Fe-Ni-Co BASE ALLOY HAVING LOW THERMAL EXPANSION CONTAINING BORON CAPABLE OF PREVENTING SURFACE DEFECTS GENERATED DURING HIGH TEMPERATURE WORKING SUCH AS FORGING AND HOT ROLLING

摘要

PURPOSE: To provide a Fe-Ni-Co base Kovar alloy having low thermal expansion capable of improving hot workability and microstructure stability by adding a trace of boron(B) to the alloy. CONSTITUTION: The Fe-Ni-Co base alloy having low thermal expansion contains 28 to 30 wt.% of nickel(Ni), 15.5 to 18.5 wt.% of cobalt(Co), 0.05 to 0.5 wt.% of silicon(Si), 0.1 to 0.5 wt.% of manganese(Mn), and impurities of 0.006 wt.% or less of phosphorus(P), 0.05 wt.% or less of carbon(C), 0.15 wt.% or less of chromium(Cr), 0.10 wt.% or less of aluminum(Al), 0.4 wt.% or less of molybdenum(Mo) and 0.01 wt.% or less of sulfur(S), wherein the Fe-Ni-Co base alloy additionally contains 0.001 to 0.006 wt.% of boron(B).