US1958985A - Steel alloy - Google Patents

Description

Patented May 15, 1934 UNITED STATES STEEL ALLOY George Charlton, Detroit, Mich., assignor to Wilcox-Rich Corporation, a corporation of Michigan No Drawing. Application February 7, 1930, Serial No. 426,597

4 Claims.

One object of this invention is to produce a steel alloy having pronounced qualities for resisting wear and abrasive action when subjected to either hot or cold operating conditions.

My alloy is suitable for all wearing parts, has been found to be particularly suitable for centers such as are used in lathes, steady rests, cam contacting surfaces for tappets of internal combustion engines, cams, and other similar articles. Extensive experiments have been conducted to produce a steel particularly suitable for the cam contacting faces of valve tappets for internal combustion engines, and the other uses mentioned, without particular success, and to date no steel has been produced for these purposes which will Wear satisfactorily. My new alloy fills this need, and the wearing qualities are comparable and even superior to the qualities of chilled and white cast iron, which are now regarded as more satisfactory than steel for many of these uses, particularly for tappets.

In addition to the uses mentioned, which call for resisting abrasion in the cold state, the new alloy is also particularly suitable for making hot work dies or hot work extruding dies, because of its ability to resist loss of hardness when heated to temperatures which would soften ordinary alloy steel. v

The following are typical analyses of my new alloy, whcih have been tested and proved to have the unusual wearing qualities desired:

I am aware that there is a widely used steel alloy having an approximate analysis as follows, which I designate as analysis X, for purposes of convenience, and which is a typical high carbon The following described test indicates the unusual advantages of my new alloy over the nearest known equivalent as typified by analysis X. The test constituted a lathe center made from my new alloy, which was operated for twenty days without requiring regrinding, while centers made from analysis X required regrinding each day.

My new analyses produce an alloy having physical properties considerably different fromv physical properties of alloys made up in accordance with analysis X. These differences are illustrated in the following comparative characteristics:

In the soft state my alloy is non-magnetic, while analysis X is magnetic. The alloys respond differently to heat treatment. Alloys made in acordance with analysis X heated for a long period of time at temperatures from 1600 to 1800 Fahrenheit and cooled slowly, will anneal or become soft, and have a Brinnell hardness of approximately 223. My alloy, subjected to the same treatment, will harden under slow cooling, and will obtain a Brinnell hardness of approximately 574, and will become magnetic, and be unusually resistant to wear and abrasion. The characteristic of increasing hardness with heating and slow cooling is particularly valuable when the material is used for hot work, as the hardness and wear resistant qualities are retained under hot operating conditions. The quality of becommg hard under slow cooling also eliminates the strains and distortions inevitably developed in the hardening of steels of the type of analysis X which require a rapid cooling or quenching to obtain hardness.

The following is an approximate range' of analyses for the essential and desirable elements of my new alloy, although it will be understood that such variations from this range as assure the retention of the increasing hardness characteristic on slow cooling from annealing temperatures is well within the scope of my invention:

high chromium type. Carbon Silicon Manganese Chromium Nickel Carbon Manganese Silicon Chromium Phosphorus Sulphur 1.75 1.00max. 1. 00 300 No ne to 0 0 o This material, compared with ordinary alloy steels, possesses good wearing qualities, but does not approach the wearing qualities of my new alloy.

The element nickel helps to retain the hot hardness value but is not essential for the wear resisting value of the alloywhen used for cold working parts. The elements molybdenum and cobalt indicated in the typical analyses hereinbefore listed may be omitted, and the elements tungsten, vanadium, aluminum or zirconium may be added without seriously afiecting or changing the essential characteristics of my alloy. The elements phosphorus and sulphur, although not specifically indicated in'my analysis, are present in amounts common in other alloy steels.

It is also to be understood that I am aware that my alloy may be put to other uses than those specifically mentioned herein, and that such are deemed to be within the scope of my invention.

Formal changes may be made in the specific 1 remainder being iron.

2. An alloy characterized by its ability to resist loss of hardness when hot worked, combined with the property of retaining its hardness in the presence of slow cooling, containing and comprising from 1.90 to 2.48 per cent of carbon, from .90 to 1.00 per cent of silicon, from 1.61 to 2.67 per cent of manganese, from 13.00 to 14.41 per cent of chromium, and from 3.05 to 3.40 per cent of nickel, the remainder being substantially iron.

3. An alloy characterized by its resistance to wear and abrasion when subjected to either hot or cold working conditions, combined with the property of hardening in the presence of slow cooling, containing and comprising, approximately 2.29 per cent of carbon, 1.00 per cent of silicon, 2.67 per cent of manganese, 13.00 per cent of chromium, 3.28 per cent of nickel, the remainder being substantially iron.

4. An alloy characterized by its resistance to wear and abrasion when subjected to either hot or cold working conditions, combined with the property of hardening in the presence of slow cooling, containing and comprising,'approximate- 1y 2.48 per cent carbon, .90 per cent silicon, 1.71 per cent manganese, 14.41 per cent chromium, 3.40 per cent nickel, the remainder being substantially iron.

GEORGE CHARLTON.