Opportunities and dangers of using residual elements ... - Jernkontoret

Table 14 Influence of residual elements on processing and end-properties of long products, from reference [2]Product Steel type Operation Residual element Content CommentWeldability, toughness, service Cu0.585No deteriorationpropertiesSn0.03LongHeavy plate materials,CMnNb gradeStrength and elongation Sn 0.02 Slight effect, OK42 CrMo4, 34 CrNiMo6, 15MohardenabilityCrNi6CuMo and Cu most important elements for hardenabilityLC steel 20 MnCr5, 7 MB6 Hot ductilityCu0.4Degradation over these contents. Harmfull effect ceasesSn0.03 for T over 1100°C.Surface cracking Cu 0.3Critical Cu content. Lower if Sn, Sb present, higher ifNi present.LC direct quenched wire Cold bright drawing Cu 0.5 Very good results for Cu>0.5rods Cold bright drawing Cr, Mo, Ni No significant effectLC free cutting steel,Cu0.25Cutting force, tool wear, hotNo effect0.08C, 11Mn, 0.07P, 0.3S +Sn0.05ductilityBi, TeBi, Te Strong influence on hot ductilitySegregationHigh tensile pearlitic steelCu, Sn, P Sn large tendency to segregate in hot rolled rods(0.8C, 0.2Si, 0.5Mn) Mechanical propertiesCu rises slightly tensile strength, no clear effect of SnLC wireContinuous castingDescalingPhosphationg prior to drawingNickel coatingCuSnCu0.250.150.05Precipitation of Cu-rich phase at metal/scale interface,oxide penetration in steel , eliminated by oxidationduring billet reheating prior to rolling.No deteriorationNo significant effectNo significant effect53