V_innen = pi * r^2 * h
V_innen = pi * (1 - 0.01)^2 * (4 - 2 * 0.01) = 12.25471833 m³
V_gesamt = pi * 1^2 * 4 = 12.56637061 m²
V_stahl = 12.56637061 - 12.25471833 = 0.3116522800 m³ = 311652.2800 cm³
m_stahl = 311652.2800 * 7.8 = 2430887.784 g = 2430.887784 kg