• Title/Summary/Keyword: TRIP Steel

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CRASHWORTHINESS ASSESSMENT OF SIDE IMPACT OF AN AUTO-BODY WITH 60TRIP STEEL FOR SIDE MEMBERS

  • Huh, H.;Lim, J.H.;Song, J.H.;Lee, K.S.;Lee, Y.W.;Han, S.S.
    • International Journal of Automotive Technology
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    • v.4 no.3
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    • pp.149-156
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    • 2003
  • This paper is concerned with the energy absorption efficiency of auto-body side structures for the conventional steel and 60TRIP high strength steel. In order to evaluate the energy absorption efficiency, the dynamic crash analysis is carried out with the regulation of US-SINCAP. The analysis adopts the Johnson-Cook model for the dynamic material properties, which have been obtained from dynamic material tests. For the sake of the dynamic material properties, the analysis has been accurately peformed for the crashworthiness assesment. The analysis result provides deformed shapes, amounts of penetration and accelerations at several important points during crash. The result confirms that 60TRIP greatly improves the crashworthiness of the side members without sacrificing the weight and thus can be used for the light-weight design of an auto-body.

Hydrogen Embrittlement of TRIP Steel Charged with Hydrogen Under Two Type Electrolytes (2종 전해질 분위기하 수소주입된 TRIP 강의 수소취성)

  • Choi, Jong-Un;Lee, Sang-Wook;Lee, Kyung-Min;Kang, Kae-Myung
    • Journal of the Korean Institute of Gas
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    • v.19 no.1
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    • pp.57-63
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    • 2015
  • The hydrogen was charged TRIP steel by electrochemical method under 0.5M $H_2SO_4$ electrolyte and 0.5M NaOH electrolyte with hydrogen charging conditions respectively. The degree of hydrogen embrittlement of TRIP steel was evaluated by using micro Vickers hardness tests. These results showed that the degree of hydrogen embrittlement in acidic electrolyte with hydrogen penetration and hydrogen diffusion through the depth of specimen was more sensitive than its alkaine electrolyte between two type electrolytes. However, it was investigated that micro Vickers hardnesses of surface in acidic electrolyte under two electrolyte were higher than those of alkaine electrolyte. It was thought that in case of hydrogen embrittlement in acid-ice electrolyte, hydrogen charging time was more effective than current density, in case of alkaine electrolyte, hydrogen current density was more effective than charaging time.

Technical Development using High Strength Steel of mP Type on Automobile Parts (TRIP형 고장력강판의 부품적용 기술개발)

  • 류성지;이상제;이규현;이문용
    • Journal of Welding and Joining
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    • v.20 no.3
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    • pp.46-53
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    • 2002
  • The expolitation of substitute material and new manufacturing technology of the automobile body panel for next generation cars have been steadily professed by advanced automobile companies. High strength steel of TRIP (Transformation of Induced Plasticity) type is developed in response to demands about crash safety and high strength of automobile. In this study, basic technologies can fix up problems occurring on the mass production and applied to the other forming methods will be prepared through rasping a property of TRIP material.

2-D & 3-D Observations on the microstructures of Super Bainitie TRIP Steels using Total Analysis System (TAS (Total Analysis System)를 이용한 SB-TRIP강에서의 2-D & 3-D 미세구조 분석 연구)

  • Seol, J.B.;Lim, Y.R.;Park, C.G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2009.10a
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    • pp.209-212
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    • 2009
  • It has been widely reported that carbide-free bainitic steels or super-bainite WP (SB-TRIP) steels for the automotive industry are a new family of steels offering a unique combination of high strength and ductility. Hence, it is important to exactly evaluate the volume fraction of RA and to identify the 3-D morphology of constituent phases, because it plays a crucial role in mechanical properties. Recently, as electron back-scattered diffraction (EBSD) equipped with focused ion beam (FIB) has been developed, 3-D EBSD technique for materials science are used to these steels. Moreover, newly developed atom probe tomography (APT) technique can provide the exact distribution and chemical concentration of alloying elements in a sub-nm scale. The APT analysis results indicate exactly the distribution and composition of alloying elements in the austenite and bainite phases of SB-TRIP steels with the atomic-scale resolution. And thus, no partitioning of aluminum and manganese atoms was showed between the austenite containing $7.73{\pm}0.39$ at% C and the bainitic ferrite associated with $0.22{\pm}0.06$ at% C in the SB-TRIP steel.

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Effect of Fabrication Processes on the Mechanical Properties of 0.14C-6.5Mn TRIP Steels (0.14C-6.5Mn TRIP강의 기계적 성질에 미치는 제조공정의 영향)

  • Lee, O-Yeon;Ryu, Seong-Il
    • Korean Journal of Materials Research
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    • v.11 no.5
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    • pp.431-437
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    • 2001
  • This research was examined the effect of intercritical heat treatment on the mechanical Properties and retained austenite formation in 0.1C-6.5Mn steels for the development of a high strength high ductility steel. using of transformation induced plasticity due to retained austenite. The stability of retained austenite is very important for the good ductility and it depend on diffusion of carbon and manganese during reverse transformation. It is effective to heat treat at$ 645^{\circ}C$ in order to obtain over 30 vol.% of retained austenite. However, it is more desirable to heat treat at $620^{\circ}C$, considering the volume fraction and mechanical stability of retained austenite. The strength-elongation combination in cold rolled steel sheets after reverse transformed at $620^{\circ}C$ for 1hr was about 4000k9/mm7, but it decreased rapidly with increasing holding time at high temperature due to the decrease of ductility. The addition of 1.1%Si in 0.14C-6.5Mn TRIP steel does not improve the mechanical properties and retained austenite formation.

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Optimization of Welding Parameters for Resistance Spot Welding of TRIP Steel using Response Surface Methodology (저항 점 용접에서 반응표면분석법을 이용한 고장력 TRIP강의 최적 용접 조건 설정에 관한 연구)

  • 박현성;김태형;이세헌
    • Journal of Welding and Joining
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    • v.21 no.2
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    • pp.76-81
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    • 2003
  • Due to the environmental problem, automotive companies are trying to reduce the weight of car body. Therefore, WP(Transformation Induced Plasticity) steels, which are hish strength and ductility have been developed. The application of TRIP steel to the members has been reported to increase the energy absorption capability. Welding process is a complex process; therefore deciding the optimal welding conditions is an effective method on the basis of the experimental data. However, using a trial-and-error method from the beginning in such a wide area, in order to decide the optimal conditions requires too many numbers of experiments. To overcome these problems and to decide the optimal conditions, response surface methodology was used. Response surface methodology is a collection of mathematical and statistical techniques that are for the modeling and analysis of problems in which a response of interest is influenced by several variables and the objective is to optimize this response. The introduced method was applied to the resistance spot welding process of the TRIP steel and the welding parameters were optimized. (Received December 6, 2002)

Developments and applications of high strength cold rolled steel sheets for automobiles (자동차용 고강도 냉연강판의 개발 및 적용현황)

  • Kim S. J.;Chin K. G.
    • Proceedings of the Korean Society for Technology of Plasticity Conference
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    • 2004.08a
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    • pp.45-52
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    • 2004
  • Continuing pressure for the weight reduction of vehicles and improvement of collision safety is driving the development of new high strength steel with excellent formability. The formable high strength steels which have excellent drawability have been developed and applied to the complicated inner panels. Although BH steel have mainly occupied the material market for outer panels, it is challenged by DP steel which have low yield strength and good bake hardenability. The advanced high strength steel, TRIP steels and DP steels which have excellent formability are new alternatives to conventional HSLA steel for structural parts such as members and pillars. HSLA steels also have been used for automotive bumper reinforcements due to their high yield ratio. Higher grade complex phase steel(CP) were developed for bumper reinforcements by addition of precipitation hardening to transformation strengthened steel. The usage of the advanced high strength steel ale increasing and will become the main material in structural parts near future. This paper describes the features of newly developed high strength cold rolled steels for automobiles.

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Effect of Annealed Oxides on the Formation of Inhibition Layer During Hot-Dip Galvanizing of 590Mpa Trip Steel

  • Kim, Seong-Hwan;Huh, Joo-Youl;Lee, Suk-Kyu;Park, Rho-Bum;Kim, Jong-Sang
    • Corrosion Science and Technology
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    • v.10 no.1
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    • pp.6-12
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    • 2011
  • The selective surface oxidation of a transformation-induced-plasticity (TRIP) steel containing 1.6 wt.% Mn and 1.5 wt.% Si during annealing at $800^{\circ}C$ was investigated for its influence on the formation of an inhibition layer during hot-dip galvanizing. The selective oxidation of the alloying elements and the oxide morphology were significantly influenced by the annealing atmosphere. The pure $N_{2}$ atmosphere with a dew point $-40^{\circ}C$ promoted the selective oxidation of Mn as a crystalline $Mn_{2}SiO_{4}$ phase, whereas the $N_{2}$ + 10% $H_{2}$ atmosphere with the same dew point $-40^{\circ}C$ promoted the selective oxidation of Si as an amorphous Si-rich oxide phase. During hot-dip galvanizing, the $Mn_{2}SiO_{4}$ phase was reduced more readily by Al in the Zn bath than the Si-rich oxide phase. Consequently, the pure $N_{2}$ atmosphere resulted in a higher formation rate of $Fe_{2}Al_{5}$ particles at the Zn/steel interface and better galvanizability than the $N_{2}$ + 10% $H_{2}$ atmosphere.