|Publication number||US2835022 A|
|Publication date||May 20, 1958|
|Filing date||Feb 8, 1955|
|Priority date||Feb 8, 1955|
|Publication number||US 2835022 A, US 2835022A, US-A-2835022, US2835022 A, US2835022A|
|Inventors||Harris Edward J|
|Original Assignee||Jessop Steel Company|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (8), Referenced by (5), Classifications (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
May 20, 1958 E. J. HARRIS PROCESS OF MAKING METAL PRODUCT Filed Feb. 8, 1955 [fixer-Mb? [OM/A20 d. fimee/s & K;%
United States Patent POfifice 2,835,022 Patented May 20, $1 958 PROCESS OF MAKINGMETALPRODUCT Edward J. Harris, Washington, Pa., assignor to Iessop Steel Company, Washington, 2a., .a corporation of Pennsylvania Application February 8, 1955 Serial No. 486,823 1 Claim. (CI. 29-19) This invention relates to a newprocess of producing light gauge metal stripsand more particularly to aprocess that is particularly adapted for the rolling of highly alloyed materials and pure metals.
In the hot rolling of highly alloyed materials, such as stainless steel and strips of relatively scarcer pure metal, such as titanium, zirconium and tungsten, difficulties have heretofore been experienced with edgecrack ing due to a temperature dilterential between the center and the edges of the article being rolled. Likewise, certain hlghly alloyed materials, as, for example, high speed steels, have a strong tendency toward surface .decarburization due to reaction of gases present in .the'surrounding atmosphere or furnace. Similarly, pure metals have a tendency to absorb furnaces .gaseswhich is detrimental to the product and results in inferior finished products.
It is an object of this invention to provide a process of hot rolling highly alloyed or.pure:1netals in.a. manner which would negate the effect of temperature diiferential and at the same time provide adequate surface protection against decarburization and against unwanted gases.
Another object of this invention :is 'to .provide :a process of hot rolling a composite metal article comprising an enclosed strip ofmetal wherein both the closure and the strip are contemporaneously .rolled and may :be subsequently separated as and when desired.
Still another object of the invention is to provide a process of hot rolling a composite article including a protective sheath for a strip being reduced to a predetermined gauge and wherein the sheath may also be used as a shield during subsequent handling and even shaping of the product.
In accordance with the general features of this invenflon, there is provided in a process of rolling metal strips, the steps of coating a strip to be treated with a material to prevent it from forge welding to a casing in a subsequent hot rolling step, inserting the coated strip endwise into a longitudinal casing, closing each of the ends of the casing to enclose substantially completely within the casing the inserted strip, heating the casing and .strip assembly, hot rolling and flattening the assembly to reduce the inserted strip to a predetermined thickness while the strip is substantially out of contact with the atmosphere, and during such heating and rolling steps venting gases through openings in the ends of the casing.
Another feature of the invention relates to shearing at least one edge of the casing, sheath or closure beyond an adjoining edge of the rolled insert strip to facilitate separation of the two.
Another feature of the invention relates to-the use of a. simple refractory material as a coating for the strip insert to prevent forge welding of it to the outer closure during the hot rolling operation.
Other objects and features of this invention may more fully appear from the following detailed description taken in connection with the accompanying drawings which illusgrate a single embodiment thereof and in which- Figure 1;is aperspective View, partly broken away, of a strip of metal to be reduced during rolling;
Figure 2 is an end view, on a reduced scale, of a me tallic tube for use as a closure .for'the strip during subsequent hot rolling of .a composite of the two;
Figure 3 is a perspective view of a composite article comprising the strip of Figure 1 in the tube of Figure 2 after the tube has been partially collapsed on the;inserted strip and the ends of :the tube welded with suitable gas .vent openings therein;
Figure 4 is a cross sectional view taken on the line IVIV of Figure 3 looking in the direction indicated by the arrows showing the strip separated from .the enclosing flattened tube lay-coatings and showing'the longitudinal edges of the tube extending beyond the side edges of the strip;
Figure 5 is 'a side view of the composite .article of Figure 3 partly broken away after the article has been reduced by hot rolling to vprovide the desired gauge of strip on the interior of the enclosing tube or sheath and showing by vertical .lines how the edges of the sheath may be sheared beyond the side edges of the enclosed strip to facilitate removalof the strip from theclosure or sheath; and
Figure 6 is a fragmentary perspective view partly broken away showing the reduced strip after it has been removed from the enclosure.
As shown on the-drawings:
The :reference character =10 designates generally a metallic strip or insert which is to be reduced to a predetermined gauge. This strip may be of any suitable length and can be of a metal such as a highly alloyed metal, high speed and heat resisting steel or even a relatively pure .metal such, for example, as titanium, zirconium or tungsten. Such material is usually quite expensive and it is. highly desirable to reduce to a minimum losses in hot rolling of the strip such as isoccasioned.by-e'dgercraokscaling, et cetera. In the :case of the rarer metals, this itemalone can bequite an-expensive-faetor.
The reference character 11 designates in Figure .2 :a metal tube, sheath, closure or casing which may be made of any suitable steel, such, for example, as a low carbon steel i. e. SAE 1010 to 1020. A tube of a length slightly in excess of that of the strip 10 to be reduced is provided; and it should be of a diameter such that after partial collapsing it can receive therein the metal strip 10 as shown in Figure 4.
Prior to the insertion of the strip 10 in the tube, it is first coated with a suitable material known as a separating compound and which is employed to prevent the inserted strip from forge welding to the tube or casing 11 in the subsequent hot rolling operations. Such a coating 13 may be applied all around the strip or at least to both sides of the strip as shown in Figure 4. Excellent results have been obtained by employing a refractory compound of aluminum oxide suspended in a lacquer and thinner. For illustration, such a compound can be made by mixing one part of a suitable thinner, one and onehalf parts of a suitable lacquer and one part of aluminum oxide (Norton 2F grain).
The foregoing constituents of the coating are mixed together into a paste or paint-like substance which may be brushed or painted on the strip 10 to provide the coatings 13-13.
It will be perceived that when the composite product is assembled, as shown in Figures 3 and 4, the elliptical or flattened steel tube 11 has its longitudinal edges slightly spaced at 14-44 from the adjoining longitudinal edges of the strip 19.
The next step in the process is to close the ends 15-15 of the casing or tube with the strip or insert 10 therein.
during the subsequent operations.
The prepared assembly or composite article shown in Figure 3 is then heated to a suitable or conventional forging temperature and the entire assembly is then passed through conventional forging rolls to reduce the same to an extent sufficient to provide the required gauge thickness of a rolled strip 18. One or more passages of the composite article or assembly through conventional rolls as required may be eifected. This results in the flattened composite product shown at 17 in Figure 5.
Now this flattened article 17 may be shipped to the customer in this form in which event the outer casing or tube serves as a protective shield for the interior strip 18 until the customer desires to use the strip. On the other hand, the tube or sheath may be removed in cases of less precious metal and the strip 18 may be shipped without the enclosing sheath or tube, such strip being shown in Figure 6.
In order to effect separation of the tube, sheath or casing from the strip 18, the longitudinal edges of the same may be sheared or cut as designated by the lines 2020 in Figure 5. It will be appreciated that at least one edge should be sheared in order to enable the strip to be removed from the casing or tube. If only one edge is sheared, the sides of the tube may be spread apart and the strip removed. If both edges are sheared at 20-40, then removal may be effected by simply separating the upper and lower sides of the sheared tube or sheath from the enclosed flattened insert.
It should also be noted that in some cases it might be desirable not only to ship the strip in encased form, but also to fabricate products from the strip by stamping clear through the sheet and strip by any suitable press equipment. In that event, the outer layers of the case or enclosure serve to protect the enclosed strip during the stamping operation and to minimize the formation of burrs on the edge of the pieces of the strip as the same is sheared in the press equipment.
Some of the advantages of this process are as follows:
(1) It eliminates the necessity of a cold rolling operation, such as is quite generally required to reduce light gauges of metal.
4 (2) It eliminates the necessity for intermediate anneal- (3) It minimizes the likelihood of edge cracking on the reduced strip.
(4) It increases yields and conserves highly strategic materials by virtue of the minimizing of loss from edge cracking, scaling, et cetera.
(5) It also considerably minimizes so called surface decarburization of the reduced strip.
(6) Lastly, it minimizes the absorption of harmful gases by the enclosed strip during the reduction operations.
It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.
1 claim as my invention:
In a process of rolling metal strips, the steps of coating a strip to be treated with a refractory material, partially flattening a longitudinal metal tube, inserting the coated strip endwise and completely into the partially flattened protective metal tube, closing each of the ends of the tube to enclose substantially completely the inserted strip therein, providing the tube with gas vent openings beyond the edges of the strip inserted therein, heating the tube and strip assembly, hot rolling and flattening the assembly to reduce the inserted strip to a predetermined thickness while the strip is substantially out of contact with the atmosphere except at the aforesaid vent openings, and shearing at least one of the longitudinal edges of the flattened tube so that the inserted strip may be removed therefrom.
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