Cu%(WT) W%(WT) RWMA Class Density (Min) Electric conductivity (Min) Hardness (Min) Heat conductivity Thermal expansion CuW55 452 Balance 10 12.30 g/cm3 49% IACS 125HB ~260(W/mK) ~11.7(10-6/K) CuW60 402 Balance 12.75 g/cm3 47% IACS 140HB CuW65 352 Balance 3.30 g/cm3 44% IACS 155HB CuW70 302 Balance 13.80 g/cm3 42% IACS 175HB ~240(W/mK) ~9.7(10-6/K) CuW75 252 Balance 11 14.50 g/cm3 38% IACS 195HB 200~230 (W/mK) 9.0~9.5 (10-6/K) CuW80 202 Balance 12 15.15 g/cm3 34% IACS 220HB 190~210(W/mK) 8.0~8.5 (10-6/K) CuW85 152 Balance 15.90 g/cm3 30% IACS 240HB 180~200(W/mK) 7.0~7.5(10-6/K)