| Title |
Research Papers / Transformations : A Study on Low Temperature Transformation Ferrite in Ultra Low Carbon IF Steels ( 1 ) - Effects of Manganese and Annealing Conditions |
| Authors |
정우창(Woo Chang Jeong),이재현(Je Hyun Lee),진영술(Young Sool Jin) |
| ISSN |
1738-8228(ISSN), 2288-8241(eISSN) |
| Abstract |
An investigation was made to determine the effects of Mn content and annealing conditions on the formation of the low temperature transformation products in ultra low carbon interstitial free steels. With increasing the Mn content, yield and tensile strengths increased, but yield ratio decreased. The Mn was found to be effective to decrease the yield point elongation, causing continuous yielding in 3% Mn steel. Low temperature transformation ferrites such as quasi-polygonal ferrite, granular bainitic ferrite, and bainitic ferrite more easily formed with higher Mn content, higer annealing temperature, longer annealing time, and faster cooling rate. Polygonal ferrite grain was readily identified in the light microscope and was characterized by the polyhedral and equiaxed shape while quasi-polygonal ferrite showed the irregular changeful grain boundaries. It was found that both granular bainitic and bainitic ferrites revealed some etching evidence of substructures in the light microscope. |