| 摘要 |
PROBLEM TO BE SOLVED: To provide an injection sleeve for die casting machine in which the corrosion resistance and the wear resistance to molten metal are provided and the excellent heat retaining property is provided and the thermal fatigue crack is hardly generated. SOLUTION: This injection sleeve is provided with a three-layer structure and constituted of an inner cylinder 1, an outer cylinder 3 and an intermediate layer 2 arranged between both cylinders. The outer cylinder 3 is made of an alloy tool steel SKD61 and the inner cylinder 1 is made of a cermet having >=40% hardened phase and the intermediate layer 2 is made of the cermet having lower ratio of the hardened phase in comparison with the inner cylinder 1. The total value of the thicknesses of the inner cylinder 1 and the intermediate layer 2 is 2-4 mm. In this example, the inner cylinder 1 is made of Ni-B-Si-Mo series cermet and the ratio of the hardened phase is about 47% and this thickness is 0.5 mm. The intermediate layer 2 is made of the same kind of the cermet as the inner cylinder and the ratio of the hardened phase is about 24% and this thickness is 3.3 mm.
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