| 摘要 |
A composite utility knife blade and method of making such a blade involves butt joining a high speed steel wire to a front edge of a carbon steel backing strip. Electron beam welding the wire to the backing strip and, in turn, forming a composite strip defining a first metal portion formed by the steel backing strip, a second metal portion formed by the high speed steel wire, and a weld region joining the first and second metal portions. The composite strip is then annealed, and the annealed strip is straightened to eliminate any camber therein. Then, a plurality of notches are formed, such as by punching, in axially spaced locations relative to each other along the back edge of the first metal portion of the annealed composite strip. The annealed and punched composite strip is then hardened such that the first metal portion defines a surface hardness within the range of approximately 38 Rc to approximately 52 Rc, and the second metal portion defines a surface hardness within the range of approximately 60 Rc to approximately 75 Rc. The hardened strip is then subjected to at least two tempering and quenching cycles. Then, facets are formed on the edge of the second metal portion by grinding, honing and stropping to, in turn, form an approximately straight, high speed steel cutting edge along the side of the composite strip opposite the back edge of the first metal portion. The composite strip is then die cut along shear lines axially spaced relative to each other. Each shear line is oriented at an acute angle relative to the back edge of the first metal portion, and two notches are located between adjacent shear lines. The die cutting of the composite strip forms a plurality of utility knife blades, wherein each utility knife blade defines an approximately trapezoidal peripheral configuration.
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