| The effect of double steps heat treatment on the microstructure of nanostructure bainitic medium carbon steels |
| Paper ID : 1374-UFGNSM-FULL |
| Authors: |
|
milad foughani *1, alireza kolahi2, yahya palizdar2 1no.140- darbandy st - tajrishv sq - tehran - iran 2Materials and Energy Research Center (MERC) |
| Abstract: |
| Nowadays, Nano structure bainitic steel have attracted attention mostly because of its special mechanical properties such as high tensile strength, hardness, appropriate toughness and low manufacturing cost. The main concern for the mass production of this type of steels is prolong austempering process which increases the production costs as well as time. In this research, in order to accelerate the bainitic transformation and decrease the production time, a medium carbon steel has been prepared and two steps austempering process was employed to prevent the bainite laths thickening. The Samples were austenetized at 1000ᵒC for 15 min and were kept in the salt bath between 1 - 12 hours at 290ᵒC in one step and between 1 - 12 hours at the temperature range of 250ᵒC - 300ᵒC in two steps bainite transformation. The obtained micro structures were studied by the optical and scanning electron microscopy (FESEM) and the mechanical properties were investigated by using tensile and hardness tests. The results show that the two steps austempering process and lower carbon concentration lead to lower austempering time as well as the formation of more stable retained austenite and nanostructured bainite lath which results in higher mechanical properties. |
| Keywords: |
| Medium Carbon Steels, Nanostructure Bainite, Two Steps Austempering, Mechanical Properties |
| Status : Paper Accepted (Poster Presentation) |
