US3907551A - Corrosion resistant austenitic steel - Google Patents

Corrosion resistant austenitic steel Download PDF

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US3907551A
US3907551A US355394A US35539473A US3907551A US 3907551 A US3907551 A US 3907551A US 355394 A US355394 A US 355394A US 35539473 A US35539473 A US 35539473A US 3907551 A US3907551 A US 3907551A
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copper
nitrogen
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Iii Albert G Hartline
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Allegheny Ludlum Corp
Pittsburgh National Bank
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    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N

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  • the steel includes from 15-45% manganese, from 10-30% chromium, from l3% copper, from 0.853% nitrogen, from 0-2% silicon, from 01% carbon, and the balance iron and residuals.
  • the alloys must be such that:
  • Corrosion resistant steels known as stainless steels have long been known and are presently available with a variety of properties.
  • Austenitic stainless steels which are those consisting substantially of asingle austenite phase, possess the best properties of corrosion resistance and good mechanical properties, particularly at high temperature.
  • Austenitic stainless steels in the past have been steels in which chromiumand nickel are the principal alloying agents.
  • nickel is not an abundant metal and the increased demand for it has increasedits price and made its supply uncertain, particularly in critical times.
  • Substitutes for nickel in the chromium-nickel austenitic stainless steels have long been sought.
  • Recently the combined use of manganese andnitrogen along with chromium in carefully limited ratios has produced an austenitic stainless steel. In that steel, at least 0.85% nitrogen is required to produce the austenitic structure but large amounts of'nitrogen cause the steel ingot to be porous. Accordingly, it has been found that the nitrogen content of such a steel must be limited to less than 3%.
  • the manganese in the above-noted steel must be present inamounts of from 15-45%. Manganese is necessary to increase the solubility of nitrogen in steel, in addition to itself contributing to the austenitic structure. I i
  • chromium-manganese-nitrogen stainless steel is an excellant austenitic stanless steel, it has been found to be subject to attack by sulfuric acid to a significant extent and accordingly its use is limited to those environments where sulfuric acid is not present.
  • the present invention is a chromium-manganesecopper-nitrogen alloy that is non-porous, austenitic, and highly resistant to attack by sulfuric acid.
  • the alloy of this invention contains from 1'5-45 manganese, from 10-30% chromium, from l-3% copper, from 0.853% nitrogen, from -2% silicon, from 0l% carbon, and the balance iron and residuals Residuals are impurities in the iron that are not deliberately added to the alloy and have no significant detrimental effect in the alloy.
  • chromium In the alloys of the presentinvention, chromium must be present to produce the.”same effect that it does in prior art alloys.
  • the alloys of this invention must con-- tain from 10-30% chromium- At least 10% chromium is required to give the steel its outstandingcorrosion resistance.
  • Chromium also has a secondary effect upon the strength Of the steel and is a primary element; in increasing the steels solubility for nitrogen. When more than chromium is present in the alloy, a ferrite phase is formed which degrades the mechanical properties of the steel and accordingly more tha 30% chromium should not be present.
  • a preferred chromium content is in the range from 15 -27% in that steels containing this range of chromium are easy to process Manganese in excess of produces no further beneficial effectand should be avoided as wasteful and because large quantities of manganese in an alloy tend to attack furnace refractories.
  • Nitrogen is a strong austenitizer and should be present in the steel in amounts from 0.85 -3%. At least 0.85% is requiredto provide the austenitic structure of the steel while amounts of nitrogen in excess of 3% tend to yield porous ingots which are not-satisfactory.
  • the nitrogen content of the alloy of this invention preferably is from 1.05 1.5%.
  • the copper content of the alloy of this invention must be between 1 3%.
  • copper has been known as an alloy additive to increase resistance to sulfuric acid attack, it has in the past been used in nickelcontaining alloys and in large amounts.
  • the copper of previously known acid-resistant alloys has caused a sacrifice in other properties.
  • relatively'little copper is effective to produce the sulfuric acid resistant alloy, and the alloys of this invention have substantially the same mechanical properties as their counterparts containing no copper or only residual amounts.
  • alloys of this invention containing up to 1.5% copper have been found to be hot-workable so that they may be rolled,'forged or otherwise shaped and their'properties altered for specific uses that could not be readily obtained in the as-cast condition.
  • Carbom of course, is a well-known austenitizer and strengthener for steels and. is employed in the alloys of this invention in amounts up to 1%.
  • the concentration of carbon must be maintained below that level in that larger amounts remove chromium from the solid solu-. tion by forming chromium carbide, which requires higher annealing temperatures to dissolve the carbide. It is preferred that less than 0.15% carbon be present inthe alloy of this invention. 1 r
  • the alloys of the present invention may tolerate silicon concentrations as high as 2% but preferably the silicon is below 1%. Higher quantities of silicon tend to remove manganese from the alloy in the form of mariganese silicates and tend to form inclusions in the steel.
  • the residuals in the iron need not be identified and do not significantly affect the properties of the alloy, the usual residuals maybe identified as molybdenum, phosphorus, sulfur, tungsten, cobalt and nickel.
  • the stainless steel composition of this invention is desirably a substantially one-phase austenitic material, thermal treatments that tend to precipitate other phases .should beavoided.
  • the method ofpreparation employed should avoid long dwell periods in the 1000-l600F temperaturerange. Long dwelll periods would be characterized by furnace cooling. Air cooling or quenching are sufficient to carry the alloy through the 10001600F range for ordinary thicknesses quickly enough to avoid precipitation of detrimental phases such as sigma phase.
  • the accompanying drawing is a plot of the 1.0% nitrogen section of the iron-chromium-manganesenitrogen quaternary phase diagram of an alloy that also contains 1% copper.
  • line l-A Copper does not have a significant effect on austenitic structure and accordingly doesnt appear as a factor in equation (1) dry forth above, which defines the line l-A of the drawing.
  • the area above line l-A generally represents compositions where a two-phase alloy of austenite and ferrite exist. As mentioned above, this two-phase system is undesirable because it does not have the good mechanical or chemical properties of a single phase austenitic alloy.
  • the area below line l-A is a single phase austenitic alloy.
  • Equation (2) defines the line 2-B.
  • the area below the line 2-B represents compositions where nitrogen comes out of solution during solidification and creates porous ingots.
  • the area above line 2-B is where nitrogen remains in solution during solidification and non-porous ingots are formed.
  • the area A-C-B therefore represents the area in which the alloys of this invention fall for this particular cross section of the quaternary phase diagram.
  • Lines LA and 2-B are the best lines to represent mildly scattered data obtained from analysis of 26 heats which included a significant number in the porous ingot zone, in the two-phase austenite-ferrite zone and in the onepha'se non-porous austenite zone.
  • Alloy l is not an alloy in accordance with this invention because its copper content is substantially below 1% and in fact is at the residual level. All other alloys are within the scope of this invention containing nominally 1%, 2% and 3% copper.
  • Ingots of alloys .1 and 2 were hot rolled, annealed at 1950F for a period of 60 minutes per inch of cross section thickness, were then cold rolled to a 50% thickness reduction and finally annealed again at 1950F for a period of 60 minutes per inch of thickness.
  • the annealed strips were never furnace cooled in order to bring them through the lO0-1600F temperature range slowly and as a result the finally rolled, annealed strips were austenitic.
  • the strips were cleaned by the usual techniques, a number of specimens taken from each and their properties measured.
  • the mechanical properties of alloys 1 and 2 are set forth in Table Two.
  • Specimens of alloy 1 and 2 were subjected to standard corrosion testing to measure their resistance to sulfuric acid. Resistance of an alloy to sulfuric acid is measured by exposing an alloy specimen in sulfuric acid and obtaining both the anodic polarization data and 1 the cathodic polarization data and determining theirintersection point on the same plot of voltage versus current. A correlation is known to exist between the intersection points of these lines and the resistance of the specimen to sulfuric acid corrosion. Intersection of these lines at lower current flows indicates better resistance to sulfuric acid.
  • Table Three contains data obtained in the foregoing test on specimens of alloy 1 and alloy 2.
  • the resistance to sulfuric acid corrosion was measured at three different sulfuric acid concentrations, namely, 1.0 normal, 5.0 normal and 10 normal.
  • composition is such that:
  • Table Three indicates that an alloy of this invention 0 r a l) with a minimum copper concentration, 1%, has signifi- %Cr M 88(%N Q1) (285 cantly greater resistance to sulfuric acid than the prior %Cu) 2 0 (2) art alloys containing only residual amounts of copper.
  • a hot workable alloy in accordance with claim 1 The two order of magnitude difference in intersection mpri ing o abOUt l -5 copper.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
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  • Metallurgy (AREA)
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  • Heat Treatment Of Steel (AREA)

Abstract


D R A W I N G
A substantially non-porous, sulfuric acid resistant austenitic stainless steel and a method for making it are disclosed. The steel includes from 15-45% manganese, from 10-30% chromium, from 1-3% copper, from 0.85-3% nitrogen, from 0-2% silicon, from 0-1% carbon, and the balance iron and residuals. In addition to containing the foregoing elements within the above-noted composition ranges, the alloys must be such that:

Description

[ Sept. 23, 1975 CORROSION RESISTANT AUSTENITIC STEEL [75] Inventor: Albert G. Hartline, III,
Brackenridge, Pa.
Allegheny Ludlum Industries, lnc., Pittsburgh, Pa.
22 Filed: Apr. 30, 1973 21 Appl. No.: 355,394
[73] Assignee:
[52] U.S.'Cl 75/122; 75/125; 75/126 .1 [51] Int. Cl C22c 39/14; C22c 39/26 [58] Field of Search 75/125, 122, 126 .I
[56] References Cited UNITED STATES PATENTS 2,184,305 12/1939 Kropt 75/125 2,198,598 4/1940 Becket..... 2,850,380 9/1958 Clarke 75/125 2862812 12/1958 Dulis 75/125 3,112,195 11/1963 Souresny 75/125 FOREIGN PATENTS OR APPLICATIONS 778.597 7/1957 United Kingdom 75/126 R Primary ExaminerL. Dewayne Rutledge Assistant Examiner-Arthur J. Steiner Attorney, Agent, or Firm-Vincent G. Gioia; Robert F. Dropkin [5 7] ABSTRACT A substantially non-porous, sulfuric acid resistant austenitic stainless steel and a method for making it are disclosed. The steel includes from 15-45% manganese, from 10-30% chromium, from l3% copper, from 0.853% nitrogen, from 0-2% silicon, from 01% carbon, and the balance iron and residuals. In addition to containing the foregoing elements within the above-noted composition ranges, the alloys must be such that:
30 (%C %N) 0.5 (%Mn) 1 5 %Cr+ 1.5 (%Si) (2) %Cr+ 0.8 (%Mr1) 11.88 (%N 0.1) (28.5 %Cu) 5 0 i 7"Claims, 7 Drawing Figures BACKGROUND or THE 'INVENT'IQN,"
Corrosion resistant steels known as stainless steels have long been known and are presently available with a variety of properties. Austenitic stainless steels, which are those consisting substantially of asingle austenite phase, possess the best properties of corrosion resistance and good mechanical properties, particularly at high temperature.
Austenitic stainless steels in the past have been steels in which chromiumand nickel are the principal alloying agents. However, nickel is not an abundant metal and the increased demand for it has increasedits price and made its supply uncertain, particularly in critical times. Substitutes for nickel in the chromium-nickel austenitic stainless steels have long been sought. Recently the combined use of manganese andnitrogen along with chromium in carefully limited ratios has produced an austenitic stainless steel. In that steel, at least 0.85% nitrogen is required to produce the austenitic structure but large amounts of'nitrogen cause the steel ingot to be porous. Accordingly, it has been found that the nitrogen content of such a steel must be limited to less than 3%. Throughout the specification and claims all references to percent in composition shall be percent by weight of the total composition.
The manganese in the above-noted steel must be present inamounts of from 15-45%. Manganese is necessary to increase the solubility of nitrogen in steel, in addition to itself contributing to the austenitic structure. I i
Although the chromium-manganese-nitrogen stainless steel is an excellant austenitic stanless steel, it has been found to be subject to attack by sulfuric acid to a significant extent and accordingly its use is limited to those environments where sulfuric acid is not present.
SUMMARY OF THE INVENTION The present invention is a chromium-manganesecopper-nitrogen alloy that is non-porous, austenitic, and highly resistant to attack by sulfuric acid. The alloy of this invention contains from 1'5-45 manganese, from 10-30% chromium, from l-3% copper, from 0.853% nitrogen, from -2% silicon, from 0l% carbon, and the balance iron and residuals Residuals are impurities in the iron that are not deliberately added to the alloy and have no significant detrimental effect in the alloy.
In addition to the forgoing ranges, the c'ompo' siton of the alloys must be balanced in accordance withthe following equations: 7
%Cu) 2 0 g I (2) In the alloys of the presentinvention, chromium must be present to produce the."same effect that it does in prior art alloys. The alloys of this invention must con-- tain from 10-30% chromium- At least 10% chromium is required to give the steel its outstandingcorrosion resistance. Chromium also has a secondary effect upon the strength Of the steel and is a primary element; in increasing the steels solubility for nitrogen. When more than chromium is present in the alloy, a ferrite phase is formed which degrades the mechanical properties of the steel and accordingly more tha 30% chromium should not be present. A preferred chromium content is in the range from 15 -27% in that steels containing this range of chromium are easy to process Manganese in excess of produces no further beneficial effectand should be avoided as wasteful and because large quantities of manganese in an alloy tend to attack furnace refractories.
Nitrogen is a strong austenitizer and should be present in the steel in amounts from 0.85 -3%. At least 0.85% is requiredto provide the austenitic structure of the steel while amounts of nitrogen in excess of 3% tend to yield porous ingots which are not-satisfactory. The nitrogen content of the alloy of this invention preferably is from 1.05 1.5%.
The copper content of the alloy of this invention must be between 1 3%. Although copper has been known as an alloy additive to increase resistance to sulfuric acid attack, it has in the past been used in nickelcontaining alloys and in large amounts. The copper of previously known acid-resistant alloys has caused a sacrifice in other properties. In the present invention relatively'little copper is effective to produce the sulfuric acid resistant alloy, and the alloys of this invention have substantially the same mechanical properties as their counterparts containing no copper or only residual amounts. In fact, alloys of this invention containing up to 1.5% copper have been found to be hot-workable so that they may be rolled,'forged or otherwise shaped and their'properties altered for specific uses that could not be readily obtained in the as-cast condition.
Carbom of course, is a well-known austenitizer and strengthener for steels and. is employed in the alloys of this invention in amounts up to 1%. The concentration of carbon must be maintained below that level in that larger amounts remove chromium from the solid solu-. tion by forming chromium carbide, which requires higher annealing temperatures to dissolve the carbide. It is preferred that less than 0.15% carbon be present inthe alloy of this invention. 1 r
The alloys of the present invention may tolerate silicon concentrations as high as 2% but preferably the silicon is below 1%. Higher quantities of silicon tend to remove manganese from the alloy in the form of mariganese silicates and tend to form inclusions in the steel.
Although the residuals inthe iron need not be identified and do not significantly affect the properties of the alloy, the usual residuals maybe identified as molybdenum, phosphorus, sulfur, tungsten, cobalt and nickel.
Since the stainless steel composition of this invention is desirably a substantially one-phase austenitic material, thermal treatments that tend to precipitate other phases .should beavoided. Although the alloys of this invention are not particularly sensitive to precipitation of other phases, the method ofpreparation employed should avoid long dwell periods in the 1000-l600F temperaturerange. Long dwelll periods would be characterized by furnace cooling. Air cooling or quenching are sufficient to carry the alloy through the 10001600F range for ordinary thicknesses quickly enough to avoid precipitation of detrimental phases such as sigma phase.
DETAILED DESCRIPTION OF THE INVENTION The accompanying drawing is a plot of the 1.0% nitrogen section of the iron-chromium-manganesenitrogen quaternary phase diagram of an alloy that also contains 1% copper.
Copper does not have a significant effect on austenitic structure and accordingly doesnt appear as a factor in equation (1) dry forth above, which defines the line l-A of the drawing. The area above line l-A generally represents compositions where a two-phase alloy of austenite and ferrite exist. As mentioned above, this two-phase system is undesirable because it does not have the good mechanical or chemical properties of a single phase austenitic alloy. The area below line l-A is a single phase austenitic alloy. I
Equation (2) defines the line 2-B. The area below the line 2-B represents compositions where nitrogen comes out of solution during solidification and creates porous ingots. The area above line 2-B is where nitrogen remains in solution during solidification and non-porous ingots are formed.
The area A-C-B therefore represents the area in which the alloys of this invention fall for this particular cross section of the quaternary phase diagram. Lines LA and 2-B are the best lines to represent mildly scattered data obtained from analysis of 26 heats which included a significant number in the porous ingot zone, in the two-phase austenite-ferrite zone and in the onepha'se non-porous austenite zone.
To demonstrate the benefits of this invention, four alloys were prepared having compositions set forth in Table One.
TABLE ONE Alloy l is not an alloy in accordance with this invention because its copper content is substantially below 1% and in fact is at the residual level. All other alloys are within the scope of this invention containing nominally 1%, 2% and 3% copper.
All heats were melted in an air induction furnace and cast to ingot form without the occurrence of ingot porosity. Microscopic examination of specimens from each ingot revealed that all had austenitic structure. Alloys 3 and 4 showed some segregation of copper at interdendritic regions. When alloys 3 and 4 were hot rolled, they cracked in the manner of hot shortness.
Ingots of alloys .1 and 2 were hot rolled, annealed at 1950F for a period of 60 minutes per inch of cross section thickness, were then cold rolled to a 50% thickness reduction and finally annealed again at 1950F for a period of 60 minutes per inch of thickness. The annealed strips were never furnace cooled in order to bring them through the lO0-1600F temperature range slowly and as a result the finally rolled, annealed strips were austenitic. The strips were cleaned by the usual techniques, a number of specimens taken from each and their properties measured. The mechanical properties of alloys 1 and 2 are set forth in Table Two.
TABLE TWO PROPERTIES ALLOY 1 ALLOY 2 Tensile strength as annealed 0.2% yield Strength (KS1) longitudinal 97.5-99.2 1083-1089 transverse 982-1005 ll 1.4-1 1 1.6 Ultimate tensile strength (KS1) longitudinal 146.1l46.4 l52.8-152.9 transverse 147.7-149.2 l56.0-157.3 Elongation longitudinal 50-52 44-46 transverse 45-50 44.5-46 Hardness (Rockwell) 28 31 Tensile strength after cold reduction of annealed strip 10% reduction 0.2% yield strength (KS1) longitudinal 158.2-1 62.0 121 .9-1 26.9 transverse 151.4151.8 119.6-1 19.9 Ultimate tensile strength KS1) longitudinal 186.6-187.9 163.6-163.7 transverse 184.7-l91.2 163.0163.1 Elongation longitudinal 28-30 36-38 transverse 27.5-30 37.5-38 Hardness (Rockwell) 40 36.5 25% reduction 7 0.2% yield strength (KS1) longitudinal 201 .9204.4 191 .9-192.6 transverse 193.0-194.8 183.3-183.8 Ultimate tensile strength (KSI) longitudinal 21 8.82l9.4 215.9- 217.0 transverse 222.4-224.2 2l5.42l8.8 Elongation longitudinal 18- l 9.5 18 transverse 13-155 16 Hardness (Rockwell) 46 45.5 50% reduction 0.2% yield strength (KSI) longitudinal 256.5-263.8 254.0-256.5 transverse 246.7-250.3 224.6-226.1 Ultimate tensile strength KS1) longitudinal 275.3283.8 276.6277.0 transverse 288.6-289.6 262.7264.6 Elongation v longitudinal 7-7.5 3-4 transverse 8.0 7.5-8.0 Hardness (Rockwell) 49.8 49.5 Strain Hardening Exponent 0.36 0.36
From the data in Table Two it is evident that alloys of this invention with a copper content of 1% are capable of being worked. It is also evident that the presence of copper in the alloy has no significant effect on the mechanical properties, of the worked alloy.
Specimens of alloy 1 and 2 were subjected to standard corrosion testing to measure their resistance to sulfuric acid. Resistance of an alloy to sulfuric acid is measured by exposing an alloy specimen in sulfuric acid and obtaining both the anodic polarization data and 1 the cathodic polarization data and determining theirintersection point on the same plot of voltage versus current. A correlation is known to exist between the intersection points of these lines and the resistance of the specimen to sulfuric acid corrosion. Intersection of these lines at lower current flows indicates better resistance to sulfuric acid.
Table Three contains data obtained in the foregoing test on specimens of alloy 1 and alloy 2. The resistance to sulfuric acid corrosion was measured at three different sulfuric acid concentrations, namely, 1.0 normal, 5.0 normal and 10 normal.
TABLE THREE acid or to attack by chlorides than alloy 2. What is claimed is: 1. An alloy consisting essentiall of about 15-45% manganese, about -30% chromium, about l3% Anodic-cfllhodic Polarization 5 copper, about OBS-3% nitrogen, about 0-l% carbon, m N H250 'mersecuon about 0-2% silicon and the balance iron and residuals ALLOY 1 ALLOY 2 at (milliamp/cm") 5.0 .012
5.0 N H so, intersection wherein the composition is such that:
at (milliamp/cm 9.0 .012
10.0 N H.2804 intersection at (milliamp/cm 1.50
Table Three indicates that an alloy of this invention 0 r a l) with a minimum copper concentration, 1%, has signifi- %Cr M 88(%N Q1) (285 cantly greater resistance to sulfuric acid than the prior %Cu) 2 0 (2) art alloys containing only residual amounts of copper. A hot workable alloy in accordance with claim 1 The two order of magnitude difference in intersection mpri ing o abOUt l -5 copper.
points represents a very significant difference in sus- An ll y in ac o a ce ith claim 1 comprising ceptibility to sulfuric acid corrosion. The intersection 21-30 nganesepoint of alloy 1 was not measured in the 10 normal sul- 4. An alloy in accordance with claim 1 comprising furic acid solution because the current at which the in- 15-27% chromium. tersection occurred would be too large to be meaning- 5. An alloy in accordance with claim 1 comprising ful. 105-1 .5% nitrogen.
When subjected to tests to measure susceptibility of 6. An alloy in accordance with claim 1 comprising the alloys to chloride pitting, it was found that both 00.15% carbon. alloy 1 and alloy 2 have high resistance to chloride pit- 7. An alloy in accordance with claim 1 comprising ting and are about equivalent in this regard. 0-l% silicon.
Alloys 3 and 4 are more resistant to attack by sulfuric

Claims (7)

1. AN ALLOY CONSISTING ESSENTIAL OF ABOUT 15-45% MANGANESE, ABOUT 10-30% CHROMIUM, ABOUT 1-3% COPPER, ABOUT 0.85-3% NITROGEN, ABOUT 0-1% CARBON, ABOUT 0-2% SILICON AND THE BALANCE IRON AND RESICUALS WHEREIN THE COMPOSITION IS SUCH THAT:
2. A hot workable alloy in accordance with claim 1 comprising from about 1-1.5% copper.
3. An alloy in accordance with claim 1 comprising 21-30% manganese.
4. An alloy in accordance with claim 1 comprising 15-27% chromium.
5. An alloy in accordance with claim 1 comprising 1.05-1.5% nitrogen.
6. An alloy in accordance with claim 1 comprising 0-0.15% carbon.
7. An alloy in accordance with claim 1 comprising 0-1% silicon.
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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1069202A1 (en) * 1999-07-15 2001-01-17 Schoeller-Bleckmann Oilfield Technology GmbH & Co KG A paramagnetic, corrosion resistant austenitic steel with high elasticity, strength and toughness and a process for its manufacture
US20080000554A1 (en) * 2006-06-23 2008-01-03 Jorgensen Forge Corporation Austenitic paramagnetic corrosion resistant material

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2184305A (en) * 1935-04-08 1939-12-26 Kropf Alfred Corrosion-resistant chromium-manganese-iron alloys
US2198598A (en) * 1938-11-03 1940-04-30 Electro Metallurg Co Austenitic alloy steel
US2850380A (en) * 1957-03-04 1958-09-02 Armco Steel Corp Stainless steel
US2862812A (en) * 1958-05-16 1958-12-02 Crucible Steel Co America Substantially nickel-free austenitic and corrosion resisting cr-mn-n steels
US3112195A (en) * 1959-06-04 1963-11-26 Schoeller Bleckmann Stahlwerke Drill stems for deep-well drill rods from non-magnetizable austenitic manganese-chromium alloy steels

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2184305A (en) * 1935-04-08 1939-12-26 Kropf Alfred Corrosion-resistant chromium-manganese-iron alloys
US2198598A (en) * 1938-11-03 1940-04-30 Electro Metallurg Co Austenitic alloy steel
US2850380A (en) * 1957-03-04 1958-09-02 Armco Steel Corp Stainless steel
US2862812A (en) * 1958-05-16 1958-12-02 Crucible Steel Co America Substantially nickel-free austenitic and corrosion resisting cr-mn-n steels
US3112195A (en) * 1959-06-04 1963-11-26 Schoeller Bleckmann Stahlwerke Drill stems for deep-well drill rods from non-magnetizable austenitic manganese-chromium alloy steels

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1069202A1 (en) * 1999-07-15 2001-01-17 Schoeller-Bleckmann Oilfield Technology GmbH & Co KG A paramagnetic, corrosion resistant austenitic steel with high elasticity, strength and toughness and a process for its manufacture
US6454879B1 (en) * 1999-07-15 2002-09-24 Schoeller-Bleckman Oilfield Technology Gmbh & Co. Kg Process for producing a paramagnetic, corrosion-resistant material and like materials with high yield strength, strength, and ductility
US20080000554A1 (en) * 2006-06-23 2008-01-03 Jorgensen Forge Corporation Austenitic paramagnetic corrosion resistant material

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