skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back

Abstract

In order to numerically evaluate hydro-formed DP-steel tubes on crash performance considering welding heat effects, finite element simulations of crash behavior were performed for hydro-formed tubes with and without heat treatment effects. Also, finite element simulations were performed for the sequential procedures of bending and hydro-forming of tubes in order to design process parameters, particularly for the boost condition and axial feeding, considering formability and spring-back. Effects of the material property including strain-rate sensitivity on formability as well as spring-back were also considered. The mechanical properties of the metal active gas (MAG) weld zone and the heat affected zone (HAZ) were obtained utilizing the continuous indentation method in this work.

Authors:
; ; ;  [1];  [2];  [3];  [4]
  1. Department of Material Science and Engineering, Intelligent Textile System Research Center, Seoul National University, 56-1, Shinlim-dong, Kwanak-ku, Seoul 151-742 (Korea, Republic of)
  2. Automotive Steel Applications Research Group, Technical Research Labs., POSCO, 699 Gumho-dong, Gwangyang-si, Jeonnam, 545-090 (Korea, Republic of)
  3. Materials and Processes Lab., GM R and D and Planning, General Motors Corporation, Warren, MI 48090-9055 (United States)
  4. Manufacturing Systems Research Lab., GM R and D and Planning, General Motors Corporation, Warren, MI 48090-9055 (United States)
Publication Date:
OSTI Identifier:
21057046
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 907; Journal Issue: 1; Conference: 10. ESAFORM conference on material forming, Zaragoza (Spain), 18-20 Apr 2007; Other Information: DOI: 10.1063/1.2729550; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; BENDING; COMPUTERIZED SIMULATION; DESIGN; FINITE ELEMENT METHOD; HEAT AFFECTED ZONE; HEAT TREATMENTS; MATERIALS WORKING; MECHANICAL PROPERTIES; METALS; PERFORMANCE; STEELS; STRAIN RATE; STRESSES; TEMPERATURE DEPENDENCE; THERMAL ANALYSIS; WELDED JOINTS; WELDING

Citation Formats

Chung, Kyung-Hwan, Kim, Junehyung, Lee, Wonoh, Chung, Kwansoo, Lim, Ji-Ho, Kim, Chongmin, and Wenner, Michael. L. Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back. United States: N. p., 2007. Web. doi:10.1063/1.2729550.
Chung, Kyung-Hwan, Kim, Junehyung, Lee, Wonoh, Chung, Kwansoo, Lim, Ji-Ho, Kim, Chongmin, & Wenner, Michael. L. Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back. United States. doi:10.1063/1.2729550.
Chung, Kyung-Hwan, Kim, Junehyung, Lee, Wonoh, Chung, Kwansoo, Lim, Ji-Ho, Kim, Chongmin, and Wenner, Michael. L. Sat . "Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back". United States. doi:10.1063/1.2729550.
@article{osti_21057046,
title = {Crash Performance Evaluation of Hydro-formed DP-steel Tubes Considering Welding Heat Effects, Formability and Spring-back},
author = {Chung, Kyung-Hwan and Kim, Junehyung and Lee, Wonoh and Chung, Kwansoo and Lim, Ji-Ho and Kim, Chongmin and Wenner, Michael. L.},
abstractNote = {In order to numerically evaluate hydro-formed DP-steel tubes on crash performance considering welding heat effects, finite element simulations of crash behavior were performed for hydro-formed tubes with and without heat treatment effects. Also, finite element simulations were performed for the sequential procedures of bending and hydro-forming of tubes in order to design process parameters, particularly for the boost condition and axial feeding, considering formability and spring-back. Effects of the material property including strain-rate sensitivity on formability as well as spring-back were also considered. The mechanical properties of the metal active gas (MAG) weld zone and the heat affected zone (HAZ) were obtained utilizing the continuous indentation method in this work.},
doi = {10.1063/1.2729550},
journal = {AIP Conference Proceedings},
number = 1,
volume = 907,
place = {United States},
year = {Sat Apr 07 00:00:00 EDT 2007},
month = {Sat Apr 07 00:00:00 EDT 2007}
}
  • The increase demand for stronger, lighter and economic sheet metal products, make the Hydromecanical deep drawing process lately more and more popular. The Hydromecanical process is used in almost all types of sheet metal parts from home appliances and kitchenware to automotive and aviation industries. Therefore, many common materials were tested and characterized by their ability to sustain large strains via the well known Forming Limit Diagram (FLD).The aim of this work is to examine the forming capability if the Hydromecanical process in production of hemisphere parts made of materials commonly used in the aviation and aerospace industries. Experimental proceduresmore » were carried out to assess their ductility through FLD and the Forming Limit Carve (FLC).Two type of material sheets were tested herewith for demonstrating the procedure: commercial pure titanium and stainless steel 316L. A numerical simulation of the Hydromecanical process was examined and compared to self made Hydromecanical deep drawing of hemispherical parts.« less
  • Friction stir spot welding has been shown to be a viable method of joining ultra high strength steel (UHSS), both in terms of joint strength and process cycle time. However, the cost of tooling must be reasonable in order for this method to be adopted as an industrial process. Recently a new tool alloy has been developed, using a blend of PCBN and tungsten rhenium (W-Re) in order to improve the toughness of the tool. Wear testing results are presented for two of these alloys: one with a composition of 60% PCBN and 40% W-Re, and one with 70% PCBNmore » and 30% W-Re. The sheet material used for all wear testing was 1.4 mm DP 980. Lap shear testing was used to show the relationship between tool wear and joint strength. The Q70 tool provided the best combination of wear resistance and joint strength.« less
  • Type 304 stainless steel 0.8-mm-thick sheets were deep drawn by a complex working process using a hot die and cold punch. The working temperature ranged from 25 to 150 C. In room-temperature performance, the sheet metal failed because of severe work hardening. As the temperature was raised, it also failed in shear instability due to its poor ductility and small rate of work hardening. The drawability was improved by nonhomogeneous deformation with a heated die and a cooled punch. This effect disappeared as the temperature was increased to 150 C. The microstructures appearing under various working conditions were investigated, andmore » effects on drawability of steel sheets are discussed.« less
  • The effects of welding and post-weld heat treatment (PWHT) on nanoscale co-precipitation, grain structure, and mechanical properties of an ultra-high strength steel were studied through a combination of atom probe tomography (APT) and mechanical tests. Our results indicate that the welding process dissolves all pre-existing nanoparticles and causes grain coarsening in the fusion zone, resulting in a soft and ductile weld without any cracks in the as-welded condition. A 550 °C PWHT induces fine-scale re-precipitation of NiAl and Cu co-precipitates with high number densities and ultra-fine sizes, leading to a large recovery of strength but a loss of ductility withmore » intergranular failure, whereas a 600 °C PWHT gives rise to coarse-scale re-precipitation of nanoparticles together with the formation of a small amount of reverted austenite, resulting in a great recovery in both strength and ductility. Our analysis indicates that the degree of strength recovery is dependent mainly upon the re-precipitation microstructure of nanoparticles, together with grain size and reversion of austenite, while the ductility recovery is sensitive to the grain-boundary structure. In conclusion, APT reveals that the grain-boundary segregation of Mn and P may be the main reason for the 550 °C embrittlement, and the enhanced ductility at 600 °C is ascribed to a possible reduction of the segregation and reversion of austenite.« less
  • Gas springs are devices in which the compressibility of a gas is used to provide a force varying with distance. The force-distance relationship is similar to that provided by a mechanical spring. Experiments were performed on a piston-cylinder gas spring. Speed, cyclic mean pressure, gas, bore/stroke ratio, volume ratio, and internal extended surface geometry were varied. Hysteresis loss, pressure wave magnitude, and pressure-volume phase shift were measured. Nondimensional variables were found to correlate results, and a theoretical model was found to predict results well, over most of the operating range.