takes only 100 milliseconds, results very minimum Heat Affected Zone (HAZ), normally no more than 1 mm. The minimum HAZ achieves excellent structural integration for better performance of transmission. If two work pieces are same metals, sputtering free bonding is possible.
2017-03-28
Technical Paper
2017-01-0472
Gyoko Oh
To prevent the corrosion of the inlet part with aqueous ammonia injection, high chromium corrosion-resistant materials have been applied for the welded joints. The bending fatigue strengths of the flange-pipe welded joint samples were defined by the fatigue experiments,  modeling that high fluctuating stresses exist in the inlet and outlet flange-pipes of the muffler caused by the vibration of a moving vehicle. The factors that caused the fatigue to failure such as the welding bead shape and metallographic structure have been identified by the local stress measurement, FEM stress simulation, microscopic observation, and SEM-EDS composition analysis. By comparing the sample A having a smaller flank angle with the sample B having a larger flank angle, the result suggested that the difference of the bending fatigue strengths at 2x105 cycles was 24% when based on the nominal stress, and the difference was 10% when based on measured maximum stress.
2017-03-28
Technical Paper
2017-01-0476
Seiji Furusako, Masatoshi Tokunaga, Masanori Yasuyama
In order to reduce the weight of automobile body, application of high strength steel sheets is expanding. And also a middle and high carbon steel is expected to be used to lower the environmental impact and cost in the field of automobile steel sheet. However, it is necesarry for its realization to enhance the joint strengh of the steel sheets. In this study, hat-shape components were made by resistance spot welding or arc-spot welding using S45C steel sheet of 1.4mm in thick with strength of 1200MPa grade . Then dynamice three-point bending test was carried out on the components and crashworthiness of them was compared. Absorbed energy of the arc-spot welded component was higher than that of the resistance spot-welded one by 30%. Some spot welds fractured (separated) during the three-point bending test but arc-spot welds did NOT fractured. Arc-spot welding is therefore seemed to be effective to improve strength and toughness of weld for a middle and high carbon steel sheet.
2017-03-28
Technical Paper
2017-01-0349
Thomas Seifert, Philipp von Hartrott, Kristopher Boss, Paul Wynthein
Increasing the efficiency of heavy duty internal combustion engines is directly related to increasing specific power and, thus, increasing combustion pressure and temperature. One key component of the engine is the cylinder head which must withstand these higher temperatures and higher pressures. The path of increasing loads intensifies design conflicts, as e.g. associated with the fire deck of cylinder heads: the deck should be as thin as possible to avoid critical thermal stresses during the low frequency thermal transients but sufficiently thick to avoid failures due to the high frequency combustion pressure. A superficial solution of the design conflict is the usage of superior cast iron materials. Vermicular graphite cast iron show higher strength and fatigue resistance than the classically used lamellar graphite cast iron. However, due to their lower thermal conductivity, higher thermal stresses will arise.
2017-03-28
Technical Paper
2017-01-0346
Radwan Hazime, Thomas Seifert, Jeremy Kessens, Frank Ju
Increasing the efficiency of heavy duty internal combustion engines is directly related to increasing specific power and, thus, increasing combustion pressure and temperature. One key component of the engine is the cylinder head which must withstand these higher temperatures and higher pressures. The path of increasing loads intensifies design conflicts, as e.g. associated with the fire deck of cylinder heads: the deck should be as thin as possible to avoid critical thermal stresses during the low frequency thermal transients but sufficiently thick to avoid failures due to the high frequency combustion pressure. A superficial solution of the design conflict is the usage of superior cast iron materials. Vermicular graphite cast iron show higher strength and fatigue resistance than the classically used lamellar graphite cast iron. However, due to their lower thermal conductivity, higher thermal stresses will arise.
Viewing 1 to 30 of 7535

Filter

  • Range:
    to:
  • Year: