Diffusion bonding of WC – 10% Co hard metal to mild steel (S2OC) was carried out by holding at 1000 ～ 1075℃ for 30 min under the applied pressure of 0.5 ～ 1.5 kgf/mm² in vacuum using Ni foil (10 ～ 500 μm in thickness) as an insert-metal. The tensile strength of joints increased through a maximum at 100 μm thickness of Ni foil. Beyond100 μm however, the strength of the joint was almost independent of the thickness of Ni foil. The improvement of the bonding strength was interpreted by the decrease of the thermal stress which is due to the difference in the coefficients of thermal expansion of the hard metal and the steel during the cooling of the joints. Thermal stresses have been estimated by the theory of thermal elastic analysis based on the finite element method.
Ni箔をインサート材としたWC-Co系超硬合金と鉄鋼の拡散接合
kiyo41_rikou_pp71-85.pdf
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