The development of reducing sizing mill technology for high-speed rod rolling has made possible significant improvements in thermomechanical processing of many steel grades in addition to improvements in size control and mill productivity. The ability to finish roll many products at reduced temperatures provides the opportunity to refine the microstructure in the as-rolled product, which can result in advantages in post-rolling heat treatments and in final product properties. Thermomechanical rolling was applied to the rolling of high-carbon rod through the use of reducing sizing mills in the rolling line. Rolling trials were conducted and demonstrated that a decrease in finishing rolling temperature from 910 deg C to 820 deg C caused the following changes in average mechanical properties:4.8 percent decrease in ultimate tensile strength,7 percent increase in ROA values, and4 percent increase in elongation.Rolled rod from both thermomechanical and conventional rolling practices was drawn successfully from 6.5 mm down to 1.2 mm. Although drawing results were good, insufficient material was produced to definitely conclude that improved ROA and elongation properties outweighed the negative effect of increased interlamellar pearlite spacing. Further investigation into the effect of thermomechanical processing of high-carbon grades is needed in order to quantify these effects.
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