CN1447863A - Oxidation and corrosion resistant austenitic stainless steel including molybedenum - Google Patents
Oxidation and corrosion resistant austenitic stainless steel including molybedenum Download PDFInfo
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- CN1447863A CN1447863A CN01810365A CN01810365A CN1447863A CN 1447863 A CN1447863 A CN 1447863A CN 01810365 A CN01810365 A CN 01810365A CN 01810365 A CN01810365 A CN 01810365A CN 1447863 A CN1447863 A CN 1447863A
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
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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
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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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
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
Abstract
An austenitic stainless steel comprising, by weight, 19 to 23 % chromium, 30 to 35 % nickel, 1 to 6 % molybdenum, and less than 0.8 % silicon. The addition of molybdenumt the iron-base alloys of the invention increases their resistance to corrosion at high temperatures. The austenitic stainless steel may consisting essentially of, by weight, 19 to 23 % chromium, 30 to 35 % nickel, 1 to 6 % molybdenum, 0 to 0.1 % carbon, 0 to 1.5 % manganese, 0 to 0.05 % phosphorus, 0 to 0.02 % sulfur, less than 0.8 % silicon, 0.15 to 0.6 % titanium, 0.15 to 0.6 % aluminum, 0 to 0.75 % copper, iron, and incidental impurities. Austenitic stainless steels according to the present invention exhibit enhanced resistance corrosion by salt at a broad temperature range up to at least 1500 DEG C. Thus, the stainless steel of the present invention would find broad application as, for example, automotive components and, more particularly, as automotive exhaust system components and flexible connectors, as well as in other applications in which corrosion resistance is desired.
Description
Technical field and industrial applicability
The present invention relates to a kind of anti-oxidant and protection against corrosion austenitic stainless steel.More particularly, the present invention relates to a kind ofly be suitable under high temperature and corrosive environment the austenitic stainless steel that for example in automotive exhaust system component, uses.Austenitic stainless steel of the present invention is specially adapted to for example be rich in the parts that use in the muriatic water up to 1800 temperature and corrosive environment.
Background of invention
In the manufacturing of automotive exhaust system component, the common target is to reduce cost and weight reduction, also keeps the globality of system simultaneously.Usually, in order to alleviate the weight of parts, be used for the trolley part in these fields with thin stainless steel manufacturing, therefore, parts must be the height rot-resistant, to prevent corrosion failure occurring because of perforation or other modes.Anticorrosion is complicated, and this is because the parts that use in some automobile exhaust system field are to work under the at high temperature harsh caustic chemical environments.Be subjected to the pollution of road surface ice-removal salt when particularly, automotive exhaust system component and other automotive engine components are worked under hot conditions because of the hot waste gas of discharging.The stainless steel of working under these conditions and other metal partss are responsive to the corrosive attack complex way that is called hot brine corrosion.
Usually, at high temperature, oxidation to taking place on the surface that is exposed to air, to form the metal oxide protective layer in parts of stainless steel.The metal of oxide skin protection bottom also reduces its further oxidation and other forms of corrosion.But the deposition of road surface ice-removal salt can corrode and degrade this protective oxide film.When protective oxide film was degraded, underlying metal just exposed out and harsh corrosive environment is become responsive.
Therefore, the metal alloy of selecting for automotive exhaust system component should be able to use in the scope of requirement condition.Be crucial the work-ing life of automotive exhaust system component, because user, articles of confederation have requirement to prolongs life, the declaration form of manufacturers also has requirement to this.In order to make automotive exhaust system component select more complicated alloy, in these fields, recent development is to adopt metal flexible joint pipe, and the effect of pipe connecting is two fixed exhaust system component can be linked together submissively.Adopt the flexible joint pipe can slow down and be connected relevant problem with other with using welding, slippage.Selection at flexible joint pipe material therefor should stand high-temperature corrosion environment, and the both must be plastic, and heat-resisting brine corrosion and various other corrosion, for example in warm oxidation, the erosion of general corrosion and chloride stress cracking is split.
The alloy that uses in the automobile exhaust system flexible joint pipe often will stand the pyritous condition after being subjected to such as the pollution of road surface ice-removal salt.Halide salts can play fusing assistant, removes the oxide skin of formed protection on the general pipe connecting at high temperature.Under this condition, pipe connecting can degrade quite soon.Therefore, depending merely on the protection against corrosion that simple atmospheric oxidation test is not enough to reproduce truly in the use degrades.
Automotive industry adopts several alloys to make automotive exhaust system component.These alloys comprise that the moderate corrosion-resistant material is expected the senior alloy material that expensive erosion resistance is bigger cheaply.Lower-cost moderate corrosion resisting alloy is AlSi type 316Ti (UNS registration number S31635).If 316Ti type stainless steel is placed under the high temperature, corrosive is just faster so, therefore, when temperature is higher than about 1200 °F, does not generally use the stainless steel of this model in automobile exhaust system flexible joint pipe.316Ti type stainless steel only is used for the automotive exhaust system component do not moved usually under high exhaust temperature.
Usually adopt that cost is higher, more the high-grade alloy material to be to make the used flexible joint pipe of automobile exhaust system of at high temperature working.Making the effective exemplary alloy of using under the high-temperature corrosion environment of flexible joint is the austenitic nickel-based superalloy of UNS registration number N06625, and it is a kind of commercial goods, for example ALLEGHENY LUDLUM ALTEMP 625 (hereinafter referred to as " AL 625 ").AL 625 is a kind of austenitic nickel-based superalloys, has excellent anti-oxidant and preservative property under the etching condition of broad, and has fabulous workability and high intensity.UNS registration number N06625 alloy generally contains (by weight): about 20～25% chromium, about 8～12% molybdenums, about 3.5% niobium and 4% iron.Although select for use the flexible joint pipe of such alloy manufacturing automobile exhaust system best, to compare with 316Ti type stainless steel, prices are rather stiff for it.
Automotive exhaust system component manufacturers can adopt other alloys to make exhaust system flexible joint pipe.But, do not have a kind of high corrosion resistance that has in these alloys, especially when high temperature and corrosive contaminants are for example used in the ice-removal salt of road surface.
Therefore, people have a kind of demand to the impregnating material that uses under the high temperature corrosion environment, this anticorrosive and senior alloy, and UNS registration number N06625 alloy difference for example, and production cost is lower than this class superalloy.More particularly, people have a kind of demand to ferrous alloy, this ferrous alloy can be made such as lightweight flexible joint pipe and automobile exhaust system miscellaneous part, and under the opposing high temperature such as the corrosion of salt deposit and other road surface anti-freezing product class corrosivess.
Brief summary of the invention
The present invention is devoted to the demand, and a kind of austenitic stainless steel is provided, and it comprises 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum and less than 0.8% (weight) silicon.The interpolation molybdenum has strengthened the preservative property under its high temperature in ferrous alloy.
It is a kind of mainly by 19～23% (weight) chromium that the present invention also provides, 30～35% (weight) nickel, 1～6% (weight) molybdenum, 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus, 0～0.02% (weight) sulphur is less than 0.8% (weight) silicon,～0.6% 0.15 (weight) titanium,～0.6% 0.15 (weight) aluminium, 0～0.75% (weight) copper, the austenitic stainless steel that iron and unavoidable impurities are formed.
Austenitic stainless steel of the present invention has enhanced salt tolerant corrodibility in the wide temperature range up at least 1500.As mentioned above, the present invention also provides the goods made from austenitic stainless steel.Therefore, stainless steel of the present invention has wideer Application Areas, for example is used to make trolley part, more particularly, makes automotive exhaust system component and flexible joint pipe, and uses in the corrosion resistant other field of needs.Alloy of the present invention has excellent high-temperature oxidation resistance, therefore, has wideer purposes under hot conditions, for example as the heating unit valve jacket.The present invention also provides the goods made from austenitic stainless steel, and described austenitic stainless steel contains 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum and less than 0.8% (weight) silicon.
The reader will realize above-mentioned details of the present invention and advantage and other under the opinion during embodiment of the present invention is described in detail below.When making and/or using stainless steel of the present invention, the reader also can realize some other details of the present invention and advantage.
The accompanying drawing summary
Can be more readily understood the features and advantages of the present invention with reference to accompanying drawing, wherein:
Fig. 1 contrasts to be coated with 0.0,0.05 and 0.10mg/cm respectively
2Salt deposit and 1200 °F down the dull and stereotyped test piece sample of 72 hours alloys of the present invention (sample 2) of test and prior art alloy carry out the weight change data plot of hot brine corrosion test-results;
Fig. 2 contrasts to be coated with 0.0,0.05 and 0.10mg/cm respectively
2Salt deposit and 1500 °F down the dull and stereotyped test piece sample of 72 hours alloys of the present invention (sample 2) of test and prior art alloy carry out the weight change data plot of hot brine corrosion test-results;
Fig. 3 contrasts to be coated with nominal 0.10mg/cm respectively
2The weight that a kind of alloys of the present invention (sample 2) of salt deposit and test under 1200 and the welding teardrop shape sample of prior art alloy carry out hot brine corrosion test-results changes data plot;
Fig. 4 contrasts to be coated with nominal 0.10mg/cm respectively
2The weight that a kind of alloys of the present invention (sample 2) of salt deposit and test under 1500 and the welding teardrop shape sample of prior art alloy carry out hot brine corrosion test-results changes data plot;
Fig. 5 illustrates typical corroding metal sample to illustrate according to the analytical results of the ASTMG54-standard test operation that is used for the simple static oxidation test;
Fig. 6 be contrast alloy of the present invention (sample 2) and prior art alloy sample according to ASTM G54 to being coated with nominal 0.10mg/cm
2The welding teardrop shape sample of salt deposit is at the depth of penetration figure of 1200 following test-results;
Fig. 7 be contrast alloy sample of the present invention (sample 2) and prior art alloy according to ASTM G54 to being coated with nominal 0.10mg/cm
2The welding teardrop shape sample of salt deposit is at the depth of penetration figure of 1500 following test-results.
The detailed description of invention
The invention provides a kind of austenitic stainless steel of high-temperature corrosion resistance.Corrosion-resistant austenitic stainless steel of the present invention is particularly useful for automotive industry, more particularly, is used for automotive exhaust system component.Austenitic stainless steel is the alloy that comprises iron, chromium and nickel.Generally speaking, austenitic stainless steel is used for needing corrosion resistant field, it is characterized in that chromium content is higher than 16%, and nickel content is higher than 7%.
Usually, corrosion process is the reaction process of metal or metal alloy and its environment.Metal or alloy is determined corrosion-resistant the be made up of with other factors it to small part usually under specific environment.The corrosive by product is metal oxide normally, for example ferric oxide, aluminum oxide, chromic oxide etc.It is favourable forming some oxide compound, especially chromic oxide on stainless steel, and it has stoped further degrading of underlying metal effectively.The corrosion meeting is quickened because of the existence of heating or etching reagent.
The stainless erosion resistance of using in the automotive field becomes complicated because of the pollution that suffers the road surface ice-removal salt under the hot conditions.This pollution is owing to the interaction between oxide compound that forms under the high temperature and pollution salt causes the corrosive complex formsization.The feature of high temperature oxidation is directly to react with airborne oxygen by metal, forms protective oxide film.Sedimentary road surface ice-removal salt can corrode and degrade protective oxide film on the trolley part.When protective layer degraded, underlying metal was further corroded.Halide salts, especially chloride salt promote the local formation of erosive, for example pit or crystal grain boundary oxidation.
Austenitic stainless steel of the present invention comprises 1～6% (weight) molybdenum.Molybdenum adds as alloying agents, so that alloy has erosion resistance, toughness, intensity and high temperature resistant creep properties.Austenitic stainless steel of the present invention also comprises 19～23% (weight) chromium, 30～35% (weight) nickel and less than 0.8% (weight) silicon.The high temperature corrosion-resisting of austenitic stainless steel of the present invention is better than prior art 316Ti type alloy, therefore, will more be widely used as a kind of auto exhaust parts.But the cost of this erosion resistance of the present invention is lower than UNS registration number N06625 alloy, because the present invention is a kind of ferrous alloy, and the N06625 alloy is more expensive nickel-based superalloy.
Austenitic stainless steel of the present invention preferably contains the molybdenum that is higher than 2% (weight).Another preferred embodiment of the present invention comprises the molybdenum less than 4% (weight).This molybdenum concentration has improved erosion resistance with reasonable price.0～0.8% (weight) silicon that adds in austenitic stainless steel of the present invention makes alloy have the adhesivity of bigger oxide skin.Silicon forms the oxide on surface thin layer that one deck stops the further oxidation of underlying metal.The present invention can randomly contain other alloy compositions, for example carbon, manganese, phosphorus, sulphur and copper.Stainless steel of the present invention also can contain for example 0.15～0.6% (weight) titanium, 0.15～0.6% (weight) aluminium and other unavoidable impurities.
An electric heating element valve jacket generally comprises a resistive conductor that is sealed in the metal valve jacket.Resistive conductor can be bearing in the valve jacket and pass through fine and close refractory materials integument (thermally conductive material) and valve jacket electrical isolation.The normally spirally-wound wire parts of resistive conductor, and the heat conduction refractory materials can be granular magnesium oxide.
Prepare stainless steel of the present invention, and be evaluated at the erosion resistance under the high temperature corrosion environment.Make two kinds of alloy melts and the objective composition fusion that comprises 19～23% (weight) chromium and 30～35% (weight) nickel.First kind of alloy has 2% target molybdenum, and second kind of alloy has 4% target molybdenum.The actual composition of alloy melt sample 1 of the present invention and sample 2 has been shown in the table 1.Sample 1 contains 1.81% (weight) molybdenum, and sample 2 contains 3.54% (weight) molybdenum.Sample 1 and 2 alloys prepare according to a conventional method, more specifically, prepare concentration near goal standard by the vacuum fusion alloy compositions.Broken then formed ingot metal also carries out hot rolling under about 2000 temperature, making thickness is 0.1 inch, and width is 7 inches a plate.The plate of making is carried out sandblasting and removes descaling with acid.Cold rolled sheet then, making its thickness is 0.008 inch, and carries out anneal in rare gas element.The sheet material that forms is made the teardrop shape sample of level and smooth test piece in two sides and welding.
For comparison purpose, obtain other commercially available alloys, and make the teardrop shape sample of level and smooth test piece and welding.Sample 3 is founded into commercially available AlSi 332 types (UNS registration number S08800) specification.332 type alloys are a kind of composition and sample 1 and 2 similar austenitic stainless steels, but do not comprise the molybdenum that adds in advance.Normally a kind of nickel chromium stainless steel that is intended to high temperature oxidation resisting and carbonization of 332 type alloys.Table 1 shows the analytical results of test 332 type samples.332 type alloys generally can be used as our alloy that comprises about 32% (weight) nickel and about 20% (weight) chromium.Selecting 332 type alloys is in order to compare, to determine improving erosion resistance because of adding molybdenum in sample 1 and 2 in hot brine corrosion test.
For more also having tested the sample of AlSi type 316Ti (UNS registration number S31635) (sample 4) and AL625 (UNS registration number N06625) (sample 5).The flexible joint pipe that is used for automobile exhaust system at present adopts these two kinds of alloys, because they be shapable and anti-in warm oxidation, general corrosion and chloride stress cracking corrosion cracking, especially high-load road surface pollutent for example ice-removal salt in the presence of.Table 1 shows the composition of sample 4 and 5.AlSi 316Ti type alloy be current in low temperature automotive exhaust system used low-cost alloy in the flexible joint pipe field.On the other hand, AL 625 is the wider higher materials of cost of a kind of current application scope, comprises the flexible joint pipe that is higher than 1500 automobile exhaust system as temperature.
Sample 1 sample 2 samples 3 samples 4 samples 5
T332+2Mo T332+4Mo T332 T316Ti AL625 alloy C 0.020 0.019 0.013 0.08 maximum 0.05N--0.0045--0.10 is maximum--Al 0.34 0.30 0.55 0.30Si 0.37 0.40 0.41 0.75 maximum 0.25Ti--0.35 0.37 0.70 0.30Cr 20.72 20.70 20.55 16-18 22.0Mn 0.95 0.91 0.97 2 maximum 0.30Fe aequum 4.0Ni 31.07 30.74 31.19 10-14 aequum Nb--------3.5+TaMo 1.81 3.54 0.19 2-3 9.0
Design a kind of test, to determine in high-temperature corrosion resistance and oxidation-resistance that said sample in the presence of the sedimentary corrosion solid is arranged.The enforcement of special corrosion test is these high-temperature corrosion environments of simulation.Now, maximum test that high temperature resistant brine corrosion is carried out to alloy is divided into " cup " test or " dipping " test.
In cup test, alloy sample is placed in the cup that is generally how much shapes of Swift or Erichsen.Then, fill the test aqueous solution with known salt concentration of known volume in the cup.In stove, evaporate the water in the cup, stay the salt that is coated on the sample.Under circulation or isothermal condition, make sample stand high temperature, the salt tolerant corrosion of assessment sample.In dip test, tabular or the forniciform sample immersion of U-shaped are had in the aqueous solution of known salt concentration.Evaporating off water in stove stays the salt that is coated on the sample.Assess the salt tolerant corrosion of sample then.
But, determine that with above-mentioned two kinds of tests there are some problems in the salt tolerant corrosion.Test-results may be inconsistent, and test with test between be not easy to compare, reason be the coating at salt on the whole surface that will test be uneven or sample between be inconsistent.Adopt cup test or dip test, salt generally in the end the exsiccant area deposition get the most intensive.In order to force salt to be deposited on more equably on the sample, the inventor has adopted and has simply executed the salt method.Method is included in a kind of salt-containing solution of spraying on the dull and stereotyped sample.Adopt this method, can deposit the layer of even salt deposit with the aerosol spray of mainly forming by the sodium-chlor that is dissolved in the deionized water.In aerosol spray deposition, heating sample is to about 300 °F, with guarantee water from the aqueous solution fast, evaporation equably.Between spraying, by the monitoring deposition salt amount of weighing, and with surface concn (mg salt/cm
2Specimen surface is long-pending) expression.Calculating shows: if adopt this method carefully, can make the deposition of salt be controlled at pact ± 0.01mg/cm
2After the spraying, can be when being still the test air or needing in the retort furnace under various other envrionment conditionss, the thermal cycling that sample was carried out a time 72 hours is at least at high temperature handled.In the test,, preferably adopt special test furnace and test vessel for avoiding the crossed contamination between other test materialss.After the test, the various not adherent corrosion products of weigh separately sample and collection.The result represents with proportion, as mentioned above, and with change value representation with respect to original (uncoated) example weight.
At first dull and stereotyped test piece is tested, because for the screening alloy of hot brine corrosion sensitivity, this is the easiest method.Before test, measure the weight of each sample.Each tested alloys sample of 1 * 2 inch is applied the layer of even salt deposit.The chloride salt dilute aqueous that is dissolved in the deionized water is sprayed on each such sample.The preheating sample is to about 300 °F on hot-plate, to guarantee that water fast, evaporate equably from solution.After each spraying, by sedimentary salt amount on each sample of monitoring of weighing.After the spraying, sample is placed the alumina crucible of high type, and in retort furnace, carry out 1500 pyroprocessing.Under the high temperature that is still the test air, generally the processing cycle is 72 hours.After the processing, the sample of weighing.Any not adherent corrosion products of collecting respectively and weigh.The increase of the various calculated values of sample or minimizing are because the reaction of metal and atmosphere and by the cause of the various residual salts of coating.The salt amount that applies changes and be significantly less than weight usually owing to interact with environment, like this, generally will underestimate.
Also to test the influence of the unrelieved stress that moulding or welding cause.To this test, sample is processed into " teardrop shape " sample of welding.By " thick dull and stereotyped sample bends to teardrop shape manufacturing " teardrop shape " sample, then from the edge of fusion welding collocation with 0.062 on anchor clamps.Before standing high temperature, adopt to be similar to the method that applies dull and stereotyped sample, apply sample with chloride salt.Dactyoideus coating is not applied in quantitative mode.But the result of coating is smooth, the uniform salt deposit of deposition one deck.The salt amount that estimation is deposited on the teardrop shape sample outside surface is about 0.05～0.10mg/cm
2The sample that applies is placed the lab setup of automatic thermogravimetric amount cyclic oxidation.Per 24 hours, remove salt coating on each sample by evaporation, the sample of weighing then reduces or increase because of the weight that places environment to cause determining.After weighing, apply the salt coating again and proceed test.
Table 2 combines the test that sample 1～5 each sample is carried out.Table 2 test sample has identical matrix
Kind test piece test teardrop shape test sample 1 the present invention----sample 2 the present invention 0.008 " thick 0.061 " thick sample 3 T-332 0.008 " thick 0.058 " thick sample 4 T-316Ti 0.008 " thick 0.062 " thick sample 5 AL625 0.008 " thick 0.059 " are thick
Corrosion test result
Utilize dull and stereotyped test piece test that the preliminary surveying of a performance is provided, the teardrop shape of welding then test is to confirm the result of dull and stereotyped test piece test and expanding test.
Dull and stereotyped test piece test-results
Test is four kinds of listed test materialss of his-and-hers watches 1, and promptly the dull and stereotyped test piece sample of sample 2～5 carries out, and measures the corrosion-resistant influence of the temperature of the salt concn that increases and raising to alloy.2～5 pairs on listed sample is not to apply the salt coating and to apply 0.05mg/cm in the table 1
2And 0.10mg/cm
2The test piece of each composition of salt coating is tested.Test piece is two temperature, promptly tests under 1200 °F and 1500 °F.Before applying salt, the sample of weighing is earlier determined its original weight, then each test is applied the salt of appropriate amount, and is placed in 1200 the environment, to measure the heat-resisting salt oxidation corrosion of each alloy.After at high temperature exposing 72 hours, from stove, take out sample, make it be cooled to room temperature.Remove the salt of staying on the sample, and the sample of weighing, determine final sample weight.
Fig. 1 shows the result of dull and stereotyped test piece sample hot oxidation corrosion test.Fig. 1 contrasts to be coated with 0.0,0.05 and 0.10mg/cm respectively
2Salt deposit and at 1200 following weight change data plots of the hot brine corrosion test-results of the dull and stereotyped test piece sample of a kind of alloys of the present invention (sample 2) of 72 hours of test and prior art alloy.The weight change is to deduct the primary sample weight with final sample weight to obtain, and this result is divided by the original table area of dull and stereotyped test piece sample then.
All alloy all fine carrying out under 1200 in this test.Each sample of each alloy shows that weight has increase slightly, and this has pointed out to adhere to oxide skin and has formed.If it still sticks on the metallic surface, this metal oxide layer of Xing Chenging shields to material bodies so.Usually, along with the increase of salt coating amount, the weight of sample increases and becomes big.The result shows: along with the increase of salt concn, the degree of oxidation of specimen surface increases.The weight of T316Ti (sample 4) increases maximum, surpasses 1mg/cm
2, and the weight of alloy of the present invention (sample 2) and T332 (sample 3) increases minimum, is lower than 0.5mg/cm
2
Under 1500 °F, identical sample has been carried out similar test, the results are shown among Fig. 2.Positive according to expectation, the alloy T-316Ti that low temperature is used uses relatively poorly.Notice serious peeling off, and, scribble 0.05mg/cm
2And 0.10mg/cm
2The original table area loss of every square centimeter of test piece more than 10 milligrams.This test has confirmed that T-316Ti is unsuitable for using down at high temperature (more than 1200), and has confirmed to be used for the reliability of the test method that the heat-resisting salt oxidation of comparative alloy carries out.Every other tested alloys is carried out finely.The weight loss that T-332 (sample 3) illustrates under this test conditions is about 1.3mg/cm
2Higher AL 625 superalloys (sample 5) weight under these test conditionss of cost has increased about 1.7mg/cm
2This weight increase with alloy surface on the formation of metal oxide protective layer and this protective layer minimum peel off consistent.Weight does not almost change alloy of the present invention (sample 2) under this test conditions.Compare the heat-resisting brine corrosion that about 4% (weight) molybdenum that exists in the sample 2 has improved alloy of the present invention with the heat-resisting brine corrosion of prior art T-332 alloy (sample 3).For not having the salt coating or having 0.05mg/cm
2The sample of salt coating, the weight of sample 3 almost do not change.But, if make sample 3 place 0.10mg/cm
2Salt concn in, then protective oxide film degrades, weight loss is greater than 1.5mg/cm
2
In this test, alloy of the present invention has very strong heat-resisting salt oxidation corrosion.Molybdenum concentration in the sample 2 makes the erosion resistance of alloy be higher than the erosion resistance of T332 alloy (sample 3).
The dactyoideus test-results of welding
The dactyoideus test of welding is consistent with dull and stereotyped test piece test.The dactyoideus test-results of welding changes per-cent with weight and represents.In (more than the 200 hours) beginning and the test piece of weighing termly during the whole test.Fig. 3 and 4 contrasts to be coated with nominal 0.10mg/cm respectively
2The weight of the hot brine corrosion test-results of the teardrop shape sample of the welding of salt deposit and a kind of alloy of the present invention (sample 2) tested under 1200 and 1500 respectively and prior art alloy changes data plot.In two width of cloth figure, can easily see: T316Ti uses very poorly again, proves the alloy that can not use in high-temperature corrosion environment.Shown in Fig. 3 and 4, the performance of other all test sample is equal to basically.The erosion resistance of alloy of the present invention (sample 2) under these test conditionss is best, and weight loss is less than 1%, and after testing 30 hours first approximately, weight no longer changes.The performance of alloy A L625 (sample 5) is better preferably than performance in the prior art for the performance of this alloy, and the alloy of sample 5 is after testing for a long time under 1500 °F, and original weight has reduced about 3%.The heat-resisting salt oxidisability of alloy of the present invention is than the excellence of other tested alloys.
In general, weight change information only is an incomplete parameter that is determined at than total effect of degrading under the vigorous erosion environment.Than the erosion in the vigorous erosion environment, for example hot salt oxidation corrosion is irregular often at occurring in nature, can take all factors into consideration most of cross section of alloy component, and single analytical results that changes from weight.Therefore, measure metal loss (representing) according to the standard test operation (Standard Practice for Simple Static Oxidation Testing) of the simple static oxidation test of ASTM-G54 with the per-cent that remains cross section.Fig. 5 has illustrated the parameter-definition that is obtained by this analysis.Test sample 30 has an initial thickness, T
0, distance 32 as shown in Figure 5.The percentage ratio of residual metallic is by the thickness T of carrying out the test sample after the corrosion test
M1(distance 34) determined divided by initial thickness (32).Unaffected metal percentage ratio is by the thickness T of the test sample that does not show the corrosion signal
m(distance 36 shown in Fig. 4) determined divided by initial thickness (32).To degrade fully under the situation of metal testing plate in corrosion, these results are better than simple weight loss measuring result.
Fig. 6 and 7 shows the metallographic test result.To low-temperature alloy, the analysis revealed of T-316Ti (sample 4) is under two kinds of test conditionss, and promptly the corrosion under 1200 and 1500 is obvious.After test under 1500, the original cross section of T316Ti test piece has only kept 25%.
Other tested alloys are 1200 use down fine, and unaffected sample 2,3 and 5 starting materialss that keep are higher than 90%.The loss percentage ratio of the original thickness of the Ni-based AL625 superalloy sample 5 that the analytical results explanation cost of test piece after test under 1500 is higher is low, but, begin to occur pit as shown in cross-sectional area percentage ratio (about 93%) that keeps and the difference between the unaffected metal percentage ratio (82%).As according to shown in the analytical results of ASTM-G54 method, the local pit of material has pointed out that material exists local corrosion to destroy the data of possibility.The test piece that contains the T332 alloy is at 1500 also some pits a little after the test down, and the unaffected starting materials part of reservation is less than 75%.
Alloy of the present invention (sample 2) under two temperature the test after, the unaffected percentage ratio maximum that retains.This result shows: molybdenum has delayed degrading of protective oxide film and has separated.The percentage ratio of cross section that the test back keeps and the uninfluenced area that retains approximates 90%.This shows: alloy of the present invention is uniformly by the hot brine corrosion on the whole surface of test test piece, does not cause too early corrosion failure because of partial corrosion failure.On the contrary, partial corrosion failure has appearred in prior art T332 alloy (sample 3).Analysis revealed to sample 3: pit is arranged slightly, have local corrosion destructive possibility.
Should be clear: this specification sheets has illustrated with clear understands those aspects of the relevant the present invention of the present invention.Aspects more of the present invention are conspicuous for those skilled in the art, therefore, oversimplify in order to make description of the invention, do not put down in writing more elusive content in the text.Be described although the present invention is directed to some embodiment,, those skilled in the art should be realized that according to foregoing description the present invention can have many improvement and change.All this class improvement and changes that the present invention is made are all covered by foregoing description and accompanying Claim book.
Claims (17)
1. an austenitic stainless steel comprises 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum and less than 0.8% (weight) silicon.
2. the austenitic stainless steel of claim 1 further comprises 2～4% (weight) molybdenum.
3. the austenitic stainless steel of claim 1 further comprises 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus and 0～0.02% (weight) sulphur.
4. the austenitic stainless steel of claim 1 further comprises 2～4% (weight) molybdenum, 0.15～0.6% (weight) titanium and 0.15～0.6% (weight) aluminium.
5. the austenitic stainless steel of claim 4 further comprises 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus and 0～0.02% (weight) sulphur.
6. austenitic stainless steel, mainly by 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum, 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus, 0～0.02% (weight) sulphur, less than 0.8% (weight) silicon, 0.15～0.6% (weight) titanium, 0.15～0.6% (weight) aluminium, 0～0.75% (weight) copper, iron and unavoidable impurities are formed.
7. austenitic stainless steel, mainly by 19～23% (weight) chromium, 30～35% (weight) nickel, 2～4% (weight) molybdenum, 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus, 0～0.02% (weight) sulphur, less than 0.8% (weight) silicon, 0.15～0.6% (weight) titanium, 0.15～0.6% (weight) aluminium, 0～0.75% (weight) copper, iron and unavoidable impurities are formed.
8. manufacturing goods that comprise austenitic stainless steel comprise 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum and less than 0.8% (weight) silicon.
9. the manufacturing goods of claim 8, wherein austenitic stainless steel comprises 2～4% (weight) molybdenum.
10. the manufacturing goods of claim 8, wherein austenitic stainless steel further comprises 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus and 0～0.02% (weight) sulphur.
11. the manufacturing goods of claim 8, wherein austenitic stainless steel further comprises 2～4% (weight) molybdenum, 0.15～0.6% (weight) titanium and 0.15～0.6% (weight) aluminium.
12. the manufacturing goods of claim 8, wherein austenitic stainless steel further comprises 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus and 0～0.02% (weight) sulphur.
13. make goods for one kind, comprise a kind of mainly by 19～23% (weight) chromium, 30～35% (weight) nickel, 1～6% (weight) molybdenum, 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus, 0～0.02% (weight) sulphur, less than 0.8% (weight) silicon, 0.15～0.6% (weight) titanium, 0.15～0.6% (weight) aluminium, 0～0.75% (weight) copper, the austenitic stainless steel that iron and unavoidable impurities are formed.
14. make goods for one kind, comprise a kind of mainly by 19.2～23% (weight) chromium, 30～35% (weight) nickel, 2～4% (weight) molybdenum, 0～0.1% (weight) carbon, 0～1.5% (weight) manganese, 0～0.05% (weight) phosphorus, 0～0.02% (weight) sulphur, less than 0.8% (weight) silicon, 0.15～0.6% (weight) titanium, 0.15～0.6% (weight) aluminium, 0～0.75% (weight) copper, the austenitic stainless steel that iron and unavoidable impurities are formed.
15. the goods of each manufacturing of claim 8～14, wherein the goods of Zhi Zaoing are to be selected from automobile, automotive exhaust system component, flexible joint pipe, heating unit valve jacket and liner.
16. a method of making goods comprises:
A kind of 19～23% (weight) chromium that comprises is provided, 30～35% (weight) nickel, 1～6% (weight) molybdenum and less than the austenitic stainless steel of 0.8% (weight) silicon is made goods with this austenitic stainless steel.
17. the method for claim 16, wherein goods are to be selected from automotive exhaust system component, flexible joint pipe and liner.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US64131700A | 2000-08-17 | 2000-08-17 | |
| US09/641,317 | 2000-08-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN1447863A true CN1447863A (en) | 2003-10-08 |
Family
ID=24571858
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN01810365A Pending CN1447863A (en) | 2000-08-17 | 2001-08-17 | Oxidation and corrosion resistant austenitic stainless steel including molybedenum |
Country Status (13)
| Country | Link |
|---|---|
| EP (1) | EP1317571A1 (en) |
| JP (1) | JP2004519555A (en) |
| KR (1) | KR20030022111A (en) |
| CN (1) | CN1447863A (en) |
| AU (1) | AU2001286538A1 (en) |
| BR (1) | BR0111078A (en) |
| CA (1) | CA2406341A1 (en) |
| MX (1) | MXPA02010477A (en) |
| NO (1) | NO20030688L (en) |
| PL (1) | PL365626A1 (en) |
| RU (1) | RU2003104279A (en) |
| WO (1) | WO2002014570A1 (en) |
| ZA (1) | ZA200209033B (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101709463B (en) * | 2009-11-30 | 2011-04-27 | 华南理工大学 | Surface treatment method for improving wear resistance and corrosion resistance of austenitic stainless steel shell |
| CN103244251A (en) * | 2012-02-10 | 2013-08-14 | 佛吉亚排放控制技术德国有限公司 | Exhaust system |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US20040156737A1 (en) * | 2003-02-06 | 2004-08-12 | Rakowski James M. | Austenitic stainless steels including molybdenum |
| US7985304B2 (en) | 2007-04-19 | 2011-07-26 | Ati Properties, Inc. | Nickel-base alloys and articles made therefrom |
| CN106929739A (en) * | 2017-04-20 | 2017-07-07 | 天津达祥精密工业有限公司 | A kind of microalloying chromium nickel series austenite heat resisting steel and its preparation method and application |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS6199661A (en) * | 1984-10-22 | 1986-05-17 | Sumitomo Metal Ind Ltd | High strength and high toughness welded clad steel pipe for line pipe |
| US4784831A (en) * | 1984-11-13 | 1988-11-15 | Inco Alloys International, Inc. | Hiscor alloy |
| JP2760004B2 (en) * | 1989-01-30 | 1998-05-28 | 住友金属工業株式会社 | High-strength heat-resistant steel with excellent workability |
| US5827377A (en) * | 1996-10-31 | 1998-10-27 | Inco Alloys International, Inc. | Flexible alloy and components made therefrom |
| JP2000001754A (en) * | 1998-06-18 | 2000-01-07 | Hitachi Ltd | Austenitic alloy and structure using the same |
| JP2000192205A (en) * | 1998-12-22 | 2000-07-11 | Daido Steel Co Ltd | Heat resistant alloy excellent in oxidation resistance |
-
2001
- 2001-08-17 EP EP01965992A patent/EP1317571A1/en not_active Withdrawn
- 2001-08-17 PL PL01365626A patent/PL365626A1/en unknown
- 2001-08-17 CA CA002406341A patent/CA2406341A1/en not_active Abandoned
- 2001-08-17 JP JP2002519692A patent/JP2004519555A/en active Pending
- 2001-08-17 RU RU2003104279/02A patent/RU2003104279A/en not_active Application Discontinuation
- 2001-08-17 KR KR1020027014538A patent/KR20030022111A/en not_active Application Discontinuation
- 2001-08-17 AU AU2001286538A patent/AU2001286538A1/en not_active Abandoned
- 2001-08-17 CN CN01810365A patent/CN1447863A/en active Pending
- 2001-08-17 BR BR0111078-0A patent/BR0111078A/en not_active Application Discontinuation
- 2001-08-17 MX MXPA02010477A patent/MXPA02010477A/en unknown
- 2001-08-17 WO PCT/US2001/025849 patent/WO2002014570A1/en not_active Application Discontinuation
-
2002
- 2002-11-06 ZA ZA200209033A patent/ZA200209033B/en unknown
-
2003
- 2003-02-12 NO NO20030688A patent/NO20030688L/en not_active Application Discontinuation
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101709463B (en) * | 2009-11-30 | 2011-04-27 | 华南理工大学 | Surface treatment method for improving wear resistance and corrosion resistance of austenitic stainless steel shell |
| CN103244251A (en) * | 2012-02-10 | 2013-08-14 | 佛吉亚排放控制技术德国有限公司 | Exhaust system |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2004519555A (en) | 2004-07-02 |
| NO20030688D0 (en) | 2003-02-12 |
| CA2406341A1 (en) | 2002-02-21 |
| PL365626A1 (en) | 2005-01-10 |
| AU2001286538A1 (en) | 2002-02-25 |
| ZA200209033B (en) | 2004-02-23 |
| WO2002014570A1 (en) | 2002-02-21 |
| RU2003104279A (en) | 2004-12-27 |
| KR20030022111A (en) | 2003-03-15 |
| BR0111078A (en) | 2004-07-06 |
| EP1317571A1 (en) | 2003-06-11 |
| MXPA02010477A (en) | 2003-03-10 |
| NO20030688L (en) | 2003-02-12 |
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