US2409016A - Shock-resistant silicon steel hardened with titanium - Google Patents

Description

Patented Oct. 8, 1946 ENED WITH TITANIUM i Linwood M. Brown, Homestead, Pa.

No Drawing. Application October 19, 1942,

Serial No. 462,508

c Claims. 1 (01. 75-123) 1 My invention relates to steel alloys, and particularly, though not exclusively, to steel alloy used in making percussion tools.

The object of the invention is to provide a steel alloy in which high resistance to fatigue and crystallization is obtained in conjunction with increased tensile strength, hardness, and toughness.

Another object is to provide a self-hardening, the characteristics men Per cent Carbon 0.40 to 1.00 Manganese 0.35 to 2.50 Silicon 0.80 to 2.75 Molybdenum 0.15 to 2.90 Titanium 0.10 to 0.90 Iron Remainder The combined molybdenum and titanium ranges substantially from 0.25% to 3.80%. The phosphorus and sulphur impurities are held to normal values. I

The steel alloy will preferably be produced in an electric furnace, and it will be understood that traces of other usual elements may be present in the product, depending upon the composition of the melts that were previously made in the melting furnace. For example, immediately prior to making a batch of my steel, the steel producer may have been using the furnace for the production of stainless steel, or high chromium steel, in which case-the lining of the furnace may be contaminated with chromium, or nickel, or copper, or tungsten, or other alloys or combinations, and if the furnace is not thoroughly washed out by the melting of one or more heats of plain carbon steels, certain inclusions, not desired, but permissible, will be found in my steel. In a typical case a heat of my steel picked up chromium in the amount of from 0.06% to 0.07%, W i e this chromium was not desired, it was permissible. The same may be said of other alloys that will ordinarily be picked up in the melting furnace.

The carbon, manganese, and silicon will be added to the mix in the furnace, and the molybdenum and titanium additions preferably, although not necessarily, will be made in the ladle,

in which case the temperature of the mix in the ladle Will be increased approximately two hundred degrees above normal pouring temperature.

Ordinarily, ferro-compounds of silicon, manganese, molybdenum, and titanium are best to use in the mix.

In the manufacture of titanium steels hitherto, substantial quantitiesof the added titanium have been lost, ordinarily as much as 25%. (See page 21 of the book entitled:Titanium and Its Use in Steel,-copyrighted in the year 19 10 by The Titanium AlloyManufacturing Company of Niagara Falls, New York. 1 See also page 951 of The Making-Shaping and Treating of Steel, Fifth edition, by The Carnegie-Illinois Steel Corporation, published in Pittsburgh, Pennsylvania, 1940.) I have discovered that if, the silicon content of the molten bath of metal is maintained greater than, and preferably from one and one quarter to three or more times as great as, the titanium content,-

the titanium will not be lost, but will substantially all persist as an alloying component of the finished steel.

It has been known in the art that both titanium and silicon may be used as deoxidizers in the production of steel, but so far as I am aware, no one has heretofore realized that, in the case of a titanium steel, particularly a titanium steel containing molybdenum, silicon may be used as an effective agent to prevent the loss of any substantial portion of the titanium introduced to the mix.

It is believed that in the improved steel alloy of my composition a molybdenum-titanium carbide is formed, this being indicated by the fact that from 12% to 1 1% of the carbon originally added to the melt is absorbed. The steel is of fine grain structure, great density and toughness, and exceedingly high tensile strength.

Titanium when present in steel, particularly in amounts above 0.10%, is'known as an inhibitor of the hardenability of the steel, and it is remarkable that the titanium steel of my invention possesses high self -hardening qualities. When forged and cooled in the atmosphere, the steel develops a hardness of from C to 62 C, Rockwell. The steel may also be heat treated, by raising it to a temperature of 1600 F. and cooling it in water or in oil, and it may be used with or without tempering, depending upon the particular service. The steel possesses high red-hardness. It has high resistance to fatigue and crystallization and will not fail under shock, and (by virtue of its high red-hardness) it is enduring under conditions of service in which heat is generated by 3. friction and abrasion. Possessing such qualities as these my steel is excellent for use in cutter bits of mining machinery, pneumatic chisels for chipping and cutting hot or cold metal, cold cutters, heading dies, forging dies, bushings for pneumatic hammers, shear blades for hot or cold Work, rivet bull dies for either pneumatic or. hydraulic machines, battering mauls: and sledges; andihollow and solid drills. And it Will be und'erstoodthat many other fields lie open to the use of such steel.

The application for these Letters Patent consisted in a continuation inpart; of application Serial No. 407,439, filed by me on August.1'9; 1 941", for Titanium steel and method of production.

Many variations in the proportionsofthe alloying elements may be made without: lenarting from the invention, as defined in the appended claims.

I claim as my invention:

1. A shock-enduring steel alloy of high hardenability havingsubstanti'ally the composition: carbon, DAG-1.00%; manganese, 0.35-2.50 silicon, 0.80-2.75%; molybdenum, ;1'5'-2;90.% titanium, 0.10-0.90%'; the silicon being in excess of the titanium, and the remainder substantially iron.

2. A shock-enduring: steel alloy of high hardenability having substantially the composition: carbon, GAO-1.00% manganese, 0 .35 2 .50 g silicon, 0.80-2.7 molybdenum, (HS-2.90%; titanium, GAO-0.90%; the sili'con being i excess of the titanium, and theeremaindersubstantially iron, the titanium content of the steel alloy comprising almost all-of thetitanium introduced to themix.

3; A shock enduring steel alloyof high hardenability containing, in addition to its essential ferrous content, carbon, manganese, silicon.

4 I molybdenum, and titanium as the principal alloying ingredients, the combined molybdenum and titanium content ranging substantially from 0.25% to 3.80% and including at least 0.10% titanium and 0.15% molybdenum, and the silicon being in excess of the titanium.

I 4. A shock-enduring steel alloy of high hardenability cpntaimng, in. addition to; its essential ferrous content, carbon, manganese, silicon. molybdenum, and titanium as the only alloying ingredients, the combined modybdenum and titanium content. ranging substantially from 0.25% to 3.80% and including at least 0.15% molybdenum and 0.10% titanium, the silicon ranging between 0.80 and 2.75%.

A shock-enduring steel alloy of high hardenability containing, in addition to its essential ferrous content, carbon, silicon, molybdenum, and titanium as the only alloying ingredients, the combined molybdenum and titanium content ranging substantially from 0.25% to 3.80% and including at least 0.10% titanium and t least 0.15% molybdenum, the: silicon content beingv at leastone and onequarter times the titanium content.

6. A. shock-enduring. steel alloy of high hardena'bility containing, in addition. to its essential ferrous content, carbon, silicon, molybdenum and titanium, these being the only: alloying ingredients, the combined molybdenum: and titanium content ranging substantially from 0.25 to 3.80%. and: including at least. 0.10% titanium and at l'east.0.1.5% molybdenum, and the silicon content being at least one and one-quarter times the titanium content, the titanium content of the steel. alloy comprising almost all of the: titanium introduced to the mix. v

LINWOOD M. BROWN.