Metal working – Method of mechanical manufacture – Combined manufacture including applying or shaping of fluent...
Patent
1987-05-13
1988-09-06
Echols, P. W.
Metal working
Method of mechanical manufacture
Combined manufacture including applying or shaping of fluent...
29 33, 15 88, 1510404, 118DIG11, 118317, 4273837, B23P 1700, B05B 1300
Patent
active
047682809
DESCRIPTION:
BRIEF SUMMARY
This invention is concerned with the roll forming of metal articles from hot rolled steel strip.
BACKGROUND OF THE INVENTION
In the manufacture of roll formed steel articles the feedstock may be hot rolled or cold rolled steel strip. Hot rolled steel strip when supplied from the steel mill is coated with a tough skin of steel oxide (predominately Fe.sub.3 O.sub.4) known as "mill scale" oxide while cold rolled steel is usually supplied with a smooth surface free of blemishes ("bright" steel).
To enable the later application of decorative or protective surface finishes such as paint or electroplating to the roll formed article it is customary to remove mill scale from hot rolled strip by immersion in a pickling bath. Pickling may be carried out on the coil of steel strip before the roll forming process or the roll formed articles may be pickled prior to surface finishing.
The pickling process however has largely fallen into disfavour due to its excessive and costly consumption of time, energy and pickling chemicals and at the same time creates an environmental problem in the disposal of spent chemicals. Further difficulties associated with the pickling process relate to the creation of surface defects such as pitting in the treated surface and the effective de-passivation of the steel leading the surface corrosion on the strip coils before rolling as well as on the roll formed products. Although surface corrosion may be alleviated by treating the strip coils or the roll formed articles with protective film of a mineral or synthetic oil, there are further costs and environmental problems associated with the removal and disposal of the protective oil.
In order to alleviate the problems associated with roll forming of hot rolled steel, it has been proposed to produce a clean bright steel by cold rolling the hot rolled strip.
In cold rolling of steel strip, the coil may be pickled to remove the major portion of adhering mill scale and then passed through a four or five roll mill to produce a steel strip of superior dimensional tolerances. During the cold rolling operation a lubricant such as mineral oil or synthetic oil is used and this must be removed from the surface of the strip before or during the subsequent high temperature annealing process to avoid surface carburization.
Lubricant removal may be effected by a variety of methods. The coils, coated in lubricant, may be annealed in a carefully controlled atmosphere of steam, nitrogen and hydrogen to remove the carbon residues from the surface of the strip. Alternatively the rolling mill lubricant may comprise a low boiling point composition which evaporates during the annealing process.
Other lubricant removal processes are effected by spraying onto the surface of the steel strip detergent compositions either just before entry into the last roll stand or just after exit. Although detergents are generally satisfactory for removal of lubricant and adhered metal particles from the strip surface, the use of detergents is known to cause problems in a cold rolling mill due to a marked decrease in lubricity which in turn causes production of a large amount of metallic particles on the strip surface.
The problems associated with the use of detergents for removal of lubricating oils are addressed in Austrailian Pat. No. 552870. In Australian Pat. No. 552870 it is stated that the "problems caused by the detergent method" using water or a detergent can be solved by injecting at high pressure a rolling mill lubricant emuslion of the concentration of 0.5-2.0% onto the surface of the strip at the entrance or exit of the last stand and injecting at a low pressure a rolling mill lubricant emulsion of the same concentration to the rolls as a lubricant.
Australian Pat. No. 552870 also suggests that in the prior art high pressure detergent method, an oil separator is necessary for recovery of the oil and detergent for later use.
Although certain economies may be achieved by utilizing hot rolled steel strip as feedstock for roll forming, most of these economies are lost wit
REFERENCES:
patent: 2683436 (1954-07-01), Marantz
patent: 2794448 (1957-06-01), Marantz
patent: 2826235 (1958-03-01), Gudmestad
patent: 3044907 (1962-07-01), Bernhardt
patent: 3559280 (1971-02-01), Mailhiot et al.
patent: 3561096 (1971-02-01), Krengel et al.
patent: 3620952 (1971-03-01), Chiappe
patent: 3696503 (1972-10-01), Krengel et al.
patent: 3927816 (1975-12-01), Nakamura
patent: 4002144 (1977-01-01), Lang et al.
patent: 4273798 (1981-06-01), Scheiber
patent: 4290841 (1981-09-01), Fukuhara
patent: 4441238 (1984-04-01), Hijuelos et al.
patent: 4621399 (1986-11-01), Qureshi et al.
Tool and Manufacturing Enginee--s Handbook, vol. 2-"Forming", 4th Ed.-Published by SME.
Metals Handbook, 8th Ed., vol. 14, "Forming", Published by A.S.M.
Encyclopedia of Materials Handling by Woodley, vol. 1-Pergamon Press, 1964.
Japatic English Language Abstract (Hitachi Kinzoku K.K.) , Oct. 2, 1981; 56-126025.
Palmer Leslie H.
Palmer Ross L.
Arbes Carl J.
Echols P. W.
Palmer Tube Mills (Aust.) Pty. Ltd.
LandOfFree
Roll forming of metal articles does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Roll forming of metal articles, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Roll forming of metal articles will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-1599142