High Performance Austenitic Stainless Steel

High PerformanceAustenitic Stainless SteelCharacteristic properties• Very good resistance to uniform corrosion• Good to exceptionally good resistance to pitting and crevice corrosion• Very good resistance to various types of stress corrosion cracking• Very good ductility• Good weldability• Excellent formabilityApplications• Process equipment in chemical industry• Bleaching equipment in the pulp and paper industry• Flue gas cleaning• Desalination• Seawater handling• Hydrometallurgy• Food and beverage• Pharmaceuticals• Heat exchangersSteel gradesOutokumpu EN ASTM904L 1.4539 N08904254 SMO® 1.4547 S312544529 1.4529 N08926/N083674565 1.4565 S34565654 SMO® 1.4652 S32654Outokumpu International Chemical composition, % National steel designations, steel name steel No typical values superseded by EN EN ASTM C N Cr Ni Mo Others BS DIN NF SS4404 1.4404 316L 0.02 – 17 10 2.1 – 316S11 1.4404 Z3 CND 17-11-07 2348 4439 1.4439 S31726 0.02 0.14 18 13 4.1 – – 1.4439 Z3 CND 18-14-05 Az –904L 1.4539 N08904 0.01 – 20 25 4.3 1.5 Cu 904S13 1.4539 Z2 NCDU 25-20 2562254 SMO® 1.4547 S31254 0.01 0.20 20 18 6.1 Cu – – – 23784529 1.4529 N08926/N08367 0.01 0.20 20 25 6.5 Cu – 1.4529 – –4565 1.4565 S34565 0.02 0.45 24 17 4.5 5.5 Mn – 1.4565 – –654 SMO® 1.4652 S32654 0.01 0.50 24 22 7.3 3Mn, Cu – – – –2205 1.4462 S32205* 0.02 0.17 22 5.7 3.1 – 318S13 1.4462 Z3 CND 22-05 Az 23772507 1.4410 S32750 0.02 0.27 25 7.0 4.0 – – – Z3 CND 25-06 Az 2328* Also available as S31803 General characteristicsHigh performance austenitic stainless steels differ substanti-ally from more conventional grades with regard to resistance to corrosion and, in some cases, also mechanical and physical properties. This is mainly due to the high contents of chro-mium, nickel, molybdenum and nitrogen. High performance austentic stainless steels have good weldability and excellent formability. Outokumpu manufactures a number of steels of this type: 904L, 254 SMO®, 4565 and 654 SMO®. Grade 4529 can also be delivered if specified. The properties of 4529 are in general terms very similar to those of 254 SMO®.Chemical compositionThe typical chemical composition of Outokumpu grades are shown in Table 1. The chemical composition of a specific steel grade may vary slightly between different national standards. The required standard will be fully met as specified on the order.Chemical composition Table 1www.outokumpu.comDuplex Austenitic 2 High Performance Austenitic Stainless SteelMechanical propertiesThe strength and elongation of 904L are similar to those for conventional austenitic stainless steels. The addition of nitrogen in 254 SMO®, 4529, 4565 and 654 SMO® gives higher proof strength and tensile strength, see tables 2 and 3.Despite the greater strength of these steels, the possibilities for cold as well as hot forming are very good.MicrostructureThe high performance austenitic stainless steels have a fully austenitic microstructure in the quench annealedcondition. They can, however, contain traces of interme-tallic phases (sigma phase) at the centre of the material. Normally, this does not affect the corrosion resistance or mechanical properties of the steel. Provided that the recom-mendations given for hot forming, welding and heat treat-ment are followed, such precipitates typically have negligible effect on usability. 904L 254 SMO® 4529 4565 654 SMO®Density g/cm3 8.0 8.0 8.1 8.0 8.0 Modulus of elasticity GPa 195 195 195 190 190 Linear expansion at (20 ? 100)°C x10-6/°C 15.8 16.5 15.8 14.5 15 Thermal conductivity W/m°C 12 14 12 12 11Thermal capacity J/kg°C 450 500 450 450 500Electric resistivity µ?m 1.0 0.85 1.0 0.92 0.78Tensile properties at elevated temperatures, minimum values according to EN, MPa Table 3Typical values according to EN 10088 Table 4Physical PropertiesIn Table 4 typical values of some physical properties are given for 904L, 254 SMO®, 4565 and 654 SMO®.Mechanical properties at 20°C Table 2 Minimum values, Typical values according to EN 10088 P H C P (15mm) H (4mm) C (1mm)904L Proof strength Rp0.2 MPa 220 220 240 260 280 340Proof strength Rp1.0 MPa 260 260 270 300 330 370Tensile strength Rm MPa 520 530 530 600 600 700Elongation A5 % 35 35 35 50 45 54Hardness HB – – – 155 150 163254 SMO®Proof strength Rp0.2 MPa 300 300 320 340 390 380Proof strength Rp1.0 MPa 340 340 350 380 440 420Tensile strength Rm MPa 650 650 650 680 740 740Elongation A5 % 40 35 35 50 45 59Hardness HB – – – 160 190 1784529Proof strength Rp0.2 MPa 300 – – 320 – *Proof strength Rp1.0 MPa 340 – – 360 – *Tensile strength Rm MPa 650 – – 700 – *Elongation A5 % 40 – – 50 – *Hardness HB – – – 180 – *4565Proof strength Rp0.2 MPa 420 420 420 440 – *Proof strength Rp1.0 MPa 460 460 460 480 – *Tensile strength Rm MPa 800 800 800 825 – *Elongation A5 % 30 30 30 55 – *Hardness HB – – – 200 – *654 SMO®Proof strength Rp0.2 MPa 430 430 430 475 – 520Proof strength Rp1.0 MPa 470 470 470 510 – 590Tensile strength Rm MPa 750 750 750 860 – 950Elongation A5 % 40 40 40 60 – 59Hardness HB – – – 200 – 226 P = hot rolled plate. H = hot rolled strip. C = cold rolled coil and strip. *new product, typical values under establishment. 904L 254 SMO® 4529 4565 654 SMO® Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm Rp0.2 Rp1.0 Rm100°C 205 235 500 230 270 615 230 270 560 350 400 750 350 390 680200°C 175 205 460 190 225 560 190 225 520 270 310 640 315 355 620300°C 145 175 440 170 200 525 170 205 480 240 270 640 300 335 585400°C 125 155 – 160 190 510 160 190 – 210 240 610 295 330 5603High Performance Austenitic Stainless SteelTemperature, °C100 80 60 40 20 0 2 4 6 8 10HCI % 254 SMO®654 SMO®904L254 SMO® 654 SMO®904L4404Temperature, °C100 80 60 40 20 0 10 20 30 40 50H2SO4 +2000 ppm Cl Temperature, °C10080604020254 SMO®654 SMO®904L440444040 10 20 30 40 50 60 70 80 90 100 H2SO4 % 440445654565Temperature, °C100 80 60 40 20 0 2 4 6 8 10HCI % 254 SMO®654 SMO®904L254 SMO® 654 SMO®904L4404Temperature, °C100 80 60 40 20 0 10 20 30 40 50H2SO4 +2000 ppm Cl Temperature, °C10080604020254 SMO®654 SMO®904L440444040 10 20 30 40 50 60 70 80 90 100 H2SO4 % 440445654565Fig. 2. Isocorrosion curves, 0.1 mm/year, in sulphuric acid containing 2000 ppm chloride.Fig. 1. Isocorrosion curves, 0.1 mm/year, in pure sulp-huric acid.Temperature, °C100 80 60 40 20 0 2 4 6 8 10HF % 254 SMO®654 SMO®904LTemperature, °C100 80 60 40 20 0 5 10 15 20 25 30 35 H2SiF6 % 254 SMO®654 SMO®904L44044404Fig. 5. Isocorrosion curves, 0.1 mm/year, in pure fluosilicic acid.Temperature, °C100 80 60 40 20 0 2 4 6 8 10HF % 254 SMO®654 SMO®904LTemperature, °C100 80 60 40 20 0 5 10 15 20 25 30 35 H2SiF6 % 254 SMO®654 SMO®904L44044404Fig. 4. Isocorrosion curves, 0.1 mm/year, in pure hydrofluoric acid.Temperature, °C100 80 60 40 20 0 2 4 6 8 10HCI % 254 SMO®654 SMO®904L254 SMO® 654 SMO®904L4404Temperature, °C100 80 60 40 20 0 10 20 30 40 50H2SO4 +2000 ppm Cl Temperature, °C10080604020254 SMO®654 SMO®904L440444040 10 20 30 40 50 60 70 80 90 100 H2SO4 % 440445654565Fig. 3. Isocorrosion curves, 0.1 mm/year, in pure hydrochloric acid.Corrosion resistanceUniform corrosionThe high content of alloying elements gives the steels 904L, 254 SMO®, 4565 and 654 SMO® exceptionally good resis-tance to uniform corrosion. 904L was originally developed to withstand environ-ments involving dilute sulphuric acid and it is one of the few stainless steels that, at temperatures of up to 35°C, pro-vides full resistance in such environments within the entire range of concentration, from 0 to 100%, Figure 1. 904L also offers good resistance to a number of other inorganic acids, e.g., phosphoric acid, as well as most organic acids. Acids and acid solutions containing halide ions can, howe-ver, be very aggressive and the corrosion resistance of 904L may be insufficient. Examples of such acids are hydrochloric acid, hydrofluoric acid, chloride contaminated sulphuric acid, phosphoric acid produced according to the wet pro-cess (WPA) at elevated temperatures, and also pickling acid based on nitric acid and hydrofluoric acid mixtures. In these cases 254 SMO®, 4565 and 654 SMO® are preferable and in certain cases they can be an alternative to other considerably more expensive alloys, Figures 2-5 and Tables 5 and 6. Steel grade PRE4404 254439 332205 35904L 352507 43254 SMO® 434529 454565 46654 SMO® 56 The PRE value can be used for rough comparisons of different materials. A much more reliable means is to rank the steel according to the critical pitting temperature of the material (CPT). There are several different methods available to measure the CPT. Figure 6 shows the CPT, as measured in the Avesta Cell (ASTM G 150), in a 1M NaCl solution (35,000 ppm or mg/l chloride ions). The actual values of mill finish surface may vary between different product forms.4 High Performance Austenitic Stainless SteelFractional distillation of tall oil often need better material than the 4404, or even the more frequently used 4439. Table 7 presents the results of exposing test coupons at a Swedish tall oil plant with the object of determining suita-ble material for woven packings of stainless steel. In this particular case, packings produced from about 20,000 km of 0.16 mm diameter 254 SMO® wire were used. In hot concentrated caustic solutions the corrosion resistance is mainly determined by the nickel content of the material, and 904L in particular can be a good alternative to more conventional stainless steels. For more detailed information concerning the corrosion resistance of the different steels in other environments, see the Outokumpu Corrosion Handbook.Pitting and crevice corrosionResistance to pitting corrosion (and also crevice corrosion) is determined mainly by the chromium, molybdenum and nitrogen content in the material. This is often illustrated using the pitting resistance equivalent (PRE) for the mate-rial, which can be calculated using the formula:PRE = %Cr + 3.3 x %Mo + 16 x %N. PRE values are pre-sented in Table 8.Steel grade Corrosion rate, mm/year4404 >6904L 0.47254 SMO® 0.27654 SMO® 0.06*Composition: 20% HNO3 + 4% HF.Uniform corrosion in pickling acid* at 25°C Table 6Corrosion rates in a fatty acid column for thedistillation of tall oil at 235°C Table 7PRE values for different stainless steels Table 8Steel grade Corrosion rate, mm/year4404 0.884439 0.29904L 0.06254 SMO® 0.01Composition: 54% P2O5, 0.06% HCl, 1.1% HF,4.0% H2SO4, 0.27% Fe2O3, 0.17% Al2O3, 0.10% SiO2, 0.20% CaO and 0.70% MgOUniform corrosion in wet processphosphoric acid at 60°C Table 5Steel grade Corrosion rate, mm/year4404 >5904L 1.2254 SMO® 0.05Grade 4565, and especially 654 SMO®, have such a good resistance to pitting that common test methods are not suffi-ciently aggressive to initiate any corrosion. A better measure of resistance is given by evaluating the results of various cre-vice corrosion tests.CPT, °C span CPT min - CPT max010Austenitic Duplex3020405070608090100430744044436254 SMO®4564529 5654 SMO®LDX 2101®2304LDX 2404®22052507904LFig. 6. Typical critical pitting corrosion temperatures (CPT) in 1M NaCl measured according to ASTM G150 using the Avesta Cell. Test surfaces were wet ground to 320 mesh. CPT varies with pro-duct form and surface finish.5High Performance Austenitic Stainless SteelIn narrow crevices the passive film may more easily be attacked and in unfavourable circumstances stainless steel can be subjected to crevice corrosion. Examples of such narrow crevices may be under gaskets in flange fittings, under seals in certain types of plate heat exchangers, or under hard adherent deposits. Crevice corrosion occurs in the same environments as pitting, i.e. in chloride (halogenide) containing environme-nts. Higher contents of chromium, molybdenum or nitrogen enhance the corrosion resistance of the steel, see Figure 7. Guide to material selectionFigure 8 illustrates to which approximate temperatures stain-less steel can be used in aerated waters of varying chloride content. It should be underlined that the resistance of a material is also influenced by factors other than temperature and chloride content. Examples of such factors are weld defects, presence of oxide from welding, contamination of the steel surface by particles of non-alloyed or low-alloyed steel, microbial activity, pH and chlorination of water. For very severe crevices, such as under the seals of plate heat exchangers or inside threaded connections, the lines for crevice corrosion will move to the left, i.e. lower chloride content/temperature can be accepted. Fig. 7. Typical critical crevice corrosion tem-perature (CCT) according to ASTM G48 Method F. Test surfaces were dry ground to 120 mesh. CCT varies with product form and surface finish. 8070605040302010 100 1000Cl- ppmp=pitting, full line c=crevice corrosion, broken line807060504030204307 p4404 c4307 c4404 p100 10000 100000Cl- ppmp=pitting, full line c=crevice corrosion, broken line 1000904L c 254 SMO® c4404 c4404 p2205 c2205 p904L p254 SMO® pTemperature, °C Temperature, °CFig. 8. Engineering diagram illustrating the risk of pitting and crevice corrosion on high performance stainless steel in water of different chloride content or temperature.CCT, °C 010Austenitic Duplex302040507060254 SMO®4565654 SMO®LDX 2404®22052507904L6 High Performance Austenitic Stainless SteelIn crevice-free, welded constructions, 254 SMO® may normally be used in chlorinated seawater with a chlorine content of up to 1 ppm at temperatures up to about 45°C. 654 SMO® should be used for flange joints, or the sealing surfaces should be overlay welded, e.g., using an ISO Ni Cr 25 Mo16 type filler, if the temperature exceeds 30°C. Higher chlorine content can be permitted if chlori nation is intermittent.Tests have indicated that 654 SMO® can be used in plate heat exchangers with chlorinated seawater as a cooling medium at temperatures up to at least 60°C. The risk of crevice corrosion in non-chlorinated seawater is considerably lower. 254 SMO® has sucessfully been used in some fifty installations for desalination of seawater accor-ding to the reverse osmosis process. 654 SMO® is resistant to pitting in natural boiling seawater. Minimum stress for failure, % of Rp0.2 at 200 °C1201008060402004404 2205 904L 2507 254 SMO® 654 SMO®<10Fig. 9. Typical threshold stresses determined using the drop evaporation test.Stress corrosion crackingConventional stainless steels such as 4307 and 4404 are sen-sitive to stress corrosion cracking (SCC) under certain condi-tions, i.e. a special environment in combination with tensile stress in the material and often also an elevated temperature. Resistance to SCC increases with the increased content of above all nickel and molybdenum. This implies that the high performance austenitic steels 904L, 254 SMO®, 4565 and 654 SMO® have very good resistance to SCC. Different methods are used to rank stainless steel grades with regard to their resistance to SCC. The results can vary depending on the method and testing environment. The resistance to stress corrosion cracking in a chloride solution under evaporative conditions can be determined according to the drop evaporation method. Here a salt solution is allowed to slowly drip onto a heated specimen, being subjected to tensile stress. By this method the threshold value is determined for the maximum relative stress resulting in rupture after 500 hours testing. The threshold value is usually expressed as a percen-tage of the proof strength of the steel at 200°C. Figure 9 shows the results of such a test, where high perfor-mance austenitic steels and duplex steels offer considerably better resistance to SCC than grade 4404, Figure 9.SeawaterNatural seawater contains living organisms, which very quickly form a biofilm on stainless steel. This film increases the corrosion potential of the steel and thus, also the risk of pitting and crevice corrosion. The activity of the biofilm is temperature related. The different organisms are adapted to the natural water tem-perature of their habitat. Their activity varies between the different seas around the world. This means that in cold seas the natural water is most aggressive at 25-30°C while the corresponding value in tropical seas is just above 30°C. The biological activity ceases at higher temperatures. In many seawater systems the water is chlorinated with either chlorine or hypochlorite solutions to reduce the risk of fouling. Both chlorine and hypochlorite are strongly oxi-dising agents and they cause the corrosion potential of the steel surface to exceed what is normal in non-chlorinated seawater, which in turn means increased risk of corrosion. In chlorinated seawater the aggressiveness increases as the tem-perature rises.7High Performance Austenitic Stainless SteelThe resistance to alkaline SCC is more dependent on the nickel content of the material and also in this respect high performance austenitic steels are superior to conventional stainless steels. Nickel-based alloys are, however, to be pre-ferred in the most demanding conditions.Sulphide-induced stress corrosion crackingHydrogen sulphide can sometimes cause embrittlement of ferritic steel and even of cold-worked duplex and austenitic steels. The sensitivity to cracking increases when the envi-ronment contains both hydrogen sulphide and chlorides. Such “sour” environments occur for example in the oil and gas industry. NACE MR0175/ISO 15156-3 provides requirements and recommendations for selection of corrosion resistant alloys for use in oil and natural gas production in H2S environ-ments. It identifies materials that are resistant to cracking in a defined H2S containing environment, but does not gua-rantee that the material selected using the standard will be immune from cracking under all service conditions. Austenitic steels 904L, 254 SMO®, 4565 and 654 SMO® are included in NACE MR0175/ISO 15156-3. In accordance with NACE MR0175/ISO 15156-3 solution annealed 904L, 254 SMO®, 4565 and 654 SMO® are acceptable for use for any component or equipment up to 60oC in sour environments, if the partial pressure of hydrogen sulphide (pH2S) does not exceed 1 bar (15psi), or without restriction on temperature and pH2S if the chloride concentration does not exceed 50 ppm. Further, solution annealed 254 SMO®, 4565 and 654 SMO® are acceptable for use up to 171oC or pH2S up to 7 bar (100 psi) if the chloride concentration does not exceed 5000 ppm.Intergranular corrosionHigh performance austenitic steels have such a low carbon content that the risk of conventional intergranular corrosion caused by chromium carbide precipitates in connection with welding is negligible. This means that welding can be performed without risk of intergranular corrosion.Erosion corrosionUnlike copper alloys, stainless steel generally offers very good resistance to impingement attack and there are no motives for limiting the velocity of water, e.g. in piping systems that convey seawater. Further, stainless steel is not sensitive to seawater that has been contaminated by sulphur compounds or ammonia. In systems subjected to particles causing hard wear, e.g., sand or salt crystals, the higher surface hardness of duplex steels can in some cases be an advantage.Corrosion rate, mm/year1.00.80.60.40.20.01 2 3 4 5 10Area ratio 254 SMO /MetalMuntzmetalCuNi70/30MonelAl-bronzeFig. 10. Galvanic cor ro sion of cop per alloys in slow moving sea wa ter at ambient tem pe ra ture.Galvanic corrosionThe high performance austenitic steels 254 SMO®, 4565 and 654 SMO® are not affected by galvanic corrosion if they are connected to titanium in systems used for conveying seawater. However, the rate of corrosion for copper alloys is increased if they come into contact with most stainless steels (or with titanium). The intensity of corrosion is closely rela-ted to the surface area ratio between the stainless steel and the copper alloy, Figure 10. The tests presented have been carried out with 254 SMO® but the relation is the same for other high performance steels. The galvanic effect is reduced somewhat if the seawater is chlorinated.8 High Performance Austenitic Stainless SteelFig. 11. Enginering stress-strain curves for high performance austenitic grades and standard austenitic grade 4404 (1.0 mm thick cold rolled).Fig. 12. r-values for high performance austenitic grades and standard austenitic grade 4404.Fig. 13. Formability ranking of high performance austenitic grades in relation to standard austenitic grade 4404.FabricationForming All Outokumpu high performance austenitic grades have very good formability properties and are suitable for all form-ing processes available for stainless steel. The somewhat higher proof strength and in some cases lower fracture elongation com-pared to the most common standard austenitic steel grades can impose small differences in forming behaviour, depending on chosen forming technique, such as an increased springback. This can be compensated for, especially if the forming process can be designed for the specific steel grade. Moreover, an excel-lent interplay between the high proof strength, work hardening rate and elongation, make the high nitrogen containing grades 4565 and 654 SMO® excellently suited for light weight and cost effective applications with complex shapes. The impact of a high strength varies for different forming techniques. Common for all high performance austenitic grades are that the estimated forming forces will be higher than for the standard austenitic stainless steel grades. This effect will be reduced if down gauging is possible. A common issue for the high strength steels is the high proof strength which may result in higher demands on the tool materials and the lubricant. Also in this respect attention should be given to the possibility of down gauging. For more information on forming properties, please contact Outokumpu. Cold forming The high strength of the high nitrogen containing grades 4565 and 654 SMO® is clearly demonstrated when the stress- strain curves of high performance austenitic stainless steel grades are compared with the standard austenitic grade 4404, Figure 11. The deformation hardening rate is almost similar for all the austenitic grades presented in Figure 11. The formability of Outokumpu’s high performance austenitic stainless steel grades can be characterized in several ways. A sheet materials ability to withstand thinning during forming is demonstrated by the r-value in different tensile directions and the higher the r-value the better, 654 SMO® shows excellent r-values as illustrated in Figure 12. Figure 13 gives a relative comparison of the formability in plain strain condition between Outokumpu high perfor-mance austenitic grades and the standard grade 4404. The ranking represents the most critical failure mode in sheet forming, especially in forming operations dominated by thin-ning (stretching). In pure drawing, all austenitic grades are comparable in that about the same limiting drawing ratio can be drawn.Hot formingSuitable temperatures for hot forming are shown in Table 9. Higher tempera tures cause a deterioration in ductility and an increase in the formation of oxides (scaling). Normally hot working should be followed by solution annealing and quenching but, for 904L, if the hot forming is discontinued at a temperature above 1100°C and the material is quenched directly thereafter the material may be used without subse-quent heat treatment. It is important that the entire work-piece has been quenched from temperatures above 1100°C. In the case of partial heating or partial cooling below 1100°C 904L440410008009007006004005002003001000Engineering stress (MPa)Engineering Plastic Strain (%)0 20 40 604565254 SMO®654 SMO®1.41.210.80.60.40.20r-valueAngle to rolling direction0 45 904404904L254 SMO4565654 SMO®®1.00.80.70.90.60.50.40.30.20.10.04404904L 4565Formability in plane strain condition254 SMO® 654 SMO®9High Performance Austenitic Stainless SteelMachiningAustenitic stainless steels work harden quickly and this, together with their high toughness, means that they are often perceived as problematic from a machining perspective, e.g. in operations such as turning, milling and drilling. This applies to an even greater extent to most highly alloyedsteels and especially those that have a high nitrogen content, i.e. 254 SMO®, 4565 and 654 SMO®. However, with the right choice of tools, tool settings and cutting speeds, these materials can be sucessfully machined. For further information see the Outokumpu Machining Guidelines for these grades.WeldingAll these steels are well suited for welding and the methods used for welding conventional austenitic steels can also be used on 904L, 254 SMO®, 4565 and 654 SMO®. However, due to their stable austenitic structure, they are somewhat more sensi-tive to hot cracking in connection with welding and generally welding should be performed using a low heat input. On delivery, sheet, plate and other processed products have a homogeneous austenitic structure with an even dist-ribution of alloying elements in the material. Solidification after partial remelting, e.g. by welding, causes redistribution of certain elements such as molybdenum, chromium and nickel. These variations, segregation, remain in the cast structure of the weld and can impair the corrosion resistance in certain environments. Segregation tendency is less evident in 904L and this steel is normally welded using a filler of the same composition as the base material and it can even be welded without fil-ler. For 254 SMO®, 4565 and 654 SMO®, the variation for molybdenum in particular is so great that it must be com-pensated for by using fillers, which have a higher content of molybdenum. EN ISO Ni Cr 21 Mo Fe Nb type of filler is normally used for welding 254 SMO® and 4529 and 904L 254 SMO® 4529 4565 654 SMO®Hot forming** 1150 - 850 1200 - 1000 1150 - 850 1200 - 950 1200 - 1000Solution annealing** 1060 - 1140 1150 - 1200* 1120 - 1180 1120 - 1170 1150 - 1200Pressure vessel approval -196 - +400 -196 - +400 -196 - +400 -196 - +400 RT - +427**** Quenching with water at a thickness above 2 mm, below 2 mm an annealing temperature of 1120-1150°C and cooling with air/water can be used.** According to EN 10088-2*** ASME Code Case 2195-1Characteristic temperatures, °C Table 9ISO Ni Cr 25 Mo 16 type filler is recommended for the welding of 4565 and 654 SMO®. The effect of segregation after welding can also be reduced by subsequent heat treatment and quench annealing, but such action is normally limited to uncomplicated geome-tries, e.g., pipes, pipe fittings and end pieces.* Avesta Welding designation. For use in certain oxidi-sing environments, e.g. chlorine dioxide stage in pulp bleaching plants, when welding 254 SMO® or 4565. Table 10Steel Welding consumables grade Covered electrodes Wires ISO 3581 ISO 14343 ISO 14172 ISO 18274 904L 20 25 CuL 20 25 CuL254 SMO® Ni Cr 21 Mo Fe Nb or Ni Cr 22 Mo 9 Nb Ni Cr 25 Mo 16 or P54* 4529 Ni Cr 21 Mo Fe Nb or Ni Cr 22 Mo 9 Nb Ni Cr 25 Mo 16 or P54* 4565 Ni Cr 21 Mo Fe Nb or Ni Cr 22 Mo 9 Nb Ni Cr 25 Mo 16 or P54* 654 SMO® Ni Cr 25 Mo 16 Ni Cr 25 Mo 16 or if the cooling has been too slow, hot working should always be followed by solution annealing and quenching. 254 SMO® 4565 and 654 SMO® should be quenched at a temperature of at least 1150°C after hot working to avoid residual intermetallic phases. These phases can also rebuild if the subsequent cooling process is too slow, resulting in impaired corrosion resistance.Welding consumables In the case of multi-run welding, the workpiece should be allowed to cool to 100°C before welding the next run. This is the case for all four steels. For further information regarding joint selection and pre-paration, welding techniques, heat input and post-weld clea-ning, see the Outokumpu Welding Handbook.Post fabrication treatmentIn order to restore the stainless steel surface and achieve good corrosion resistance after fabrication, it is often necessary to perform a post fabrication treatment.There are different methods available, both mechanical methods such as brushing, blasting and grinding and chemical methods, e.g. pickling. Which method to apply depend on what conse-quences the fabrication caused, i.e. what type of imperfections to be removed, but also on requirements with regard to corro-sion resistance, hygiene and aesthetic appearance.For more information, see the Outokumpu Welding Handbook.10 High Performance Austenitic Stainless Steel ProductHot rolled plate, Hot rolled sheet and stripCold rolled sheet and stripBarsTube and PipePipe fittings Wire rod and drawn wire904L 254 SMO® 654 SMO® 45654529see also www.outokumpu.comProductsOutokumpu products Table 1111High Performance Austenitic Stainless SteelMaterial standards Table 12EN 10028-7 Flat products for pressure purposes – Stainless steelsEN 10088-2 Stainless steels – Corrosion resisting sheet/plate/strip for general and construction purposesEN 10088-3 Stainless steels – Corrosion resisting semi-finished products/bars/rods/wire/sections for general and construction purposesEN 10088-4 Technical delivery conditions for sheet/plate and strip of corrosion resisting steels for construction purposesEN 10088-5 Technical delivery conditiions for bars, rods, wire, sections and bright products of corrosion resistant steels for construction purposesEN 10272 Stainless steel bars for pressure purposesEN 10283 Corrosion resistant steel castingsASTM A182 / ASME SA-182 Forged or rolled alloy-steel pipe flanges, forged fittings etc for high temperature serviceASTM A193 / ASME SA-193 Alloy and stainless steel bolts and nuts for high pressure and high temperature serviceASTM A240 / ASME SA-240 Heat-resisting Cr and Cr-Ni stainless steel plate/sheet/strip for pressure purposesASTM A249 / ASME SA-249 Welded austenitic steel boiler, superheater, heat exchanger and condenser tubesASTM A269 Seamless and welded austenitic stainless steel tubing for general serviceASTM A276 Stainless and heat-resisting steel bars/shapesASTM A312 / ASME SA-312 Seamless and welded austenitic stainless steel pipeASTM A351 / ASME SA-351 Steel castings, austenitic, duplex for pressure containing partsASTM A358 / ASME SA-358 Electric fusion-welded austenitic Cr-Ni alloy steel pipe for high temperatureASME SA-403 Wrought austenitic stainless steel piping fittingASTM A409 / ASME SA-409 Welded large diameter austenitic pipe for corrosive or high-temperature serviceASTM A473 Stainless steel forgings for general useASTM A479 / ASME SA-479 Stainless steel bars for boilers and other pressure vesselsASTM A743 Castings, Fe-Cr-Ni, corrosion resistant for general applicationASTM A744 Castings, Fe-Cr-Ni, corrosion resistant for severe serviceNACE MR0175 Sulphide stress cracking resistant material for oil field equipmentASTM B649 / ASME SB-649 Bar and wireNorsok M-CR-630 Material data sheets for 6Mo stainless steelVdTÜV WB 473 Austenitischer Walz- und Schmiedestahl. Blech, Band, Schmiedestück, Stabstahl für DruckbehälterVdTÜV WB 537 Stickstofflegiertes austenitischen Stahl X2CrNiMnMoN 25-18-6-5 Werkstoff-Nr 1.4565 Information given in this brochure may be subject to alterations without notice. Care has been taken to ensure that the contents of this publication are accurate but Outokumpu and its affiliated companies do not accept responsibility for errors or for information which is found to be misleading. Suggestions for or descriptions of the end use or application of products or methods of working are for information only and Outokumpu and its affiliated companies accept no liability in respect thereof. Before using products supplied or manufactured by the company the customer should satisfy himself of their suitability.1044EN-GB:6. Centrum Tryck AB, Avesta, Sweden. March 2011.www.outokumpu.comOutokumpu Stainless AB, Avesta Research CentreBox 74, SE-774 22 Avesta, Sweden Tel. +46 (0)226 810 00, Fax +46 (0)226 810 77research.stainless@outokumpu.comOutokumpu is a global leader in stainless steel. Our vision is to be the undisputed number one in stainless, with success based on operational excellence. Customers in a wide range of industries use our stainless steel and services worldwide. Being fully recyclable, maintenance-free, as well as very strong and durable material, stainless steel is one of the key building blocks for sustainable future. What makes Outokumpu special is total customer focus - all the way, from R&D to delivery. You have the idea. We offer world-class stainless steel, technical know-how and support. We activate your ideas. (www.outokumpu.com)