Spheroidal graphite cast iron for locomotive wheel brakes and wheel brakes for locomotives

摘要

PROBLEM TO BE SOLVED: To provide a locomotive brake block having wear resistance equivalent to that of an existing product without requiring addition of or an increase in Cr or Mn.SOLUTION: There is provided the locomotive brake block made of spheroidal graphite cast iron which has a chemical composition containing C:3.6 to 4.0%, Si:2.35 to 2.95%, Mn:0.55 to 0.60%, P:0.05% or less, S:0.02% or less, Cu:0.30 to 0.37%, Mg:0.025 to 0.050% and the balance Fe with inevitable impurities, and which has: an average particle diameter of the spheroidal graphite of 55 m or more; the number of particles of the spheroidal graphite of 60/mmor less; metal structure in which a base structure composed of ferrite with an area percentage of 5% or less and the balance a sorbite structure is a sorbite structure with ferrite percentage of 5% or less; and mechanical property with a Brinell hardness of 280 to 320 HBW10/3000/30.