US1496979A - Alloy steel for metal-cutting tools - Google Patents

Description

'Patented June 10, 1924.

NITED STATES I PrATENr oFFics'. 1

,nnwm scams, or'xnnwoon, AND use? a. a. Aaeisraoeie, or momma, nnw YORK.

ALLOY STEEL r03. METAL-CUTTING 30 Drawing.. Continuation of application Serial No. 420,432, filed October 29, 1920. This application I filed January 5, 1922. Serial No. 527,228.

To all whom it may concern:

Be it known that we, EDWIN CoRNINe, a citizen of the United States, and. a resident of Kenwood, count of Albany, and State of New York, and knnor 'A. E. ARM- s'rnoNo, a subject of the King of Great Britain, and a resident of Loudonville, county of Albany, and State of New York, have invented a new and use 1 Im rove- 1 ment in A110 Steel for Tools, of whic the following is a specification; a

This invention relates to alloy steel for metal cutting tools, having properties generally intermediate between carbon steel and high-speed steel.

The present application is a continuation of our co-pendmgfapplication Serial No. 420,432, alloy steel for metal cutting tools,

2 filed Oct. 29, 1920.

' For small metal cutting tools, such as drills, taps, reainers and the like, carbon steel answers sufficiently well, takes a keen cutting edge and produces smooth finished work, but is limited in its application, be-

cause under heat it softens and dulls rapidl fiigh speed steel, which is commonly used for somewhat larger drills and, similar tools which have to withstand greater heat, is not, of course, rapidly softened by frictional heat, but, in addition to its high price, has the objection that the work roduced is not so smooth and well finishe ascan be .ob-

' tained by sharp edge carbon steel tools, for example,. and a subse uent separate finish-' ing operation is usua y required. For ex.-;

ample, drilled holes require finish reaming to produce satisfactory work. Further- 0 more, in the case of ta s, for example, the

- teeth of the tap areo ten injured by the high temperatures required for heat treatment of high-speed steel.

The present mventi able' properties of both carbon steel and high s p is very stron and at til-not soften w an drawn to medium telnetalutting f and I on relates to the pro-- 46 vision of an alloy steel having the desn' eed steel, that is, which will re-v tam a, ard, keen cutting edge and which e same time will peratures, such as 500-700 F. The steel of peratures as in the case of high speed steel,

so that there is fipractically no tendency for any burning o of the tips. of the teeth of taps and. similar tools during heat treatment. This steel has other features of advantage as will appear from the following description.

An important feature of the invention relates to the employment of silicon as one of the components of the alloy. The silicon appears to serve as a sort of solvent for other components and-causes them to form 76 a chemical combmation with one another roduces an alloy steel having im-' prove properties. A secondfunction of the silicon is to raise the transformation point of the resulting alloy, thus imparting to the alloy steel the very valuable property of hardening at relatively high temperatures. A third function of the silicon is to enhance the. air hardening properties of the alloy. Silicon enables the chromium and molybdenum in combination with the carbon and iron to take on a tremendously enhanced air hardening property. It also which would cause ;a strai ht c romium,

carbon I or chromium-moly denum-carbon steel to soften.

I According to another feature, an alloy steel is provided having as one'of its com- 05' ponents a predetermined proportion of var nadium. This alloy steel has an increased red hard property. The use of vanadium also creates a la to transformation, that is to y. when t e steel 15 rehea ed 9.1- a

hardening, 1t is given very short period after beingquenched for a la to the breaking down of the solid solution produced in quenching. Consequently, cutting tools made of the alloy so made can withstand overheating of their cutting edges for limited times without destruction of their cutting ability.

According to another feature, an alloy steel is provided having as one of its components a predetermined proportion of co-- with-the carbonand iron adds to the hardness and improves other desirable physical qualities. Chromium in combinationwith the molybdenum and carbon adds materially to the air hardening edect of such. combination.

One example of a composition for an alloy steel in accordance with the present invention is as follows:

Percent. Carbon .50 Chromium 1.50 Molybdenum l .Manganese All) Silicon Vanadium .75 Cobalt approximately l Balance iron with small amounts of phosphorus and sulfur.

Tn; order to harden this alloy it is heated as quickly as possible to substantially 1900" 181, without quenching in oil or water. riations in manganese in this alloy will require inverse variations in the temperature to which the alloy is if the manganese is increased to.l% theteml500- F, while if the manganese is increased to 1.5% the temperature should be reduced to substantially 14:50 F.

Another example of an alloy made in accordancewith the present invention is of about the following composition:

. Percent. Carbon l Chromium 2 Molybdenum 2 Manganese fi -.f. All) Silicon, 1 Vanadium 1 Cobalt .1

Balance iron with small-amounts of phosphorus and the quality of having heated for example,

In order to harden this alloy it should be heated as quickl as possible to substantially 1800 R, an quenched in oil or water. Variations in manganese require Variations in the heat treatment temperature as in the preceding example.

A third example of an alloy made in accordance with the present invention is of about the following composition:

, Per cent. Carbon 1.50

Chromium 2 Molybdenum a 2 Manganese .40 Silicon 2 Vanadium .50 Cobalt 2 Per cent. Carbon .50 Chromium l0 Molybdenum 5.7 5 Manganese .40 Silicon 2.5 Vanadium 2 GObfilll 2 Balance iron with small amounts of phosphorus and sulfur.

In the heat treatment of this alloy heat should be applied until the alloy has a temperature of substantially 2100? F. The alloy should then be cooled in-the air. This alloy may be cast for use in forming cutting tools.

More'or less variation is possible without any substantial detriment to the desirable are obtained with varying quantities of the several components within substantially the following range:

Per-cent.

. This represents a but good results may be obtained with smaller proportions of some of the alloy com erature should be changed to substantially qualities 0f h material and gmfl msulls' r25 Balance; iron with small amounts of phosphorus and sulfur. o about the outside limits,

' ponents, with composition about as follows:

carbon .252%, molybdenum .502%, silicon .50-2%, chromium .50-2%, vanadium up to 1%, manganese up to 1%, cobalt up to 1%, and the balance principally iron.

We have found that good results are obtained with heat treatment of alloys made in accordance with the present invention, which consists of heating the alloy to a temperature of approximately 1800 F., in as short .a time as possible, after which the "alloy may be air hardened or quenched in i are increased, The as; Wil

oil or water. It is preferably not held atthis temperature more than. a half-minute or so longer than necessary to heat the piece throughout.

Another alloy steel may comprise, for example, components within substantially the following range:

. Per cent. Carbon .25- 2 Molybdenum .50- 5. Silicon .50-2.5 Chromium .50-10 Vanadium .25- 2 Manganese 0- 1. 5

Balance-iron with small amounts of phosphorus and sulfur. Heat treatment substantially as given for previously described alloy steels. r The cobalt steel may comprise, for exam le, components wit in substantially the fol owing range:

' P61 cent.

Carbon .25- 2 Molybdenum .50- 5.75 Silicon .50- 2. 5 Chromium 350-10 Man anese 0- 1.5

Coba t .25- 2 Balance iron with small amounts of phosphorus and sulfur.

Another modification com rises com-' ponentswithin substantially t e following range;-

- x Per cent.

Carbon .25- 2. Molybdenum 50- 5. 75 Silicon .50- 2. 5 i Chromium .50-10 Manganesenn 0- 1.5

becomes quite easy to machine when properly annealed. There is very little tendency for this alloy combination to move, that is to say, to exhibit tendenc to warp-- ing, or other malformation upon eating up and quenching, which is a feature of cat advantage in heat treatment of tools. The characteristic grinding spark given off in grinding articles made ofour improved alloy steel, which does not contain tungsten, is markedly different from the tun ten colored spark. This is 'afeature 0 marked advantage both in manufacture and use, as this alloy steel can be readily distinguished from high speed steels by observation of the spark produced upon grinding. The fore-. going applies whether the alloy steel is in the annealed or hardened state.

We claim:

1. As anew com osition' of matter, an alloy steel of analys1s having substantially the following range: carbon .25-2%, chromium .50-10%, molybdenum .50-5.75%,

silicon 50-25%, vanadium 0-2%, manganese 0-1.5%, cobalt 0-2%, and the principal part of the remainder iron;

2. Metal cutting tools made from alloy steel as claimedin claim 1.

3. Drills for drilling metal made from alloy steel as claimed in claim 1.

4. As a new composition of matter, an

alloy steel of analysis having substantiallythe following range: carbon .25-2%, molybdenum .50-5.75%, silicon 50-25%, chromium 50-10%, vanadium .25-2%, manganese O-1.5%, and the principal part of the remainder iron. v

5. Metal cutting tools made from alloy steel as. claimed in claim 4.

6. Drills for drilling metal made from alloy steel as claimed in claim 4.

7. As a new composition of matter, an

alloy'steel of analysis having substantially the following range: carbon .25-2%, molybdenum .505.75%, silicon .50-'-2.5%, chromium 50-10%, manganese 0-1.5%, cobalt .25-2%, and the principal part of the remainder iron.

8. Metal cutting tools made from alloy steel as claimed in claim 7.

9. Drills for drilling metal made from alloy steel as claimed in claim 7.

1.0. As a newcomposition of matter, an alloy steel of analys1s having substantially the following range: carbon .25-2%, molybdenum .50-5.7 5%, silicon .50-2.5%, chromium 50-10%, manganese 0-1.5%, and the princi a1 part of the remainder iron.

11. etal cutting tools made from alloy steel as claimed in claim 10.

12. Drills'for drilling metal made from alloy steel as claimed -in claim 10.

13. 'Anair hardening alloy steel ada ted to withstand temperatures of about 500- 00 F., without material softening, of analysis {5 I moooio' ivilli'iii substantially the following mmac: l5. Drills for drilling melol medic Emmi carbon .25-2%, chromium Jill-2%, molylo alloy steel as claimed in claim 13.

mum .502%, Silicon .502%, vanadium up to 1%, mam onese up to 1%, cobalt up to names hereto. 6 1%, and; the mlonce principoll iron.

' ll. Metal cutting tools mace fromolloy steel as claimed in claim 13.

PERCY A. E. ARMSTMlNG. EDWIN CURNIING,

In witness whereof, We hove signed om?" W V