Nippon Koshuha Steel Co., Ltd.

Kobe Steel, Ltd.

Junji Yoshida

Kenji Yamamoto

Yasuhiro Hayashida

Yuji Machida

Masaaki Otakane

Keiichi Hayashida

The present invention provides a shearing die having longer life and a method for manufacturing the same. The shearing die includes a pair of substrates, at least one of which has a hard film formed by an arc ion plating method and located at least on a region of a curved surface and on an adjacent region from the end part of the curved surface on the side facing to the surface of the sheet or plate material to 300 &#x3bc;m along the surface of the substrate. The hard film comprises Al and one or more of Ti and Cr, and has a thickness of 1 to 5 &#x3bc;m, such that a number of metal particles having a diameter of 20 &#x3bc;m or more, which are present on a line segment having a length of 10 mm on a surface of the hard film, is 2 or less.

Shearing die and method for manufacturing the same

Cold tool steel having superior machinability, wear-resistance and minimized heat treatment size-change were obtained by specifying components and contents thereof, especially of C, Cr, Si, V and Mo, not by high-temperature soaking. Further, such prehardened cold tool steals as having excellent machinability even after heat-treatment together with minimum size-change were manufactured by further strictly specifying components, particularly of C, Si, Mn, Mo, V, and by specifying heat-treatment conditions.

Cold tool steel featuring high size stability, wear-resistance and

Growing community of inventors

Toyama, Japan

Junji Yoshida