Abbott Firestone curve of a low-carbon steel

Abbott Fire Stone curve can determine actual surface subjected to stress during service. The objective of the investigation is to study the surface texture behavior of low and medium-carbon steels machine elements in acidic environment using Abbott Firestone curve depending upon MATLAB software. The chemical composition of low carbon steel is 0.16C-0.27Si-1.47Mn-0.02Al while medium-carbon steel is 0.49C-0.30Si-0.91Mn-0.03Al. They were hot rolled at 1200°C for 30 min followed by air cooling. Two different heat treatment processes were applied on the hot-rolled samples. The first treatment was quenching after martensite finish (QAM) and the second one was quenching and partitioning (Q&P).
For 0.16C, the microstructure gives bands of ferrite and pearlite after hot-rolling of steel.
However, 0.49C produces coarse pearlite islands surrounded by ferrite phase. While, the microstructure after QAM and Q&P processes contain ferrite, bainite, lath martensite, and retained austenite for 0.16C steel, and polygonal ferrite, lath martensite, and retained austenite for 0.49C steel, respectively. In low-carbon steel (0.16C), after hot-rolling, steel suffers from low exploitation zone (44%) of surface texture. However, after QAM, low-carbon steel (0.16C) gives lower surface texture (36%). In addition, hot-rolled steel (0.16C) produces 40% voids zone while after QAM voids zone increases to 52% of surface texture. In medium-carbon steel (0.49C), after hot-rolling, steel produces 78% exploitation zone of surface texture. Furthermore, Q&P slightly enhances surface texture (exploitation zone) to 82%. At the same time, hot-rolled and Q&P of 0.49C steels exhibit very small number of voids for surface texture (1–4%). Therefore, 0.16C steel (hot-rolled and QAM), is highly subjected to severe failure in etchy environment. However, 0.49C steel (hot-rolled and Q&P) is highly recommended in case of moderate safety factor.

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