낮은 - 부식 저항을위한 합금 각도 강철 (예 : 풍화 강철)은 황 (황) (<0.035%) and phosphorus (<0.040%) to minimize embrittlement. Instead, it adds chromium (0.40-0.65%), nickel (0.25-0.50%), and copper (0.20-0.40%) to form a protective oxide layer, reducing rusting. These elements enhance atmospheric corrosion resistance without compromising mechanical properties.