Impact toughness improvement of high boron-chromium steel by different isothermal heat treatment durations

MURATHAN Ö. F., KOCATEPE K., ERDOĞAN M.

MATERIALS TESTING, cilt.65, sa.7, ss.1015-1024, 2023 (SCI-Expanded) identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 65 Sayı: 7
  • Basım Tarihi: 2023
  • Doi Numarası: 10.1515/mt-2022-0377
  • Dergi Adı: MATERIALS TESTING
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Sayfa Sayıları: ss.1015-1024
  • Anahtar Kelimeler: carboboride, cleavage fracture, critical temperatures, impact toughness of high boron steel, isothermal heat treatment, ABRASIVE WEAR BEHAVIOR, MECHANICAL-PROPERTIES, DILATOMETRIC DETERMINATION, CAST ALLOY, MICROSTRUCTURE
  • Ankara Üniversitesi Adresli: Evet

Özet

This research investigates the improvement of impact toughness by changing isothermal heat treatment time for an alloy having high boron/chromium constituents. Different boron contents (0.5-5.00 wt% B) were added into high chromium steel by sand casting. Along with JMatPro program, dilatometry used to calculate critical temperatures and transformation diagrams as well. After austenization at 1050 degrees C for an hour, at 390 degrees C high B/Cr alloys isothermally heat treated for three different time intervals (24, 96, and 168 h). According to experimental findings, isothermal heat treatment enhanced hardness and impact toughness of the alloys (excluding 3.10 and 4.75 wt% boron containing alloys) due to the elimination of microsegregations and lowering carboboride sharpness. However, for every alloy wear resistance was not affected by isothermal heat treatment because carbide/boride fraction controls wear properties of the high B/Cr alloys. According to scanning electron microscope microstructures, cleavage fracture, and plowing were observed in isothermally heat treated specimens. It is noted that, isothermal heat treatment time showed no effect in mechanical properties of the high B/Cr alloys because the large amount of alloying elements shifted the phase transformation curve longer times which was more than JMatPro estimations.