Metal treatment – Process of modifying or maintaining internal physical... – Processes of coating utilizing a reactive composition which...
Patent
1997-03-24
1999-07-27
Simmons, David A.
Metal treatment
Process of modifying or maintaining internal physical...
Processes of coating utilizing a reactive composition which...
72236, 148277, 148287, 4284722, 492 1, 492 58, 492 60, C23C 2200
Patent
active
059284412
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a method for the hot rolling of steel products and also to a hot rolling roll for steel products. In particular, the present invention relates to a hot rolling method of steel products and a hot rolling roll for steel products, both of which are effective in preventing steel products, such as steel bars, steel sections, steel plates, steel sheets in coil, steel tubes, steel flats and steel wire rods, particularly stainless steel products, from seizing between the rolls and the steel products to be rolled, preventing wear of the rolls, and preventing the deterioration of both the rolls and the steel products, when these steel products are subjected to hot rolling.
TECHNICAL BACKGROUND
In recent years, a diversity of steel products has been demanded, which frequently requires the hot rolling of steel products under severe conditions. The hot rolling under severe conditions often causes the seizure between the rolls for hot rolling (i.e. hot rolling rolls constituted essentially of iron-based materials and hereinafter referred to simply as "rolls") and the steel products to be rolled. As the wear of the rolls advances, the rolls suffer deterioration on the surfaces, thus, presenting the problem that the deterioration of the rolls transfers to the surface of the steel products being rolled. For instance, where H beams are hot rolled by means of a universal mill, the seizure occurs between the rolls and the H beams especially at a portion where a sliding velocity relative to the H beams becomes great or at a portion where a normal stress becomes locally high, thereby causing problems. To avoid this, it is inevitable that frequent care must be done for the rolls and the rolled steel products. This takes uncountable time and cost.
Especially, where stainless steel H beams are hot rolled, the seizure is very likely to occur. The countermeasures therefore have been extensively studied from different angles. For instance, high chromium cast iron or high speed steels have been developed from the standpoint of materials for the rolls. However, when these materials are used as the rolls, it is not always possible to completely prevent the seizure. At present, for the prevention of the seizure, lubricants such as graphite compounds have to be used.
To prevent the seizure, an attempt has been made to treat the roll surfaces. For instance, a roll is covered on the surface with Cr by a chromium-plating method, TiN by a CVD method (i.e. a chemical vapor deposition method), and TiC by a PVD method (i.e. a physical vapor deposition method).
However, the time and cost required for these treatments are vast. When using the rolls which have been subjected to the above-mentioned surface coating treatments, the film on the roll is liable to peel off under such severe conditions as of the hot rolling. In this sense, any stable anti-seizing property and wear resistance have not been developed to date.
Extensive studies have also been made on lubricants for hot rolling rolls. Among known lubricants, organic lubricating oils often undergo shortage of oil film or combustion, so that satisfactory lubricating effects cannot be expected. JP-A No. 5-212419 discloses a technique wherein graphite is deposited on roll surfaces as a lubricant by means of a combustion burner using a hydrocarbon fuel. The method proposed in this publication is certainly effective in preventing the seizure. However, the use of graphite has the problem that steel products to be rolled undergo "carburization" under hot (high temperature) conditions because of the use of graphite and that steel products to be rolled are apt to slip on rolling. In addition, the graphite particles scatter to worsen the working environment.
JP-B2 No. 3-25241 discloses a technique wherein, while a mixed liquid paint, composed of an anti-seizing agent, consisting of metal oxide powder and a binder is continuously supplied to and coated onto the peripheral surface of a disk roll-type guide shoe, steel products are pierced. The method pr
REFERENCES:
patent: 2105015 (1938-01-01), Singer
patent: 2835616 (1958-05-01), Rausch et al.
Izawa Masaru
Kusaba Yoshiaki
Tsubouchi Kenji
Koehler Robert R.
Simmons David A.
Sumitomo Metal Industries Ltd.
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