Abstract For a ductile iron of the type which has been heated, after casting, to its austenization temperature and austenized and subsequently heat-treated isothermally by quenching in a hot bath to start a bainite reaction which is continued until a desired fraction of the austenite have formed into bainite, improved properties are achieved by adding as alloying elements molybdenium 0.10 - 0.26 % and magnanese 0.3 - 1.4 % by weight and preferably also an additional alloying element which promotes the formation of a pearlite micro-structure during casting and, consequently, accelerates the austenization, said additional element consisting of nickel in an amount less than 2.5 % by weight, and tin and/or copper. Preferably said iron contains molybdenium 0.15 - 0.22 % by weight and less than 0.2 % by weight of tin and/or less than 1.0 % by weight of copper.
Inventors
👤 Jouko Vourinen
👤 Yrjo Ingman
👤 Matti Johansson
👤 Martti Kurkinen
Bibliographic Details
Application Number—
JurisdictionUS
Data Sourcegoogle_patents
Last Synchronized2026-11-05 23:32
CPC Classifications
C; C22; C22C; C22C37/00; C22C37/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
15 words
A ductile iron as in claim 1 wherein the molybdenium content is 0.15-0.22% by weight.
Claim 2
Dependent Claim
14 words
A ductile iron as in claim 1 containing tin up to 0.2% by weight.
Claim 3
Dependent Claim
14 words
A ductile iron as in claim 1 containing copper up to 1.0% by weight.
Claim 4
Independent Claim
72 words
A method of producing an austenitic-bainitic ductile iron, comprising austenitizing a ductile iron containing as alloying elements molybdenium 0.10-0.26 per cent by weight and manganese 0.3-1.4 per cent by weight by heating it to the austenitization temperature and austenitizing it, then quenching it in a hot bath to form isothermal bainite, and cooling it further when the bainitic ductile iron so transformed still contains 20 to 50% by volume of retained austenite.
Claim 5
Dependent Claim
14 words
A method as in claim 5 including machining the ductile iron before quenching it.
Claim 6
Dependent Claim
11 words
A machine element constructed of the ductile iron of claim 1.