Metal treatment – Compositions – Heat treating
Patent
1984-09-14
1986-07-22
Andrews, Melvyn J.
Metal treatment
Compositions
Heat treating
266 51, B23K 706
Patent
active
046017623
DESCRIPTION:
BRIEF SUMMARY
CROSS REFERENCE TO RELATED APPLICATION(S)
The invention described in this application is described in PCT Application No. PCT/BE84/00001, filed Jan. 13, 1984 on which Applicant is claiming priority under 35 USC 1.119.
BACKGROUND OF THE INVENTION
The invention relates to an improved method for treating metal products. It applies in particular to heat treating of products obtained by rolling or continuous casting, such as steel slabs.
The term "treatment" when applied to metal products generally refers to sets of different operations usually comprising examination of the product with a flaw detector, elimination of the detected flaws, monitoring of said elimination, and possibly a final cleaning of the product.
The treatment proposed by the present invention relates to surface and subsurface ("subcutaneous") defects, i.e., defects disposed at depths not exceeding 10 mm from the surface of the product.
In the following description, reference is made in particular to continuous cast steel slabs. Obviously, the description is in no way limiting in character; the inventive method may equally be applied to numerous other metal products.
Steel works have always striven to produce products with minimum defects, so as to ensure finished products of high quality. However, to date it has not been possible to produce slabs which are complete free of defects. Consequently there is a need to detect and eliminate the kinds of defects which may be detrimental to the quality of finished products.
Treatment techniques currently employed are mostly empirical in nature, and their effectiveness tends to be dependent on the skill and experience of the operator.
One method in particular is known according to which the slab is cooled and a zone along the longitudinal axis on the top face of the slab is scarfed with a torch. This scarfed zone is generally not more than 5 mm deep and is 50 to 60 mm long. When the torch flame encounters a defect its shape and luminous intensity are altered momentarily; the operator must interpret these changes in order to assess the nature and degree of the defect.
In the case of certain very high quality steels, an additional two zones are sometimes scarfed, disposed near the longitudinal edges of the slab, parallel to the scarfed zone which was executed on the logitudinal axis.
In either case, the quality of the entire surface is assessed by extrapolating the results obtained by scarfing the zone(s) on the top face of the slab.
This method is very slow, and its empirical nature stands in the way of attainment of objective and reproducible results. Moreover, it basically only covers a small part of the surface of the product, and thus does not provide any real, practicable information concerning the rest of the surface.
There is also known a point scarfing apparatus, employed when gross defects are sought to be eliminated. A frame or carriage bearing a certain number of torches is displaced automatically along the slab to be treated, and the torches clean the surface by their action (scarfing, flame chipping, descaling, torch deseaming, etc.), at locations the coordinates of which are communicated to the control means of the said apparatus.
However, in order to use this apparatus, one must previously have located the defects which are to be eliminated. Furthermore, the apparatus does not allow the treated zone or the scarfing operation itself to be inspected; thus one suffers the hazards of operating blind.
A more recent method, applicable to products maintained at a temperature of 800.degree. to 1000.degree. C., consists of scarfing a zone of the type indicated supra, and transmitting the image of the flame of the torch to a remote location, with the aid of a television camera and monitor. The operator may thus observe the flame without being exposed to the heat emitted by the product at high temperature. The method gives the coordinates (the positions in the said zone) of the defects as indicated by the variations in shape and luminosity of the flame. The hot product is then conveyed to a trea
REFERENCES:
patent: 3953943 (1976-05-01), Nakaoka
patent: 3992826 (1976-11-01), Nakaoka et al.
patent: 4120703 (1978-10-01), Engel
patent: 4131490 (1978-12-01), Oishi et al.
patent: 4175729 (1979-11-01), Karlsson
patent: 4336923 (1982-06-01), Shiraiwa et al.
patent: 4337099 (1982-06-01), Hiroshima et al.
"The Modern Way--Automatic Inspection and Conditioning of Billets and Blooms", George N. Villee, Iron and Steel Engineer, vol. 55, No. 5, May 1978, pp. 44-48.
Andrews Melvyn J.
Centre de Recherches Metallurgiques--Centrum voor Research in de
LandOfFree
Methods for conditioning metal products does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Methods for conditioning metal products, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Methods for conditioning metal products will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-864477