US2198775A - Ferrous alloy - Google Patents

Description

UNITED STATES PATENT OFFICE.

FERROUS ALLOY Walter E. Jominy, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware No Drawing. Application November 5, 1938, Serial No. 239,022

6 Claims. (Cl. 75126) This application relates to ferrous alloys and cast irons which would, of course, be rather difllmore particularly to cast iron compositions which cult to machine. have very good properties of wear resistance. There are many instances when other specific The alloys forming the subject matter of the properties in addition to the ability to resist wear 4 present invention possess the resistance to scorare required in a cast iron. Such a property as 5 ing characteristic of cast iron and have extra high strength in larger size casings, as well as good properties as regards resistance to wear good hardness near the center of large castings. under severe conditions, The alloys in accordis frequently essential. Also, in many cases it n w th my invention are especially adapted is highly desirable that the iron have extra good for such parts as cylinder liners, piston rings, fluidity at ordinary casting temperatures and/or pistons, Valves, valve guides, tappets, bearings be easily m l in h p l In ny cases and other parts ordinarily subjected to w ar, it is highly desirable that the casting be leak The invention comprises alloys composed of es carbon, silicon, titanium, copper, manganese, The following compositions having the esseni chromium. and iron as essential constituents. ial t u nts in app mat y th p p Ordinary impurities as sulphur, phosphorus, etc., tions stated have been found especially good as are present in small amounts. For example, the rd resistance to W In bars 78" X 1 x sulphur is usually present from a, tra up t 12" cast in green sand molds these compositions .12%. In some cases slightly greater amounts, are readily machinable- The Several examples I say up to may be present without unduly given each have good resistance to wear and 20 affecting the beneficial effects of the essential a w so va o in ot des e p y a constituents. The phosphorus is ordinarily kept p p low, that is, under about .20%. However, higher mp O- 1 amounts up to about 1% may be present 2.86% carbon, 2.18% silicon, .16% titanium.

5 The several essential constituents are in ap- 94% copper. 52% manganese, 51% chromium,

proximately the following proportions: 2.25- balance on 4.00% carbon, l.50-3.50% silicon, .05-.60% tita- Exam 1 Na 2 nium, .501.50% copper, .30-1.00% manganese, 1 .40-2.00% chromium, balanc m 3.17% carbon, 2.29% silicon, .14% titan um,

l A preferred narrower range of the essential coPperi manganesechmmmm' ingredients is the following: 2.7s 3.75% carbon, balance 2.oo-3.20% silicon, .10 .45% titanium, .55-1.1o% Example 3 copper, -30% m nganese, .2 chro- 3.26% carbon, 2.61%. silicon, 28% titanium, miu b e iron- .99% copper, 55% manganese, 1.13% chromium,

i In addition to the ability to resist scoring and balance iron. 35

wear, the alloys of my invention are ordinarily Example No. 4

comparatively easy to machine. It will be understood by those skilled in the art that the carbon and silicon content may be modified within the ranges given to suit the casting size and/or Example 5 cooling rate in orderto obtain extremely good machinability. It is common knowledge in the 326% carbOn, 251% 511mm iltaniumi field of metallurgy that small castings by reason Copper manganfesei 113% chromlumi of their faster cooling will have more combined phosphorus Palance 'f carbon and less graphitic carbon than will cast- The several alloymg Qstltuents may be P ings of large size when both are made of the same corpora? any convenwjnt mannerchemical composition. Higher combined carbon gards convement f F P and less graphitic carbon will make machining ing the same is 1n the form of a silicon titanium more diflicult so that the composition must be alloy- Order to redufie the Penfiency 0f the modified to compensate for this condition This titanium to become oxidized, it is preferably may be done by adding more silicon, more earadded at a late stage in the melting process. If bon, or more of b th il d a b n, desired to add silicon late to get higher strength Within the range of composition given it is it is permissible. Any suitable melting furnace possible in certain section sizes to obtain white may be used,

2.90% carbon, 2.38% silicon, 26% titanium, 1.05% copper, .49% manganese, 1.19% chromium,

balance iron. 0

I claim: i

1. An alloy comprising the following elements as essential constituents in approximately the amounts stated: 2.25-4.00% carbon, 1.50-3.50% silicon, .05-.60% titanium, .50-1.50% copper, .30-

1.00% manganese, .40-2.00% chromium, balance substantially all iron.

.2. An alloy composed of the following elements as essentialons'tituents in approximately the amounts given: 2.75%-3.75% carbon, 2.00-3.20% silicon, .10-.4.-5% titanium, .55-1.10% copper, .40- .80% manganese, .50-1.25% chromium, balance 'iron.

3. An alloy composed oi the following elements as essential constituents in approximately the proportions given: 2.86% carbon, 2.18% silicon,

.16% titanium, .94% copper, .62% manganese, .51% chromium, balance iron.

4. An alloy composed of the following elements as essential constituents in approximately the proportions given: 3.17% carbon, 2.29% silicon, .14% titanium, 58% copper, 114% manganese,

58% chromium, balance iron.