|Publication number||US2506518 A|
|Publication date||May 2, 1950|
|Filing date||Jul 28, 1947|
|Priority date||Jul 28, 1947|
|Publication number||US 2506518 A, US 2506518A, US-A-2506518, US2506518 A, US2506518A|
|Inventors||Norris William H|
|Original Assignee||Allegheny Ludlum Steel|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (5), Referenced by (4), Classifications (6)|
|External Links: USPTO, USPTO Assignment, Espacenet|
Patented May 2,1950
STEEL ALLOY CONTAINING COLUMBIUM William H. Norris, Titusville, Pa., assignor to Allegheny Ludlum Steel Corporation, a. corporation of Pennsylvania N Drawing. Application July 28, 1947, Serial No. 764,245
, '7 Claims.
This invention pertains to the improvement of hot working properties of chromium-nickel high alloy steels and, more particularly, of those steels which have copper and molybdenum additions to impart to them special properties. Previous to my invention these steels could be worked only with great difficulty and. great cost and with an extremely poor recovery. Due to my invention, described hereafter in detail, these steels can be produced by ordinary steel mill practice at reasonable cost and with a fair and commercial recovery. This improvement I have been able to make by suitable additions of columbium.
Starting, for example, with even a nine inch ingot which may weigh as little as 750 pounds, it is, from a practical standpoint, impossible to produce steels of the type involved by hammer forging and mill rolling methods to obtain a decent recovery. Corner and face cracking will be prevalent and after grinding out deep defects, the recovery is so small that the steel cannot be produced at a reasonable cost figure. If these steels are made without proper columbium additions, the recovery may be less than a third, and sometimes even much lower, in which event the cost of production will be substantially doubled. Employing the principles of my present invention, a normal recovery of high alloy steel of about twothirds or better of the melted weight can be obtained.
It is an object of my invention to provide a high alloy steel having improved hot working properties.
Another object is to provide an improved form of alloy steel having columbium additions.
A further object of my invention has been to provide a less expensive improved high alloy steel having a columbium content such that the hot physical properties obtained by the addition of the main ingredients of the alloy are favorably efiected thereby.
These and many other objects of my invention will appear to those skilled in the art from the exemplary embodiments thereof, the description, and claims.
By this invention, I have been able to produce austenitic steels of so high a chromium and nickel content that they, in conjunction with other elements, produce a particular type of stainless steel which is resistant to a wide range of acids and other chemicals which lower chromium-nickel steels do not resist at all. These high chromiumnickel steels are always very difficult to produce, but when they are incorporated with other special elements such as are set forth in my examples,
they are almost impossible to produce by ordinary steel methods. They can now be produced by proper columbium additions as indicated in Tables I and II.
My invention pertains particularly to a chromium-nickel steel having a molybdenum, manganese and copper content, as illustrated by the following exemplary table:
TableI Per cent C (maximum) .15 Mn .50- 2.50 Si .30- 3.75 Cr 17.00-23.00 Ni 21.00-25.00 M9 1.50- 5.00 Cu .50- 2.00 S and P, each (maximum) .040- Cb .15- 2.50
Remainder iron The following table is exemplary of two alloy grades within the broader range group previously specified:
Table II Grade A Grade B Per cent Per cent 0 (maximum) Mn Remainder iron For these two grades, I have shown the preferred range of columbium, as based on difierent proportionate amounts of silicon and copper. I have found that a good working percentage of columbium is somewhat intermediate the range or about 1.00% for grade A and about 1.50% for grade B. That is, Within the critical range 01' columbium, I prefer to operate substantially between the upper and lower limits (mean) thereof; this has an additional advantage in that it allows for normal plus and minus deviations in melting range practice. Although up to .15% maximum carbon has been employed, I prefer to use up to about .10% maximum.
The lower columbium limit of the ranges of Tables I and II is the minimum that can be used to produce a noticeable improvement in the hot working of the steel; and it is desirable to have Mag-M more than the minimum to obtain optimum results. The maximum limit of zcolumbium is determined by a number of factors, including a tendency of the columbium to adversely efiect desired characteristics of the particular alloy metal. I have also determined that hot workability does not increase directly in proportion 'to the percentage of columbium and that the percentage of colu bium is determined by the amount of silicon, copper, and other elements of the alloy. Generally speaking, I prefer to employ 3 to 3 /2% molybdenum.
In speaking of a high alloy steel, have refer-- ence to a steel having a minimum chromium content of about 17% and a minimum nickel content of about 21%, see the exemplary-tables in column 2 of the specification. In accordance with my invention, I have provided a copper-bearing high alloy steel of greatly improved workability which is resistant to a wide range of acids and other chemicals. As indicated by the tables in column. 2 the: minimum copper content is about 50%. As previously intimated, it will be apparent that the maximum copper content will be goyerne'd'or determined'by the specified columbium range and the production of a copper-bearing high alloy steel characterized by itshot workability.
Although for the purposeof illustrating my invention I have disclosed two species of alloys within the broader type of alloy, it will be apparent to those skilled in the art that other species can be-employed, other-elements added and normal impurities and tramp additionsmay be present without departing from the spirit and scope of my invention'asindicated by the appended claims.
What I claim is:
1. A steel alloy containing up to about maximum carbon, about .50- to 2.5% manganes .30 to 1.00% silicon, 17.00 to 23.00% chromium, 21.00 to 25.00% nickel, 1.50 to 5.00% molybdenum, .50'to 2.00% copper, .50 to 1.50% colum'bium,'a'nd the balance substantial-ly' aill iron.
2. A steel alloy containing up to about 15 maximum carbon, about. 35033120 2.50% manganese, .30 to.1.00% silicon, 17.00 to. 23.00% chromium, 21.00to 25.00% nickel, 1.50 to 5.00% molybdenum, .50 to. 2.00% copper, up to about 040% maximum each of sulphur and phosphorus, .50 to 1.50% columbium, and the balance substantially all iron.
3. A steel alloy containing up to abo ufi".15%. maximumcarbon, about .50 to 2.50% manganese, 2.00 to 3.75% silicon, 17.00 to 23.00% chromium, 21.00to 25.00% nickel, 1.50 to 5.00% molybdenum, 1.00 t;o'2.00% copper, 1.00 to 2.00% columbium, and the remainder iron.
4:. A steel alloy containing up to' about 15% maximum carbon, about .50 to 2.50% manganese, 2.00 to 3.75% silicon, 17.00 to 23.00% chromium, 21.00 to 25.00% nickel, 1.50 to 5.00% molybdenum, 1.00 to 2.00% copper, up to about 040% maximum each of sulphur and phosphorus, 1.00 to 2.00% columbium, and the remainder iron.
5. steel alloy conta irii'iig about .15% maximum carbon, about 21 -to-2=5% nickel, 1-7 to 23% chromium, .50 to 2.00% copper, .50 to 2.50% manganese, .30 to 3.75% silicon, 1.5 to 5% molybdenum, .15 to 2.5%v columbium, about 04% maximum' of each of the elements sulfur and phosphorus'and the. balance substantially all iron.
6. An auste'nitic-high alloy stainless steel having about 15 maximum carbon, about 21 to 25% nickel, 17 to 23% chromium, about .50 to 2.00% copper, .50 to 2.50% manganese, .30 to 3.75 silicon, 1.50 to 5.00% molybdenum, .15 to 2 .50% columbium, the balance substantially all iron; the nickel, chromium, copper, manganese, silicon, molybdenum; col-umbium and iron all being essential elements, andthe nickel and chromium each being in percentages: such that the percentage of iron predominates the total percentage of the. other essential elements of the that the percentage of iron predominates the total percentage of the other essential elements of the alloy, the alloy being characterized by it's im proved' workability andres'is'tance to a wide range of acids and chemicals.
7 H. NORRIS.
REEERENGE S CITED The-following references are of record in the file of; this patent;
UNITED STATES PATENTS Number- Name Date 2,134,670 Parsons Qct. 25, 1938 2,138,289 i 1938 2,214,128 Q 1940 2,225,730 p 1940 2,447,897 Clarke -1 Aug. 24:, 1948
|Cited Patent||Filing date||Publication date||Applicant||Title|
|US2134670 *||Sep 20, 1938||Oct 25, 1938||Duriron Co||Corrosion resisting ferrous alloys|
|US2138289 *||Jun 11, 1936||Nov 29, 1938||Electro Metallurg Co||Chromium-manganese-nickel steel|
|US2214128 *||May 27, 1939||Sep 10, 1940||Du Pont||Composition of matter|
|US2225730 *||Aug 15, 1939||Dec 24, 1940||Percy A E Armstrong||Corrosion resistant steel article comprising silicon and columbium|
|US2447897 *||May 23, 1946||Aug 24, 1948||Armco Steel Corp||High-temperature stainless steel|
|Citing Patent||Filing date||Publication date||Applicant||Title|
|US2865741 *||Nov 6, 1957||Dec 23, 1958||United States Steel Corp||Acid resistant austenitic stainless steel|
|US4000984 *||Jul 14, 1975||Jan 4, 1977||Gebr. Bohler & Co. Ag||High silicon-containing austenitic-iron-chromium-nickel alloys|
|US4824638 *||Apr 1, 1988||Apr 25, 1989||Carondelet Foundry Company||Corrosion resistant alloy|
|WO1989000209A1 *||Jun 28, 1988||Jan 12, 1989||Carondelet Foundry Co||Corrosion resistant alloy|
|U.S. Classification||420/45, 420/582, 420/49|