PLATED STEEL SHEETS FOR HOT PRESS FORMING HAVING EXCELLENT IMPACT TOUGHNESS AFTER HOT PRESS FORMING HOT PRESS FORMED PARTS AND MANUFACTURING METHODS THEREOF

• Main Authors: CHO YEOL RAE, KIM SEONG WOO, KIM SANG HEON, OH JIN KEUN
• Format: Patent
• Language: English; Korean
• Published: 30.06.2020
• Subjects: ALLOYS; CHEMICAL SURFACE TREATMENT; CHEMISTRY; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATIONOR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY IONIMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; COATING MATERIAL WITH METALLIC MATERIAL; COATING METALLIC MATERIAL; DIFFUSION TREATMENT OF METALLIC MATERIAL; FERROUS OR NON-FERROUS ALLOYS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUSMETALS OR ALLOYS; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION INGENERAL; MAKING METAL MALLEABLE BY DECARBURISATION, TEMPERING OR OTHERTREATMENTS; MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; METALLURGY; METALLURGY OF IRON; MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; PERFORMING OPERATIONS; PUNCHING METAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THESURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WORKING OR PROCESSING OF SHEET METAL OR METAL TUBES, RODS ORPROFILES WITHOUT ESSENTIALLY REMOVING MATERIAL

The present invention provides a plated steel sheet for hot press forming having an excellent impact toughness after hot press forming, a hot press formed member manufactured by using the plated steel sheet for hot press forming, and manufacturing methods thereof. The plated steel sheet comprises: a base steel sheet which includes 0.15-0.4 wt% of C, 0.1-1 wt% of Si, 0.6-8 wt% of Mn, 0.001-0.05 wt% of P, 0.0001-0.02 wt% of S, 0.01-0.1 wt% of Al, 0.001-0.02 wt% of N, 0.01-0.5 wt% of Cr, and the balance Fe and other impurities; and a plated layer which is formed on a surface of the base steel sheet and is made of zinc, aluminum, or alloy containing zinc and aluminum. The ratio (C_S/C_B) between the content of C in the base steel sheet (C_B) and the content of C in the surface layer (C_S) is 0.6 or less. The ratio ((Mn_S+Cr_S)/(Mn_B+Cr_B)) between the sum of the content of Mn and Cr in the base steel sheet (Mn_B + Cr_B) and the sum of the content of Mn and Cr in the surface layer (Mn_S + Cr_S) is 0.8 or greater. 본 발명은 중량 %로, C : 0.15~0.4%, Si : 0.1~1%, Mn : 0.6~8%, P : 0.001~0.05%, S : 0.0001~0.02%, Al : 0.01~0.1%, N : 0.001~0.02%, Cr : 0.01~0.5%, 잔부 Fe 및 기타 불순물을 포함하는 소지강판; 및 상기 소지강판의 표면에 형성된 아연, 알루미늄 또는 이들을 포함한 합금으로 이루어진 도금층;을 포함하고, 상기 소지강판의 C함량(C) 대비 표층부의 C함량(C)의 비(C/C)가 0.6 이하이고, 상기 소지강판의 Mn 및 Cr 함량의 합계(Mn+Cr) 대비 표층부의 Mn 및 Cr 함량의 합계(Mn+Cr)의 비((Mn+Cr)/(Mn+Cr))가 0.8 이상인 열간성형 후 충격특성이 우수한 열간성형용 도금강판, 상기 열간성형용 도금강판을 이용하여 제조한 열간성형 부재 및 이들의 제조방법을 제공한다.