مقایسه تجربی و المان محدود خواص مکانیکی و شکل‌پذیری فولاد دوفازی و فولاد فریت - پرلیتی با ترکیب شیمیایی یکسان

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد / دانشگاه صنعتی شریف - دانشکده مهدسی و علم مواد

2 دانشجوی کارشناسی ارشد / دانشگاه صنعتی شریف - دانشکده مهندسی مکانیک

3 عضو هیات علمی دانشگاه صنعتی شریف

چکیده

فولادهای دوفازی فریت – مارتنزیتی زیرمجموعه‌ای از فولادهای استحکام بالای پیشرفته هستند؛ که با اعمال عملیات حرارتی بر فولادهای کم‌کربن تولید می‌شوند. از ویژگی‌های بارز فولادهای دوفازی، استحکام و چقرمگی بالای آنها نسبت به فولادهای فریت – پرلیتی با ترکیب شیمیایی مشابه است. در این پژوهش به بررسی و مقایسه خواص مکانیکی و نمودار حد شکل‌دهی فولاد فریت – پرلیتی و فولاد دوفازی با ترکیب شیمیایی یکسان پرداخته شده است. بدین منظور با اعمال چرخه حرارتی آبدهی بین‌بحرانی بر فولادی کم کربن با ساختار اولیه فریت – پرلیتی، فولاد دوفازی فریت – مارتنزیت پیوسته تولید شد. سپس آزمون‌های کشش و سختی‌سنجی به منظور بررسی خواص مکانیکی، و آزمون ناکازیما برای تعیین شکل‌پذیری فولاد اولیه و فولاد دوفازی تولید شده انجام گرفت. همچنین نمودار حد شکل‌دهی فولادها با استفاده از روش المان محدود در مقیاس ماکرو، مدل‌سازی و با نتایج تجربی مقایسه گردید. نتایج حاصل از آزمون‌های مکانیکی نشان داد که استحکام تسلیم، استحکام کششی و سختی فولاد دوفازی به ترتیب به میزان 65، 91 و 87 درصد نسبت به ساختار اولیه افزایش یافته است. بر اساس نتایج تجربی و مدل‌سازی حاصل از آزمون ناکازیما، فولاد دوفازی از شکل‌پذیری بهتری نسبت به فولاد فریت – پرلیتی برخوردار است. همچنین نتایج آزمون تجربی ناکازیما مطابقت خوبی با نتایج حاصل از مدل‌سازی دارد.

کلیدواژه‌ها


عنوان مقاله [English]

Experimental and finite element comparison of mechanical properties and formability of dual phase steel and ferrite - pearlite steel with the same chemical composition

نویسندگان [English]

  • Abolfazl Fazaeli 1
  • Mostafa Habibi 2
  • Ali akbar Ekrami 3
1 M.Sc Student / Sharif University of Technology - Department of Materials Science and Engineering
2 M.Sc Student / Sharif University of Technology - School of Mechanical Engineering
3 Faculty member of Materials Science and Engineering Department, Sharif University of
چکیده [English]

Ferrite - martensite dual-phase (DP) steels are a subset of advanced high strength steels which can be produced by applying heat treatment on low-carbon steels. The strength and toughness of DP steels are greater than those in ferrite – pearlite steels with the same chemical composition. In this study, mechanical properties and forming limit diagram of ferrite – pearlite and DP steels with the same chemical composition were investigated and compared. For this purpose, inter-critical quenching heat treatment was applied on a low-carbon steel with ferrite – pearlite microstructure to produce ferrite – continuous martensite DP steel. Tensile and hardness tests were used to determine the mechanical properties, and Nakazima test was used to determine the formability of ferrite – pearlite and DP steels. Forming limit diagram of steels was also simulated using finite element method in macro scale, and compared with experimental results. The results of mechanical tests showed that the yield stress, tensile strength and hardness of produced DP steel were increased 65, 91, and 87% respectively, in comparison to the same mechanical properties of ferrite – pearlite steel. Based on Experimental and simulation results of Nakazima test, the formability of DP steel is better than ferrite – pearlite steel. There was good agreement between simulation and experimental results.

کلیدواژه‌ها [English]

  • Dual-Phase steel
  • ferrite
  • martensite
  • forming limit diagram
  • Finite element modeling

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