US2395877A

US2395877A - Bimetallic products and manufacture thereof

Info

Publication number: US2395877A
Application number: US427767A
Authority: US
Inventors: Walter L Keene
Original assignee: SUPERICR STEEL CORP
Current assignee: SUPERICR STEEL Corp
Priority date: 1942-01-22
Filing date: 1942-01-22
Publication date: 1946-03-05
Anticipated expiration: 1963-03-05

Description

'March 5, 1.946. w. KEENE BIMETALLIC PRODUCTS AND MA'UF'ACTURE THEREOF Filed Jan. 22, 1942 5 .flyi

INVENTOR ceding` .om but which 'in the andy .portion thereof beneath the surface has a carbon con tent well above .08%. Such a steel not only desirably inhibits hydrogen absorption at the surf face during pickling but is readily obtainable at reasonable cost and imparts to the component desirable physical properties which it would not lhave if the carbon content throughout the component were not substantially greater than .08%. While I amnot certain as to the theory of action and make vno representations with respect there-y to, I believe that the fact that the outside layer of the rimming or capped steel component is relatively pure iron and low in carbon results in a much slower reaction between the metal and ecid than is` the case when ordinarycarbon steel is used. I believe that as the reaction rate is slower. the amount of hydrogen formed is less and consequently less hydrogen is absorbed.

When the ferrous metal component of a bimetallic billet is made out of metal of the character above described and such component is assembled with one or more other components to form the bimetallic billet and such billet is rolled into material in sheet or strip form and such material employed for the formation of cups the cups are found to be eminenti satisfactory and the cost of production desirab y low.

Other details, objects and advantages nf the be formed is tohave facing-components top and bottom. A facing component is shown at in Figure 2 and'in Figure 3 the components 2 and 5 (there being two of the latter) are shown in 5 assembled relationship but before being fastened together.

The component 2 is of ferrous metal. preferably steel. It may be formed by rolling, forging, milling or otherwise. It may be of any desired length.

As above mentioned. it is provided with channels top and bottom for receiving the facing com ponents. Each such channel Ahas a floor B and opposed side walls 1. The facing components lie against the respective floors 8 of the channels,

l5 as shown in Figure 3. The metal of the component 2 at the surfacesfthereof which form the floors 8 of the channels should have a carbon content not substantially exceeding .08%. The side walls l of the channels should preferably also zo have a carbon content not substantially exceeding .08%, although any bubbles or blisters form- 'ing at such side walls during hot rolling can ordinarily be squeezed out so that the gas will escape and not cause defects in the strip. It is g5 possible for the Ventire component 24 to be made 'y of ferrous metal having a carbon content not substantially exceeding .08% and for certain uses such-a component may be entirely satisfactory, al though, as above pointed out. it is likely to be invention will ,become apparent as the followingexpensive to obtain and its physical properties description of a present preferred embodiment `thereof and a present preferred method of praci shown in Figure 1 and two components such as shown in Figure 2 assembled but before the, components are fastened together;

Figure 4 is a view similar to Figure 3 but showing the components of the billet fastened together:

Figure 5 is a view similar to Figures l to 4. inclusive, of hot rolled strip made from the billet shown in Figure 4;

Figure 6 is a similar view of cold rolled strip made from the hot rolled strip shown in Figure 5 and after shearing off the edges; and

Figure '1 is a central cross-sectional view through a bullet jacket cup formed from the cold rolled strip shown in Figure 6; the scale of Figure '7 being greater than that of the other gures. s

Referring now more particularly to the drawing, there is shown in Figure 1 the ferrous metal component of a bimet'allic billet, such component being designated by reference numeral 2.

It comprises a body 3 and four flanges eachl designated l. As shown inFigure 1, the flanges I are arranged in pairs. two flanges at the top of the component projecting generally upwardly in opposed relationship at the side edges of the component and two flanges at the bottom of the component projecting generally downwardly in.-

opposed relationship at the side edges ofthe component. 'I'hus channels are formed at the upper and lower faces of the component 2.- viewing Figure l. for the reception of the facing components, it being understood that the billet ,to

due to its low carbon content may not be as desired. I prefer to employ a rimming or capped steel whose carbon content at the surface is not substantially greater than .08% but whose carbon asl'content beneath the surface is substantially greater than .08%. Ihave foundfthat such a steel is ideally. suited to the formation of the ferrous metal component of a bimetallic billet as herein described. When a rimming or capped 40 steel is used the component 2 is preferably formed by rolling and the outside surface of the component will have a. carbon content not substantially exceeding .08%. thisi including the surfaces 6 and the surfaces 1.

After the component 2 has been formed it is preferably thoroughly pickled to remove dirt. scale and oxides and providerparticularly at the surfaces B and l, metallically clean faces for reception of the facing components. In many cases it is desirable to carry the pickling step beyond the mere cleaning of the component and to severely pickle the component 2 sufficiently to roughen its surfaces. The purpose of this is primarily to roughen the surfaces 5 against which the facing components lie to promote a strong union between the component 2 and the facing components 5 and insure against relative slippage therebetween during the hot rolling. s v I prefer to employ 'a 5% solution of sulphuric o0 acid at a temperature of 160 to 180 F. for the pickling step. Wheny it is desired to roughen the surface of the component 2 such component will be left in the picklingtank for a time which may approach er possibly slightly exceed two 05, hours. In such time when a steel of the type above mentioned is employed the surfaces Vwill of course be thoroughly cleaned and will also be desirably roughened. When the component 2 is subjected to a' severe pickle such as just mentioned. if the carbon content of the metal thereof at the surface is substantially greater than .08% there will be undesirable hydrogen absorption cr occlusion which when the bimetallic billet is formed and rolled willI as above stated, result in the formation of bubbles and blisters between the layers of metal. Such bubbles and blisters destroy the bond between the components and render at least portions and possibly all of the carbon content not substantially exceeding .08% is used for formation of thel component 2 such component can be immersed for two hours in sulphuric acid'at a temperature of- 160 to 180 F.

.without undesirable hydrogen absorption. This is as severe a pickle as is likely to be desired at any time. Y

When the component is removed from the pickling bath it is preferably washed off'with water and then dipped in sodiumI carbonate which tends to neutralize any remaining acid. This A may be follo-wed by a soak in hot water which aids in rapid drying of the component.

The components 5 are ordinarily of non-ferrous metal such as copper. brass, gilding metal, cupronickel or other relatively soft corrosion resistant alloy. VFor example, I prefer to use a gilding metal which has a copper content of in the neighborhood/of 90% and a zinc content of in the neighborhood of Cubre-nickel having a copper content of in the neighborhood of 80% and a nickel content of in the neighborhood of 20%.v is also entirely satisfactory.

The facing components as well as the component 2 are thoroughlycleaned and thev facing components may likewise be severely pickled to roughen them. They are assembled as shown in' Figure 3 whereafter the flanges 4 are deformed inwardly to firmly hold the components 5 in place and forma bimetallic billet ready for rollingas shown in Figure 4. The billet may take various forms, that shown in Figure 4 being merely an example. For rolling sheetsa bimetallic sheet bar may be similarly or otherwise formed. Such billet or bar when hot rolled forms strip or sheets 0 When, for example, a rimming or capped steel whose outer surface has av A',I'he product formed in accordance with my invention is of highquality and free from bubbles or blisters between the layers of metal and may be made at a cost comparing favorably with .the

cost of making similar products entirely out vof non-ferrous metal. the ferrous metal component of the billet may be andl preferably is employed the amount of hydrogen absorption if any is negligible from the standpoint of formation of bubbles and blisters during hot rolling. Baking to remove absorbed v or occluded hydrogen is unnecessary. 'I'he produ ct, in addition'to being of high and uniform quality, possesses adequate mechanical strength and desirable physical properties.

While I have shown and described a present preferred embodiment of the invention and a present preferred method of practicing the same it-is to be distinctly understood that the invention is not limited thereto but may be otherwise variously embodied and practiced within the scope of the. following claims.

I claim:

1. A method of making a bimetallic billet comprising providing a component of rimmlng or capped steel having a surface vhaving a carbon content not substantially exceeding .08%, severely pickling said componentso as to substantially roughen its surface, applying to said component in its-state immediately following pickling' and in contact with said surface a component of gilding metal 'and fastening said components irmly together.

2. A bimetallic billet for rolling comprising a 36 pickled steel component having a surface having i3-hydrogen `and a :second preformed lmetal comas shown in Figure 5 in which the metal of the component 2 is faced at its central portion with the metal of the components 5. Herein the word "billet is used generically to include billets and bars and the word "strip is used generically to i include any metal in strip or sheet form.

During the hot rolling the components or layers of the bimetallic material are disposed in faceto-face contact and have their contactingv faces united to' each other substantially throughout their area of contact. The union is believed to be inthe nature of a mechanical. bond or weld, apparently being accomplished by the combination of heatfand pressure.

The strip is preferably cold rolled and either Before or after the cold rolling' step the edges which consist entirely of the metal`of the component 2 are sheared ofi', forming cold rolled strip 'as shown in Figure 6.l Such strip-is used for ponent lying against said surface, saidcompo-` nents being firmly held together ready for rolling, said freedom of said-first mentioned component from absorbed hydrogen providing for substantial freedom from bubbles and blisters between said components when the billet is hot rolled.

3. A bimetallic strip comprising a pickled steel component having a surface having a carbon content not substantially .exceeding .08% and in its state immediately following pickling being by reason of the aforementioned carbon content substantially free from absorbed hydrogen and a. second metal component lying against said surface, said components being welded together substantially throughout their area of contact, said l freedom of said iirst mentioned component from absorbed hydrogen providing for substantial freedom from bubbles and blisters between said components during rolling of the strip.

4. A bimetallic billet for rolling comprising a component of pickled .rimming or capped steel vhaving a, surface having a carbon content not substantially exceeding .08% and in its state immediately following pickling 4being by reason of the aforementioned carbon content substantially free from absorbed hydrogen and va secondmetal component lying .against said surface, said components being firmly held together ready for rolling, said freedom of said first mentioned coinponent from absorbed hydrogen providing for substantial freedom from bubbles and blisters between said componentswhen the billet is hot rolled.

lwiirfrrzsz. n. naar.

Although a severe pickle of