Widmanstatten structure is harmful which is easy to be produced in hypoeutectoid steel

0.45%C steel for piston rod of automobile shall not have Widmanstatten structure

but the 45% C steel produced by nomal process (bloom soaking at 1120-1200 ℃，end rolling at 950 ℃) has 0.5~1.0 rating Widmanstatten structure. By increasing aluminum content from original 0.013% to 0.038%

decreasing soaking temperature to 1070-1100 ℃

decreasing end rolling temperature to 800 ℃

the Widmanstatten structure rating reduces from 0.5-1.0 to 0

which effectively prevents the formation of widnianstatten structure 0.45% C steel.