Papers by Keyword: Cooling Condition

Abstract: The study of the effects of cooling conditions on mechanical properties and wear performance by coating AISI S45C steel with Chrome Nickel Amorphous wire arc spray showed that the average surface hardness of specimens under different cooling conditions such as SCCW, SCCO, SCCS and SCCNT was 601.6 HV, while the surface hardness of HAZ of SCCS and SCCW specimens decreased to 80-90 HV. The tensile test revealed that the average ultimate tensile strength of coated specimens was 706 MPa which was slightly higher than that of uncoated specimens. This result is consistent with Tukey’s one-way ANOVA method, which found a significant difference in tensile strength values at 0.05 and 0.01 levels. For wear resistance, coated specimens showed higher wear resistance compared to uncoated specimens. Overall, the results of this study showed that wire arc spray coating could increase the strength and stress and decrease %elongation of the specimens. Therefore, this technique is suitable for maintenance work to increase the strength of steel in the industry.

Abstract: In the present study, the effect of cooling condition on hot tearing tendency and hot tearing fracture surface morphology were investigated. Results show that, the hot tear fracture surface characteristics are nearly similar under different cooling conditions. The hot tear surface exhibits two main features; the brittle region and the ductile region. The results also indicate that cooling condition has multifaceted effects on hot tearing phenomenon. Increasing cooling rate increases the thermal gradient, which raises the hot tearing tendency; concomitantly it decreases the grain size and dendrite arm spacing which increases the strength of the material. The occurrence of hot tearing phenomenon under different cooling conditions is discussed and evaluated based on the competition between these opposing factors during the solidification process.

Abstract: This paper examines the effect of initial microstructure after hot rolling on the final microstructure and mechanical properties for Cu bearing Extra Low Carbon(ELC) Steel Sheets. For this purpose, two ELC steels having different initial microstructures due to different onset time of cooling after pilot hot rolling (0.4 and 1.2 second) were selected. Mechanical properties and microstructures were analyzed as well using uni-axial tensile test, electron back-scattered diffraction (EBSD) technique following pilot rolling and continuous annealing. It has been found that the reduction of onset time of cooling gives rise to the grain refinement in hot rolled sheets. The average grain sizes of hot rolled sheetss at the onset time of 0.4 and 1.2 second are 16.7μm and 20.8 μm, respectively. In addition, the planar anisotropy of the Cu bearing ELC steel sheets has improved with reducing onset time of cooling after hot rolling. However, other mechanical properties such as strength and elongation of annealed steel are similar to both cooling condition.