US2575219A - Ferrous alloys and abrasive-resistant articles made therefrom - Google Patents

Description

Patented Nov. 13, 1951 UNITED STATES PATENT OFFICE FERROUS ALLOYS AND ABRASIVE-RE SI ST- ANT ARTICLES MADE THEREFROM David J. Giles, Latrobe, Pa., assignor to Latrobe Electric Steel Company, Latrobe, Pa., a corporation. of Pennsylvania No Drawing. Application January 10, 1951,, Serial No. 205,441

Claims.

for steels having a materially greater resistance to abrasion than those commercially available and at the same time being easy to form, easy to grind and having good impact strength, i. e., ability to withstand shock. A good example is steel for use in the fabrication of router and shaper' bits and lathe tools for the woodworking industry, and for other articles which are subject to considerable abrasion and shock and are thereby rapidly worn to a point where they can nol'onger meet required tolerances in the industry and must be resharpened, resurfaced or otherwise broughtback to the tolerances of the industry.

' In alloys for use in installations such as are described above in which the metal is subject to continual or recurring abrasion and impact, it isdesirable that they be forgeable and hardenableand yet resist the action of abrasive subtances and the shock of intermittent impacts. Historically, the search for alloys having certain desirable properties has lead to various combinations of alloying elements including combinations with vanadium. I have found, however, that while the general trend in vanadium alloys of steel has been in the direction of greater hardenability this is not alone the answer to the problem of abrasion resistance, and this is especially true when resistance to shock is also required.

I have discovered certain alloys having satisfactory forgeability and hardenability which can be made abrasive-resistant by properly controlling the carbon and vanadium content in a man-- ner described in my copending application Serial No. 118,448, filed September 28} 1949, now abandoned, of which this is a continuation-in-part, without materially altering their forgeability and hardenability. One of these alloys is the subject of United States patent application Serial No. 91,002, filed May 2, 1949, now abandoned.

My present invention provides an abrasionre'sisting alloy in which carbon, within certain limits, is added in excess of that necessary to give the alloy the desired forging and hardening characteristics and vanadium is added in an amount, again within certain limits, such that the ratio of the vanadium in excess of about 1% to the aforementioned excess of carbon is about 4.2:1.

Considering only the essential elements of my alloy, the preferred analysis for most combined abrasion and shock resisting applications is:

Per cent Mo 1.1 Balance substantially iron with residual impurities' in ordinary amounts;

The composition. of my alloy may, however,

extend over a wider range and still retain its desirable abrasive resistance- It may include. alloying elements such as nickel, tungsten andcobalt in restricted amounts without detrimentally affecting the ability of the alloy to resist abrasion. The composition may fall within the limits. of. the following range of concentrations of alloying elements.

Si 1% maximum Mn 1.5% maximum Cr we--- 4%-8% Mo Less than 1.5% W -l Less than 3% Co Less than 5% Ni Less than 3% Balance substantially iron with residual impurities in ordinary amounts.

Per cent C a.'." Cr 4-6 0.1-0.7 0.2-0.9 0.8-1.3 Balance substantially iron with residual impurities in ordinary amounts.

While. I have given specific silicon and manganese ranges in the composition of my a1loy,.

these concentrations are the concentrations which normally result from the raw materials which I have used and may accordingly vary within reasonable limits depending upon the raw materials used.

By the expression less than followed by a percentage figure in this application when referring to molybdenum, nickel, tungsten and cobalt, I mean that the particular element may be present in an amount not to exceed the percentage concentration given. The presence of these elements is optional up to the amount specified in the ranges of composition given above.

The alloy is foreable and is air hardening as well as being abrasive-resistant when molybdenum is included in the composition. If it is .desired to produce an alloy having similar abrasion resistance and forgeability but at a reduced cost and for use where air hardening is not necessary, the molybdenum may be omitted without materially affecting the other desirable properties.

In order to illustrate the abrasive resistance of my new alloy several heats were made within the range of composition specified above for my new alloy. The abrasion resistance of the alloy of my present invention and of an alloy steel having similar forgeability and hardenability characteristics previously used in applications for which my new alloy is intended were compared with the abrasion resistance of an 18-4-1 highspeed steel taken as a standard of 100% abrasion.

Careful comparison of the composition of the test pieces and their resistance to abrasion shows the superiority of the alloy of my invention over the alloys now used for applications requiring abrasion resistance as well as its superiority over standard 18-41 high-speed steel. The alloy previously used has lost about nine times as much material as the preferred alloy (alloy C) of my invention while the high-speed steel standard shows more than four times as much loss of material as does my preferred alloy.

The economic importance of these results becomes more apparent when it is realized that not only has the alloy of my present invention lost less than as much material as the 184-1 high-speed steel but it does not incorporate the costly percentage of alloying elements which appear in the high-speed steel. Moreover, the alloy of this invention is easier to form, easier to grind, and is able to withstand shock better than the alloys having a higher chromium content as exemplified by the alloy described in my applica-- tion Serial No. 91,002 mentioned above. Thisnew alloy therefore serves a new field of usefulness in which resistance to shock or impact isnecessary or desirable along with resistance to abrasion.

Peculiarly, the addition of excess carbon and vanadium in excess of 1% in the ratio of 4.2% vanadium to 1% carbon although increasing the abrasion resistance to a remarkable extent has little or no effect on the forgeability or hardenability of my alloy over those same physical prop-- erties of an alloy without such excess carbon and Table! vanadium. For example, the Rockwell C hard- Per cent abrasion 1 ness of alloy C and alloy B are substantially idem-- Alloy A (standard) 100 ties}, as are their forging properties. Their abra- Alloy B 207 sive resistances, however, are sharply distin- Alloy C 23 guished as illustrated in Table I. If, how v a 1 Per cent removed by abrasion, u) marked departure from this ratio of 4.2:1 is made,

Table II Alloy 0 Cr w v Mo Si Mn A .74 4.10 18.00 1.10 .30 .25 .25 BalancesubstentiallyFe. B 1.02 5. 25 .25 1.10 0.30 0. 70 Do. 0 1.80 5. 21 3.05 1.12 0.38 0. 70 n0.

Abrasion tests were also made on modifications of alloy C within the broad limits of composition heretofore stated. The results of these abrasion tests and the composition of the test pieces are given in Tables III and IV below.

1 Per cent removed by abrasion as compared with alloy A.

then a marked change in forgeabilty and harden-' ability occurs, the direction and extent of which depends upon the nature and extent of parture from this ratio.

My researches indicate that when carbon and vanadium appear in the above described excess and ratio they modify the characteristics of the alloy by very desirably augmenting its abrasiveresistance without masking or nullifying the other physical characteristics of the basic alloy. I be- 1 lieve that the extraordinary abrasive resistance of my alloy depends upon the formation of vana dium carbides which remain out of solution and accordingly do not afiect the hardenability or forgeability of my alloy. While this theory seems to be consistent with observable facts, I do not- Table IV Alloy C Si Mn Or V M0 N1 W 00 l. 83 42 66 5. 45 4. 08 l. 22 2. 71 Balance subst nti ll 1. 91 38 57 5. 22 4. 38 1. l9 2. 48 D0. 3 a y Fe 1. 87 57 5. 92 3. 1. 31 4. 58 D0. 3. 55 47 58 5. 10 ll. 92 D0. 1. 84- 59 66 7. 40 4. 22 DO. 4. 15 63 73 7. 40 12. 76 L32 3. 02 D0.

the dey bind-myself thereto. Thetiactiis that, whatever the I'mec'hanism may he, the addition of carbon vanadium intheiaboveldes'cribedfproportions vanadium, and the balance substantially iron with residual impurities 1 in o'rdinary 'am'ounts,::in which ialloy the vanadium in excess of ab'out 1 is combinedwith carbon in a ratio of 'about:.42:1.

2. 'iln-abrasion-resi'sting'alloycomprising about 1.65% to 1.95% of carbon, about-4% ta-6% f chromium, about 0.1% to 0.7% of 'silic'on, about 0.2% to 0.9% of manganese, about 0.8% to 1.3%

of molybdenum, about-3% to of vanadium, and the balance substantially iron with residual impurities inordinary amounts, in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio'of about 4.2: 1.

An abrasion-resisting alloyccomprisin'g about 1.8% of carbon, about 5% of chromium, about 0.3% of silicon,ab,out 0.7% of manganese, about 4% of vanadium, and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the-vanadium in excess dfabout 1% "is combined withcarbon in *aratio of about 42:1.

4. An abrasion-resisting alloy comprising about 1.8% of carbon, 5% of chromium, about 0.3% of silicon, about 0.7% of manganese, about 1.1% of molybdenum, about 4% of vanadium, and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of about 1 is combined with carbon in a ratio of about 4.2: 1.

5. An abrasion-resisting alloy having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.65% to 1.95% of carbon, about 4% to 6% of chromium, about 0.1% to 0.7% of silicon, about 0.2% to 0.9% of manganese, about 3% to 5% of vanadium, and the balance substantially iron with residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 4.2: 1.

6. An abrasion-resisting alloy having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.65% to 1.95% of carbon, about 4% to 6% of chromium, about 0.1% to 0.7% of silicon, about 0.2% to 0.9% of manganese, about 0.8% to 1.3% of molybdenum, about 3% to 5% of vanadium, and the balance substantially iron with residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 4.2 1.

7. An abrasion-resisting alloy having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.8% of carbon, about 0.3% of silicon, about 0.7% of manganese, about 5% of chromium, about 1:70 of vanadium, and the balance substantially with tesiduarimpurities. inordinary amounts,

in which the concentrations of vanadium "and carbon within :the given. limits are :adjusted -:so that :the #ratio :of vanadium in excess cor "about 1% to the excess carbon is about 4.211.

B.=-An abrasionesisting alloy having carbon in excess of that-necessary to give it the desired hardenability characteristics comprising rabout '1.85% 10fcarbomabout 0.3% :ofxsilicon, about 0.7

of manganesegabout 1.1 of molybdenum, about 5% of chromium, about 4% of vanadium, and the balance substantially iron with residual impurities iii-ordinary amounts, in which the concentrations of vanadium and carbon Within the given "limits are adjusted-so that the ratio of vanadium in exc'essof about 1% to the excess carbon is mi about 4.2 1.

9. abrasion-resisting article formed 'from a forgeable -abrasion-resisting steel comprising about 1'.65% to 1.95% cf carbon, about 4% to 6 .df-chr'oxniumabout 0.1% to 0.7% of silicon, about 0. 2 'to 0.9% ofmanganese, about 3% to 5 of-vana'diumand the'balance substantially iron "with residual impurities in ordinary amounts, in'which' alloys the vanadium lHGXCGSS dfjabout 1 %=is combinedwith carbon ina ratio of about "42251, said article :being characterized by a "factor iof hardenability and forgeability comparable-to a steelhaving less than 1% vanadium and a carbon content less than said -article by a' value equal to about 'thepercent vanadiumrin said article 1% 10. abmsion-resisting article formed from a forgeable abrasion-resisting steel comprising about 1.65% to 1.95% of carbon, about 4% to 6% of chromium, about 0.1% to 0.7% of silicon, about 0.2% to 0.9% of manganese, about 0.8% to 1.3 of molybdenum, about 3% to 5% of vanadium, and the balance substantially iron with residual impurities in ordinary amounts, in which alloys the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.2:1, said article being characterized by a factor of hardenability and forgeability comparable to a steel having less than 1% vanadium and a carbon content less than said article by a value equal to about the per cent vanadium in said article- 1% 4.2

11. Anabraslon-resisting article formed from a forgeable abrasion-resisting steel comprising about 1.8% of carbon, about 5% of chromium about 0.3% of silicon, about 0.7% of manganese, about 1.1% of molybdenum, about 4% 01 vanadium, the balance substantially iron with residual impurities in ordinary amounts in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 4.2:1, said article being characterized by factors of hardenability and forgeability comparable to a steel having less than 1% vanadium and a carbon content less than said article by a value equal to about the per cent vanadium in said article- 1 4.2

12. An article formed of forgeable abrasionresisting steel having carbon in excess of that necessary to give it the desired hardenability characteristics comprising about 1.65% to 1.95% of carbon, about 4% to 6% of chromium, about 0.1% to 0.7% of silicon, about 0.2% to 0.9% of manganese, about 0.8% to 1.3% of molybdenum,

the per cent vanadium in said artic1e1% 4.2

13. An abrasion-resisting alloy comprising I about 1.4% to 4% of carbon, about 4% lie-8% chromium, about 3% to 13% vanadium, about 1% maximum silicon, about 1.5% maximum manganese, less than about 1.5% molybdenum; less than about 3% nickel, less than about 3% tungsten, less than about 5% cobalt and the balance substantially iron with residual impurities in ordinary amounts, in which alloy the vanadium in excess of about 1% is combined with carbon in a ratio of about 42:1.

14. An abrasion-resisting alloy having carbon in excess of that necessary to give it-the desired hardenability characteristics comprising about 1.4% to 4% of carbon, about 4% to 8% chromium, about 3% to 13% vanadium, about 1% maximum silicon, about 1.5% maximum manganese, ,less than about 1.5 molybdenum, less than about 3 tungsten, less than about 5% cobalt and the balance substantially iron with residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon-are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 4.211. 15. An abrasion-resisting article formed of abrasion resisting steel having carbon. in excess of'that necessary to give it the desired hardenability characteristics comprising about 1.4% to 4% carbon, about 4% to 8% chromium, about 3% to 13% vanadium, about 1% maximum silicon; about 1.5% maximum manganese, less than about 1.5% molybdenum, less than about 3% tungsten, less than about 5% cobalt and the balance substantially iron with residual impurities in ordinary amounts, and in which the concentrations of vanadium and carbon within the given limits are adjusted so that the ratio of vanadium in excess of about 1% to the excess carbon is about 412:1, said article being characterized by high resistance to abrasion and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by an amount equal to the the per cent vanadiurn l 4.2

DAVID J. GILES. H

REFERENCES CITED I FOREIGN PATENTS Number Country Date 832,703 France Oct. 3, 1938. 834,198 France Nov. 15, 1938

Claims (1)

1. AN ABRASION-RESISTING ALLOY COMPRISING ABOUT 1.65% TO 1.95% OF CARBON, ABOUT 4% TO 6% OF CHROMIUM, ABOUT 0.1% TO 0.7% OF SILICON, ABOUT 0.2% TO 0.9% OF MANGANESE, ABOUT 3% TO 5% OF VANADIUM, AND THE BALANCE SUBSTANTIALLY IRON WITH RESIDUAL IMPURITIES IN ORDINAKRY AMOUNTS, IN WHICH ALLOY THE VANADIUM IN EXCESS OF ABOUT 1% IS COMBINED WITH CARBON IN A RATIO OF ABOUT 4.2:1.