CN104120358B - A kind of containing trace tin element, high intensity, the ultra-low-carbon steel and preparation method thereof of corrosion-resistant and easy-formation - Google Patents

Abstract

nullThe invention discloses a kind of element Han trace tin、High intensity、The corrosion-resistant ultra-low-carbon steel with easy-formation，The mass percent of its chemical composition is: C:0.001～0.005%，N:0.001～0.003%，Mn:0.1～0.5%，Cr:0.8～1.50%，Mo:0.01～0.1，Si:0.1～0.5%，Al:0.005～0.01%，Mg:0.0001～0.0015%，Ca:0.0001～0.0015%，Sn:0.01～0.30%，Nb:0.01～0.2%，Cu:0.05～0.3%，Ti:0.01～0.2%，P:0.001～0.010%，S≤0.003%，Remaining is Fe.The present invention by smeltings in sensing heating, vacuum stove, ingot casting, hot rolling, pickling and cold-rolling, recrystallization annealing temperature, roll prepare contain trace tin, phosphorus content is low, intensity is high, the steel that have the aqueous corrosion performances such as good complex part processability and anti-oil field extracted water, can use safely in the complex drilling completion of oil gas field and other environment, the method principle is reliable, production technology is simple, easy and simple to handle, practical.

Description

A kind of containing trace tin element, high intensity, the ultra-low-carbon steel and preparation method thereof of corrosion-resistant and easy-formation

Technical field

The invention belongs to metal material field, having of relating to need in modern industry field to work in aqueous medium is corrosion-resistant, high intensity, high-mouldability can steel and preparation method thereof, particularly industrial gas oil relates to complex drilling expansion tube and high-level stage branch well bifurcation device etc. need anticorrosive, high intensity, high-mouldability can workpiece steel and preparation method thereof.

Background technology

IF (Interstitial-Free) steel, also known as gapless atomic steel, third generation deep punching steel, is generation after the eighties in last century.The feature of IF steel is: phosphorus content is the lowest, after adding Ti and Nb, forms C, N compound of Ti and Nb.Due to gap-free atom in steel, and make it have deep drawability, high-ductility strain ratio, high-elongation, high hardenability value and the relatively low yield tensile ratio of excellence, and there is the non-ageing of excellence.Traditional IF hardness of steel is the lowest, its yield strength R_POnly less than 150MPa, it is difficult to be suitable for the workpiece that some requirement of strength are higher.In recent years research finds, in IF steel, add a small amount of Mn, Si and the element such as trace P (0.001～0.008%), B (0.001～0.008%) intensity of IF steel can be improved, and then developed the IF steel of high intensity, the yield strength of the IF steel of this high intensity can reach more than 200MPa, keep good processability simultaneously, be referred to as high strength type IF steel.

But, for IF steel and the IF steel of the high intensity containing P, Mn, Si and micro alloying element, also often serious corrosion phenomena and the crystal grain IF steel corrosion resistance caused of growing up is caused to decline due to the existence of second phase particles and surface because of the skewness of Mn element.Therefore, for industrial gas oil needs the workpiece of high-mouldability energy, as: for solving the hole diameter bulged tube technology steel pipes such as the big expansion rate of employing (expansion rate is more than 20%) of leakage and narrow pressure density window during the complex drilling in oil and gas industry, the pressure-bearing six-stage branch well bifurcation device steel (bifurcated pipe of high-grade six-grade branch well less than 10MPa, it is the angle large bevel tee that only has 1-3 °), owing to these workpiece in use long period of soaking is in the water base corrosive environment of high salinity of oil field mining liquid, use the workpiece that high-strength IF steel is made through complicated molding, its anti-Corrosion Protection substantially can not meet the demand of Practical Project.Therefore need in industrial gas oil, be badly in need of developing high-mouldability can the high intensity of complex part, high-mouldability energy steel that corrosion resistance is good.

Improving steel resistance to corrosion in aqueous medium, adding Cr element in steel is maximally efficient means.Cr is can to form continuous solid solution with ferrum, reduces the element of austenite phase field, and Cr forms densification, stable Cr in an oxygen-containing environment₂O₃Protective film; it is to stop medium that metallic matrix continues penetrate into corrosion there is the element of the strongest passivation ability; additionally Cr adds the corrosion potential that can improve steel in steel to as alloying element; reduce corrosion current; and reach finite concentration at Cr content; i.e. when the atomic ratio of Cr reach 1/8,2/8,3/8 ... n/8, the electrode potential of iron-based solid solution can increase to saltatory, and the most therefore corrosion weakens.The decay resistance of steel can improve significantly, Cr is one of more weak element of the solution strengthening effect to steel, and under conditions of Cr content is less than 1.5%, along with the increase of steel Cr content, steel corrosion potential in group water solution increases, corrosion current reduces.According to the alloying principle of steel, when in steel, Cr content is the highest with the combining addition steel anti-corrosion property can be improved more effectively of Cu element.Therefore the corrosive power combining the anti-aqueous medium adding Cr and Cu element for improving steel in steel is maximally efficient.

Sn element is periodic system of elements group iva element, atomic number 50, atomic weight 118.69.Sn element is typical internal adsorption element in steel, the amount forming solid solution in steel with Fe is the most small, major part Sn element is at grain boundaries with low-melting-point metal form segregation, causing the high-temperature hot processing characteristics containing Sn steel to degenerate, this most traditional metallurgical idea thinks that Sn element is the basic reason of harmful element in steel always.But, also it is believed that, discounting for the Sn impact on steel high-temperature behavior, steel adds pettiness amount Sn and can improve the corrosion resistance of steel, its intensity also improves, and affects plasticity not quite.As: in cast iron, add trace Sn element, the performance of raising cast iron that can be obvious.

In recent years, due to the development of adjoint vacuum degassing technology RH, VOD, the AOD of the development of smelting iron and steel technology, particularly clean steel ultra-clean steel technology, the generation of the Ultra-low carbon super-purity ferrite stainless steel caused, and segregation Strengthening and Toughening is theoretical altogether^[5]Development, particularly 2010, Zhu Jin rustless steel company of Nippon Steel (NSSC) establishes the Sn element by adding mass ratio about 0.1%, making ferrite type (chromium class) stainless Cr content can reduce by more than 3%, the decay resistance of steel obtains the technology of tremendous raising simultaneously.The Sn element that the technology being with historically new significance is thick atom size that this whole world is initiated application in steel opens new approach.

Due to the forming process of high-mouldability energy steel part, almost all is carried out through drawing or punching press.Therefore, the processability (i.e. inefficacy resisted in bearing deformation process by steel plate, such as fracture, bent, wrinkling, the shape distortion of wooden dipper etc.) of steel depends on characteristic and the deformation condition of steel itself.Here steel self performance is primarily referred to as the yield strength (Rp) of steel, tensile strength Rm obtained by one way tensile test), percentage of total elongation ((A) and two important basic indexs evaluating steel plate forming performances: i.e. Lankford r value and strain hardening exponent n value.

For high formability energy steel, one is in fact, it should have relatively low yield strength, relatively low yield tensile ratio and a higher elongation percentage, and higher strain hardening exponent n value and higher Lankford r value (r value also referred to as the coefficient of normal anisortopy).

For strain hardening exponent n: be the true stress-true stain relational expression of Hollomon plastic elongation deformation

σ=K εⁿ (1)

Index n in formula, is referred to as strain hardening exponent.

The physical significance of n value is the material parameter of the ability characterizing material and steel pipe homogeneous deformation.N value is organizational structure responsive parameter, and n is relevant with the Molecular segregation Chengdu of the stacking fault energy size of material, tissue；N value is that steel plate uniform power one in plastic history is measured.For thin plate steel, its true homogeneous strain, is that the auxetic performance with thin plate has close ties, and n value is the highest, and auxetic performance is the best.

Owing to n value difference surveyed by the sample of cold-rolled steel sheet different orientation, being therefore to take to become with rolling direction 0 °, 45 °, the tensile sample of 90 ° on steel plain in Practical Project, mean strain hardenability value n value formula is as follows:

$\stackrel{\‾}{n}=(n_0+{2n}_{45}+n_{90})/4---\left(2\right)$

For ultralow-carbon IF steel, the degree of purity depending mainly on the size of steel of n value and ferrite grain size, the degree of purity and the suitably reduction ferrite grain size that improve steel can increase n value.After relation between the Morrison research n value of low carbon steel plate and ferrite grain size, summarize equation below:

$n=5/(10+d^{-\frac{1}{2}})---\left(3\right)$

In formula, d is average crystal grain diameter, and unit is μm.

The coefficient of normal anisortopy r value is the logarithmic strain of width and thickness direction logarithmic strain ratio in simple tension sample drawing process, i.e.

R=ε_w/ε_t (4)

This index is proposed in nineteen fifty by Lankford, and it is that the one of thin plate plastic anisotropy is measured.Identical with work hardening index, the sample r value of different orientation is different, therefore defines average plastic strain ratioOr: r_mValue and in-plane anisotropy value △ r be:

$\stackrel{\‾}{r}=(r_0+{2r}_{45}+r_{90})/4---\left(5\right)$

$\mathrm{\Δr}=(r_0-{2r}_{45}+r_{90})/2---\left(6\right)$

By (4) it can be seen that r value is the biggest, in sheet material auxetic forming process, the thin ability of resistance is the strongest, and deep drawability is the best；R value is the least, then material is the most thinning on thickness direction when deformation, is easily caused cracking phenomena, and punching performance is bad.

(6) the △ r in formula reflects the uniformity coefficient of all directions r value on plate face, and it has close relationship with the size of lug time stamping, and the biggest then lug of △ r value is the biggest.For making sheet deformation uniformly reduce lug, △ r should be the least, as △ r=0, occurs without ears or side handles of a utensil defect.

Research provesValue depends on the preferable grain orientation (i.e. texture) in steel plate, and { 111} texture is stronger, { 100} texture is the most weak, thenThe highest, deep drawability is the best.

Existing research is it has been proved that the texture of IF steel is mainly formation in cold-rolled process, in order to the later stage can obtain more satisfactory annealing recrystallization texture, it is desirable to the deformation texture formed in the cold deformation stage is sufficiently strong.In cold-rolled process, the dislocation in crystal starts sliding under external force, and its slide surface gradually tends to the face of rolling in the process, glide direction tend to being parallel to rolling to.Meanwhile, along with the continuous sliding of dislocation in crystal, the orientation of crystal also can occur to rotate accordingly.Along with the increase of cold-rolling of steel plate reduction ratio, gradually to a certain or neighbouring rotation of some feature orientation, and then can there is the preferred orientation of crystal grain in each crystal grain in polycrystal.Further, the degree of preferred orientation is as the increasing of deflection and strengthens.During cold deformation, the crystal grain in IF steel is oriented on α orientation line and γ orientation line to be assembled, and along with the increase of deflection, accumulated amount is consequently increased.And research finds, in the cold rolling texture of IF steel develops, drafts is when 0～50%, and gamma fiber texture has obvious growth, but when drafts continues to increase, the Strength Changes of gamma fiber texture is not the most inconspicuous；And the intensity of alpha fibers texture has significantly growth all the time along with the increase of drafts.So mainly comprising 4 kinds of texture components in IF steel plate after cold-rolled, be respectively 111}<110>, 111}<112>, 112}<110>and 001}<110>.

Desirable texture in IF steel, be finally by heavy reduction cold rolling after recrystallization annealing formed, the forming core of crystal grain recrystal grain to be occurred of deformation and growth process, the formation of simultaneous annealing recrystallization texture in annealing process.Here mainly carrying out by " oriented nucleation " and " growth selection " mechanism theory, in steel plate, the forming core of different orientation crystal grain is with to grow up be a process vied each other.So-called " oriented nucleation " refer to cold rolling after IF steel content of gamma fiber texture component after recrystallization annealing more, this is owing to defining more γ orientation nucleus in the initial period of annealing, and its speed of growth is quickly, i.e. " oriented nucleation " theory of recrystallization starting stage；In annealing process, the energy storage when driving force of crystal grain recrystallization is cold roller and deformed, and there is certain relation between the size of this energy storage and crystal grain orientation.Main four kinds of texture components after IF steel is cold-rolled, its size order storing energy is E_{111}<112>>E_{111}<110>>E_{112}<110>>E_{001}<110>, therefore during recrystallization annealing, and 111}<112>storing can be the highest, preferential forming core, next to that 111}<110>.Further, in 111}<112>deformation matrix formed be new 111}<110>crystal grain, in 111}<110>deformation matrix formed be then new 111}<112>crystal grain, and growth course behind annex other orientation crystal grain.And at the late stage of recrystallization annealing, " growth selection " that deformation storage can cause plays pivotal role, after large deformation, the nucleus of a large amount of different orientations is present in metallic matrix, and nucleus that deformation texture is favorably orientated just can be grown up to only have those to correspond to during annealing.During IF steel recrystallization annealing nucleus growth, the { 111}<112>crystal grain that is orientated and { 111}<110>the growing up of crystal grain that be orientated is exactly the result of this growth selection.As in why IF steel recrystallization annealing after cold deformation, can be formed and benefit the γ desirable texture that deep drawability improves, research proves the illeffects of the Mn-C dipole that trace alloying element Ti, the Nb formed due to Ultra-low carbon and strong carbide causes and alleviates and cause with crystal grain refinement.

In view of above technical background, inventor is on the basis of high intensity third generation deep punching steel IF steel, a small amount of corrosion resistance alloying elements cr, Cu, Mo and the micro alloying element such as the Sn element of trace and Ti of improving of sublimate smelting technique, interpolation is used to develop a kind of high-strength corrosion-resistant high-mouldability energy steel containing trace Sn element, and it is of value to improves the sheet fabrication of processability and tubular object extruding, and be applied in natural petroleum gas field in the preparation of complex equipment part, achieve good effect.

Summary of the invention

It is an object of the invention to overcome the shortcoming of prior art, a kind of steel are provided, these steel are low containing trace tin, phosphorus content, intensity is high, there is the aqueous corrosion performances such as good complex part processability and anti-oil field extracted water, it is possible to use safely in the complex drilling completion and other environment of oil gas field.

Another object of the present invention is to provide this to contain the preparation method of the ultra-low-carbon steel of trace tin element, high intensity, corrosion-resistant and easy-formation, the method principle is reliable, and production technology is simple, easy and simple to handle, practical.

The purpose of the present invention is achieved through the following technical solutions:

The present invention is on the basis of high-strength IF steel, cast by composition design, vacuum metling, control, cogging forging, hot rolling, cold rolling more than 80% drafts, and the process program of recrystallization annealing obtains a kind of containing trace tin element, high intensity, the corrosion-resistant and ultra-low-carbon steel of easy-formation of the present invention, can apply in oil and gas field etc. is containing water base corrosive medium environment.

The present invention's is a kind of containing trace tin element, high intensity, the corrosion-resistant and ultra-low-carbon steel of easy-formation, and its composition is as follows, is mass percent:

C:0.001～0.005%, N:0.001～0.003%, Mn:0.1～0.5%, Cr:0.8～1.50%, Mo:0.01～0.1, SI:0.1～0.5%, Al:0.005～0.01%, Mg:0.0001～0.0015%, Ca:0.0001～0.0015%, Sn:0.01～0.30%, Nb:0.01～0.2%, Cu:0.05～0.3%, Ti:0.01～0.2%, P:0.001～0.010%, S≤0.003%, remaining is Fe.

Above-mentioned containing trace tin element, high intensity, the preparation method of ultra-low-carbon steel of corrosion-resistant and easy-formation, it comprises the following steps:

S1. smelting: with ingot iron, chromium, manganese, stannum, Antaciron as raw material, using lime crucible is 1 × 10 in vacuum^-4～1 × 10^-3Smelting in the vaccum sensitive stove of Pa, fusion process uses twice refining route, initial refining temperature to be 1550～1600 DEG C, and refining time is 30～50min, and double refining temperature is 1550～1600 DEG C, and refining time is 30～50min；

S2. ingot casting: forcing deoxidation with fine aluminium, pure magnesium and pure calcium after smelting, carry out ingot casting after vacuum outgas, molten steel casting temperature is 1500～1550 DEG C, uses control to be cast into steel billet, and pouring pressure is 1～3atm, and poring rate is 35～40mm/s；

S3. hot rolling: steel billet is after 1250 DEG C of heating cogging forgings, and hot rolled steel plate of making, hot rolling initial temperature is 1200～1250 DEG C, finishing temperature >=850 DEG C, air cooling after hot rolling；

S4. pickling and cold-rolling: the steel plate after hot rolling is carried out pickling, then through cold rolling more than 80% of drafts, make the steel of given size；

S5. recrystallization annealing temperature: after cold rolling, steel are carried out recrystallization annealing temperature process, annealing temperature is 780～800 DEG C, and the time is 2～4 hours；

S6. roll: the steel after recrystallization annealing temperature are batched 600～650 DEG C of temperature the steel making specific thickness.

Further, phosphorus content≤0.0218% of described ingot iron, purity are 99.8～99.9%, purity >=99.5% of chromium, manganese and purity >=99.5% of Antaciron, purity >=99.5% of stannum.

Further, the pickle composition of described pickling is: hydrochloric acid 20%, phosphoric acid 2%, alkyl acid phosphate phenol polyethenoxy ether 1.5%, sodium lauryl tri(oxyethyl) sulfate 1.5%, di-o-tolyl-thiourea 1.5%, pickling additive 2%, and pickle temperature controls at 60～80 DEG C.

Present component design feature is: use extremely low carbon (≤0.005%), nitrogen (≤0.003%) content, and for C remaining in steel in smelting, N to use the mode adding strong carbonitride microelement Ti and Nb to be fixed, in order to improve ferritic high intensity, the processing characteristicies such as the welding simultaneously considering steel, add appropriate reinforced ferrite element: P (0.001～0.010%), Mn (0.10～0.50%) and Si (0.01～0.5%) element, it is used for improving the intensity of steel, add appropriate Cr (0.8～1.5%), Mo (0.01～0.1%), Cu (0.05～0.3%) element and no more than 0.3% Sn element to improve steel corrosion resistance；Add Mo element jointly to act on Sn element, the red brittleness both having prevented Sn element to cause in the single segregation of grain boundaries, define again the common aggregate effect useful to steel Strengthening and Toughening；The Ca element adding pettiness amount acts on jointly with Sn and the S element in steel, can improve the cold-forming property of steel further, it is also possible to improve the degree of purity of steel；The Mg element adding pettiness amount can carry out degree of depth deoxidation to improve its degree of purity to steel.

The smelting mode of the present invention uses smelting in sensing heating, vacuum stove, double refining, deep desulfuration deoxidation, vacuum outgas, control casting, it it is particularly the cleanliness factor improving steel further in smelting, S in steel is reduced to less than 0.003%, and the yardstick of nonmetal inclusion controls below 10 μm.

Use composition design as above and process means, i.e. can get one element Han trace tin of the present invention, high intensity, the corrosion-resistant ultra-low-carbon steel with easy-formation, can apply in oil and gas field etc. is containing corrosive medium environment, this steel matrix is ferrite, through hot rolling, there is after cold rolling processing and recrystallization annealing strong { 111} texture, including 111}<110>and { 111}<112>texture, texture degree>35%, its yield strength is 170～260MPa, tensile strength is 350～440MPa, elongation after fracture>=30%, strain hardening exponent>=0.15, the coefficient of normal anisortopy>=1.2.

Compared with existing high-strength IF steel, the present invention has the following characteristics that containing trace tin element, high intensity, corrosion-resistant and easy-formation ultra-low-carbon steel

A. the steel of the present invention has relatively low P content (solution strengthening element P is the highest is less than 0.1%), and relatively low Mn, Si content；

B. the steel of the present invention contains the Sn element of certain Cr, Cu element and trace simultaneously, to improve the water resistant based sols corrosive power of steel；

C. the steel of the present invention be use pure Al, Mg, Ca deoxidation there is alap S constituent content and the clean steel of nonmetal inclusion content, this be to ensure that steel obtain deep drawing quality, the key of the highest processability；

D. possibly together with the Mo element of trace in the steel of the present invention, this is because with the addition of a small amount of crystal grain thinning and improve the Mo element of heat resistance, Mo element can act on jointly with Sn element, both prevented Sn element to cause red brittleness in the single segregation of grain boundaries, the common aggregate effect useful to steel Strengthening and Toughening can have been formed again.

The invention have the advantages that

(1) by using phosphorus content less than 0.0218%, the purity ingot iron up to 99.8%～99.9%, Cr, Mo, Cu, Mn, Si of purity >=99.5% and the Sn of purity >=99.5% and ferrophosphorus are raw material, double refining in vaccum sensitive stove and the secondary deep deoxidation of employing Al, Mg, Ca, desulfurization, vacuum outgas, be finally obtained the clean high formability energy steel of ultralow C, N content；

(2) for the steel of the present invention, by controlling casting after smelting, cogging forges, the drafts multi-pass more than 80% is carried out cold rolling after the hot rolling of 850～1250 DEG C, carrying out recrystallization annealing process after cold rolling, annealing temperature is 780～800 DEG C, and temperature retention time is air cooling after 2～4 hours, this makes steel obtain the strongest { 111} texture, there are good deep-draw and complicated processability, its strain hardening exponent >=0.15, the coefficient of normal anisortopy >=1.2；

(3) by the addition of P, Mn, Si, Cr solid solution element, enhance the ferritic performance of steel matrix, by addition and the common effect of micro alloying element Ti, Nb of Mo element, steel are made to have aplitic texture, the final steel yield strength obtained is 170～260MPa, tensile strength is 350～440MPa, elongation after fracture >=30%, has that intensity is high, plasticity is good, processability is good a feature；

(4) by the addition of Cr, Cu, Mo, Sn element, improve steel corrosion resistance in group water solution, improve the corrosion potential of steel, reduce the corrosion current of steel, improve the pitting corrosion resistant performance of steel, be finally obtained the feature of excellent corrosion resistance；

(5) the inventive method principle is reliable, and production technology is simple, easy and simple to handle, practical.

Accompanying drawing explanation

Fig. 1 is the schematic illustration of tissue after the embodiment 1 hot rolled air cooling of steel processes；

Fig. 2 is embodiment 1 steel schematic illustration of tissue after drafts is 80% cold-rolling treatment；

Fig. 3 be embodiment 1 steel through 790 DEG C, 3 hours recrystallization annealing temperatures process after schematic illustration of tissue；

Fig. 4 is Mechanics Performance Testing sample and specimen size schematic diagram in embodiment 1-3；

Fig. 5 is the interception way schematic diagram of Mechanics Performance Testing sample in embodiment 1-3.

Detailed description of the invention

Below in conjunction with the accompanying drawings and embodiment the present invention will be further described, protection scope of the present invention is not limited to the following stated.

Embodiment 1: a kind of containing trace tin element, high intensity, the corrosion-resistant and ultra low carbon steel slab of easy-formation, described steel plate composition is as follows, is mass percent: C:0.001%, N:0.003%, Mn:0.3%, Cr:0.8%, Mo:0.1, Si:0.2%, Al:0.005%, Mg:0.0015%, Ca:0.0015%, Sn:0.01%, Nb:0.2%, Cu:0.25%, Ti:0.01%, P:0.010%, S:0.003%, remaining is Fe；

The preparation method of above-mentioned ultra low carbon steel slab, it comprises the following steps:

S1. smelt: with phosphorus content≤0.0218%, purity be 99.8%～99.9% ingot iron, purity >=99.5% chromium, purity >=99.5% stannum, purity >=99.5% manganese, Antaciron as raw material, using lime crucible is 1 × 10 in vacuum^-3Smelting in the vaccum sensitive stove of Pa, fusion process uses twice refining route, initial refining temperature to be 1550 DEG C, and refining time is 30min, and double refining temperature is 1550 DEG C, and refining time is 30min；

S2. ingot casting: forcing deoxidation with fine aluminium, pure magnesium and pure calcium after smelting, carry out ingot casting after vacuum outgas, molten steel casting temperature is 1500 DEG C, uses control to be cast into steel billet, uses control to be cast into steel billet, and pouring pressure is 1atm, and poring rate is 35mm/s；

S3. hot rolling: steel billet is after 1250 DEG C of heating cogging forgings, and hot rolled steel plate of making, hot rolling initial temperature is 1200 DEG C, and finishing temperature is 850 DEG C, air cooling after hot rolling；

S4. pickling and cold-rolling: the steel plate after hot rolling is carried out pickling, pickle composition is: hydrochloric acid 20%, phosphoric acid 2%, alkyl acid phosphate phenol polyethenoxy ether 1.5%, sodium lauryl tri(oxyethyl) sulfate 1.5%, di-o-tolyl-thiourea 1.5%, pickling additive 2%, pickle temperature controls at 60 DEG C, again through drafts be 80% cold rolling, make the steel plate of given size；

S5. recrystallization annealing temperature: after cold rolling, steel plate is carried out recrystallization annealing temperature process, annealing temperature is 790 DEG C, and the time is 3 hours；

S6. roll: the steel plate after recrystallization annealing temperature is batched 600 DEG C of temperature and makes the thick steel plate of 8mm, after tested, phase transition temperature A of this steel plate_c1It is 720～740 DEG C, A_c3It it is 880～900 DEG C.

Above-mentioned steel plate is carried out mechanics, corrosion resistance electro-chemical test and contextual analysis of organization, experimental technique and result as follows:

1. contextual analysis of organization: intercepting metallographic specimen on recrystallization annealing plate, corroding through pre-grinding, polishing and 4% nitric acid ethanol, be prepared as metallographic observation sample, its microstructure of optical microphotograph Microscopic observation of 500 times.Fig. 1-3 is observed result, and wherein Fig. 1 is the schematic illustration of tissue after the hot rolled air cooling of steel processes, and Fig. 2 is steel schematic illustration of tissue after drafts is 80% cold-rolling treatment, Fig. 3 be through 790 DEG C, 3 hours recrystallization annealing temperatures process after schematic illustration of tissue.Metallographic observation from-3 pairs of embodiments of Fig. 11: after steel are hot rolled, for typical single ferritic structure, after cold rolling through heavy reduction, present serious ribbon-like fibre shape tissue, cold rolling after after recrystallization annealing, revert to the ferritic structure of equiax crystal, its grain size is 9 grades.

2. Mechanics Performance Testing: Mechanics Performance Testing intercepts respectively on the steel plate of recrystallization annealing after cold rolling, the Mechanics Performance Testing of steel uses plate tensile sample, specimen size is as shown in Figure 4, in figure, the unit of specimen size is mm, and following the example of of sample intercepts respectively according to angular direction parallel with rolling direction vertical with rolling direction and at 45 ° with rolling direction.Along rolling direction, the steel of embodiment 1 is become 0 °, 45 ° and 90 °, and line cuts into the tensile sample that gauge length is 50mm, and as shown in Figure 4, the interception way of sample is shown in Fig. 5 to Mechanics Performance Testing sample.

The true stress-true stain curve utilizing steel simple tension tries to achieve the mean strain hardenability value of steelThick anisotropy index with steelValue and Δ r value, r value test is to record when draw direction produces 15% strain.

Wherein:

$\stackrel{\&OverBar;}{n}=(n_0+{2n}_{45}+n_{90})/4$

In-plane anisotropy:

It the results are shown in Table 1.

Table 1: the mechanical experimental results of embodiment 1 steel

In table: Rel is yield strength, Rm is tensile strength, and A is elongation after fracture,For strain hardening meansigma methods,For the coefficient of normal anisortopy meansigma methods, Δ r is in-plane anisotropy.

3. texture degree measures:. use pit method to measure { the 111} texture of embodiment 1 steel, metallographic pit method utilizes the feature of the low index crystal plane preferential etch of cubic system, it is orientated different plate surfaces at crystal grain and creates different pit, pit reflect crystallographic position to, can directly draw out the texture degree of the cold rolling rear recrystallization texture of example 1 steel with orientation from the measurement of pit.

The caustic composition of display embodiment 1 steel low index crystal plane pit is as follows:

A liquid: H₂O₂-15 milliliters, HF-5 milliliter, H₂O-80 milliliter；

B liquid: HC1-1 milliliter, H₂O-100 milliliter, FeCl₃*6H₂O-10 gram；

C liquid: 1%HNO₃Alcoholic solution.

Pitting nucleation is in A liquid, and B liquid mainly removes the oxide-film on pit surface, and the effect of C liquid is to clean surface and display crystal boundary.

About 200 crystal grain of random observation under the microscope, mark the number of die of favourable orientation, finally calculate favourable orientation crystal grain and account for the percentage rate of total number of die, can approximate the favourable degree of orientation obtaining this sample.

Texture degree (the favourable degree of orientation) %=profit orientation number of die/crystal grain total number X 100%

The result of calculation of embodiment 1 steel is: texture degree=38.9%

4. corrosion resistance electro-chemical test: in view of petroleum gas engineering down-hole ambient temperature on corrosion impact, corrosion electrochemistry test is to carry out in the NICE standard solution A of 50 DEG C of not degasification, use three-electrode system: auxiliary electrode be platinum electrode, reference electrode be saturated calomel electrode, Electrode be example 1 sample, solution temperature is with water-bath temperature control at 60 DEG C, and electrochemical apparatus is ZF-9 type potentiostat.For the ease of contrast, use conventional IF-1 steel as reference frame.Use potentiostatic method measure steel polarization curve, determine the corrosion potential V of steel_corr, corrosion current I_corr；Potentiodynamic scan technique is used to measure the pitting potential Eb100 of steel.Owing to embodiment 1 steel and IF-1 steel are Ultra-low carbon low-alloy steel, in view of solution under the conditions of not degassing, owing to the dissolved oxygen in solution is higher, the passivation ability of steel and the stability of passivating film are greatly enhanced, weaken the pitting potential sensitivity to solution ph to a certain extent, it is thus possible to relatively accurately and measure the pitting potential of carbon steel/low-alloy steel easily.To this end, carry out dynamic potential scanning polarimetric test under the conditions of not degassing to survey pitting potential.When not degassing carries out polarimetric test, sample is put into after electrolyzer at-1000mV (vs.SCE) cathodic polarization 30min, to remove the oxide-film on test face, after current stabilization, controlling potential scans to positive direction, and sweep speed is 1mV/s, and current of polarization is reached 100 μ A/cm²Potential value as the critical potential of pitting initiation, i.e. pitting potential Eb100.Test result is shown in Table 2.

Table 2: the anticorrosive Electrochemical results of embodiment 1 steel

As can be seen from Table 2: due to the addition of Cr, Mo, Sn element in embodiment 1 steel so that the corrosion potential of steel relatively IF-1 steel raises, corrosion current reduces, pitting potential E_b100Substantially rise.Compared with tradition IF steel, the corrosion potential more conventional IF steel of embodiment 1 steel improves 64mV, and corrosion current value is reduced to 0.0064mA, pitting potential E_b100Increasing 132mV, steel corrosion resistance in NICE standard solution solution A significantly improves.

Embodiment 2: a kind of containing trace tin element, high intensity, the corrosion-resistant and ultra low carbon steel slab of easy-formation, described steel plate composition is as follows, is mass percent: C:0.005%, N:0.002%, Mn:0.1%, Cr:1.50%, Mo:0.06, Si:0.1%, Al:0.01%, Mg:0.001%, Ca:0.0001%, Sn:0.30%, Nb:0.08%, Cu:0.05%, Ti:0.2%, P:0.005%, S:0.002%, remaining is Fe；

The preparation method of above-mentioned ultra low carbon steel slab, it comprises the following steps:

S1. smelt: with phosphorus content≤0.0218%, purity be 99.8%～99.9% ingot iron, purity >=99.5% chromium, purity >=99.5% stannum, purity >=99.5% manganese, Antaciron as raw material, using lime crucible is 1 × 10 in vacuum^-4Smelting in the vaccum sensitive stove of Pa, fusion process uses twice refining route, initial refining temperature to be 1600 DEG C, and refining time is 50min, and double refining temperature is 1600 DEG C, and refining time is 50min；

S2. ingot casting: forcing deoxidation with fine aluminium, pure magnesium and pure calcium after smelting, carry out ingot casting after vacuum outgas, molten steel casting temperature is 1550 DEG C, uses control to be cast into steel billet, and pouring pressure is 3atm, and poring rate is 40mm/s；

S3. hot rolling: steel billet is after 1250 DEG C of heating cogging forgings, and hot rolled steel plate of making, hot rolling initial temperature is 1250 DEG C, and finishing temperature is 900 DEG C, air cooling after hot rolling；

S4. pickling and cold-rolling: the steel plate after hot rolling is carried out pickling, pickle composition is: hydrochloric acid 20%, phosphoric acid 2%, alkyl acid phosphate phenol polyethenoxy ether 1.5%, sodium lauryl tri(oxyethyl) sulfate 1.5%, di-o-tolyl-thiourea 1.5%, pickling additive 2%, pickle temperature controls at 80 DEG C, again through drafts be 85% cold rolling, make the steel plate of given size；

S5. recrystallization annealing temperature: after cold rolling, steel plate is carried out recrystallization annealing temperature process, annealing temperature is 780 DEG C, and the time is 2 hours；

S6. roll: the steel plate after recrystallization annealing temperature is batched 650 DEG C of temperature and makes the thick steel plate of 8mm.

Above-mentioned steel plate carries out mechanics, texture degree measures, corrosion resistance electro-chemical test, and experimental technique is with embodiment 1, and texture degree is 39.2%, and mechanical experimental results such as table 3, corrosion resistance Electrochemical results is as shown in table 4:

Table 3: the mechanical experimental results of embodiment 2 steel

Table 4: the anticorrosive Electrochemical results of embodiment 2 steel

Embodiment 3: a kind of containing trace tin element, high intensity, the corrosion-resistant and ultra low carbon steel slab of easy-formation, described steel plate composition is as follows, is mass percent: C:0.003%, N:0.001%, Mn:0.5%, Cr:1%, Mo:0.01%, Si:0.5%, Al:0.008%, Mg:0.0001%, Ca:0.0015%, Sn:0.2%, Nb:0.01%, Cu:0.3%, Ti:0.1%, P:0.001%, S:0.001%, remaining is Fe；

The preparation method of above-mentioned ultra low carbon steel slab, it comprises the following steps:

S1. smelt: with phosphorus content≤0.0218%, purity be 99.8%～99.9% ingot iron, purity >=99.5% chromium, purity >=99.5% stannum, purity >=99.5% manganese, Antaciron as raw material, using lime crucible is 0.5 × 10 in vacuum^-4Smelting in the vaccum sensitive stove of Pa, fusion process uses twice refining route, initial refining temperature to be 1580 DEG C, and refining time is 35min, and double refining temperature is 1570 DEG C, and refining time is 42min；

S2. ingot casting: forcing deoxidation with fine aluminium, pure magnesium and pure calcium after smelting, carry out ingot casting after vacuum outgas, molten steel casting temperature is 1520 DEG C, uses control to be cast into steel billet, and pouring pressure is 2atm, and poring rate is 38mm/s；

S3. hot rolling: steel billet is after 1250 DEG C of heating cogging forgings, and hot rolled steel plate of making, hot rolling initial temperature is 1230 DEG C, and finishing temperature is 950 DEG C, air cooling after hot rolling；

S4. pickling and cold-rolling: the steel plate after hot rolling is carried out pickling, pickle composition is: hydrochloric acid 20%, phosphoric acid 2%, alkyl acid phosphate phenol polyethenoxy ether 1.5%, sodium lauryl tri(oxyethyl) sulfate 1.5%, di-o-tolyl-thiourea 1.5%, pickling additive 2%, pickle temperature controls at 700 DEG C, again through drafts be 90% cold rolling, make the steel plate of given size；

S5. recrystallization annealing temperature: after cold rolling, steel plate is carried out recrystallization annealing temperature process, annealing temperature is 800 DEG C, and the time is 4 hours；

S6. roll: the steel plate after recrystallization annealing temperature is batched 625 DEG C of temperature and makes the thick steel plate of 8mm.

Above-mentioned steel plate carries out mechanics, texture degree measures, corrosion resistance electro-chemical test, and experimental technique is with embodiment 1, and texture degree is 38.5%, and mechanical experimental results such as table 5, corrosion resistance Electrochemical results is as shown in table 6:

Table 5: the mechanical experimental results of embodiment 3 steel

Table 6: the anticorrosive Electrochemical results of embodiment 3 steel

Claims (3)

1. null1. an element Han trace tin、High intensity、The preparation method of the corrosion-resistant ultra-low-carbon steel with easy-formation，It is characterized in that，Described ultra-low-carbon steel composition is as follows，It is mass percent: C:0.001～0.005%，N:0.001～0.003%，Mn:0.1～0.5 %，Cr:0.8～1.50%，Mo:0.01～0.1，Si:0.1～0.5%，Al:0.005～0.01%，Mg:0.0001～0.0015%，Ca:0.0001～0.0015%，Sn:0.01～0.30%，Nb:0.01～0.2%，Cu:0.05～0.3%，Ti:0.01～0.2%，P:0.001～0.010%，S≤0.003%，Remaining is Fe，Described preparation method comprises the following steps:

   S1. smelting: with ingot iron, chromium, manganese, stannum, Antaciron as raw material, using lime crucible is 1 × 10 in vacuum^-4～1 × 10^-3Smelting in the vaccum sensitive stove of Pa, fusion process uses twice refining route, initial refining temperature to be 1550～1600 DEG C, and refining time is 30～50min, and double refining temperature is 1550～1600 DEG C, and refining time is 30～50min；

   S2. ingot casting: forcing deoxidation with fine aluminium, pure magnesium and pure calcium after smelting, carry out ingot casting after vacuum outgas, molten steel casting temperature is 1500～1550 DEG C, uses control to be cast into steel billet, and pouring pressure is 1～3atm, and poring rate is 35～40mm/s；

   S3. hot rolling: steel billet is after 1250 DEG C of heating cogging forgings, and hot rolled steel plate of making, hot rolling initial temperature is 1200～1250 DEG C, finishing temperature >=850 DEG C, air cooling after hot rolling；

   S4. pickling and cold-rolling: the steel plate after hot rolling is carried out pickling, then through cold rolling more than 80% of drafts, make the steel of given size；

   S5. recrystallization annealing temperature: after cold rolling, steel are carried out recrystallization annealing temperature process, annealing temperature is 780～800 DEG C, and the time is 2～4 hours；

   S6. roll: the steel after recrystallization annealing temperature are batched 600～650 DEG C of temperature the steel making specific thickness.
2. A kind of containing trace tin element, high intensity, the preparation method of ultra-low-carbon steel of corrosion-resistant and easy-formation, it is characterized in that, phosphorus content≤0.0218% of described ingot iron, purity are 99.8～99.9%, purity >=99.5% of purity >=99.5% of chromium, manganese and Antaciron, purity >=99.5% of stannum.
3. A kind of containing trace tin element, high intensity, the preparation method of ultra-low-carbon steel of corrosion-resistant and easy-formation, it is characterized in that, the pickle composition of described pickling is: hydrochloric acid 20%, phosphoric acid 2%, alkyl acid phosphate phenol polyethenoxy ether 1.5%, sodium lauryl tri(oxyethyl) sulfate 1.5%, di-o-tolyl-thiourea 1.5%, pickling additive 2%, and pickle temperature controls at 60～80 DEG C.