US1357550A - Chemical ware or technical apparatus and alloys for making same - Google Patents

Description

UNITED STATES;

jmrm OFFICE.

FRANK A. or cLnvnLANb, omo.- CHEMICAL WARE oavrncnmien. ,nrzia'Artis AND ALLoYs non MAKING sAmn.

No Drawing.

T 0 all whom it may concern:

Be it known that I, F RANK A. FAHRnN- WALD, a citizen of the United States, residing at Cleveland, in the county of Cuya-- and has for itsobject the provision of an inexpensive, chemically resistant alloy for the construction oftanks, valves, pipes, fittings, evaporation pans, stirrer-s, and the like which shall be sufficiently strong to resist accidental breakage, and also soft enough to permit being machined to shape. All such devices I include under the term chemical apparatus.

In the production and manipulation of acids, corrosive salts, and some alkalis it is impossible to employ ordinaryfmetals for the parts named because of the contamination of the product and the corrosion of the apparatus. Gold, palladium and platinum are prohibitively expensive; glassand porcelain are subject to breakage as well as being difficult to machine or fit together; and even lead, which is used for some purposes, igmechanically weak. My improved alloy herein described avoids all these difficulties and possesses an extremely high chemical resistivity. My improved alloy consists essentially of chromium, an iron group metal,

and a second metal from the chromium group. Carbon and silicon may be present but their quantity should be small since otherwise the alloy will be unduly hard. Tungsten is more resistant chemically than molybdenum when equal atomic proportions are considered, but molybdenum alloys are the more workable and when used in equal weight-percentages the molybdenum has the greater chemical effect owing to its smaller atomic weight which causes the presence of almost twice the number of molecules in a given weight. v

For the iron group metal I usually employ iron because of its peculiar availability and its low cost but from a chemical standpoint either nickel or cobalt is superior and of these nickel is the best. Indeed the very best alloy from the chemical standpoint i composed of nickel and tungsten,- each of which is the most resistant chemically of spiaciflcatlon of Letters Patent. Application filed Angnst 25, 1919. Serial No. 319,821.

' the members of their respective groups, oombmed with enough chromium to constitute A B o n Chromium so 55 e0 (40-60) Iron roup metal 20 25 30 (10-40) Moly denum like metal 20 20 10 (10-20) C aybon Less than 1 Silicon Less than 1 0 Column A gives the alloy that appears to be the most resistant chemically of any I have investigated. 7 Columns B and C give the compositions which are most easily made when the iron group metal employed is iron. Column D indicates the limits of favorable composition.

The alloys can be made in any convenient manner and no especial precautions are necessary except to keep the carbon and silicon low. Thus any of the alloys can be made by melting the pure ingredients in an electric or other furnace out of contact with carbon. Owing to the fact that chromium generally occurs in connection with iron as in chromite ore, (FeCr OQ it is most con- 'veniently obtained in the form of ferro chrome, which is an alloy of approximately iron 34.5 and chromium 65.5, along with small quantities of"carbon -and silicon. If suitable precautions are observed in the reduction, such as the employment of the alumino-thermic process or that rocess explained in my application filed Ju y 13, 1920' Ser. No. 1,346,187, the presence of carbon and silicon can be almost entirely avoided, and in fact by other known methods these can bebrought suficiently low to ,pro-

duce a workable alloy. It ,is merely necessary to add metallic tungsten or molybdenum to such molten ferro-chrome to produce the alloys shown in columns B and C, and for this reason I esteem these most highly, notwithstanding the greater IGSlStlVr Patented Nov. 2, 1920.

ertain ity of the nickel alloy. I do not restrictmyself to such a small proportion of carbon and silicon as shown in the preferred example, since somewhat larger quantities will not interfere with the use of the alloy for most purposes, and such alloys can be made more cheaply.

It will be understood that other ingredients ma be added Within the scope of my invention and that changes may be made within the scope and purview of m claims. It will also be understood that donot confine myself to the use of only one iron group metal or only one molybdenum like metal in my improved alloy.

Having thus described my invention what I claim is 1'. An alloy for the purpose described containing. 40% to 60% of chromium together with 10% to 20% of one or more other metals of the chromium group, the balance consisting principally of one or more iron group metals.

2. An alloy for the purpose described consisting essentially of ferro-chrome With the addition of ten to twenty per cent. of molybdenum-like metal.

3. An alloy for the purpose described, containing a preponderance of chromium, an iron group metal, and at least ten per cent. of a second metal from the chromium group.

4. An alloy for the purpose described containing a preponderance of chromium, and at least ten per cent. each of a metal or metals from the iron group and of another metal or metals from the chromium group.

5. Chemical apparatus made of an alloy containing 40 to 60 per cent. of chromium, together with 10 to 20 per cent. of-one or more other metals of the chromium grou and 10 to 20 per cent. of one or more meta s from the iron group.

6. Chemical apparatus made of an alloy consisting essentially of ferro-chrome with the addition of ten to twenty per cent. of a molybdenum-like metal.

containing a preponderance of chromium, an-

iron group metal, and at least ten per cent. of a second metal from the chromium group. 10. Chemical apparatus made of an alloy containing chromium, iron, and a molybdenum-like metal, each of the last two being present to a proportion of at least about ten per cent, and the chromium being presentto a proportion at least as great as either of the other metals.

11. The process of making a chemically resistant metallic alloy which contains the steps of first reducing chromite ore and second adding from ten to twenty percent. of a molybdenum like metal to the molten prodnet of such reduction.

12. An alloy for the purpose described containing nickel, chromium, and tungsten,

' FRANK A. FAHRENWALD.