| 摘要 |
To provide a metal ring excellent in durability by reducing decrease in margin of strength and concentration of tensile stress at its both widthwise end portions and to efficiently realize a production method of the same, a metal ring is formed in an endless band-like body having a nitride layer on its surface portion and constituting part of a metal belt of a belt type continuously variable transmission, the nitride layer being constituted by a first nitride layer portion positioned on an outer circumferential side, a second nitride layer portion positioned on an inner circumferential side, and third nitride layer portions positioned on both widthwise end sides, and the layer thicknesses of the third nitride layer portions being smaller than either one of the layer thicknesses of the first nitride layer portion and the second nitride layer portion.
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