Usui Kokusai Sangyo Kabushiki Kaisha, Ltd.

Iyoshi Watanabe

Kazuo Suzuki

Teruhisa Takahashi

A steel material that has on its surface a non-hexavalent-chromium type corrosion-resistant coating film formed by a composite of a metal layer and a resin layer. The steel material having or not having a copper layer is formed with 1) a Zn and/or Zn-based alloy layer, 2) a Zn/Ni alloy layer which is on this Zn and/or Zn-based alloy layer, 3) a de-Zn layer which is on the Zn/Ni alloy layer and is obtained by chemically treating the surface of the Zn/Ni alloy layer, and 4) at least one resin covering layer which is on this de-Zn layer, which are successively formed to make a corrosion-resistant coating film, the corrosion-resistant coating film, which is superior in adhesion between the metal layer and resin layer, being obtained by way of taking into account the use of a trivalent chromium type chromate layer instead of a hexavalent chromium type chromate layer (which is a substance that places a burden on the environment).

Non-hexavalent-chromium type corrosion resistant coating film structure having a resin layer and a metal layer that is superior in terms of adhesion to the resin layer

An oil-through type push rod for, for instance, internal combustion engines including a metal pipe and a metal end fitting which has an oil hole formed therein and is welded to the end of the metal pipe, the metal pipe being provided with a covering layer of a low-melting-point metal for fixing a welding spatter generated during welding, and such a low-melting-point metal covering layer being disposed on at least an inside wall surface of the metal pipe so as to be near an area where the metal end fitting is welded.

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Numazu, Japan

Iyoshi Watanabe