US1346191A - Firearm and alloy for making same - Google Patents

Description

FRANK A. FAHRENWALD; or CLEVELAND HEIGHTS, OHIO.

FIREARM AND ALLOY FOR MAKING SAME.

No Drawing.

To all whom it may concern:

Be it known that I, FRANK A; FAHREN- WALD, a citizen of the United States, re siding at Cleveland-Heights,in the county of Cuyahoga and State of Ohio, have invented-a certain new and .useful Improvement in Firearms and Alloys for Making Same, of which the following is a full, clear, and exact description.

This invention relates to firearms and ordnance and has for its object a provision of metallic alloy for use in construction of the same which shall be more resistant to corrosion by the combustion products of the explosives as well as less effected by atmospheric conditions and salt solutions (such as sea water or perspiration) than any of the materials now in use vfor the purpose; which shall be at least as easily manufactured as the steels at present employed, which shall be at least equally resistant with steel to mechanical erosion and less subject than steel to becoming fouled by the material of the bullets or projectiles employed; and which shall not be unduly high in intrinsic value.

Practically the only substance now in use for the barrels of firearms and ordnance is some kind of a steel, in otherwords contains a considerable percentage of carbon in the form of iron carbid dissolved in' an excess of iron. This is sometimes modified;- by the presence of a very small percenta e of nickel, vanadium, tungsten, etc., but t e essential characteristics are, those of steel,

which includethe capacity of becoming hardened by heating and quenching together with high susceptibility to the 'corro-- sive effect of powder r gases, powder re,- sidues, salt solutions and other rusting con ditions. Furthermore such carbids are seldom disseminated with perfectuniformity throughout the mass of material, 'andbesides, owing to their susceptibility to temperature influences, it is seldom that. all parts are giyen the same degree of hardness or temper which produces ity of strain within the material. The consequence is that when a barrel of steel is bored, the effect of the perforation is to release this strain unequally in different parts of the barrel which therefore auto-- matically bends in one direction or the other as a result of the borin operation alone and hence requires a care 1 stralghtenmg op- Specification of Letters Patent.

' nickel, possesses resistivity an inequal- Patented July 13, 1 920.

Applicationvfiled December 15, 1919. Serial Nol 345,083.

eration which is a task fit only for the most expert of workmen. such a barrel when-heated by repeated firing always becomes Warped and thus pro-,

duces a deflection of the bullet depending upon the temperature.

According to my invention I avoid the faults due to these characteristics of steel by reducing the carbon content to the lowest ,possible extent, and secure the necessary hardness and toughness of the metal by the use of some substance other than carbon which shall have the added capability of shielding the fundamental metal against corrosive action. Owing. to 1ts cheapness Furthermore and availability I prefer to employ iron as the fundamental metal, although other metals of the iron group can equally be employed, and'in fact. serve the purpose to a degree even superior to iron, although the iron-base alloy is sufiicient for every practical purpose. The two' basic protective metals for use with iron are chromium and nickel. They 'may be used either ,separately, or together, either with or without other substances. An alloy of iron with 10% of either of the metals, chromium or to corroding influences farsuperior to anything hereto-.

fore used in firearms as also does an alloy of iron combined with both chromium and than in the case of an alloy not containing.

these ingredients and as a result it is neces- "nickel up to this percentage, the latter ocsary to keep the amount of carbon very low. .2 of 1% appears to be about the uppermost desirable limit of carbon, and with the higher percentages of either or bothof the'metals, nickel or chromium, the carbon ought to be retained below about .1 of 1%. The necessary hardness in .the alloy is se vcured by either. nickel or chromium inamounts of 10% "or upward and these amounts: also afford marked chemical re- 'sistivity, The upper limit of chromium is about 25% since above this amount the alloy becomes too hard for convenient fabricating, there is no limit upon the proportion of nickel other than economic considerations.

These alloys can readily be'macle in the 2 v i,sae,ioi

electric furnace by rifled and otherwise fabricated with the same facility as steel. Barrels made of the same do not require 'to be straightened after boring as in the case of steel and do not show any tendency v to deflection upon heating. The surface of the metal tends to become smoother and more polished the more frequently it is fired and. offers far less tendency than steel barrels to become fouled or eroded by the material of the projectiles; barrels containing upward of about 10% of chromium are highly immune to gases and residues of all explosives, even when left uncleaned for long periods, while chromium alloys above about 12% are completely immune. Barrels of iron alloyed with 30% or more of nickel will withstand severe neglect and alloys containing 15% of nickel together with 10% of chromium are entirely immuned.

10% of nickel is not enough to confer highv immunity for barrel use, but produces an Y alloy which is excellent for breech blocks,

actions, etc., since it is markedly resistant to atmospheric influences. i

There are other metals than nickel or chromium which will exert a protective effect upon iron together with the hardening effect made necessary by the reduction in carbon content, but suffer the disadvantage either of requiring undue amounts to con fer equal chemical resistivity or exert i-njurious effects upon the physical properties when employed to a suflicient extent to produce by themselves the desired protection effect. Cobalt is the full "equivalent of nickel in this relation but is ofwless practical value because of its comparatively high cost. Small'quantities of vanadium, titanium, or

manganese are very the use of pure mate; rials and can be melted, cast, forged, drilled,

I 1 signature. desirable for use as scavengers and the presence of small amounts of vanadium or manganese in the finishedalloy is an advantage but titanium or zirconium, if used as scavengers should be restricted to the' exact amount which will be eliminated inprocess unless carbon and silicon are substantially entirely eliminated. These substances are to be used in addition to the'nickel or chronium and not in substitution therefor, wherefore I consider the preferable alloy to be essentially that of .iron with either or both nickel and (or) chromium, the highest limit of chromium beingabout 25 and the highest limit of Qiron about 90, and the lowest limit of nickel or chromium or some combination of the 7 two being about 10%.

While I'have suggested this principally in connection with the barrels of firearms I do not exclude its use for breech blocks, firing mechanisms, etc.,*"wh-ioh parts are also subjected to some extent to powder fumes and residues and to an equal or greater extent to atmospheric and salt conditions.

Having thus described my invention, what Iclaim is:

1. A firearm barrel made of an alloy containing iron combined with at least about thirty per cent. of one or more other metals of the iron group. I 4

2. A firearm barrel made of an alloy conthat the .total amount .of non-ferrous metal in the alloy shall constitute about t'wenty- I five per cent. of the whole, and the chromium constituting at leastabout five per cent. of the whole.

In testimony whereof,\l hereunto affix my FRANK A. FAHRENWALD.