US2056424A

US2056424A - Process of applying finishes to metallic sheets and the like

Info

Publication number: US2056424A
Application number: US627848A
Authority: US
Inventors: Ray M Fenton
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-08-08
Filing date: 1932-08-08
Publication date: 1936-10-06
Anticipated expiration: 1953-10-06

Description

Oct. 6, 1936. RPM. FENTON PROCESS OF APPLYING FINISHES TO METALLIC SHEETS AND THE LIKE Filed Aug. 8, 1952 Fatenteol @ct. 6, l fi untrue stares attain Parent IPRGCIESS @IF AiPlPlLlYlING FINISHES Till) METALLEC SHEETS AND THE MIKE 1 Claims.

This invention relates as indicated to the process of applying finishes to metallic sheets and the like and refers more specifically to a process for producing metallic sheet metal having a uniform substantially smooth surface such as is required in the manufacture of automobile bodies and like articles, where the nature of the coating ultimately applied to such sheets requires that the same be as nearly perfect as possible in order that no imperfections in the surface of the metallic sheet may be reflected in the paint or like finish ultimately applied thereto.

In my Patent No. 1,995,382 which issued on my copending application Ser. No. 509,563, filed Jan. 19, 1931, is disclosed an apparatus capable of subjecting the surface or surfaces of a metallic sheet and/or strip of steel or like material to a uniform abrading action throughout the extent of such surface and the process comprising my invention and presently to be explained more in detail contemplates the employment of such a machine for the purpose of abrading the surface of the sheet as one step in the-process.

The above identified apparatus is particularly 2 desirable for the purpose of performing one of the steps of the process presently to be explained for the reason that such machine may be employed to rapidly and efficiently abrade the sheets so that not only may production proceed in the 30 usual manner and at the usual rate common in steel mill practice but such apparatus is particularly adapted for large scale, low cost operation.

As is well known to those familiar with the art of sheet steel manufacture, the surface of the sheets may, either during the rolling operation or during any of the other steps in the process of its manufacture, have imperfections formed thereon such as might be due to the inclusions of flakes of scale in the surface or the formation of lines on the surface of the sheet due to crowding of the metal as the same passes through the rolls. Other imperfections are equally well known to those familiar with the art and it is one of the objects of my invention to provide a. process for applying a finish to metallic sheets which will not only remove such imperfections but will produce a finish superior to any'achieved by means heretofore employed.

As is likewise well known to those familiar with the art, the production of full finish steel sheets is not possible in a straight line continuous manner by apparatus at present employed, for the reason that the sheets, in being rolled and heated, have adhering to their surfaces considerable quantities of scale which, at the present time, is

removed by bundling such sheets, placing the same on trays and then immersing the same in an acid bath in order to remove such scale before the final finishing steps in the complete process may be performed. This interruption of 5 the continuous straight line movement of the sheets prevents the sheet making process from being carried on as a full continuous operation without the installation of enormously expensive equipment which has limited straight line producl tions in this country to only a few isolated installations.

By the employment of the process comprising my invention, the process of producing full finish sheets may be carried on continuously in a 15 straight line production manner without the necessity for heavy investments in equipment.

Even though extensive pickling is resorted to in order to remove scale inclusions in the surface of the sheets, prior to a cold rolling operation employed for the purpose of imparting a full finish to such sheets, nevertheless, it has been found that when such scale inclusions are considerable in area and depth, thereby producing a material indentation in the surface of the sheet, the pickling step may remove such scale inclusion but the subsequent cold rolling operation is not sufficient to remove the traces of such defect. This is believed to be due to the fact that a cold rolling operation is incapable of supplying the necessary material required to fill out such indentations so that instead of removing all traces of the imperfection, the cold rolling operation has a tendency to aggravate the blemish in the sheet.

As is likewise well known to those familiar with the art, one of the difficulties inherent in socalled strip steel which has been reduced by cold rolling under high pressures is that the mirrorlike finish of such strip is unsuited to have applied thereto a coating of certain types of enamel, paint, etc. By the operation comprising my vention it is possible to convert such mirror-like surface found on sheets and/or strips into a surface which is sufficiently open to permit the ready adherence thereto of finished coats such as the above-mentioned.

It is among the objects of my invention to provide a process for applying finishes to metallic sheets which shall be capable of producing sheets having all of the above-named desirable characteristics. Other objects of my invention will appear as the description proceeds. I

To the accomplishment of the foregoing and related ends, said invention, then, consists of the ll steps hereinafter fully described and particularly pointed out in the claims:

The annexed drawing and the following description set forth in detail one approved method of carrying out the invention, such disclosed method, however, constituting but one of the various ways in which the principle of the invention may be used.

In said annexed drawing:

Fig. 1 is an illustration of a micro-photograph showing the surface of the steel sheet magnified 50 diameters and showing such surface after the same has been subjected to the abrading action, which is one step in the process comprising my invention; Fig. 2 is a micro-photograph of the same surface illustrated in Fig. 1 but magnified only 6 diameters; and Fig. 3 is the same surface as has been illustrated in Fig. 2 magnified 6 diameters but after such surface has been subjected to a cold rolling operation.

The process comprising my invention generally stated comprises the steps of subjecting a metallic v sheet which has surface imperfections to an abrading action such as would be produced by the apparatus disclosed and claimed in my aforesaid patent. As most clearly illustrated in Fig. 1, this abrading action upon the sheet has a tendency to produce a surface which, when magnified many times, has a plowed effect, i. e., the surface of the sheet has been disturbed to form a large number of very fine longitudinally extending ridges. In subjecting the sheet to such abrading action, however, all or approximately all of the scale normally adhering to the surface of the sheet is mechanically removed and where there have been indentations due to excessive scale inclusions, the metal is plowed over so that such inclusions are substantially filled in and a sheet having a uniform roughened finish is produced.

After the scale has been removed in the above defined manner and the sheet roughened by the abrasive action, the same is subjected to a cold rolling operation with the line of movement of the material through the rolls in substantial alignment with the direction of the grooves formed by the abrading action. This cold rolling step flattens out the grooves formed by the abrading action and the resultant sheet, as most clearly illustrated in Figure 3, possesses a uniformly smooth finish which could not be secured were the scale of the sheet removed by pickling and the sheet then subjected to simply a cold rolling operation.

In certain cases, it may be found necessary to cleanse the sheet after the abrading step and before the cold rolling operation for two principal reasons, namely, the abrading action on the sheet may not extend deeply enough into the surface to remove all scale inclusions in slight pits and similar imperfections. A subsequent pickling operation will, therefore, be necessary or at least desirable in order to remove the scale which has not been reached during the abrasive action. The other reason for the cleansing action following the abrading action is to remove all adhering foreign material which may have a tendency to remain on the surface of .the sheet after it has been abraded.

In any event, however, the type of pickling required to cleanse after the abrading operation need not be very severe so that the step commonly referred to in the art as a wash picking process may be employed to produce this cleansing action. By wash pickling is meant conveying the sheets and/or strip through a suitable acid bath but due to the fact that most of the scale has been removed by the abrading action and only minute inclusions of scale and loosely adhering foreign material need be removed from the sheet, such. wash pickling action is sufficient to properly cleanse the surface and as is well known to those familiar with the art, wash pickling does not ordinarily result in any appreciable etching of the metal.

After the wash pickling step, it is usually desirable to scrub and dry the surface in the manner well known in the art, so that the sheet may be perfectly clean before it passes into the cold rolls.

As an example of several specific applications of the process comprising my invention, several cases will be considered wherein such process may be employed in the production of finished sheets.

One set of operations which may admirably include the process above defined, consists of the following steps preferably performed in the order enumerated: The sheets are hot rolled, sheared, annealed, cold rolled, abraded to remove scale and produce a uniform roughened surface on the sheet, continuous wash pickled, scrubbed and dried in order to properly cleanse the sheet and to impart thereto the desired surface.

For certain uses, the uniform roughened surface of the sheet is desirable but for other purposes requlring a higher finish, the sheets, after they have been cleansed subsequent to the abrading step, will be subjected to a cold rolling operation for the purpose of smoothing down the ridges previously explained as having been formed by the abrading action.

In straight line continuous production of metallic sheets, the following examples are illustrations of the manner in which the process comprising my invention may be advantageously employed: For sheets which have passed through the regular finishing process but upon final inspection show defects in their surface, such sheets may be reclaimed and a full finished surface imparted thereto by causing the same to beabraded in the manner above defined and then wash pickling and 1 cold rolling the same in order to remove the defect present in the original finished state of the sheet.

Frequently, at an inspection stage preliminary to the usual final cold rolling step, imperfections are noted in the sheet which, in the experience of the inspector, are of the character such that the cold rolling operation will clearly not remove the same. Accordingly, instead of permitting such sheet to pass through the cold rolling stage, it will be found desirable to withdraw such sheet from the regular process and then immediately subject the same to an abrading action for the purpose of removing the imperfection and imparting thereto a roughened surface, whereupon the sheet may be cold rolled to produce a surface free from the noted imperfection.

As previously indicated, strip steel manufactured in the usual process by cold rolling under high pressure, such as exerted by a four-high rolling mill, usually have a surface which is mirror-like in character and hence, really too smooth for the proper adherence thereto of finishing coats such as paints-enamels and the like. It is one of the objects of my invention to pass such continuous strip through the apparatus disclosed in my previously identified patent to subject the same to an abrading action such as forms one of the steps in the process comprisingmy present invention and by such abrading action, sufllciently roughen the surface of the sheet so that it has the appearance, most clearly illus-- trated in Fig. 2 of the drawing, which is some ciently uniform so as not to show through the finish coat but suiiiciently open so that such a ish coat may readily adhere thereto.

By the process comprising my invention, the sheets or strips may be treated in a continuous manner for the production of a high-grade iull finish sheet or such process may be employed for the purpose of reclaiming sheets previously fin= ished but which, upon inspection, have. been found to contain defects in their surface which cannot be removed by ordinary processes. The process comprising my invention, therefore, not

only insures an initially high-grade sheet superior to any heretofore employed, lout enables sheets having surface imperfections, which would normally cause such sheets to he classified as seconds. to be reclaimed and sold as first-class stock.

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the process herein disclosed, provided the step or steps stated by any of the following claims or the equivalent of such stated step or steps be employed.

I, therefore, particularly point out and distinctly claim as my invention:

1. The method of finishing metallic sheets which comprises the following steps: cold rolling, abrading, continuous wash pickling, scrubbing, drying, and then cold rolling.

2. In a method of prep the adhesion of a non-metallic finish coat, the steps which comprise removing scale and loosely attached particles from the surface of such sheet by abrading in parallel lines and restoring the smooth surface by cold rolling.

3. In a method of preparing a steel sheet for the adhesion oi a non-metallic finish coat, the steps which comprise removing scale and loosely attached particles from the surface of a commercial cold-rolled sheet by abrading in parallel lines and restoring smoothness to the surface by coldrolling in the direction of said lines.

t.- In the method of preparing a steel sheet for the esion of a finish coat, the steps which comprise removing surface defects from the surface of such sheet by ahrading in parallel lines, and restoring the smooth surface by cold rolling.

5. The method of finishing metallic sheets which comprises the following steps: cold rolling, abrading, pickling, and then cold rolling.

t. The method of finishing a metallic sheet which comprises the following steps: cold rolling, removing defects from the surface of the sheet without etching the same and then restoring the smooth surface by cold rolling.

'i, The method of finishing a metallic sheet which comprises removing the surface defects from the sheet by abrading, cleaning the surface of the sheet without etching the same, and then restoring the smooth surface by cold rolling.

Y M. FEN'ION.