Патент USA US2128089код для вставки
- Patented Aug. 23,‘ 1938 2,128,089 v UNITED STATES‘ PATENT OFFICE 2.128.089 7 ARTICLE or MANUFACTURE .Franz R. Hcnsel and Earl I. Larsen, Indianapolis, Ind., assignors to Westinghouse Electric & Manufacturing Company, East PittsburgL'Pa" a corporation-of Pennsylvania _ No Drawing. Application March 12, 1938,‘ . Serial No.~68,452‘ ' I 2 Claims. This invention relates to an article of manu facture, and particularly, to metallic products prepared to facilitate the making of copper base (CI.- 75-42) - I to protect the melt from the atmosphere. Where such a protective ?lm is employed to cover the melt, it is found that the powdered metallic prod alloys. ' uct compacted under the lower pressures to give Q ' This application is a continuation in part of . form and coherence to the powdered mixture is 5 copending application Serial -No. 714,614, ?led suitable for. obtaining a good dispersion of chro March 8, 1934, and directed to copper alloys. , mium when it is introduced into the melt. In preparing copper base alloys containing If‘ the compacted mixture of the powders is chromium, it is found to be quite di?lcult to intro to be added to a copper melt which is not pro " duce the chromium into the molten copper. The tected from the atmosphere, the intermixed pow- 10 chromium has a high melting point and dissolves ders ‘of predetermined ?neness maybe subjected but slowly in’ copper. Further, since the chro -to a pressure suf?cient .to impart Ia density to V mium is lighter than copper, it is difficult to keep the compacted mixture greater than that of the chromium submerged for the time necessary molten copper. Unless a'density greater than ll to: dissolve it. The chromium tends to rise to,‘ that of the vmolten copper is imparted to the 15 the surface of the melt where it is oxidized. The compacted mixture of copper and chromium pow oxides formed contaminate the resulting alloy," ders,‘the resulting metallic product has a tend ’ and the loss of chromium increases the expense of manufacture. I ency to ?oat on the surface of the molten copper . which-may result in high loss of chromium caused . ' Where free chromium is added'to the melt it by oxidation, particularly in", the absence of a 20 may tend to segregate either during‘ melting or _ protective ?ux or atmosphere over the copper. during freezing, since the free chromium di?ers Where such a high density is impartedto the ‘ in density from the copper. Such segregation .mixture of copper and chromium powders, the - ‘causes clack of homogeneity in the resulting compacted mixture sinks in and is dispersed 28 solid product. This is particularly true if the throughout the molten copper. In practice, it 25 amount of chromium exceeds the solid solubility has been found that with a pressure of about limit of chromium and copper. ' 60,000 pounds per square inch, a density of about An object of this invention is to prepare chro 8.5‘ may be imparted to a mixture of copper and mium in a form for use in the making of alloys 80 to ‘facilitate a good alloying dispersion through out a melt of molten copper. chromium powders in which the chromium con tent is about 10% by weight. , 30 In a modi?cation of this invention the copper In making the copper base alloys, chromium is ‘ and chromium powders of predetermined ?ne introduced into the copper melt in a ?nely divided ness may be subjected to a’ low pressure .‘sumcient form prepared in accordance with the teachings.‘ to give form and coherence to the powdered mix-' ‘ ture, after which the compacted mixture is heat.- 35 In preparing the metallic product to be intro-l‘ ed in a reducing atmosphere to sinter the pow duced into the copper melt, chromium is pow-' ders. In sintering the compacted mixture, it is a of this invention.‘ dered in any suitable ‘manner as in a ball mill, » heated to a temperature of between 900° C. and well known to the trade, to a size of between 10 ' the eutectic temperature of copper-chromium do and 500 mesh and preferably between 100 and 200 - (approximately 1060“ C.) in a reducing atmos- 40 mesh, and then thoroughly intermixed with cop v phere and held at that temperature for a period per powder of approximately the same size. of time ranging from a few minutes to several The copper and chromium powders of pre , hours depending on the ?neness of the powders determined ?neness are then thoroughly inter and the pressure employed to compact the pow 45 mixed and placed in a suitable die. and subjected ders. , V _ 45 to a pressure ranging from a. few hundred pounds In practice, the chromium content of the com per square inch, to a‘ pressure as great as 200,000 pacted mixture of the chromium and copper pow pounds per square inch, inorder to compact them. ders depends upon the amount‘ of chromium The pressure under which the unit is compacted which it is desired to add to the .copper melt. 5o depends on the conditions to be met. As a general rule, the compacted mixture con- 50' In preparing the copper base alloys contain‘ trains approximately the same amount of chro ing chromium, the copper is ?rst melted and the mium which‘ it-is desired that the ?nal alloy ' chromium is then added to the molten copper. In practice, the copper melt is sometimes pro } vided with a protective ?lm of slag; such as borax, contain but since the ?nished product is small and compact the chromium’ is usually present in aconcentration of about ten times that de- 55 2 2,128,089 sired in the ?nal alloy. It is, therefore, desirable powders’ before compressing them. These ‘deoxl that the chromium content in the compacted dizing materials speed up the alloying action with mixture fall within the range of from 1% to 25%‘ the result that an excellent dispersion ‘of the by weight of the ?nished product where it is alloying elements is secured. Where such deoxi desired that the ?nal alloy contain from .1% dizers are employed it is found that the products compacted under the lower pressure are satisfacg to 2.5% by weight of chromium. tory for addition to the melt. Where this invention is-to be employed in mak .Where the metallic product of the compacted ing the copper chromium alloys containing an additional hardener such as‘ silver, as covered in alloying elements, as herelnbefore described, is ' formed, it is easily introduced into the *copper .. 10 Patent No. 2,033,709, issued March 10, 1936, or zirconium or thorium, as covered in'Patent No. melt‘ and the alloying elements are dispersed 2,025,662, issued December 24, 1935, or cadmium, throughout the resulting alloy. By introducing as covered in Patent No. 2,033,710, issued March them inthis manner, oxidation of the alloying elements is prevented, the tendency to segregate 10, 1936, the third alloying element, silver, zir is,lowered and a homogeneous solid product re ll conium, thorium or cadmium, may be addedto 15 ; the copper melt as an integral portion of the sults. It is to be understood that various modi?ca metallic product. This is accomplished by pow tions may be made in the metallic product as dering the third alloying element to approxi mately the same size as that of the copper and above described, without in any way departing 20 chromium powders, and thoroughly intermixing from the spirit of the invention, as set forth in the three powders in the proportions [desired be fore subjecting them to the pressure necessary to give form and coherence to the ?nished product. therappended claims. > Where these alloying elements are added to the 25 mixture of copper and chromium powders, they are added, in general, in approximately the same concentration as the chromium content in the mixture with respect to the amount of the diiler ent alloying elements desired in the ?nal alloy. 30 The 'silver,'-'zirconium, thorium and cadmium ad ditions to the compacted mixture of copper-and chromium powders may be from .1% .to 25% by weight of the ?nished product depending upon the amount of the elements desire'd‘in the alloy. In many ‘cases, it‘is found ‘to be desirable to 35 add slag forming ingredients to the mixed metal ‘ ' We claim as our invention: 1. An article of manufacture for use as an addition agent to molten metal,‘ comprising, a mixture of from 1% to 25%v by weight of chr0 mium powder, not more than 10% by weight of a deoxidizing material with the balance substan tially copper p'owderrthe mixture being sub jected to a su?lciently high pressure .to compact the‘ mixed elements into the desired form. _ 2. An article of r'nanufacture~ for use as an addition agent to molten metal, comprising a mixture of =from‘ 1% 'to 25% by weight of chro mium powder, from .1% to 25% by ‘weight of a- metal powder selected from the hardeners con 85 sisting‘ of silver, zirconium, thorium, and cadmi lic powders in order \to dissolve metallic oxides um powders, from small but e?‘ectivezamounts in the molten bath. Where this is desirable, slag 'up to 10% by weight 'of a'deoxidizing material forming ingredients, such as boric oxide,\b_orax' with the balance substantiallycopper powder, 40 or ?uor spar may be added and intermixed with the mixture being subjected‘ to a su?lciently high the alloying powders before compressing them. ‘pressure to compact ‘thé mixture into the desired Deoxidizing materials, such as calcium,‘ barium, form. boron, beryllium," calcium boride, magnesium, ‘phosphorus or silicon, may also' be added ‘in 4,5 amounts 'up to 10% by weight to the alloying FRANZ R.‘ HENSEL. ‘ EARL "i1. 1LARSEN. as.