Stock material or miscellaneous articles – Composite – Of metal
Patent
1995-03-30
1997-08-05
Yoon, Tae
Stock material or miscellaneous articles
Composite
Of metal
428332, 428334, 428336, 15624423, B32B 1508, B32B 1518, B29C 4700
Patent
active
056541040
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a polyolefin-covered steel product and particularly to a polyolefin-covered steel product, for use in steel structures, having excellent impact resistance, flaw resistance, and resistance to abrasion by littoral drift or the like.
PRIOR ART
Polyolefin-covered steel products, such as polyolefin-covered metal pipes and polyolefin-covered steel sheet piles, have become used widely as steel pipes for piping, heavy-duty anticorrosive steel pipe piles in the sea, and heavy-duty anticorrosive steel sheet piles, by virtue of excellent anticorrosive properties.
The polyolefin-covered steel products, however, are likely to suffer dents at the time of handling, such as execution of piping on the spot, flaws on the surface of the covering caused by soil, pebbles, and the like at the time of mounting by driving for polyolefin-covered steel pipe piles and polyolefin steel sheet piles, and flaws in the covering at the time of execution of works of ripraps. Thus there is a requirement for the covering layer to have further improved mechanical strength and further improved surface hardness. In order to solve these problems, for example, Japanese Unexamined Patent Publication (Kokai) No. 63-27248 proposes a polyolefin-covered steel product or the like comprising a steel product which has been subjected to surface treatment, a modified polyolefin resin layer and a polyolefin resin layer laminated on the treated surface, and, laminated thereon, a fiber reinforced modified polyolefin resin layer comprising a glass fiber or the like dispersed in a silane modified polyolefin resin, for the purpose of improving the impact resistance and the flaw resistance of the polyolefin-covered steel product. Even the above covered steel product having improved impact resistance and flaw resistance has a drawback that the covering, when exposed in a coastal region which is a sandy place rich in littoral drift, is remarkably abraded, remarkably deteriorating the durability of steel structures. Specifically, an enhancement in surface hardness and strength of the material to a relatively high value as in the case of the conventional covered steel products is effective in preventing flaws by the action of large instantaneous energy, such as flaws caused by collision and dents. However, the conventional covered steel products have a drawback that, when they are exposed to littoral drift or the like, which abrades the surface of the covered steel product over a long period of time, although the instantaneous collision energy thereof is small, the covered steel products are gradually abraded because the covering per se is hard and fragile. Therefore, in the prior art, it was difficult to provide a polyolefin-covered steel product excellent in resistance to flaws caused by collision or dents, as well as in resistance to abrasion by littoral drift and the like.
DISCLOSURE OF THE INVENTION
An object of the present invention is to provide a polyolefin-covered steel product, for use in steel structures, having excellent impact resistance, flaw resistance, resistance to abrasion with littoral drift, and the like.
The present inventors have made extensive and intensive studies with a view to solving the above problems of the prior art and, as a result, have found that, in a polyolefin-covered steel product for use in a steel structure, comprising a steel product which has been subjected to surface treatment and, laminated onto the treated surface, a modified polyolefin resin layer and a polyolefin resin layer, the covering of the surface of the polyolefin resin layer with a fiber cloth to which a modified polyolefin resin has been laminated, can offer an advantage in that, for the impact resistance, the fiber cloth provided on the polyolefin covering can prevent the occurrence of through flaws, the fiber cloth having a higher hardness than the polyolefin resin layer as an anticorrosive layer can prevent the occurrence of flaws during handling or the like at the time of execution of works and, further,
REFERENCES:
patent: 4378395 (1983-03-01), Asoshina et al.
patent: 4980210 (1990-12-01), Heyes
patent: 5100708 (1992-03-01), Heyes et al.
patent: 5516397 (1996-05-01), Takano et al.
Kariyazono Yoshihisa
Mimura Hiroyuki
Miyajima Yoshihiro
Sasaki Toshiyuki
Sato Hirotaka
Nippon Steel Corporation
Yoon Tae
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