spring steel flat bar material:55CrMnA,60Si2Mn,SUP6,SUP9... standard:random acting processing Superior quality,good price. spring steel flat bar StandardGB,JIS,DIN, ... ASTMGrade55CrMnA,60Si2Mn,50CrVA,SUP6,SUP9,SUP10......Size(5-15)mm * (60-180) * Lmaterial and standard ... hope to work together with you in thefuture.Sincerely. 55CrMnA spring steel flat bar