Nsk Corporation

Manabu Obori

Susumu Tanaka

Kenji Yamamura

An inexpensive rolling apparatus improved in resistance to fretting, acoustic performance, resistance to corrosion, life and workability is provided. At least one of an outer member, an inner member and rolling elements of the apparatus is formed of an alloy steel containing 1.5% by weight or less of C, 10% to 20% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si and less than 0.2% by weight of N, particularly, at least one of the outer member, the inner member and the rolling elements is formed of a martensitic stainless steel containing 0.6% by weight or less of C, 10% to 14% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si, less than 0.2% by weight of N, 0.5% by weight or less of Mo, 0.2% by weight or less of V, and Fe and inevitable components as the balance, wherein the relationship between the content of C and that of Cr satisfies C %&lE;&minus;0.05 Cr %&plus;1.41; the relationship between a specific relational equation eq1 indicating the content of elements accelerating the conversion of the raw material to ferrite, taken as (eq1)&equals;Cr %&plus;Si %&plus;1.5 Mo %&plus;3.5V %, and a specific relational equation eq2 indicating the content of elements accelerating the conversion of the raw material to austenite, taken as (eq2)&equals;C %&plus;0.83 N %&plus;0.1 Mn %, satisfies (eq2)&gE;0.04&times;(eq1)&minus;0.39, (eq1)&lE;14.0 and (eq2)&lE;0.8; and the total content of C and N satisfies C&plus;N&gE;0.45%.

Rolling member

An inexpensive rolling apparatus improved in resistance to fretting, acoustic performance, resistance to corrosion, life and workability is provided. At least one of an outer member, an inner member and rolling elements of the apparatus is formed of an alloy steel containing 1.5% by weight or less of C, 10% to 20% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si and less than 0.2% by weight of N, particularly, at least one of the outer member, the inner member and the rolling elements is formed of a martensitic stainless steel containing 0.6% by weight or less of C, 10% to 14% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si, less than 0.2% by weight of N, 0.5% by weight or less of Mo, 0.2% by weight or less of V, and Fe and inevitable components as the balance, wherein the relationship between the content of C and that of Cr satisfies C %&lE;&minus;0.05 Cr %&plus;1.41; the relationship between a specific relational equation eq1 indicating the content of elements accelerating the conversion of the raw material to ferrite, taken as (eq1)&equals;Cr %&plus;Si %&plus;1.5 Mo %&plus;3.5 V %, and a specific relational equation eq2 indicating the content of elements accelerating the conversion of the raw material to austenite, taken as (eq2)&equals;C %&plus;0.83 N %&plus;0.12 Mn %, satisfies (eq2)&gE;0.04&times;(eq1)&minus;0.39, (eq1)&lE;14.0 and (eq2)&lE;0.8; and the total content of C and N satisfies C&plus;N&gE;0.45%.

An inexpensive rolling apparatus improved in resistance to fretting, acoustic performance, resistance to corrosion, life and workability is provided. At least one of an outer member, an inner member and rolling elements of the apparatus is formed of an alloy steel containing 1.5% by weight or less of C, 10% to 20% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si and less than 0.2% by weight of N, particularly, at least one of the outer member, the inner member and the rolling elements is formed of a martensitic stainless steel containing 0.6% by weight or less of C, 10% to 14% by weight of Cr, 0.1% to 0.8% by weight of Mn, 0.1% to 1.0% by weight of Si, less than 0.2% by weight of N, 0.5% by weight or less of Mo, 0.2% by weight or less of V, and Fe and inevitable components as the balance, wherein the relationship between the content of C and that of Cr satisfies C%.ltoreq.-0.05 Cr%+1.41; the relationship between a specific relational equation eq1 indicating the content of elements accelerating the conversion of the raw material to ferrite, taken as (eq1)=Cr%+Si%+1.5 Mo%+3.5 V%, and a specific relational equation eq2 indicating the content of elements accelerating the conversion of the raw material to austenite, taken as (eq2)=C%+0.83 N%+0.12 Mn%, satisfies (eq2).gtoreq.0.04.times.(eq1)-0.39, (eq1).ltoreq.14.0 and (eq2).ltoreq.0.8; and the total content of C and N satisfies C+N.gtoreq.0.45%.

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Kanagawa, Japan

Manabu Obori