مقایسه تأثیر عملیات حرارتی کوئنچ- بخش‌بندی (Q-P) و کوئنچ مستقیم (D-Q) بر ریزساختار و خواص مکانیکی یک فولاد استحکام بالای حاوی میکرو آلیاژ Ti

نوع مقاله : مقاله پژوهشی

نویسندگان

1 دانشجوی کارشناسی ارشد، دانشکده مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

2 دکتری، دانشکده مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

3 استاد، دانشکده مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

4 استادیار، دانشکده مهندسی مکانیک، دانشگاه تبریز، تبریز، ایران

5 کارشناس، دانشکده مهندسی مکانیک، دانشگاه تبریز، ایران

چکیده

کوئنچ-­بخش‌­بندی یکی از روش‌­های تولید فولادهای پیشرفته استحکام بالا است. اصول عملیات حرارتی مذکور مبتنی بر نفوذ کربن از مارتنزیت به آستنیت باقیمانده (γR) و پایدارسازی γR است. در این پژوهش آلیاژ با ترکیب شیمیایی  wt%Al054/0– wt%Si 5/1 –wt%Mn 2/2 –wt%C 21/0–Fe  حاوی 08/0% Ti  به‌­عنوان یک میکروآلیاژ در یک کوره ذوب القایی در خلاء بصورت شمش ریخته گری گردید. شمش مزبور به­‌مدت 3 ساعت در دمای °C1200 تحت عملیات حرارتی همگن‌سازی قرار گرفت. شمش همگن سازی شده توسط فرآیند نورد گرم و سرد به‌­صورت ورقی به ضخامت mm 5/1 نورد شد. ورق تهیه شده تحت عملیات حرارتی Q-P و کوئنچ مستقیم قرار گرفته و از لحاظ ریزساختار و خواص مکانیکی مورد مقایسه قرار گرفته است. مقایسه تأثیر عملیات­‌های مذکور بر ریزساختار و خواص مکانیکی فولاد توسط میکروسکوپ الکترونی روبشی (SEM)، آنالیز اشعه ایکس (XRD)، ریزسختی‌­سنجی و متالوگرافی انجام شد. نتایج بدست آمده نشان داد که نمونه‌­ای که تحت عملیات حرارتی کوئنچ-­بخش‌­بندی قرار گرفته است، شکل‌­پذیری بهتری نسبت به نمونه کوئنچ مستقیم دارد. استحکام و شکل­‌پذیری نمونه حاصل از کوئنچ-­بخش‌­بندی به ترتیب MPa 1062 و 52/24 درصد و استحکام و شکل­‌پذیری نمونه حاصل از کوئنچ مستقیم نیز به ترتیب MPa‌ 1484 و 21/15 درصد گزارش شد.

کلیدواژه‌ها


عنوان مقاله [English]

Comparison of the effect of heat treatment quenching - partitioning (Q-P) and direct quenching (D-Q) on the microstructure and mechanical properties of a high strength steel containing Ti microalloy

نویسندگان [English]

  • Leyli Nasimi 1
  • Ali Almasi 2
  • Abbas Kian Vash 3
  • Abolfazl Tutunchi 4
  • Zahra Habibi 5
1 Faculty of Mechanical Engineering, University Tabriz, Tabriz, Iran
2 Faculty of Mechanical Engineering, University Tabriz, Tabriz, Iran
3 Faculty of Mechanical Engineering, University Tabriz, Tabriz, Iran
4 Faculty of Mechanical Engineering, University Tabriz, Tabriz, Iran
5 Faculty of Mechanical Engineering, University Tabriz, Tabriz, Iran
چکیده [English]

Quenching-partitioning (Q-P) is one of the methods of producing advanced high strength steels (AHSS). The principles of the mentioned thermal process are based on carbon penetration from martensite to residual austenite (γR) and stabilization of γR. In this research, the alloy with the chemical composition of 0.054 wt% Al, 1.5 wt% Si, 2.2 wt% Mn, 2.2 wt% Mn, 0.21 wt% Fe, containing 0.08% Ti as a micro-alloy in an induction melting furnace in VIM was cast as an ingot. The said ingot was homogenized for 3 hours at a temperature of 1200 °C. The homogenized ingot was rolled into a sheet with a thickness of 1.5 mm by hot and cold rolling processes. The prepared sheet was subjected to Q-P heat treatment and direct quenching (D-Q) and was compared in terms of microstructure and mechanical properties. The comparison of the effect of the mentioned operations on the microstructure and mechanical properties of steel was done by scanning electron microscope (SEM), X-ray analysis (XRD), micro-hardness measurement, and metallography. The obtained results showed that the sample subjected to Q-P heat treatment has better formability and strength than the D-Q sample. The strength and formability of the sample obtained from Q-P were reported as 1062 MPa and 24.52% respectively, and the strength and formability of the sample obtained from D-Q were reported as 1484 MPa and 15.21% respectively.

کلیدواژه‌ها [English]

  • Quenching-partitioning heat
  • Treatments (Q-P)
  • Retained austenite
  • Tensile strength
  • Fracture strain
  • Micro-alloy
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