Patent ID: 11946109
Assignee: RIKEN
Field: Materials, metallurgy (Chemistry)
Classification: CPC C | IPC C

Claim 0:
1. A spheroidal graphite cast iron comprising:
a chemical composition consisting of:
C: 3.0% to 4.0%,
Si: 2.0% to 2.4%,
Cu: 0.20% to 0.50%,
Mn: 0.15% to 0.35%,
S: 0.005% to 0.030%,
Mg: 0.03% to 0.06%, each by mass, and
the balance being Fe and inevitable impurities,
where Mn and Cu are contained at 0.45% to 0.75% in total; and

a structure in which a spheroidal graphite and a ferrite layer which is situated around and forming a boundary with the spheroidal graphite are crystallized out in a matrix of pearlite,
wherein in the structure,
part of the pearlite penetrates from the matrix of pearlite into the ferrite layer and reaches a boundary of the ferrite layer and the spheroidal graphite at one or more areas,
the ferrite layer has cluster of grains that are connected and joined to each other,

wherein the cast iron has a tensile strength of 700 MPa or more and an elongation of 10% or more.