US1536660A - Method of manufacturing steel sheets - Google Patents

Description

. tion.

Patented May 5, 1925.

WILLIAM E. CAUGHERTY AND SAMUEL C. HOCKEY, F NATRONA, PENNSYLVANIA.

METHOD OF MANUFACTURING STEEL SHEETS.

No Drawing.

To all whom it may'concem:

Be it known that we, WILLIAM E. CAUGHERTY and SAMUEL C. HOOKEY, citi- Zens of the United States, and residents, re spectively, of Natrona and Natrona, in the county of Allegheny and .State of Pennsylvania, have made a new and useful Invention in Methods of Manufacturing Steel Sheets, of which the following is a specificzu This invention relates to the manufacture of high-grade steel sheets such as required in the'automobile, metal furniture and other trades where highly finished surfaces are necessary and where the sheets must be sufficiently ductile to permit of deep drawing and stamping operations.

In an application filed by Otto H. C-unningham on October 8th, 1924, he discloses a method of manufacturing such sheets, and one of the objects of this invention is to improve and cheapen the method disclosed in said application.

A further object of this invention is to provide a method of manufacturing such sheets with the regular sheet mill equipment, but using less men, whereby a material increase in tonnage per man hour is obtained over that possible in standard sheet mill practice as well as over that with the method disclosed in said Cunningham application.

Under the present standard practice of manufacturing high-grade stamping and drawing sheets from relatively low carbon steel, in order to produce a 20-gauge sheet X 96", the sheet bars are heated and broken down to about sixty per cent of the finished length required in the sheets. These breakdowns are then pickled, matched in packs, reheated and finished to the length required.

As there is very little additional work to be done on these sheets in the subsequent operations, it is necessary to have a highgihde surface on the sheets as they leave the hot mills. This necessitates extremely smooth rolls and also requires that the sheet bars are not heated up to free scaling temper-ature. These factors all contribute to retard production and increase the difficulties of rolling,

Under the standard practice, it is customary to use a crew of ten men.

. ;ln carrying out our method in producing 20-gauge sheets 80 x 96', the sheet bars are Application filed October 13, 1924. Serial 110,143,499.

heated to a relatively high temperature and broken down to within from sixty per cent to seventy-five per cent of the length of the finished sheets.

The breakdowns are then annealed or normalized at a temperature which ranges from 1600 to 17 00 F. The normalized sheets are then pickled to remove the scale, cold rolled to length, and annealed by standard box annealing methods at a temperature sufficiently low to prevent sticking or welding.

We have discovered that, in order to obtain the necessary reduction by cold rolling (ranging from 25% to 40%), it is necessary to use oil on the rolls. Mineral oil is preferable and this is preferably sprayed onto the rolls during the rolling operation.

Because of the fact that all surface defects are eliminated by the cold rolling operation, we find that it is unnecessary to exercise the same care in heating and break-- ing down the sheet bars as in standard sheet mill practice.

In practicing our method, we are able to heat the sheet bars and the packs'more rapidly and to roll them with heavier drafts and faster than is customary in standard practice, and we find that we are able to do this with seven men instead of ten as is now customary. These factors enable us to produce a tonnage that is at least twice as great as the tonnage produced by standard practice.

By means of this method, we are enabled to produce sheets of uniformly high-grade surface; sheets that are much more accurate as to gauge than those obtained by the standard sheet mill me hods of production, and sheets that are free from Steads brittleness and, therefore, suitable for deep drawing and stamping operations.

Having thus described our invention, what we claim is 1. The method of making highly finished steel sheets free from Steads brittleness, which consists in heating the sheetbars to a relatively high temperature, then in rolling said bars to less than 75 per cent of the length of the sheets to be produced, then in annealing and pickling the semi-finished sheets, then in cold rolling the semi-finished sheets to length and then in annealing the sheets.

2. The method of making highly finished steel sheets free from St-eads brittleness, which consists in heating the sheet bars to a relatively high temperature, then in rolling said bars to between '60 per cent and 7 5 per cent of the length of the sheets to be produced, then in annealing and ickling the semi-finished sheets, then in col rolling the semi-finished sheets to length and then in annealing the sheets.

3. The method of making highly finished steel sheets free from Steads brittleness, which consists in heating the sheet bars to a relatively high temperature, then in rolling said bars to 60 per cent of the length of the sheets to be produced, then in annealing and pickling the semi-finished sheets, then in cold rolling the semi-finished sheets to length and then in annealing the sheets.

4. The method of making highly finished steel sheets free from Steads brittleness, which consists in quickly heating sheet bars to a relatively high temperature, then in quickly rolling said bars to less than 7 5 per cent of the length of the sheets to be produced then in annealing and pickling the seminished sheets, then in cold rolling the semi-finished sheets to length and then in box annealing the sheets at a temperature below Welding temperature.

5. The method of making highly finished steel sheets free from Steads brittleness, Which consists in heating the sheet bars to a relatively high temperature, then in rolling said bars to approximately 75 per cent of the length of the sheets to be produced, then in annealing and pickling the semi-finished sheets, then in cold rolling the same to length and then in annealing the sheets.

6. The method of making highly finished steel sheets free from Steads brittleness, which consists in heating sheet bars to a relatively high temperature, then in rolling said bars to approximately 75 per cent of the length of the sheets -to be produced, then in annealing or normalizing the semi-linished sheets, then in cold rolling the semifinished sheets to length and gauge and then in annealing the same,

In testimony whereof, We have hereunto set our names this 8th day of October, 192-1.

\VILLIAM E. CAUGHERTY. SAMUEL C. HOOKEY.