Metal treatment – Compositions – Heat treating
Patent
1997-05-02
2000-02-15
Yee, Deborah
Metal treatment
Compositions
Heat treating
148545, 148617, 148618, C22C 3710, C21D 506
Patent
active
060248041
ABSTRACT:
The invention is a malleable iron comprising about 250 to 400 nodules of graphite per square millimeter as observed in a photomicrograph at 100.times., and a Brinell hardness of about 195 to 550 BHN. Preferably, the malleable iron further comprises sulfur and manganese wherein the manganese is present in an excess amount of at least 2 times the amount of sulfur plus 0.15% and is formed by two separate quenching steps. The invention further comprises a method of preparing a malleable iron having a high nodule count comprising the steps of prenucleating a malleable iron casting at a temperature of about 600 to 900.degree. F. for about 3 to 6 hours; austenitizing the prenucleated casting at about 1680 to 1740.degree. F. for about 3 to 9 hours to form graphite nodules such that the malleable iron has about 250 to 400 nodules per mm.sup.2 ; and quenching the casting to form pearlite and a malleable iron made by this process.
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Ferra Charles Robert
Koepsel Mark D.
Ohio Cast Products, Inc.
Yee Deborah
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