CN102605288B - Economical double-phase stainless steel with good welding property and manufacturing method for stainless steel - Google Patents
Economical double-phase stainless steel with good welding property and manufacturing method for stainless steel Download PDFInfo
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Abstract
The invention discloses economical double-phase stainless steel with good welding property. The stainless steel comprises the following components in percentage by weight: 0.01 to 0.04 percent of C, 0.2 to 1.0 percent of Si, 1.0 to 2.5 percent of Mn, 21.5 to 22.5 percent of Cr, 3.8 to 4.5 percent of Ni, 0.05 to 0.6 percent of Cu, 1.0 to 1.5 percent of Mo, 0.16 to 0.23 percent of N, and the balance of Fe and inevitable impurities, wherein the chromium-nickel equivalent ratio Creq/Nieq is 2.3 to 2.8, Creq is %Cr+%Mo+1.5*%Si, and Nieq is %Ni+30*%C+20*%N+0.33*%Cu+0.1*%Mn. In the solidification or welding cooling process of the material, the temperature interval of a single-phase zone of ferrite is less than 5 DEG C till the single-phase temperature zone of the ferrite does not exist. After the material is welded by a conventional electric arc welding method, the austenite content in a heat affected zone is more than 35 percent, and the critical pitting temperature of a welded seam reaches over 20 DEG C and is higher than the critical pitting temperature (the typical value is 16 DEG C) of the conventional austenitic stainless steel series 316; and the steel can be used for replacing the series 316, and is particularly applied in the field of welding.
Description
Technical field
The present invention relates to two-phase stainless steel making field, especially a kind of economical diphase stainless steel and manufacture method thereof with good welds, material solidification or welding process of cooling in, the temperature range of ferrite single phase region is less than 5 DEG C, until there is not the single-phase warm area of ferrite.Material is after conventional arc-welding method welding, and heat affected zone austenite content is greater than 35%, and the critical pitting temperature of weld seam reaches more than 20 DEG C.
Background technology
Duplex stainless steel is made up of ferrite and austenitic duplex, and wherein every Phase Proportion is no less than 30%.Feature due to two-phase structure makes duplex stainless steel have the advantage of ferritic stainless steel and austenitic stainless steel concurrently, and with ferritic stainless steel ratio, its toughness is high, brittle transition temperature is low, intergranular corrosion resistance and good welding performance.Remain the advantage that ferritic steel thermal conductivity is high, the coefficient of expansion is little simultaneously.Its yield strength significantly improves compared with austenitic stainless steel, and resistance to muriate stress corrosion fracture ability, apparently higher than the austenitic stainless steel of 300 series, has excellent resistance to pitting and the ability of crevice corrosion simultaneously.
Nineteen sixty-eight stainless steel precision sweetening process--the invention of argon oxygen decarburization (AOD), makes the generation of a series of new type of stainless steel become possibility.One of many progress that AOD brings are the interpolations of alloying element nitrogen.Duplex stainless steel adds nitrogen can make the toughness of heat affected zone under welded condition and erosion resistance close to the performance of matrix metal, and nitrogen also reduces the synthesis speed of phase between poisonous metal.Nitrogenous duplex stainless steel is called as s-generation duplex stainless steel.2205 are the representative steel grade of s-generation dual phase steel and are widely used in multiple fields such as offshore oil platform, chemical industry, papermaking.In s-generation duplex stainless steel, typical composition is that the duplex stainless steel 2304 of 23Cr-4Ni-0.12N-0.3Mo also obtains widespread use in industries such as sea water desaltination, petrochemical industry, papermaking, replace expensive austenitic stainless steel 316 (nickeliferous 10%, containing molybdenum 2%).Owing to being less than 0.3% containing molybdenum in 2304, be nickeliferously less than 4%, be therefore often included into economical diphase stainless steel.
Economical diphase stainless steel refers in particular to a class Cr content about 22%, and nickel content is low, and simultaneously containing the duplex stainless steel of a small amount of molybdenum, tungsten, owing to adopting Mn, N for Ni, therefore cost is lower, is the ideal material replacing traditional austenitic stainless steel.In fact, since entering 2000, the development of duplex stainless steel presents two kinds of trend.Improve steel interalloy constituent content on the one hand further to obtain more high strength and more excellent solidity to corrosion, as Chinese patent ZL03806936.9, CN101057002 and CN1768156.Turn on the other hand exploitation containing Cr amount about 22%, low nickel amount and only containing the economical diphase stainless steel of a small amount of molybdenum, to reduce cost and the price of duplex stainless steel, thus increase duplex stainless steel and the stainless competitive edge of other types.
Chinese patent CN101090988 discloses a kind of duplex stainless steel containing the relatively low Ni of content, restriction Cr-Mo-Mn-N component has about 50: 50 to make the volume fraction of α and γ, thus the incidence making limit split minimizes to improve production yield and reduces process load, wherein, alloy compositions comprises the Cr of 19.5% ~ 22.5%, the Mo of 0.5% ~ 2.5%, the Ni of 1.0% ~ 3.0%, the Mn of 1.5% ~ 4.5%, the N of 0.15% ~ 0.25%, Fe and inevitable element, the compositing range of described alloy compositions is adjusted to make described CPT higher than 20 DEG C according to the compositing range of alloy compositions.Therefore, reduce the content of Cr, Mo and Ni and slightly improve the content of Mn, the production cost of steel is reduced; Ensure that corrosion resisting property is better than SUS 304 steel and 316L steel; Reduce the incidence split by limit during hot rolling, thus reduce the load in ensuing process; Decrease surface imperfection, thus improve production yield.This patent does not relate to the welding property of material.Chinese patent CN102002646A then discloses low Mo height N duplex stainless steel, and high N content makes mother metal have higher mechanical property and good solidity to corrosion, for replacing 304, the austenitic stainless steel such as 316L.This patent does not relate to the welding property of material equally.
European patent EP 2258885 discloses a kind of V of adding and the Mo content economical diphase stainless steel that is less than 1%, and this material weld heat affected zone has excellent solidity to corrosion and plasticity and toughness.Its composition range is C≤0.06%, Si 0.1% ~ 1.5%, Mn 2.0% ~ 4.0%, P≤0.05%, S≤0.005%, Cr19.0% ~ 23.0%, Ni 1.0% ~ 4.0%, Mo≤1.0%, Cu 0.1% ~ 3.0%, V 0.05% ~ 0.5%, Al 0.003% ~ 0.05%, O≤0.007%, N 0.1% ~ 0.25%, Ti≤0.05%, remainder is Fe and inevitable impurity.This patent point out economical diphase stainless steel (for S32101) due to Ni, Mo lower, nitrogen content is higher, weld heat-affected zone occurs that nitride is separated out, and simultaneously because the poor chromium in local appears in the precipitation of nitride, causes weld corrosion resistance and toughness to decline.This patent of invention is by a certain degree improving Ni and Cu content, corresponding raising ferritic phase impelling strength, especially by a certain amount of V of interpolation, utilizes V to suppress the activity of N, thus avoid the nitride of weld heat-affected zone Cr to separate out, effectively can improve solidity to corrosion and the impelling strength of weld seam.In this patent, the interpolation of V suppresses the nitride of Cr to be separated out, and improves the key method of weld corrosion resistance.
Patent WO2010/070202 discloses a kind of duplex stainless steel, and its composition characteristic is Cr content 23% ~ 27%, Ni content 2.5% ~ 5.0%, simultaneously containing a certain amount of Mo and Cu.The spot corrosion equivalent PREN of this invention steel grade is greater than 28%, is mainly used in replacement 317 or more high-grade austenitic stainless steel.
The weldability of duplex stainless steel is one of key factor determining duplex stainless steel application.In practical application, the familiar lacunas major embodiment of duplex stainless steel joint is that joint fragility and solidity to corrosion decline, and it is brittle etc. mutually that concrete reason has that weld dimensions two-phase proportion is lacked of proper care, secondary phase separates out (intermetallic phase, nitride etc.), α '.Welded seam area forms primarily of three parts: weld seam (welding melting area), high-temperature heat-affected zone and the Low Temperature Thermal zone of influence; Wherein, commissure metal melts under hot input action, then solidifies in temperature-fall period; High-temperature heat-affected zone and Low Temperature Thermal zone of influence metal do not melt, but will be heated to comparatively high temps and then cool down.Wherein high-temperature heat-affected zone is due to closer to weld seam, and therefore temperature is higher.In welding process, the process that welded seam area experience heats up and lowers the temperature, during high temperature, (close to solidifying finishing temperature) duplex stainless steel is organized as pure ferrite phase, the phase transformation of ferritic phase to austenite phase is there is in temperature-fall period, in temperature-fall period, the degree of austenite phase transformation is by seam organization after decision cooling, and the key property such as its solidity to corrosion.If in process of cooling, the temperature that austenite starts to change mutually is lower, in other words, if from solidify finishing temperature to austenite mutually transition temperature there is wider interval, in this interval, material can keep single-phase ferrite area, so will occur the problem that coarse grain zone, the simultaneously austenitic phase fraction of coarse grains are less after cooling.
In fact, S32304 is as standard prod, and its solidity to corrosion is suitable with austenitic stainless steel 316 (316L), is therefore widely used in replacement 316 (316L).But, after typical economical diphase stainless steel 2304 welds, to the coarse grains district (becoming coarse grain zone) of one fixed width be there is in the high-temperature heat-affected zone of weld seam, simultaneously high-temperature heat-affected zone exist ferrite content higher than 65%, austenite phase content lower than 35% Phase Proportion imbalance.This tissue abnormalities causes the solidity to corrosion of economical diphase stainless steel 2304 weld heat-affected zone significantly to reduce, the corrosion such as spot corrosion occurs in heat affected zone, cause the solidity to corrosion of welded seam area not only lower than 2304 mother metals, also lower than 316 or the weld corrosion resistance of 316L, cause needing welding field 2304 can not reach the performance requriements of 316 at some, affect it and promote the use of.Find by analysis, will there is complete ferrite phase region in typical 2304 (N content 0.14%, Ni content 4%), this temperature reaches 85 DEG C to the temperature difference of solidifying finishing temperature more than 1325 DEG C.In welding process, Seam and heat effected zone temperature all will, higher than 1325 DEG C, cause Seam and heat effected zone to have to pass through single-phase ferrite area, thus produce above-mentioned two problems: (1) ferrite crystal grain is very easily grown up, and therefore causes occurring coarse grain zone; (2) heat affected zone ferrite content is too high.Result causes Seam and heat effected zone solidity to corrosion significantly to decline.
Summary of the invention
The object of the present invention is to provide a kind of economical diphase stainless steel and manufacture method thereof of excellent weldability, can improve or avoid weld heat-affected zone to there is the problem of coarse grain zone and Phase Proportion imbalance, guarantee that Seam and heat effected zone has excellent solidity to corrosion; The equivalent of the resistance to spot corrosion PREN of mother metal is greater than 28, higher than traditional 2304 by 2, improves the solidity to corrosion of mother metal and weld seam further.
For achieving the above object, technical scheme of the present invention is:
A kind of economical diphase stainless steel with good welds, its composition by weight percent is: C0.01% ~ 0.04%, Si 0.2% ~ 1.0%, Mn 1.0% ~ 2.5%, Cr 21.5% ~ 22.5%, Ni3.8% ~ 4.5%, Cu 0.05% ~ 0.6%, Mo 1.0% ~ 1.5%, N 0.16% ~ 0.23%, all the other are Fe and inevitable impurity; Wherein, Creq/Nieq=2.3 ~ 2.8, Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn.
The manufacture method with the economical diphase stainless steel of good welds of the present invention, it comprises the steps:
1) smelt
Duplex stainless steel, its composition by weight percent is: C 0.01% ~ 0.04%, Si 0.2% ~ 1.0%, Mn 1.0% ~ 2.5%, Cr 21.5% ~ 22.5%, Ni 3.8% ~ 4.5%, Cu 0.05% ~ 0.6%, Mo 1.0% ~ 1.5%, N 0.16% ~ 0.23%, all the other are Fe and inevitable impurity; Wherein, Creq/Nieq=2.3 ~ 2.8, Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn;
Vacuum induction is smelted, and electric furnace-argon oxygen decarburization AOD or the outer concise LF stove of electric furnace-argon oxygen decarburization AOD-stove are smelted;
2) die casting or continuous casting
Controlling superheating temperature during die casting is 30 ~ 50 DEG C, or adopts continuous casting process, and controlling superheating temperature during continuous casting is 30 ~ 50 DEG C, and during continuous casting, slab pulling rate is 0.8 ~ 2.0m/min;
3) forging or hot rolling
Die casting base or continuous casting steel billet are put into process furnace be heated to 1180 ~ 1250 DEG C and be incubated, then on forging line or Hot Rolling Mill, be machined to desired thickness;
4) annealing or pickling annealing
Annealing temperature controls at 1020 ~ 1120 DEG C, after anneal in duplex stainless steel austenite phase content between 40 ~ 60%.
In duplex stainless steel Composition Design of the present invention:
C, strong austenite former, can replace Ni to a certain extent, promotes austenitic formation, and stable austenite tissue, stainless intensity can be improved simultaneously.But when carbon content is too high, forms rich chromium carbide at crystal boundary after carbon is combined with chromium, cause intergranular corrosion.In duplex stainless steel, carbide is easily separated out, and therefore needs carbon content control at lower level.In addition, the rich chromium carbide of formation also reduces the impelling strength of steel.Therefore, designing carbon content in steel of the present invention is 0.01% ~ 0.04%.
Si, the element usually contained in Manufacture Of Iron And Steel By Melting.In duplex stainless steel, silicon is that ferrite is formed and stable element.Silicon is for deoxidation in fusion process, and silicon can improve the hot strength of ferritic phase simultaneously, therefore contains the silicon of more than 0.2% in general dual phase steel.Will the solubleness of nitrogen be reduced when but silicone content is too high, and accelerate the precipitation of intermetallic phase.Therefore, designing silicone content in steel of the present invention is 0.2% ~ 1.0%.
Mn, austenitic formation and stable element, can utilize manganese to replace nickel to a certain extent, obtains austenite structure, and the interpolation of manganese simultaneously can significantly improve the solubleness of nitrogen.But manganese is all negative on the impact of stainless erosion resistance substantially.Therefore in steel of the present invention, control Mn content is 1.0% ~ 2.5%, and object suitably improves the solubleness of alloy nitrogen, controls again it to corrosion proof disadvantageous effect simultaneously.
Cr is the most important element that steel obtains corrosion resistance nature.The minimum chromium content usually obtaining erosion resistance is 12%.But when chromium content is lower, to martensitic phase be there is in the display of Fe-Cr binary phase diagram, the raising of Cr content simultaneously significantly can strengthen corrosion resistance nature, and therefore in steel of the present invention, Cr content controls more than 21.5 ~ 22.5%, to guarantee that alloy has excellent solidity to corrosion.But when Cr too high levels, will increase intermetallic phase and separate out, simultaneously because Cr is main ferrite former, the corresponding high Ni equivalent of needs coordinates with it by therefore too high Cr, to ensure to obtain duplex structure, cost of alloy will be caused significantly to rise.Therefore, in steel of the present invention, chromium content controls 21.5% ~ 22.5%.
Ni, basic austenite former is austenizer main in austenitic stainless steel and duplex stainless steel.And the impelling strength of steel can be improved, reduce the ductil-brittle transition temperature (Ductile-brittle transition temperature is called for short DBTT) of steel, when nickel content is less than 4 ~ 5%, along with nickel content increases, impelling strength especially low-temperature impact toughness significantly improves.But because nickel is expensive, be the crucial problem reducing stainless steel production cost, therefore in steel of the present invention, nickel content controls 3.8% ~ 4.5%.
N, strong austenite former.Nitrogen is the key factor of formation and stable austenite phase in dual phase steel.Simultaneously nitrogen add the intensity and corrosion resistance nature that are conducive to improving steel, especially resistance to pitting attack performance and slit and corrosion resistant performance.The raising of nitrogen content can also promote forming core and the phase transformation of austenite phase, reduces the single-phase ferrite temperature range of high temperature, is conducive to improving welding property.But when nitrogen content is too high, will increase the risk formed mutually between nitrogen containing metal in welding process, improve melting and hot worked difficulty, especially the raising of nitrogen content will cause serious hot-rolling edge cracking rate, cause being difficult to produce on existing product line simultaneously.Therefore, nitrogen in steel content of the present invention controls 0.16% ~ 0.23%.
Mo, molybdenum is very beneficial for the corrosion resistance nature improving steel, and its mechanism is stable passive film and the enrichment of promotion chromium element in passive film, and the Main Function adding molybdenum improves erosion resistance.But the too high brittlement phase that will cause of molybdenum content accelerates to separate out, and increase cost of alloy, the molybdenum content therefore in steel of the present invention controls 1.0 ~ 1.5% simultaneously.
Cu, copper is a kind of austenite former, and adding of copper can improve the erosion resistance of dual phase steel in reductive acid, is conducive to improving slit and corrosion resistant performance simultaneously.But be unfavorable for hot workability during copper too high levels.Therefore in steel of the present invention copper content control 0.05 ~ 0.6%.
Ni, N, Mn, Cu etc. are austenite formers, and Cr, Mo, Si etc. are ferrite formers.Usually, chromium equivalent and nickel equivalent is adopted to carry out reference, Creq=%Cr+1.5%Mo+1.5%Si, Ni
eq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn.By calculating Creq and Nieq, controlling Cr equivalent in this duplex stainless steel is 2.3 ~ 2.8 with the ratio (Creq/Nieq) of Ni equivalent, can guarantee that alloy obtains the austenitic phase fraction of 40 ~ 60% after anneal on the one hand; On the other hand, guarantee that the single-phase ferritic phase temperature range of alloy high-temp is less than 5 DEG C, until there is not the single-phase ferrite phase region of high temperature, thus improve or avoid weld seam from high temperature cooling process, occur the problem of coarse grain zone and Phase Proportion imbalance.
Controlling Cr equivalent in this duplex stainless steel is 2.3 ~ 2.8 with the ratio (Creq/Nieq) of Ni equivalent, ensure in material solidification or welding process, the temperature range of the single-phase temperature of ferrite is less than 5 DEG C, until there is not the single-phase warm area of ferrite, therefore can improve or avoid weld heat-affected zone to there is the problem of coarse grain zone and Phase Proportion imbalance, guarantee that Seam and heat effected zone has excellent solidity to corrosion; Simultaneously by adding the Mo of high level, improve the solidity to corrosion of mother metal and weld seam further.After material welding, heat affected zone austenite content is greater than 35%, critical pitting temperature (the Critical PittingTemperature of weld seam, be called for short CPT) reach more than 20 DEG C, higher than the CPT (representative value 16 DEG C) of traditional austenitic stainless steel 316 (316L), therefore may be used for replacement 316 (316L), be particularly useful for the field of needs welding.
Ni content controls 3.8 ~ 4.5% by the present invention on composition, N content 0.16 ~ 0.23%, Mo content 1.0 ~ 1.5%, wherein Cr equivalent is 2.3 ~ 2.8 with the ratio (Creq/Nieq) of Ni equivalent, and Creq and Nieq determines by following formula: Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn.This Cr equivalent and Ni equivalence ratio can ensure that the single-phase ferrite temperature of material is less than 5 DEG C, until there is not the single-phase warm area of ferrite, therefore can improve or avoid weld heat-affected zone to there is the problem of coarse grain zone and Phase Proportion imbalance, guarantee that Seam and heat effected zone has excellent solidity to corrosion; Simultaneously by adding the Mo of high level, improve the solidity to corrosion of mother metal and weld seam further.This material can replace cost higher 316 and 317, especially need welding field.
Beneficial effect of the present invention:
(1) controlling Cr equivalent in this duplex stainless steel is 2.3 ~ 2.8 with the ratio (Creq/Nieq) of Ni equivalent, by adjustment Cr equivalent and Ni equivalent, guarantee from solidifying finishing temperature process of cooling, single-phase ferrite phase region temperature range is less than 5 DEG C, until there is not the single-phase ferrite phase region of high temperature.Therefore, the problem that coarse grain zone and Phase Proportion imbalance appear in welded seam area is avoided.
(2) in duplex stainless steel, Mo content improves further, guarantee that the mother metal PREN of material is higher than traditional 2304 by more than 2, the increase of Mo simultaneously can improve the solidity to corrosion of weld seam further, guarantee that the solidity to corrosion of mother metal and welded seam area is all higher than 316 (316L), therefore existing austenitic stainless steel 316 (316L) can be replaced, in particular for needing the field of welding.
(3) duplex stainless steel can utilize existing stainless steel to produce line batch production, concrete preparation method is through vacuum induction furnace, electric furnace-AOD furnace is smelted or rear casting smelted by electric furnace-AOD-LF stove, then hot-work is carried out, owing to eliminate or reducing the generation of thermal crack after hot workability improvement, therefore improve lumber recovery, save processing and manufacturing cost.
(4) mother metal and weld seam have suitable Phase Proportion and excellent resistance to pitting attack performance: mother metal pitting attack equivalent value PREN=Cr%+3.3%Mo+16N% is greater than 28, critical pitting temperature 28 DEG C ~ 34 DEG C; Welded seam area critical pitting temperature is higher than 20 DEG C.
Accompanying drawing explanation
Fig. 1 is typical 2304 calculated diagram, interval 95 DEG C of single-phase ferrite warm area in process of setting.
Fig. 2 is the embodiment of the present invention 1 calculated diagram, interval 0 DEG C of single-phase ferrite warm area in process of setting.
Fig. 3 is typical 2304 welding rod arc welding after heat zone of influence metallographs, and high-temperature heat-affected zone ferrite crystal grain is thick, and austenite is few mutually.
Fig. 4 is typical case 2304 welding high-temperature heat-affected zone metallograph, austenite phase content 29%.
Fig. 5 is that the embodiment of the present invention 1 welds high-temperature heat-affected zone metallograph, austenite phase content 44%.
Embodiment
Below in conjunction with embodiment, the present invention will be further described.
The Production Flow Chart that embodiment is smelted for electric furnace-AOD:
Ferrochrome, ferronickel and steel scrap etc. are added electric furnace melt, after melting down by molten steel to entering AOD furnace, in AOD furnace, carry out de-C, de-S and increase the blowing of N, control N, when smelting composition and reaching requirement, by molten steel to entering tundish, and cast on vertical-bending caster; The superheating temperature of continuous casting is 30 ~ 50 DEG C, and slab pulling rate is 0.8 ~ 2.0m/min; Continuous casting steel billet is put into and rolls bottom-type heating furnace and be heated to 1180 ~ 1250 DEG C, batch after hot tandem is rolled down to desired thickness; Then carry out continuous print annealing and pickling, annealing temperature is 1020 ~ 1120 DEG C, obtains the tissue with ferritic-austenitic duplex structure.
Table 1 is depicted as the chemical composition of steel embodiment of the present invention, and table 1 gives the chemical composition of the object 316L austenitic stainless steel of typically economical diphase stainless steel S32304 and steel plan of the present invention replacement at present as a comparison case simultaneously.
Table 1 gives the resistance to spot corrosion equivalent value of the embodiment of the present invention and contrast steel grade, calculates according to general formula PREN=Cr%+3.3Mo%+16N%.
Table 1 gives steel of the present invention and the contrast chromium equivalent Creq of steel grade and nickel equivalent Nieq and ratio thereof, and its calculation formula is respectively Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn.
Welding process is: plasma arc welding (PAW), does not fill silk.Table 1 gives the embodiment of the present invention and contrasts the mother metal of steel grade and the critical pitting temperature (CPT) of weld seam, testing method is with reference to ASTM-G150 standard, specific procedure is: constant externally-applied potential 750mV, scanning material corrosion electric current variation with temperature curve, rate of rise in temperature is 1 DEG C/min, is 100 μ A/cm to corrosion electric current density
2stablize after 1 minute and terminate.Definition corrosion electric current density is 100 μ A/cm
2time corresponding temperature be critical pitting temperature.Logical high-purity N in solution is continued before test and in process of the test
2deoxygenation.
From result in table 1, typical economical diphase stainless steel 2304 mother metal PREN is greater than 25, CPT higher than 26 DEG C, all higher than austenitic stainless steel 316 L, but after table 1 is also shown in welding, the CPT of 2304 welded seam areas significantly drops to 10 ~ 12 DEG C, lower than the CPT of 316L.PREN raising more than 2 compared with 2304 of the embodiment of the present invention, more significantly improve compared with 316L, therefore the CPT of mother metal is all higher than 28 DEG C.Especially, after welding, the CPT of welded seam area is higher than 20 DEG C, and change is little compared with mother metal, and as shown in Figure 5, steel of the present invention can obtain suitable austenitic phase fraction to its reason, there is not coarse-grain region simultaneously, therefore maintains good corrosion resistance nature.
In sum, the present invention is by conservative control Creq/Nieq ratio, ensure that the single-phase ferrite temperature range of high temperature of material is less than 5 DEG C or to 0, to improve or to avoid weld heat-affected zone to there is the problem of coarse grain zone and Phase Proportion imbalance, guarantee that Seam and heat effected zone has excellent solidity to corrosion, add the Mo of high level simultaneously, improve the solidity to corrosion of mother metal and weld seam further.
Compared with existing economical diphase stainless steel 2304, steel of the present invention has higher solidity to corrosion, and especially after soldering, the solidity to corrosion that weld seam has good corrosion resistance nature, particularly weld seam compares reduction not quite with mother metal.As compared to 316 series austenitic stainless steel (containing the nickel of 10% and the molybdenum of 2%), nickel in steel of the present invention and molybdenum content lower, therefore material cost is lower, the mother metal of steel of the present invention has higher corrosion resistance nature and intensity simultaneously, the solidity to corrosion of weld seam is also higher than mother metal and the weld seam of 316 series austenitic stainless steel, therefore 316 expensive series austenitic stainless steel can be replaced, in particular for needing the field of welding.
Claims (2)
1. one kind has the economical diphase stainless steel of good welds, its composition by weight percent is: C0.01% ~ 0.04%, Si0.2% ~ 1.0%, Mn1.0% ~ 2.5%, Cr21.5% ~ 22.5%, Ni3.8% ~ 4.5%, Cu0.05% ~ 0.6%, Mo1.0% ~ 1.5%, N0.16% ~ 0.23%, all the other are Fe and inevitable impurity; Wherein, Creq/Nieq=2.3 ~ 2.8, Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn; Mother metal pitting attack equivalent value PREN=Cr%+3.3%Mo+16N% is greater than 28, critical pitting temperature 28 DEG C ~ 34 DEG C; After material welding, heat affected zone austenite content is greater than 35%, and welded seam area critical pitting temperature is higher than 20 DEG C.
2. have the manufacture method of the economical diphase stainless steel of good welds, it comprises the steps: 1) smelt,
Duplex stainless steel, its composition by weight percent is: C0.01% ~ 0.04%, Si0.2% ~ 1.0%, Mn1.0% ~ 2.5%, Cr21.5% ~ 22.5%, Ni3.8% ~ 4.5%, Cu0.05% ~ 0.6%, Mo1.0% ~ 1.5%, N0.16% ~ 0.23%, all the other are Fe and inevitable impurity; Wherein, Creq/Nieq=2.3 ~ 2.8, Creq=%Cr+%Mo+1.5 × %Si, Nieq=%Ni+30 × %C+20 × %N+0.33 × %Cu+0.1 × %Mn;
Vacuum induction is smelted, and electric furnace-argon oxygen decarburization AOD or the outer concise LF stove of electric furnace-argon oxygen decarburization AOD-stove are smelted;
2) die casting or continuous casting
Controlling superheating temperature during die casting is 30 ~ 50 DEG C, or adopts continuous casting process, and controlling superheating temperature during continuous casting is 30 ~ 50 DEG C, and during continuous casting, slab pulling rate is 0.8 ~ 2.0m/min;
3) forging or hot rolling
Die casting base or continuous casting steel billet are put into process furnace be heated to 1180 ~ 1250 DEG C and be incubated, then on forging line or Hot Rolling Mill, be machined to desired thickness;
4) annealing or pickling annealing,
Annealing temperature controls at 1020 ~ 1120 DEG C, after anneal in duplex stainless steel austenite phase content between 40 ~ 60%;
The duplex stainless steel mother metal pitting attack equivalent value PREN=Cr%+3.3%Mo+16N% obtained is greater than 28, critical pitting temperature 28 DEG C ~ 34 DEG C; After material welding, heat affected zone austenite content is greater than 35%, and welded seam area critical pitting temperature is higher than 20 DEG C.
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| CN102851606A (en) * | 2012-09-05 | 2013-01-02 | 浙江汉威阀门制造有限公司 | Low cost double phase stainless steel material for valve, and preparation method thereof |
| CN103056624B (en) * | 2013-01-31 | 2015-07-08 | 郑州永通特钢有限公司 | Method for producing high-quality forged material by using large-scale vertical type continuous casting round billet, product and application thereof |
| CN103924160B (en) * | 2013-10-31 | 2016-06-29 | 保定风帆精密铸造制品有限公司 | The main chemical elements mass fraction control method of cast stainless steel without magnetic austenitic |
| CN105063462B (en) * | 2015-07-27 | 2017-10-31 | 浙江腾龙精线有限公司 | A kind of preparation method of polish stick |
| US20190323110A1 (en) * | 2016-12-21 | 2019-10-24 | Sandvik Intellectual Property Ab | An object comprising a duplex stainless steel and the use thereof |
| CN113227409B (en) * | 2018-12-28 | 2023-07-25 | 日铁不锈钢株式会社 | Welded structure and method for manufacturing same |
| JP7270724B2 (en) * | 2019-03-29 | 2023-05-10 | 日鉄ステンレス株式会社 | Duplex stainless steel weld joint and manufacturing method thereof |
| CN113817895A (en) * | 2020-06-19 | 2021-12-21 | 江苏新马新材料开发有限公司 | Manufacturing process method of 2205 dual-phase steel |
| CN112846567A (en) * | 2020-12-31 | 2021-05-28 | 钢铁研究总院 | Austenitic stainless steel welding wire and electric arc additive manufacturing process thereof |
| CN115341148A (en) * | 2022-08-19 | 2022-11-15 | 浙江德田船舶设备制造有限公司 | Ferrite-austenite dual-phase heat-resistant steel and preparation method thereof |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101684542A (en) * | 2008-09-26 | 2010-03-31 | 宝山钢铁股份有限公司 | Duplex stainless steel with pitting corrosion resistance and favourable cold temperature flexibility and manufacturing method thereof |
| CN102257174A (en) * | 2008-12-19 | 2011-11-23 | 奥托库姆普联合股份公司 | Ferritic-austenitic stainless steel |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101294262A (en) * | 2008-03-21 | 2008-10-29 | 中国印钞造币总公司 | Diphasic stainless steel |
| CN101812647B (en) * | 2009-02-25 | 2012-10-10 | 宝山钢铁股份有限公司 | Diphase stainless steel and manufacturing method thereof |
| CN102251194A (en) * | 2010-05-18 | 2011-11-23 | 宝山钢铁股份有限公司 | Two-phase stainless steel cold-rolled sheet with good surface corrosion resistance, and preparation method thereof |
-
2012
- 2012-03-13 CN CN201210064770.3A patent/CN102605288B/en active Active
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101684542A (en) * | 2008-09-26 | 2010-03-31 | 宝山钢铁股份有限公司 | Duplex stainless steel with pitting corrosion resistance and favourable cold temperature flexibility and manufacturing method thereof |
| CN102257174A (en) * | 2008-12-19 | 2011-11-23 | 奥托库姆普联合股份公司 | Ferritic-austenitic stainless steel |
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