Metallurgical and Mechanical Properties of Fusion Zones of TRIP Steels in Laser Welding

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概要

• 論文の詳細を見る

• Transformation induced plasticity (TRIP) steels are a promising solution for the production of cars with low body mass because of the combination of high strength and high plastic strain capacity that they offer. Si and Al are two important alternatives for alloying of TRIP steels in order to suppress carbide precipitation in the bainite holding temperature range during steel manufacture. Weldability of TRIP steel is one of the key factors governing its application in auto industry. In this paper, Al-alloyed TRIP steel was investigated with the diode laser welding process in terms of fusion zone metallurgical and mechanical properties, with Si-alloyed TRIP steel also included for comparison. It was found that the fusion zone of the Al-alloyed steel has a multiphase microstructure, containing skeletal ferrite, bainitic ferrite, martensite and retained austenite of two different morphologies. In contrast, the Si-alloyed steel fusion zone consists almost entirely of martensite. The high martensite content results in low fusion zone ductility in the Si-alloyed steel, only providing half the tensile elongation of the Al-alloyed steel. The Si-alloyed steel shows a greater decrease of the strength–ductility balance (ultimate tensile strength times elongation) due to welding, i.e., 62.9% compared to 45.2% for the Al-alloyed steel in quasi-static tensile testing. High strain rate tensile testing with a Hopkinson Bar apparatus shows no significant effect of strain rate on the fusion zone ductility for either steel. The fusion zone of the Al-alloyed steel does not exhibit a detectable TRIP effect probably due to the low carbon content in the retained austenite. Al and Si are both relevant as agents to suppress cementite precipitation, but they are found to exert very different influences on steel weldability.

• 社団法人 日本鉄鋼協会の論文
• 2008-04-15

著者

• Zhao Lin

  State Key Laboratory Of Advanced Steel Processes And Products Central Iron & Steel Research Inst

• Zhou Y.

  Centre For Advanced Materials Joining University Of Waterloo

• XIA Mingsheng

  Centre for Advanced Materials Joining, University of Waterloo

• TIAN Zhilin

  Central Iron & Steel Research Institute

• ZHAO Lin

  Central Iron & Steel Research Institute

• Tian Zhiling

  State Key Laboratory Of Advanced Steel Processes And Products Central Iron & Steel Research Inst

• Xia Mingsheng

  Centre For Advanced Materials Joining University Of Waterloo

関連論文

• Effects of Heat Input and Martensite on HAZ Softening in Laser Welding of Dual Phase Steels
• Metallurgical and Mechanical Properties of Fusion Zones of TRIP Steels in Laser Welding
• Fusion Zone Microstructure Evolution of Al-Alloyed TRIP Steel in Diode Laser Welding
• マイクロ接合とナノ接合における最近の進歩
• Porosity and Nitrogen Content of Weld Metal in Laser Welding of High Nitrogen Austenitic Stainless Steel
• Microstrcture and Mechanical Properties of Heat-affected Zone of High Nitrogen Steel Simulated for Laser Welding Conditions

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