US2669534A - Production of alloys - Google Patents

Description

Patented Feb. 16, 1954v 2,669,534 PRODUCTION OF ALLOYS William Henry Richard son, Datchet, England,

assignor to Langley Alloys Limited, Langley, England, a body corporate of Great Britain No Drawing. Application February 19, 1951, Serial No. 211,808

Claims priority, application Great Britain February 20, 1950 8 Claims.

This invention relates to 'the production of alloys and more especially to aluminium bronzes consisting of copper and from 812% aluminium with optionally up to 8% of any one or more of the elements iron, nickel, cobalt and manganese, and in which bronzes smaller proportions of other elements such as antimony, arsenic, bismuth, chromium, lead, magnesium, phosphorus silicon or zinc each in amounts not exceeding 0.3% may be present intentionally or as impurities.

Normally, for highly stressed components, aluminium bronzes are employed in the wrought condition having been hot worked at temperatures of about 800-1050 C. depending on the aluminium content and the presence of additional constituents to the binary alloy, the working temperatures being higher in the case of those alloys containing smaller proportions of aluminium within the specified range, and also when the additional constituents, such as iron, nickel, cobalt, manganese and/or chromium are present and lower in the case of alloys containing higher percentages of aluminium within the specified range or when additional elements such as silicon, tin and/or zinc are present:

The invention has for its object to provide an improved method of manufacturing articles from alloys and especially from aluminium-bronzes of the character in question by which consistently homogeneous products having improved mechanical properties and particularly high fatigue strength, may be readily and consistently obtained.

Further and favourable objects from the following description.

Broadly stated, theimproved method of manu-. facturing articles from aluminium bronzes according to the invention consists in subjecting the material to a heat treatment within the temperature range 800 0. up to about 1050 C. according to the particular constitution of the alloy, to bring it substantially to a beta condition where substantially the whole of the aluminium is in solid solution and then quenching the. material to below 600 C. virtually to retain thiscondition and to ensure that any alpha particles that may be present are in the form of a fine dispersion, prior to reheating the alloy for its final hot working or forging to a finished shape within a temperature range at which alpha particles are still present. f

Following the quenching treatment and prior to final hot working, the alloy' may if desired, be further heat treated withinitheltemperature will appear range 400 to 800 C. and by thisxmeanszthe quantity and distribution of alpha particles can be more closely controlled.

In this condition the alloy is reheated to the required temperature and subjected to'itsfinal hot working to the required shape.

Depending upon the particular constitution of the alloy and the method offin'al heating and working, a temperature range found suitablefor such hot working is 700 C.-1000 C.

The alloy as cast may be subjected to hot ro'1l-. ing, forging or extrusion to produce bar stock prior to the treatment, or heat treatment and subsequent quenching according to the present invention may be effected immediately after the aluminium bronze has been cast conveniently in chill moulds, or at any time after it has been subjected to the preliminary hot'work and-"prior to the final working.

It will be appreciated that the pressed, forged, rolled or extruded article may be finally sub-i jected to a tempering or artificial ageing treatment at a temperature not above the temperatureat which it has been hot worked and that in this after-treatment the article may be quenched in a suitable medium orcooled slow 1y or allowed to cool naturally inair to the temperature of the ambient atmosphere.

In the practice of the invention, as appliedan aluminium bronze including 11% aluminium, 5% iron, 5% nickel and 1% manganese with the remainder copper, exceptfor the impurities referred to hereafter, the billets are preliminarily hot worked by rolling, forging or extruding into suitable stock at about 900C.

Thereafter they are subjected to heat treatment as described at 910 C. so that-asubstantially beta condition is'produc'ed and continue the treatment for a period of A1 of an hour following; by quenching, and any alpha particles present are in the form of a fine dispersion unis formly distributed throughout the matrix. ,.In this condition the stock is then ready for final forming to shape, preferably by being extruded, pressed into moulds or shaped diesor rolling :or forging at BOO-890 0., after which treatment the material possesses an extremely fine grain struce ture in which the alpha particles are uniformly distributed throughout the matrix and; are of .a size not exceeding '50 microns.

The shaped articles,such as turbine orcompressor blades are then, if desired. subjectedito the. final optional artificial tempering treatment a BO 00 C. when they-areiound-toexhibit enhanced mechanical properties and especial :ly high fatigue strength even:atzelevated .t'em

peratures and under working conditions involving considerable vibration.

Although hitherto it has been possible to produce an aluminium bronze of this type possessing high proof stress and tensile strength, the methods heretofore employed for producing such properties have resulted in lack of uniformity, but by the improved method according to the present invention it is possible to produce a far superior combination of properties and further, these properties can be consistently obtained. Typical properties of the aluminium bronze treated as aforementioned are as follows:

0.1% proof stress tons per sq inch.. 45.1 Maximum stress do 56.? Elongation percent 16 Endurance limit tons per sq. inch +25 Analysis of a specimen of the aluminium bronze showed the following impurities to be present:

Percent Arsenic 0.005 Chromium 0.001 Lead Y 0.01 Silicon 0.07 Tin 0.005 Zinc 0.01 Magnesium 0.05 Phosphorus 0.01

In another example of the practice of the invention as applied to an aluminium bronze having the following composition:

Percent Aluminium 10.72 Iron 5.26 Nickel 5.15 Manganese 0.23 Arsenic 0.005 Chromium 0.001 Lead 0.015 Silicon 0.05 Tin 0.007 Zinc 0.02 Magnesium 0.05 Phosphorus 0.01

with remainder copper, the treatment is carried out as in the first example except that after rolling at 900 C. and cutting to size, if necessary, the billets are heated at 930 C. for three quarters of an hour and then quenched in water before final shaping by hot work at 800 C.900 C. and artificial tempering for 2 hours at 650 C.

t Typical specimens showed the following proper- 0.1% proof stress tons per sq. inch 38.5 Maximum stress do 55.0 Elongation percent 19 Such known material exhibited the following mechanical properties:

0.1% proof stress tons per sq. inch 34.25 Maximum stress do 57.25 Elongation percent 10.5

The invention is also particularly advantageous in the reheating of billets for not working when a high frequency induction process of heating is used.

In normal extruded or rolled bar stock as used for forgings the alpha particles occur as comparatively large and often elongated lakes. In heating for hot working, time must be allowed for these large particles of alpha to be taken into solution in the beta matrix and consequently when high frequency induction methods of heating are used it may not be possible to take the fullest advantage of the extremely rapid rate at which this method of heating raises the billets to the desired temperature since much of the alpha would remain still undissolved.

If however, the billets are treated in accordance with this invention the very fine distribution of alpha in the billets prior to re-heating enables the heating to be effected at a much more rapid rate while still obtaining the necessary degree of solution of the alpha particles in the beta phase and full advantage can therefore be taken of the rapid rate of heating and the consequent increase in production which is possible by high frequency heating.

By the present invention, forged aluminium bronzes of enhanced mechanical properties may be conveniently and consistently manufactured.

What I claim is:

1. A method of manufacturing articles from aluminium bronzes consisting of copper and from 23-12% aluminium with smaller proportions of other ingredients comprising subjecting the article to a heat treatment within the temperature range 800 C. up to about 1050 C. according to the particular constitution of the alloy, to bring it substantially to a beta condition where substantially the whole of the aluminium is in solid solution and then quenching the material to below 600 C'. virtually to retain this condition and to ensure that any alpha particles that may be present are in the form of a fine dispersion, and then reheating the alloy and subjecting it to final not working to a finished shape at a temperature within the range 800-900 C. at which alpha particles are still present.

2. A method of manufacturing articles from aluminium bronzes according to the preceding claim wherein for controlling the quantity and distribution of the alpha particles in the alloy, it is subjected, after quenching and prior to final hot working, to a soaking treatment within the temperature range 400-800 C.

3. A method of manufacturing articles from aluminium bronzes according to the preceding claim 1 wherein the alloy as cast is subjected to preliminary hot work at 900 C.: 0 C. to produce stock which is then subjected to the heat treatment at a higher temperature followed by quenching to condition the material for the final hot working to shape by forging.

4. A method of manufacturing articles from aluminium bronzes according to the preceding claim 1 wherein the shaped article is finally subjected to a tempering or artificial ageing treatment at a temperature not above the temperature 1; at which it has been hot worked.

5. A method of manufacturing articles from aluminium bronzes according to the preceding claim 1 and consisting of 11% aluminium, 5% iron, 5% nickel and 1% manganese with remainder copper except for impurity elements wherein the cast alloy is subjected to preliminary hot work at about 900 C. followed by heat treatment at 910 C. for about three quarters of an hour, uniformly to disperse the alpha particles throughout the matrix prior to final hot Working to shape at 800-890 C.

6. A method of manufacturing articles from aluminium bronzes according to the preceding claim 5 wherein the heat treated alloy is quenched prior to storage for subsequent hot working, and the shaped article is subjected to a final artificial tempering treatment at GOO-700 C.

7. A method of manufacturing articles from aluminium bronzes according to the preceding claim 1 and consisting of 10.72% aluminium 5.26% iron, 5.15% nickel and 0.23% manganese with remainder copper except for impurity elements, wherein the cast alloy is subjected to preliminary hot work at about 900 C. followed by heat treatment at 930 C. for about three quarters of an hour, uniformly to disperse the alpha particles throughout the matrix prior to final hot working to shape at 800-900 C.

8. A method of manufacturing articles from aluminium bronzes according to the preceding claim 1 wherein the heating for final hot working to shape is effected by high frequency induction.

WILLIAM HENRY RICHARDSON.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 2,075,509 Davis Mar. 30, 1937 OTHER REFERENCES Aluminum Bronze, by Copper Development Association, London (Reprint 1939), page 42.

Metallurgia, March 1950, paqes 242, 243.

Claims (1)

1. A METHOD OF MANUFACTURING ARTICLES FROM ALUMINUM BRONZES CONSISTING OF COPPER AND FROM 8-12% ALUMINIUM WITH SMALLER PROPORTIONS OF OTHER INGREDIENTS COMPRISING SUBJECTING THE ARTICLE TO A HEAT TREATMENT WITHIN THE TEMPERATURE RANGE 800* C. UP TO ABOUT 1050* C. ACCORDING TO THE PARTICULAR CONSTITUTION OF THE ALLOY, TO BRING IT SUBSTANTIALLY TO A BETA CONDITION WHERE SUBSTANTIALLY THE WHOLE OF THE ALUMINIUM IS IN SOLID SOLUTION AND THEN QUENCHING THE MATERIAL TO BELOW 600* C. VIRTUALLY TO RETAIN THIS CONDITION AND TO ENSURE THAT ANY ALPHA PARTICLES THAT MAY BE PRESENT ARE IN THE FORM OF A FINE DISPERSION, AND THEN REHEATING THE ALLOY AND SUBJECTING IT TO FINAL HOT WORKING TO A FINISHED SHAPE AT A TEMPERATURE WITHIN THE RANGE 800*-900* C. AT WHICH ALPHA PARTICLES ARE STILL PRESENT.