Effect of different grain sizes on the static strain aging behavior of bake hardening steel


Dugan T., GÜNDÜZ S.

MATERIALS TESTING, cilt.61, ss.674-680, 2019 (SCI İndekslerine Giren Dergi) identifier identifier

  • Cilt numarası: 61 Konu: 7
  • Basım Tarihi: 2019
  • Doi Numarası: 10.3139/120.111370
  • Dergi Adı: MATERIALS TESTING
  • Sayfa Sayıları: ss.674-680

Özet

In this study, the static strain aging behavior of a bake hardening steel (BH 220), suitable for cold forming and widely used in the automotive sector was investigated. Tensile specimens prepared from BH 220 steel were first subjected to a 40 minute solution treatment at 920 degrees C and 970 degrees C and then cooled in water to generate various grain sizes. Both as-received and heat-treated samples were pre-strained for 3 % tension and then aged at 180 degrees C for 10, 20, 30, 60, 180 and 300 min. Tensile tests were carried out to obtain the yield strength (YS), ultimate tensile strength (UTS), elongation (%) and bake hardening value (delta Y) of aged as-received and heat-treated samples. Results indicated that BH 220 steel exhibited static strain aging behavior under as-received and heat-treated conditions. Heat treated samples showed higher susceptibility to static strain aging as compared to the as-received samples. Increased grain size in all the as-received and heat-treated samples decreased the YS and UTS but increased the bake hardening value delta Y.