SE453998B - AUSTENITIC STAINLESS STEEL - Google Patents

Description

15 25 to 55 453 998 F.) n.

U.S. Pat. No. 3,989 HYU, assigned from U.S. Pat. No. 3,9U,0266, discloses hot rolled stainless steel rods and rods, cold drawn wire and strand-like articles consisting essentially of 0.06 - 0.12% carbon, 11 - 1U% manganese, up to 0.06% phosphorus, up to 0.04% sulfur, up to 1% silicon, 15.5 - 20% chromium, 1.1 - 2.5% nickel, 0.20 - 0.38% nitrogen and the rest iron in addition to accidental contamination. Again, these products exhibit substantially complete austenitic structure and have low magnetic permeability in cold-reduced form.

U.S. Pat. No. 2,778,731 discloses an austenitic steel consisting of 0.06 - 0.15% carbon, 1U - 20% manganese, 0.25 - 1.0% silicon, 17 - 18.5% chromium, 0.05 - 1.00% nickel, 0.25 - 1.0% nitrogen and the rest iron.

British Patent Specification 995 068 describes an austenitic stainless steel consisting of from a trace amount up to 0.12% carbon, 5 - 8.5% manganese, not more than 2.0% silicon, 15.0 - 17.5% chromium, 5.0 - 6.5% nickel, 0.75 - 2.5% copper, from a trace amount to 0.10% nitrogen, and the remainder iron, the components being regulated so that the martensite-forming property is less than 10% in according to a formula and the delta-ferrite-forming properties are less than 10% according to a formula. The copper content is related to the manganese content. the steel according to this patent specification is stated to indicate high austenite stability and a low degree of deformation hardening, due to the avoidance of conversion to martensite during cold working.

"Allegeny" type 211 is an austenitic stainless steel with a low degree of deformation hardening, used for deep drawing.

Its nominal composition is 0.05% carbon, 6.0% manganese, 17.0% chromium, 5.5% nickel 1.5% copper and the rest iron.

"Al1egeny" type 205 is an austenitic stainless steel containing 0.12 - 0.25% carbon, 1H, 0 - 16.0% manganese, 0.2 - 0.7% silicon, 16 - 18% chromium, 1.1 - 2.0% nickel, 0.32 - 0, H0% nitrogen and the rest essentially iron.., ..._.. - ._ .. d 10 15 20 25 50 55 455 998 \.

Other descriptions of austenitic stainless steels with relatively low nickel levels appear in U.S. Patent Nos. 2,820,725, 3,151,979, 3,192 ou1 and British Patent Nos. 882,893.

As can be seen from the above prior art, the desire to minimize the amount of nickel in austenitic stainless steels, with its attendant high cost, has led those skilled in the art to replace it with relatively high amounts of manganese, copper, carbon and / or nitrogen. Although these are less expensive than nickel, manganese and copper are in themselves relatively expensive alloying elements, and excessive amounts of them, especially when used in combination, will result in hot working problems. With the exception of U.S. Pat. Nos. 3,910,266 and 5,989,470, the techniques mentioned above generally have low strength and steel as previously exhibited a low degree of deformation hardening. In addition to cost, the most important point of view is the achievement of austenite stability and the maintenance of corrosion resistance.

A main object of the present invention is to obtain an austenitic steel with relatively low levels of controllable alloy ingredients, which at the same time exhibits high strength, excellent abrasion resistance, good formability and good heat workability, together with satisfactory corrosion resistance.

A further object of the invention is to obtain a stainless steel having an austenitic structure at hot rolling temperature of such stability that a very small amount, if any (usually not more than 1%) is converted to martensite (thermal martensite) during cooling, but as in cold rolling forms deformation martensite.

The above objects are obtained in the steel of the present invention by a critical balancing of the percentage ranges of the essential elements manganese, chromium, nickel, copper and nitrogen, and by regulating the austenite stability by an instability factor (IF) in the range between 10 15 20 25 455 998 2.5 and 8.5 according to the equation: IF = 37.2 - 51.25 (% C) ~ 2.59 (% Ni) - 1.02 (% Mn) - 0.47 ( % cr) - 34.4 (% N) - 3 (% cu).

Reference is made below to the accompanying drawings, in which Figure 1 is a state diagram showing the composition ranges in terms of nickel equivalent to chromium equivalent, and Figure 2 is a graphical representation of the relationship between instability factor and percentage of ferrite and / or martensite.

Thus, in accordance with the invention, an austenitic stainless steel having high strength, superior abrasion resistance, good heat workability, good extensibility and high degree of deformation hardness is obtained, which steel is characterized in that it consists essentially of, by weight, 0.02-0. 06% carbon, 6.0-9.0% manganese, maximum 0.06% phosphorus, maximum 0.06% sulfur, maximum 1.0% silicon, 13.0-17.0% chromium, from 1.0 to less than 3.0% nickel, 0.5-0.85% copper, 0.15-0.25% nitrogen and the remainder essentially iron, the steel having a nickel equivalent in the range 12-15, calculated according to the equation : nickel equivalent =% Ni + 30 (% C) + 0.5 (% Mn) + 30 (% N) + 0.5 (% Cu) and a chromium equivalent in the range 14-17, calculated by the equation: chromium equivalent = % Cr +% Mo + 1.5 (% Si ¥ + 0.5 (% Nb).

The percentages and proportions of the essential elements manganese, chromium, nickel, copper and nitrogen are critical in each respect, and deviation therefrom results in the loss of one or more of the desired properties. Even if they are less critical, the carbon and silicon contents are still important in achieving the desired combination of properties.

Manganese is essentially a partial replacement for nickel as an austenite former and austenite stabilizer. A minimum of 5.5%, preferably 6.0% and especially 7.0% is necessary for this purpose. A maximum of 10.0%, preferably 9.0% and especially 8.5% manganese, should be observed and 453 998 Since higher levels reduce the degree of deformation hardening the strength levels. In addition, high manganese content results in combination with relatively high copper levels in hot working problems., Chromium is essential for its usual function of achieving corrosion resistance, and a minimum of 12.5% preferably 13.0% and especially 1H, 75% is essential for this purpose. A maximum of 20.0%, preferably 17.0% and especially 15.50%, must be observed to balance the ferrite-forming potential in relation to the austenite-forming potential of the elements carbon, manganese, nickel, copper and nitrogen. chromium exceeding the preferred maximum value of 17.0% and in all probability exceeding the higher limit of 20.0%, the degree of deformation hardening and the strength levels, which can be achieved in the cold worked state.

Nickel is essential as an austenite former, and a broad and preferred minimum of 1.0%, and a particularly preferred minimum of 1.5% is necessary for this function.

A maximum of 3.5%, preferably less than 5.0% and especially 2.5% should not be exceeded in view of the adverse effect that higher nickel levels exhibit on the degree of deformation hardening and strength levels. It is further desirable to maintain the maximum nickel content at the lowest possible level food thought at its high cost.

Copper is essential as a partial replacement for nickel - and a preferred minimum of 0.5%, especially 0.6%, should be present. However, a maximum value of 0.85% must be observed as copper has a strong effect in reducing the degree of deformation hardening and results in combination with high manganese in hot working problems. In addition, for manufactured products for use in the dairy industry, it is estimated that copper levels above about 0.85% would contaminate milk. Nitrogen is essential in view of its potent austenite-forming potential and a broad and preferred minimum of 0.15% and a particularly preferred minimum of 0.18% is necessary for this purpose. In addition, a minimum of 0.15% nitrogen improves resistance to pitting corrosion. A maximum of 0.30%, preferably 0.25% and especially 0.22% should be observed in order to maintain the balance between the nickel equivalent and chromium equivalent elements with respect to austenite and ferrite-forming tendencies.

Carbon is also a potent austenite former, and a minimum of 0.015%, and preferably 0.02%, is suitable for this purpose. A maximum of 0.10%, preferably 0.06% and especially 0.05% must be observed as carbon exceeding these levels adversely affects the resistance to grain boundary and pitting corrosion; Silicon is a strong ferrite-forming, diet-wide mafimum of 2.0%, preferably 1.0% and in particular 0.75%, should be observed to avoid disturbance of the austenite-ferrite balance.

Phosphorus and sulfur are present as common impurities, and a broad and preferred maximum of 0.06% of each, and a more preferred maximum of 0.0H% of each, can be tolerated without adverse effects.

Thus, a preferred steel according to the invention consists essentially of, in weight percent, 0.02% - 0.06% carbon, 6.0% - 9.0% manganese, at most 0.06% phosphorus, at most 0.06_% sulfur , not more than 1,0% silicon, 13,0 '% - 17,0% chromium, 1,0% to less than 5,0% nickel, 0,5% ~ 0,85% copper, 0,15% - 0 , 25% nitrogen and the remainder essentially iron, the steel having an instability factor in the range 2.5 - 8.5 calculated by equations for the instability factor as above.

A more preferred steel according to the invention consists essentially of, in weight percent, 0.02 - 0.05% carbon, 7.0 2 ~ 8.5% manganese, at most 0.0U% phosphorus, at most 0.0U% sulfur, 0.% - 10 15 20 25 30 35 453 998 m 0.75% silicon, 1H, 75% - 15.50 Z chromium, 1.5% - 2.5% nickel, 0.6% _ 0.75 % copper, 0.18 - 0.22 z nitrogen and the remainder essentially iron, the steel having an instability factor in the range 2.5 - 8.5, calculated by the instability factor equation, given above, with a nickel equivalent in range 12 - 15, calculated by the equation: Nickel equivalent =% Ni +} 0 (% C) 0.5 (% Mn) + 30 (% N) + 0.5 (% Cu), and a chromium equivalent in the range 14 - 17 , calculated by the equation: Chromium equivalent =% Cr +% Mo + 1.5 (% Si) * 0.5 (% Hb).

The instability factor is a quantitative calculation, which indicates the tendency of austenite microstructures to be converted to deformation martensite by cold working. In this context, it is understood that a ferritic microstructure is not converted to martensite by cold working. As shown below by test data, the instability factor must be in the range 2.5 - 8.5 to obtain a high degree of deformation hardening. A correlation exists between the instability factor and the amount of ferrite and thermal martensite in the hot-rolled and annealed state, which is referred to here as "ferrite number". Austenite stability can also be quantified using a modified Schaeffler diagram, in which nickel equivalent is plotted against chromium equivalent, so that the phases present are predicted at least qualitatively.

Figure 1 is a state diagram, which is a modified Schaeffler diagram. While the Schaeffler diagram was developed to predict welding microstructures, it has been found that good correlation exists in the steel of the present invention with respect to machined and annealed microstructures. The preferred and especially preferred compositions for the steels according to the invention are in the field of ABCD in Figure 1, and are thus either a completely austenitic phase or mixed austenitic and martensitic phases.

Next, reference is made to Figure 2, which is a graphical representation of the relationship between instability factor, calculated by the above equation, and the ferrite number (ferrite plus thermal martensite) in annealed and machined state. It should be noted that the ferrite number increases sharply at an instability factor of about 8.2, thus indicating a combined microstructure of austenite and martensite. It has been found that a relatively high level of thermal martensite does not result in significantly higher strength levels after drastic cold working with reductions greater than 50% and up to 60%. A higher ferrite number in the annealed and machined state does not mean that the austenite can be cold worked to a greater extent, but the higher proportion of martensite in the annealed state 'reduces the formability of the steel, thus leading to difficulties in cold working.- For this reason a maximum instability factor must of 8.5 observed._As could be expected, a higher ferrite number in annealed and machined state exhibits a higher strength level, but this is achieved only at the expense of formability. For the best balance between strength and formability in the machined and annealed state, the instability factor is preferably between 5.0 and 8.2, and the ferrite number between 1 and 2.

It has been found that the increases in the levels of nickel, chromium, manganese f nitrogen, or copper tend to lower the strength level and improve the formability. This can be assumed to be due to a lower instability factor (and thus ferrite number), with a concomitant reduction in degree of deformation hardening. Nickel and manganese plus nitrogen exert the greatest effect in terms of reducing strength. With regard to the degree of deformation hardening, copper, based on the weight percentage, has the greatest effect in terms of reducing the degree of deformation hardening, followed in descending order of nickel, chromium and manganese. An addition of 0.5% copper is about as effective as 1.5 E nickel, 3% chromium, or U% manganese in reducing the strength levels and the degree of deformation martensite formed by cold working.

The above observations were confirmed by a series of melts, which were prepared, processed and tested.

The effect of variations in nickel, chromium, manganese plus nitrogen and copper was studied both within and outside the scope of the ranges of these elements in steel according to the present invention. The compositions of these melts are given in Table I together with the calculation of the instability factor, the chromium equivalent and the nickel equivalent using the above equations. The properties of the melts in Table I in cold-rolled and annealed state are summarized in Table II.

For comparison purposes, commercial samples of AISI type 501 and BOÜ-i were tested simultaneously under the same conditions under the same conditions.

The melts were melted and cast into ingots, hot rolled from 126,000 to a thickness of 2.5 mm and annealed at 109,300.

The samples were cold-reduced by 50% to 1.5 mm and annealed at 109300. The test results in Table II are based on 1.3 mm thick annealed samples. The samples of the hot-rolled and annealed 2.5 mm material were then subjected to varying degrees of cold reduction. In particular, a set was cold-reduced by 50% to 1.5 mm thickness, annealed at 10,900, stripped, and cold-reduced a further 20% to 1.0 mm thickness. An additional set of samples was cold reduced 30% to 1.7 mm thickness, annealed at 109,300, peeled and further cold reduced H0% to 1.0 mm thickness. A final set of samples was cold reduced by 60% in a reduction to 1.0 mm thickness.

Samples, which were cold-reduced by 20%, NO% and 60%, were subjected to deformation hardening tests, while annealed samples, which were cold-reduced by 50%, were subjected to ultimate strength tests, formability tests with Olsen bowl, and GTA welding strength and formability tests. Samples of AISI type 301 and SOU were also subjected to deformation hardening tests under the same conditions for comparison purposes. The deformation hardening samples are summarized in Table III and the GTA welding mechanical properties are listed in Table IV. 10 15 20 25 30 35 455 _998 10, It appears from the data in Table II that steel according to the invention with a ferrite number of 1.0 showed higher strength than type 301 and 30H and showed formability according to Olsen bowl test, which is substantially equivalent to type 301 and 30U. For ferrite numbers greater than 1, the strength increased while formability and extensibility decreased.

Deformation hardening test according to Table III shows that the degree of deformation hardening for steel according to the invention is considerably greater than for type 301 and 3OH. In some cases, steels according to the invention exhibited values of Rockwell Island hardness approaching 50, after about 60% cold reduction. Steel according to the invention, which exhibited a ferrite number of 1 in the cold-reduced and annealed state, reached strength levels far above those exhibited by conventional alloys, and which approach the levels of heat-treated precipitation hardenable steels when subjected to more than 50% cold reduction .

The autogenous GTA welds, listed in Table IV, showed ferrite numbers that are completely comparable to the values for annealed base metal. Melts with high ferrite numbers showed 'high strength levels and low extensibility and formability. Some of the melts with low ferrite numbers also showed extensibility losses when the instability factor exceeded 8.0.

With a low ferrite number and an instability factor of less than 8, welds made of steel according to the invention were comparable in terms of strength and formability. with the values of the corresponding base metals.

Additional steel melts in accordance with the invention were prepared and subjected to abrasion resistance tests.

For comparison purposes, samples of carbon steel, AISI type 301 and 30H, and a steel in accordance with the above-mentioned U.S. Pat. No. 3 QNO 266 (which is marketed under the registered trade name "Nitronic 33") were also tested with the same tests. The compositions of these steels are given in Table V. Several series of abrasion tests were performed and ». de .. 10 15 20 25 30 35 453 998 11 results are given in Tables VI - IX. In Table VI the steel according to the invention was in a hot rolled state, while in Tables VII - IX steel according to the invention was in a hot rolled and annealed state.

The test in Table VI using pea shingle (series 1 and 2) was a rigorous abrasion test with only slight corrosion effects. The tests in Table VI (Series 3) and Tables VII and VIII using phosphate ore were a combination of abrasion and corrosion effects.

The mixing test in Table VI, using a wet phosphate slurry, mimicked the conditions of use in dredging pipes due to the high slurry rate and the open system.

In Table VI, the relative wear life of steel according to the present invention was 2.8 - 3.9 times the values for carbon steel and was considerably superior to "Nitronic 55" in the pea shingle samples. In the phosphate slurry test in Table VI, steel according to the invention was at least four times better than koiståi and 78% better than "Nitrónic 33".

In the annealed state, as indicated in Table VII, there was a decrease in the relative wear life of the steel of the invention compared to carbon steel. Despite this, the steel according to the invention showed a relative wear life which is three times better than for carbon steel and 60% better than for "Nitronic 33". It is possible that the new annealed state underwent an abrasion process during these tests, which would have been higher than the abrasion rate achieved during the constant state.

In Table VIII, direct comparative tests were performed with stainless steel only. The steel of the present invention showed a slight improvement over type 30H and "Nitronic 33". In Table VIII, a high nickel and copper alloy was also tested for comparisons and used as an index at 1.0. At the end of the test, the steel was according to the present invention 17% more abrasion resistant than the index alloy with high nickel and copper content. In the test according to Table IX the conditions were found to give considerably higher erosion for carbon steels in all series. while performed under different conditions for mixing blade configurations, speeds and times.While the steel of the present invention was inferior to "Nitronic 33" and the high nickel and copper alloy in some series, the overall result of all five series showed that the steel of the present invention was superior to "Nitronic 33" and essentially the same for the high nickel and copper alloy.The stmxz superiority of all three ro stainless steels compared to xoisuål in table Ix are quite obvious. It is thus apparent that the steel of the present invention has a relative abrasion life in both hot rolled and hot rolled and annealed conditions which is at least 2.5 times the value of carbon steel and exhibits total superiority over all steels tested.

For a given level of extensibility (measured in percent elongation), steels of the present invention exhibited much higher hardness in deformation hardened state than standard steels from 300 series.

The present invention thus provides a steel with high strength, superior abrasion resistance, good extensibility and high degree of deformation hardening in hot-rolled and hot-rolled and annealed condition, and 0.2% yield strength greater than 1379 MPa at cold reduction at more than 50%. Although the steel can be used for a wide range of applications, the steel is particularly suitable for the production of dredged pipes by welding a hot-rolled strip, formed into a cylindrical shape, due to its highly superior abrasion resistance compared to carbon steel, which is now used for manufacture of such pipes. Furthermore, the steel according to the invention can be obtained in the form of rods, wire rod and wire, both with the wide and preferred areas for the composition. The high strength and good extensibility achieved in wire drawing provide a new combination of properties that were not previously considered achievable for steel according to prior art, in particular with reductions in cross-sectional area of greater than 50%. 453 998 l fl .å I xli. _ .. cwwc fi cc fi waaz fi cm fl muwf N flfifl N «m fl Oqm + ONQN HN« O Nm flfl ~ Q, ww fi ä nä ænïwmë NMWMW .___ fi_ ~ fi o_m fi o_ + ~ ß_ _ _ å; »__ ä: Ä Nä Mï mä www mä mä Nä mmä * m n fi w m fi _ q_m + fl ~ _ Q QN_ __ _. ß_ flfi N_ @ H ß_m + @> _ o oN_% m »_ fi m% _M fi Mmnæ mW @ Hm wmwmm wwH = _ Mmwmm * M: _ ~ fi m_ @ fi m_> + m» _o fi N_o _fi _ _> _ ~ H o_ = fi ~ _æ + @w_o fi ~ _ @ w% _ fi% w_m% @ M_ @ %% mHm m% mH% Mmmm wmmnm _w @ .fifi ß.w «n_w + fi> _ o«. n. _ Nä ä å: å. ï ï ææ mä Näämm Mmmm mä m mlml fl umw w mw + fi wfm n fi wm wmwm @ ~ _ ~ fi fi m_ @ w fi Q_ = Q ~ = _ @ «o_ = m ~ @ _Q ß m fl z mha m fi su fi z_ «z & mo fi fi m fi mw mw www mw> o @ mw ux fl> | co fl w fl mo om H Hamn flfi 453 998 15: mwc fl cc fi uaas .new Hmmm u., fi á fi 0% mm wä fl ä -I. ~. ~ «mmm om wmß @> ~ -» | > .fi «m.mæm m.mm mr» m fl m o. fi>. «H m. @ mm mm = ~ m = fi mßm o. fi m fl m fi m.æ@m O.Nm @> w mon o“ fifi_ > Q. fi = 0. O.O fi Qæm fi mmm Qm ^ n. ~ «M fl nmm @.> M = ~ w wz fl O. fi n. @ M. ~ = @ On = fl oom fi m => ww w.« Fi o. ~ Mm mm = ßmw mmm @ .fi w.æ m. = mm o.mm m = m. o fi m m. ~ ~ .H fi m. «mm o. = n www mmm o. fi www W @. fi ~ u o. @ ~ Hß fifl _ mmm mN Q m m. ~ Nu o. @ H o fi m fl 3 :: mm EE @ \ mm = e wwøm mm: mm: w = m »w dm» Hmgw-: wwHo umßwn fl m wc fi c fi ße g mcmpwppogm -xumhpm @ ~. @ -P fl k fi wm HH fifi wnmß ro mJH fl amJH fifi x ß o * INNW> opg 453 998 16 cmwcmccmmaas Hem fi mßm * OmA emma. O ”z m5 mmâ mmmm .om ^ m.> = O m. =« Mmmm mmwm mm = m mm m mmm O om Nmm fl, mmm m mm mm m “~ mm mm: mmm mmm O mm ^ mhmzo mm fl mm fi m fi m fi m .mm mm ^ mummo Q_m mmm fi Mm @ m m.mm mm m mmm Q.m fi 2 Nm m N. m QN m: am omm 9% mä m om ^ m, omo 0. » : mmm fi mm fi m_mm m om ^ _ mw = u m.% fi mM = fi fi mw fi muwm .mm O. mm om H m Nm mmm o. fi m. fi mm O. = m mmm mmm O mm ^ m.omo m. ~ omß fl mmm fi m.mm mwv mMw = um, m wmm fl mm = fi m.mm m Q mv m. ~ fi omm mm N. H m. ~ Q. fi Nm mQ ~ fl m fifl mmm Q mm ^ mHm = o mmm mmß fi mmm fi mnmm ä wfä ä mä Mmm ä mw m.mNm m.m fi o fi m fl mm: O Hmm m \ mm Es m fi mm mm: wcmmw mm: w = mmw .mmm yåëmm måšm mm fl mmmm. m ucmøwmmme uwuwnpmwn n flfl mx m nmmmxwcmww mxwmcmxwz HHH flfl mnmb m * m nuuo fi m uxumuum & m.o: wn fifi mm> oQm 453 998 17 'cmmcwccwwaas Hcw Hmum * @WM mmfi m. w. fi www mmm »O fi m wmm m. @: Nmo fi www m ww O fl @ n ^ 0.» . m fi mw o fi ï fl mfw zmm fi .fi mz fl onom m «NH m fl w fi b í.N% a fififi NHNH OnOJ mä ä MW o * m Om ^ @. @ Q.

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O H m mmm. O Nm = ~ m wqm m Nm * N CMA o.wmo _ QMA m. ~ Mo @, m www fl wmw fi æ.wm OWA mm: Q O. ~ fi oomw wæw fl 0.0: om @ Hmp o \ mm EE æ.om mms mcmpw. On the Iu fi Hass fi: MWE WCWLM ~ DH al pw f upwm wc f n f wa § -ppopm -xuwhpw & ~ .o -mn fifi x> o @ m UCNQmH .md unmwn fifi wx H nmnmxwcwww MWW al wmmmm ~ m | mwmq | wmw «| wmwmmw R 18 cmwc fi cc fi mnaz Hqw Hwum * 453998 o. wno o “m ßm flfi æßo fl mmmm m.:mo om wood nom mQ = o. fi ~ o o. ~ m Nm» ßwm m æ fi Qo> m o.æ @ mßm fi om O = @ na m “== 0 m. = OO = fi --- Om om = o m.o fi fl mm fi _ mmw fi Q: m.> Nu A @ .om @ = fifi Nm »om o.mwm. Q.n @ acw non O fi onla o. Fifl ° .æ = o o.m m @ = fi. fi = m fi ¶æH @ m o. @ O. =: @ O.o ~ wß fifi. Nmo fl æ.: N @. = O. @ Mo o.mN æmo fl www @ om. oa fi m. @ wm m.mm må »mn» O fifi Hm »o \ mm EE m fi om mm: mcmhw mm: wcm fi w nga» Ohm -p fi ppwm pmnupwm wc fi c fi ßß R -ppohm -xuwgßm § ~, o -wß flfi mx WW ucmuw | nmwnH fi mx fl mmmmxwcwww mxw fi cmxwz _ ^ m flfi wv HHH flfi mpwa 453 998 19 n: mwc fi cc fl wmms dö fi muw .f o. fl 0.N fl o.nm mm »wa» fifi @ .m o. fi N. @ o. ~ n »O fi Om Q. fi @.« Fi o. @ G www Now * Q omm Qm ^ =. = On .mmo fi mmm w Q NH ¶o. Fi @. «Fl m. = M www man *>: .m _ Om ^ @. = 0. » @ ~ o «: MN @> .m ou fi Nuo fl m.nz omm omm * m m.> m« 2 N _ @ “> mm: mmm = Nnæ O. fl oo« @. «~ www _ www n m. » m. @ _ m. = m. @ mn »: oz N m.o fi m. @ ~: .m 0 .: zzß æzz fi æ.N fi .G3 E: ... E m, om mm: wcmnw mm: wcwhw> oum .Houzmw | »fi Lpmm Hwxw- = wwH @ wc fi c fl w« _ - »» 0 »m -xumpuw R ~“ Q -wpmp fifi -fi pw »w = H muw> w IÉHÜ .Hmmmxmcmwm .mxwwcmxwz> H Sum mmm. 453 998 Sample Q Carbon steel 0.33 (AISI 1030) "Nitrone 33" 0, 053 ïyp BOH 0.068 12 * 0.058 15 * 0.059 1L1 * 'o, o56 high Ni-, high Cu- content 20 Täbell V ä ". Åi. 1.1U 0.17 12.93 0.67 1.66 o, uß 7.36 0.00 7,} U 0.58 7.18 0.35 * Steel according to the invention 17A? 18.15 114.99 111 .95 111.93 3.115 8.9 0.99 1.50 1.96 IZ o .28 o, o1 0.18 o, 1a 0.18 'IQ 0.56 0.55 0.56 453 998 21 a; ä: m; QN O; ñe fi êš m «m @ .m ._ 0 .: fl. ~ o. fi ~ ~. = wa: wz =. ~ o. fi fl..: mm Ill z fi> ohm NH> @ »M NH> 0nm. U fi = o» »Hz = Hwpw fi ox vo fl åwm .e fl v N | Eñmspmuwom de ooo fl +: w» »w> He oow fi mwmwmmm QWN .w. ~. Fi. N fi. ~ O. Fi H: mm .z fi> rm NH> rpm m fi> o @ m ° fi = o »» fl z = Hwpm fl ox fl ø fi pwm .Mwmmmmm mm qm @ «m o. = .m @ .fi fi q fi> o »m n fl> @hm N fi> 0pm Hwpm fl ox øo flfi mm fl lmwmmm ^ o. fi w @@ m> xw @ = H Hmpw fl oxv @wcmHw> fl Hwm = fi =» @:> «@ wHwm hwvmnwßcmumš fi .umå fi MSW "Maia w. .cëäE æÛm:. o f m the oo f + Hwwc fi wßpm HE DON + = m» p @> HE QOQN upwm al mwc fi ßwm toilet fi eld f w Qazßmà zoo CASX f sx. Éaawgcwmz H> HHmDmB 453 998 22 NQN QrN SO yy OJ tl et al EAX QN QN QN Well OJ _ N No than yet NJ Gå N 2A määm N.N OJ N> oum> oLm> onm. = Mm u fi conu fi zz Hmum fi ox Uo fi hmm _ äN QN QN NJ o; šu fl š fi x QN mnN QN NJ o; N QN äN 0. » must o; ¶. N> onm> onm.> Oam: mm owconu fl2 = Hmnwaox Uo fi hwm N wämw ^ o fl.fi mULm> xwUc fl Hwnw fi oxv UmcmHm> fi HmwC fi: umc> wum fi wm. .cuše NQN: .š Lspwnmgëwumesm .pmx fifl asø .Ewa m mëpmwwom HE ooo fi + Cmvvæ> HE øcw fl uhwm fl mmc fi vmm wc fi csm fi maas pw> zoo cLm> xH: x> oLQww> «» 99 m H .fl mH ~. «oH mo. fi wo. fi fl uo fl nmm nmsë fl u w. | mc fl çëm fl mmas zz N m fi nmm @ .fi. w ~. fi m ~. fi> fi »@ H = s = m Q. fl o. fi w. fi m o. fi m. fl ~ .fi N Q.H = .fi = .fi«.

.Sam ^ o, fi w @ pm> xw @: fi mä> o »wV _> o» m = mm ° fl: 0 @ »fl z =: on mha øo fi pmm fi m fi hmw @w: mHw> H fi mm: fi =» @ => fi »mH @ m LsuænmQEmpmE: h .uwx flfi msv .Ewa m ..: fi s \ s @ n. ~: .s fi mepmmwou He ooo fi + = mp» «> HE ooæ fi n fi ww fi wwn fl pwm wc fi gëm fi mm>>: : »Mz fi HmDmF HHH> 453 998 2ü .u- m« m = m.:= @. = M oH> fl »@ H = e = z n.om @ .fl @ O. @ ~ o_ fi No fi m He OO» + E fl wspwwmou HE Qom fi | Ew »ON | m w fifi ww «. @ J m.mm H.ow @ .H mo fl w cwwc fi .ë fi mëumuwom de oom fi 1 .çsm fl waas» C | E fi u m 1 m | mmmmW>.> Fl «mm @ n. ~ @ O. Fl E fi» mm IM w fi pww m. = Fl fi. O fi mo ~ o. «No fl w HE Qom + .gam fi wggz“ Emm - E fi »N - M | mwmmm: .fi m m. ~ M @. ~ = ¶ o. Fi> ohm> 0 @ m: mn 0fi = 0 »» fl z = Hwaw fl om. E fl p æ fi Aon fi wønm> xwø: fi Hmum fi oxv øm: w fi w> fl Hwwcw: @m:> fl pm fi wm Lzumnmgemuwssm Auwx fifi asw. .wn fi nww fi He coon H fifi p @@ mQm »= s fi mspmgwok He Qoo fi uämm fl wwc fi pwm co fi wonmwmc fi csm fi mamsummmom um> pmm» | Lmøcm fl m XH H fl wnß fi _ fl w fi hwm

Claims (2)

10 15 20 25 453 998 25 Patent claims 1. Austenitic. stainless steel with high strength. superior abrasion resistance, good hot workability. good extensibility and high degree of deformation hardening, characterized by the fact that it essentially consists of, in weight percent. 0.02 - - 0.06% col. 6.0 - 9.0% manganese. not more than 0.06% phosphorus. not more than 0.06% sulfur. not more than 1.08 silicon. 13.0 - 17.02 chrome. from 1.0 to less than 3.02 nickel. 0.5 - 0.85% copper. 0.15 - 0.25% nitrogen and the remainder essentially iron, the steel having a nickel equivalent in the range 12 - 15. calculated according to the equation: Nicxele equivalent = mi + aouc) + msnmn) + 300m) + os (: cu), and a chromium equivalent in range 14 - 17, calculated by the equation: Chromium equivalent =% Cr +: Mo + 1.5 (tSi) + 0.5 (% Nb). 2. Steel according to claim 1, characterized in that it essentially consists of. in weight percent. 0.02 - 0.05% col. 7.0 - - 8.53 manganese, not more than 0.04% phosphorus. not more than 0.04% sulfur, 0.4 - - 0.75% silicon. 14.75 - 15.508 chrome. 1.5 - 2.52 nickel, 0.6 - - 0.75% copper, 0.16 - 0.22% nitrogen and the rest essentially iron. ..._.__ .__ ._ ._ \ _..._..-.