US2575216A - Ferrous alloys and articles made therefrom - Google Patents

Description

Patented Nov. 13, 1951 FERROUS ALLOYS AND ARTICLES MADE THEREFROM David J. Giles, Latrobe, Pa, assignor to Latrobe Electric Steel Company, Latrobe, Pa., a corporation of Pennsylvania No'Drawing. Application May 25, 1950, Serial No. 164,293

'1 Claims. (01. 75-1123) This invention relates to ferrous alloys and articles made therefrom and in particular to ferrous alloys having high resistance to abrasion and resistance to fracture under mechanical shock. There has long been a need for steels having a materially greater resistance to abrasion and to fracture under mechanical shock than those commercially available. For example, many cold-work applications involving wear such as cold header dies, dies for cold forming tubing, mandrels, etc. are simultaneously subject to both considerable mechanical shock and abrasion. Such articles when made 'of ordinary steels are relatively quickly abraded away or broken by the repeated shock of the cold forming operations and as a result are no longer useful. Cold header dies, for example, are subject to steadily recurrent mechanical shock and abrasion as the article being headed strikes the die, is formed and released to be followed by another article to be headed. This steadily recurring shock and abrasion either cuts away the die surface or the repeated shock results in fracturing the die within a relatively short period of time.

Alloys to be suitable for such cold-work applications as are described above should be forgeable, surface hardenable, resistant to the abrasive action of the article being treated, and

yet have a tough fracture-resistmg core. Many combinations of alloys have been tried for' this purpose, however, none has proven entirely satisfactory due to the inability of the art to provide the aforementioned necessary qualities in an alloy economically feasible for the operation. It has been found generally that for cold-work applications water-hardening alloys are most desirable since they provide the tough core needed for resistance to fracture, however, prior to this invention there have been no Water-hardening alloys which combine all of the desired surface hardening and abrasion-resisting characteristics with forgeability and core toughness.

I have discovered an alloy which is forgeable and water-hardening and which is suitable for the production of high surface abrasion resistance and core toughness. My invention provides 'a water-hardening abrasion-resisting alloy in which carbon within certain limits is added in excess of that necessary to give the desired for ing and hardening characteristics, along with vanadium in an amount within certain limits such that the ratio of the vanadium in excess of about 1% to the aforementioned excess of car- 'bon is about 4.2:1. Broadly, the compositionof my alloy lies within the following ranges of con-. centrations of alloying elements:

' Per cent Carb 0.85 to 4 Si1icori=- 0.1 to 0.5 Manganese 0.2 to 0.7 Chromium Less than 2 Vanadium 2 to 12 Balance substantially iron with residual impuriities in ordinary amounts.

An alloy suitable for most abrasive-resisting and shock-resisting applications might have the following analysis:

7 Per cent Carbon 1.7 Silicon 0.2 Manganese 0.2 Chromium 0.1 Vanadium 4.5 Balance substantially iron with residual impurities-in ordinary amounts.

It has been found that abrasion-resistance varies with the amount of vanadium and carbon added to the alloy, however, below the limits of carbon and vanadium specified above there is no noticeable decrease in abrasion-resistance while if the vanadium and carbon contents are increased beyond the upper limits indicated above the forging and hardening characteristics of the alloy are adversely affected. It must be noted of course, that to achieve the phenomenal abrasionresistance and yet'retain the desired hardening .and .forging characteristics it is necessary that thecarbon in excess of that required to give these forging and hardening characteristics must be .combined with vanadium by adding vanadium 'in' 'exce'ss of 1% in the ratio of 4.2:1 to the excesscarbon. V

"While specific silicon and manganese ranges have been given in the above tabulation of analysis these concentratlons are not critical and are those which normally result from the raw materials used in the production of my alloy and may.accordingly vary within reasonable limits depending upon the raw materials used.

An alloy having a composition within the limits shock as well as being abrasive-resistant. In order to illustrate the striking resistance to abrasion characteristic of my new alloy several heats were made within the range of the above broad compositions. The abrasion-resistance of these alloys was compared with that 01' one of the principal alloys previously used for cold-work applications such as cold header dies and with the abrasion-resistance of an l8-41 tool steel taken as a standard of 100% abrasion. The results of these abrasion tests on forged? and"; hardened pieces 1' in diameter are tabulated. below along with a tabulation of the chemical compositions of the respective alloys.

Thechemical. compositions of the above-alloys areassfollows:

Table II Alloy 0 st Mn vorw ElectriteNo. l. 77 Alloy X (Prev. used alloy) 1.01

All of thealloys of my inventiontabulatednin Table II above were forgeable andwaten-harde enable. All were finished'by hammeringztdl squarebars. Careful comparison of the. composition of thetest pieces andtheir resistance .to abrasion shows the marked superiority of the A alloy of my invention over alloy Xlnow used'in cold work applications, as wellas their superiority over. the. high speed. tool'steelusedas a standard ofIabrasion-resistance. The alloy'previously used lostasmuch as 194 timesthelossshown by certainv alloys within the composition. rangevof my invention. Inevery instance it lost at least twice as, much as any of the alloys of my invention. It will be seen from Table I that the hardness .values of the alloy principally used (Alloy X) and that of the alloys of my invention are in' the same range. It is apparent from these" tabulations that the use of increasing amountsof vanadium and carbon in proper ratio leads to tremendous increases in abrasion-resistance without materially changingthe hardening characteristlos'from those of. carbon steels having'a carbon content equal to the carboncontent ofmyalloy'less an amount equal to ability of my alloy, I do notbind myself to this theory; The fact is, that whatever'the mechanism may be and whatever theory may account for the phenomenal results of my invention, the

addition of. carbon and vanadium in the above describedproportions does produce an unexpected and unusual abrasive-resistance which is of great technicalimportance'; without materially effectmg the; hardening: and forging qualities and yet retaining'atough resilient core when hardened.

While. I have. described and disclosed a pre- {erred embodiment of my invention it is to be understood that it is not so limited but may be otherwise embodied and practiced within the scope of the following claims.

I claim-:.

1:. A water-hardening, abrasion-resisting. and shockresistingsteel alloy comprising about.0.85% to4% oarbomabout 0.1% to 0.5 silicon,- about 0'.'2.%: to 0.7% manganese, lessthan about 2% chromium, about 2%: to 12% vanadiumand the balance substantially iron. with residual impurities in. ordinary. amounts, in which alloy the vanadium .irrexcessot about 1% is combined with the carbonin a ratio of'about' 4.2:1.

2-. A. water-hardening, abrasion-resisting and shock-resistingsteel comprising aboutl.'l% carhornabout 0.2% silicon, about'0.2%:- manganese, about: 0.1%. chromium and about 4.50% vanadium; balance substantially iron with residual impurities in ordinary amounts in which alloy thevanadium in excess of about 1% iscombined withrthe'oarbon in aratio of about 4.2;1.

i A water-hardening, abrasion-resisting and shock resisting steel alloy having carbon in excess ofthat necessary to give it the desired hardenability characteristics comprising about 0.85% to: 4%; carbon,,about 0.1% to 0.5% silicon, about 012%; to. 0.7% manganese, less than about-2% chromium, about 2% to 12% vanadium and. the balance substantially iron withresidual impuritiesinordinary amountsinwhich alloy theconcentrationsaof vanadium and carbon within-the given limits are adjusted. so that the ratio of vanadium inexcess of about 1% to the excess carbon is about 4. 2:1.

4. A water-hardening, abrasion-resisting. and

shock-resisting steel alloy having carbon inexcess of. that necessary to givethe desired harden.- ability characteristics comprising about. 1.7% carbon, about 0.2%. silicon, about 0.2%. manganese, about. 0.1% chromium, about 4.50% vanadium and. the balance substantially iron with'residual impurities in ordinary amounts-in which alloy the concentrationof vanadiumand carbon within the given limits are adjusted so thatthe ratio ofvanadium in excess of aboutl to the excess carbon is about 4.211..

5. A waterehardening, abrasion-resisting and shock-resisting article formed from a forgeable abrasion-resistingsteel alloy comprising about 0.85% to 4% carbon, about 0.1% to 0.5% silicon, 0.2% to 0.7% manganese, less than about 2% chromium, about 2% to 12% 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 ina ratio. of about 4.221, said article being characterized by high resistance to abrasion andiracture-under shock 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 s per cent vanadium 1 4.2

6. An abrasion-resisting and shock-resisting article formed from a forgeable abrasion-resisting steel alloy comprising about 1.7% carbdn, about 0.2% silicon, about 0.2% manganese; 01% chromium and about 4.50% vanadiumggbalance substantially iron with residual impurities in ordinary amounts in which alloy the vanadium in excesspf about 1% is combined with carbonin a ratio of about 4.2:1 said article being characterized by high-resistance to abrasion andjffracture under shock and by forging and hardening characteristics comparable to steels having a carbon content less than that of the article by anamount equal to the per cent variadium- 1 4.2

tially iron with residual impurities in ordinary amounts in which alloy 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, said article being characterized by high resistance to abrasion and fracture under shock 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 per cent vanadium1l, 4.2-

DAVID J. GILES.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Yr Date 1,638,855 Jordan et a1. Aug. 16, 1927 2,174,282 Gill Sept. 26, 1939 FOREIGN PATENTS Number Country Date 282,744 Great Britain Apr. 15, 1939 OTHER REFERENCES The Journal of the Iron and Steel Institute, No. I, 1912. page 219, Alloy No. 1309. Published by the Iron and Steel Institute, London, England.

Claims (1)

1. A WATER-HARDENING, ABRASION-RESISTING AND SHOCK-RESISTING STEEL ALLOY COMPRISING ABOUT 0.85% TO 4% CARBON, ABOUT 0.1% TO 0.5% SILICON, ABOUT 0.2% TO 0.7% MANGANESE, LESS THAN ABOUT 2% CHROMIUM, ABOUT 2% TO 12% VANADIUM AND THE BALANCE SUBSTANTIALLY IRON WIHT RESIDUAL IMPURITIES IN ORDINARY AMOUNTS, IN WHICH ALLOY THE VANDAIUM IN EXCESS OF ABOUT 1% IS COMBINED WITH THE CARBON IN A RATIO OF ABOUT 4.2:1.