Steel material for high strength constant velocity joint intermediate shaft and high strength constant velocity joint intermediate shaft
View Patent ↗A steel material for a high strength constant velocity joint intermediate shaft is provided. The steal material may preferably contain C: 0.46 to 0.52%, Si: 0.6 to 0.8%, Mn: 0.7 to 0.9%, S: 0.01 to 0.05%, Mo: 0.3 to 0.5%, B: 0.0005 to 0.005%, Al: 0.002 to 0.05%, and Ti: 0.02 to 0.09%, restricting N to 0.007% or less, Cr to 0.15% or less, and P to 0.02% or less. A structural percentage of bainite+martensite may be provided which is 40% or more. The steal material may have a hardness of 250 HV to 340 HV. A high strength constant velocity joint intermediate shaft made of that steel material may be provided which has a spline-vanishing part with a surface hardness of about 610 HV to 750 HV, and a ratio t/r of an effective hardened layer depth t and radius r of 0.35 to 0.55, having a flat part with a surface hardness of about 630 HV to 770 HV and a ratio t/r of 0.55 to 1.0, and having a core hardness of about 250 HV to 340 HV.
1. A high strength constant velocity joint intermediate shaft, comprising by wt %,
C: 0.46 to 0.52%,
Si: 0.6 to 0.8%,
Mn: 0.7 to 0.9%,
S: 0.01 to 0.05%,
Mo: 0.3 to 0.5%,
B: 0.0005 to 0.005%,
Al: 0.002 to 0.05%,
Ti: 0.02 to 0.09%,
N: less than 0.007%,
Cr: less than 0.15% (including 0%),
P: less than 0.02% (including 0%), and
the balance of iron and unavoidable impurities; and
further comprising:
a spline-vanishing part having a surface hardness of approximately 610 HV to 750 HV and an effective hardened layer depth of approximately 0.35 to 0.55 in terms of a ratio t/r, wherein t is the effective hardened layer and r is a radius, and
a flat part having a surface hardness of approximately 630 HV to 770 HV and an effective hardened layer depth of approximately 0.55 to 1.0 in terms of the ratio t/r, and having a core hardness of approximately 250 HV to 340 HV.
2. The material according to claim 1 , wherein the surface hardness, the effective hardened layer of the spline vanishing part and flat part and the core hardness of the flat part is configured to increase a torsional strength and a torsional fatigue strength of the steel material.
3. A steel material article for a high strength constant velocity joint intermediate shaft, comprising by wt %,
C: 0.46 to 0.52%,
Si: 0.6 to 0.8%,
Mn: 0.7 to 0.9%,
S: 0.01 to 0.05%,
Mo: 0.3 to 0.5%,
B: 0.0005 to 0.005%,
Al: 0.002 to 0.05%, and
Ti: 0.02 to 0.09%.
N: 0.007% or less
Cr: 0.15% or less (including 0%).
P: 0.02% or less (including 0%).
the balance of iron and unavoidable impurities,
bainite+martensite that have a structural percentage of 40% or more and a hardness of 250 to 340 HV, and
a flat part having a surface hardness of approximately 630 HV to 770 HV and a core hardness of approximately 250 HV to 340 HV;
wherein the flat part has a depth of an effective hardened layer of approximately 0.55 to 1.0 in terms of the ratio t/r, and wherein t is the effective hardened layer and r is a radius; and
further comprising a spline-vanishing part having a surface hardness of approximately 610 HV to 750 HV and an effective hardened layer depth of approximately 0.35 to 0.55 in terms of the ratio t/r.
4. The material according to claim 3 , wherein the surface hardness, the effective hardened layer of the spline vanishing part and flat part and the core hardness of the flat part is configured to increase a torsional strength and a torsional fatigue strength of the steel material.