A high strength PCM steel plate having superior elecrtric and magnetic shielding property

PURPOSE: A hot dip coated strip for PCM(precoated metal) is provided which obtains yield strength of 24 kg/mm¬2 or more and superior electromagnetic field shielding power by properly controlling constituents composing the strip and soft reduction conditions, and a manufacturing method thereof is provided. CONSTITUTION: The high strength hot dip coated strip having superior electromagnetic wave shielding property after soft reduction comprises 0.015 wt.% or less of C+N+S, 0.007 wt.% or less of O, 0.15 to 0.35 wt.% of Mn, 0.15 to 0.45 wt.% of Si, 0.1 to 0.30 wt.% of Cu+Sn, 0.01 to 0.06 wt.% of P and a balance of Fe and inevitable impurities. The manufacturing method of the high strength hot dip coated strip for PCM comprises a step of hot rolling the reheated steel slab after reheating a steel slab comprising 0.015 wt.% or less of C+N+S, 0.007 wt.% or less of O, 0.15 to 0.35 wt.% of Mn, 0.15 to 0.45 wt.% of Si, 0.1 to 0.30 wt.% of Cu+Sn, 0.01 to 0.06 wt.% of P and a balance of Fe and inevitable impurities; a step of annealing the cold rolled strip at a temperature of 750 to 880 deg.C after cold rolling the hot rolled strip to a reduction ratio of 70 to 85%; and a step of soft rolling the hot dip coated strip under the conditions that soft reduction load is 200 to 350 ton force, and soft reduction tension is 3 to 6 ton force after hot dip coating the annealed strip. 전자기장 차폐성이 우수한 용융도금강판 및 그 제조방법이 제공된다. 본 발명은, 중량%로, C+N+S: 0.015%이하, O: 0.007%이하, Mn:0.15~0.35%, Si:0.15~ 0.45%, Cu+Sn: 0.1~0.30%, P:0.01~0.06%이하, 잔부 철 및 불가피한 불순물을 포함하여 조성된 전자파 차폐성이 우수한 고강도 용융도금강판과, 상기 조성의 강슬라브를 재가열한후 열간압연하는 단계; 상기 열간압연된 강판을 60~85%의 압하율로 냉간압연한후 750 ~ 880℃에서 소둔하는 단계; 및 상기 소둔처리된 강판을 용융도금한후 경압하 하중 200 ~ 350톤(ton force), 경압하 장력 3 ~ 6(ton force)톤의 조건으로 경압연하는 단계;를 포함하는 표면외관과 전자파 차폐성이 우수한 PCM 용 고강도 용융도금강판 제조방법에 관한 것이다.