CN115976429B - 600 MPa-level corrosion-resistant steel bar and preparation method thereof - Google Patents
600 MPa-level corrosion-resistant steel bar and preparation method thereof Download PDFInfo
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- MKYBYDHXWVHEJW-UHFFFAOYSA-N N-[1-oxo-1-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)propan-2-yl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(C(C)NC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 MKYBYDHXWVHEJW-UHFFFAOYSA-N 0.000 description 2
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 2
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Classifications
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P10/00—Technologies related to metal processing
- Y02P10/20—Recycling
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- Heat Treatment Of Steel (AREA)
Abstract
The invention provides a 600MPa grade corrosion-resistant steel bar and a preparation method thereof. The steel bar comprises the chemical components in percentage by mass, and comprises the working procedures of molten iron pretreatment, converter smelting, molten steel refining, billet continuous casting, hot continuous rolling and temperature control and cooling control in the ：Cr:1.00～1.10％、Mo:0.15～0.30％、Ni:0.45～0.50％、Cu:0.50～0.55％、V:0.01～0.02％、P:0.01～0.03％、C:0.10～0.13％、Si:0.30～0.40％、Mn:0.80～1.60％、S:0.001～0.025％. method. The yield strength of the steel bar can reach more than 600MPa, and compared with the HRB600E steel bar, the steel bar has the chlorine ion corrosion resistance, the relative corrosion rate is lower than 70 percent, and the steel bar is particularly suitable for being applied to coastal construction and ocean engineering.
Description
Technical Field
The invention relates to the technical field of metallurgy, in particular to a 600 MPa-level corrosion-resistant steel bar and a preparation method thereof.
Background
According to the requirements of actively expanding the development space of ocean economy in the planning of China, the development of ocean economy and the comprehensive development of coastal areas are promoted to be accelerated, so that the accelerated development of ocean engineering and coastal infrastructures is driven, and the increasing demand of the chloride ion corrosion resistant steel bars is promoted.
The corrosion of the steel bar caused by chloride ions is always an unavoidable problem of the coastal building structure, not only is the loss and waste of natural resources caused, but also the normal use of the whole structure can be influenced by cracks or damages caused by corrosion, the service life of the coastal building is reduced, and the life safety and property safety of people are endangered.
In order to meet urgent development demands of coastal economic zones and improve reliability of ocean engineering construction, manufacturers at home and abroad develop various corrosion-resistant reinforcing bars and corrosion-resistant measures. The stainless steel bar with better corrosion resistance is suitable for various corrosion environments in marine economic construction, but has high cost, complex process and selling price which can reach 5 to 6 times of that of the common hot rolled ribbed steel bar, and cannot be put into large-area use on long coastal lines in China at present. For other corrosion prevention measures, for example, a protective coating is pre-coated on the surface of the steel bar, other inert metals are hot-dip plated on the surface of the steel bar, the thickness and uniformity of the protective layer are required to be reasonably controlled, the corrosion resistance of the steel bar is uneven due to different thickness and uniformity, and the coated and coated metals are easy to separate from the surface of the base material during the service of the building structure, so that local corrosion is caused, and the forward corrosion process is promoted.
Disclosure of Invention
An object of the present invention is to solve one or more of the problems occurring in the prior art, in view of the disadvantages of the prior art. For example, it is an object of the present invention to provide a corrosion-resistant steel bar having high yield strength and good corrosion resistance.
In one aspect of the invention, a 600MPa grade corrosion resistant steel bar is provided, which comprises the following chemical components in percentage by mass, the balance of ：Cr:1.00～1.10％、Mo:0.15～0.30％、Ni:0.45～0.50％、Cu:0.50～0.55％、V:0.01～0.02％、P:0.01～0.03％、C:0.10～0.13％、Si:0.30～0.40％、Mn:0.80～1.60％、S:0.001～0.025％, iron and unavoidable impurities, and the carbon equivalent Ceq is not more than 0.58.
In an exemplary embodiment of 600 MPa-level corrosion-resistant steel bar of the present invention, the chemical composition may be 1.98-2.00% cr+mo+ni+cu by mass percent.
In one exemplary embodiment of 600MPa grade corrosion resistant steel bar of the present invention, the tensile strength of the steel bar may be greater than or equal to 750MPa, the high yield ratio may be greater than or equal to 1.5, the elongation after break may be greater than or equal to 15%, and the total elongation at maximum may be greater than or equal to 8%.
In an exemplary embodiment of 600MPa grade corrosion resistant tendons of the present invention, 72 hour dip corrosion, the average corrosion rate may be 4.27g/m 2. H.
In an exemplary embodiment of the 600 MPa-grade corrosion resistant steel reinforcement of the present invention, the 72 hour peri-immersion corrosion may have a relative corrosion rate of no greater than 69%.
In an exemplary embodiment of 600MPa grade corrosion resistant rebar of the present invention, the rebar self-corrosion potential may be-0.575V and the self-corrosion current density may be 24.9 μa cm -2 in a 3.5% aqueous solution of NaCl mass fraction.
The invention provides a 600MPa grade corrosion-resistant steel bar preparation method, which can comprise the procedures of molten iron pretreatment, converter smelting, molten steel refining, billet continuous casting, hot continuous rolling and temperature control and cooling control, wherein the temperature control and cooling control procedures comprise: after the continuous casting of the square billets is finished, the heating temperature is controlled to 1150+/-50 ℃, the hot continuous rolling is carried out after the heat preservation is carried out for 30-50 minutes, the initial rolling temperature is 1140+/-50 ℃, the intermediate rolling temperature is 950-970 ℃, and the final rolling temperature is 1080-1100 ℃.
In an exemplary embodiment of the 600MPa grade corrosion-resistant steel bar preparation method, water penetration treatment is not carried out in the rolling process, the upper cooling bed temperature is 840-870 ℃, cooling is carried out after rolling, and the cooling rate is controlled at 1 ℃/s.
In an exemplary embodiment of the 600MPa grade corrosion-resistant steel bar preparation method, the smelting end point of the converter is that C is more than or equal to 0.05% and P is less than or equal to 0.02% in mass percent in molten steel.
Compared with the prior art, the invention has the beneficial effects that at least one of the following is included:
(1) The yield strength of the steel bar can reach more than 600MPa, the stress-strain curve yield platform is obvious, the earthquake resistance is good, the relative corrosion rate of the steel bar is lower than 70% compared with that of the HRB600E steel bar, and the steel bar has very strong corrosion resistance, and is particularly suitable for application in coastal construction and ocean engineering.
(2) The welding performance and the mechanical property of the steel bar meet the requirement of hot rolled ribbed steel bar of the 2 nd part of GB/T1499.2-2018 reinforced concrete steel for 600MPa level anti-seismic steel bar, and the service life of coastal constructions and projects can be effectively prolonged.
(3) According to the steel bar and the preparation method, the contents and the synergistic relation of the corrosion-resistant alloy elements Cr, mo, ni and Cu are reasonably designed, so that the steel bar achieves the performance described in the specification under the condition that the addition amount of Cr, mo, ni and Cu is small, and the smelting cost can be saved; and the preparation process is simple, and is suitable for popularization in coastal construction and ocean engineering.
Drawings
The foregoing and other objects and features of the invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which:
FIG. 1 is a microstructure view of a corrosion resistant tendon core in example 1 of the present invention.
FIG. 2 is a microstructure view of the edge portion of the corrosion-resistant reinforcing bar of example 1 of the present invention.
FIG. 3 is a microstructure view of 1/4 circumference of the corrosion-resistant reinforcing steel bar in example 1 of the present invention.
FIG. 4 is a graph of microstructure morphology at different multiples of the corrosion resistant steel reinforcement of example 1 of the present invention.
FIG. 5 is a graph showing corrosion weight loss in a 72-hour peri-immersion test for each of the samples of inventive example 1 and comparative example 1.
FIG. 6 is a graph showing the corrosion rate of each of the samples of example 1 and comparative example 1 according to the present invention in a 72-hour dip test.
Detailed Description
Hereinafter, a 600 MPa-grade corrosion-resistant reinforcing bar and a method of producing the same according to the present invention will be described in detail with reference to the accompanying drawings and exemplary embodiments.
One aspect of the invention provides a 600MPa grade corrosion resistant steel bar. In one exemplary embodiment of 600MPa grade corrosion resistant rebar, the rebar chemistry comprises ：Cr:1.00～1.10％、Mo:0.15～0.30％、Ni:0.45～0.50％、Cu:0.50～0.55％、V:0.01～0.02％、P:0.01～0.03％、C:0.10～0.13％、Si:0.30～0.40％、Mn:0.80～1.60％、S:0.001～0.025％, balance iron and unavoidable impurities in mass percent, and the carbon equivalent Ceq is no greater than 0.58. For example, in some embodiments, the balance of its chemical composition ,Cr:1.02～1.08％、Mo:0.18～0.27％、Ni:0.48～0.49％、Cu:0.51～0.54％、V:0.011～0.018％、P:0.012～0.027％、C:0.11～0.12％、Si:0.32～0.39％、Mn:0.81～1.58％、S:0.001～0.022％, by mass percent is iron and unavoidable impurities, and the carbon equivalent Ceq is no greater than 0.55 or no greater than 0.53 or no greater than 0.48 or no greater than 0.45 or no greater than 0.42. As is known in the art, the carbon equivalent ceq=c+mn/6+ (cr+v+mo)/5+ (cu+ni)/15.
Wherein, in the chemical components, cr element with the mass fraction of 1.00-1.10% is added to effectively reduce the self-corrosion potential in the steel bar corrosion process and promote the formation of alpha-phase passivation film on the surface of the steel bar; the Cr element exists in the rust layer in the form of oxide, so that the compactness and stability of the rust layer can be improved, and the corrosion of chloride ions on the steel bar matrix can be prevented; if Cr with the mass percentage of more than 1.10% is added, the plasticity and toughness of the steel bar are reduced, and the mechanical property of the steel bar is affected. Preferably, the Cr content can be 1.02% -1.10%, and the loss of the reinforcing steel bar in mechanical property can be effectively avoided by cooperating with the content of other chemical components of the reinforcing steel bar. For example, the Cr content may be 1.03%, 1.04%, 1.05%, 1.06%, 1.07%, 1.08%, or 1.09%.
For Ni element, the mass percent of Ni is 0.45-0.50% and the mass percent of Cr is 1.00-1.10%, so that the corrosion resistance of the steel bar in a chloride ion environment can be remarkably improved, and the synergistic effect of Ni and Cr can further improve the components of the corrosion oxide film to improve the density of the oxide film. The Ni content is also related to the passivation film property of the surface of the steel bar, and in the Ni content range of the invention, the passivation film property of the surface of the matrix can be improved along with the increase of the Ni content, so that the passivation film is thinner and has better protection. In some embodiments, the Ni content may be 0.45% to 0.48%. For example, the Ni content may be 0.46% or 0.47%.
For Mo element, 0.15-0.30% of Mo element can effectively inhibit the pitting process mainly of chloride ion corrosion and promote the generation of passivation film on the surface of the steel bar; and under the addition of the Mo element content, the grain can be further and effectively refined, and the toughness and the wear resistance of the steel bar are improved. In some embodiments, the Mo content may be controlled between 0.15% and 0.27%, for example, the Mo content may be 0.17%, 0.18%, 0.19%, 0.22%, 0.24%, or 0.25%.
For Cu element, the Cu element has excellent corrosion resistance, the content of 0.50-0.55% of the Cu element can slow down the growth speed of a rust layer on the surface of the steel bar, and the oxide formed by the Cu element can inhibit the invasion of oxygen and chloride ions; in addition, the enrichment of Cu on the surface of the steel bar can reduce the conductivity of the surface of the steel bar and delay the corrosion process; the Cu and P in the content of the invention can cooperate to promote the formation of an alpha phase passivation film. In some embodiments, the Cu content may be controlled to be 0.51% to 0.54%, for example, the Cu content is 0.52% or 0.53%.
For the P element, 0.01 to 0.03 percent of the P element is added to promote the formation of an alpha phase passivation film, prevent chloride ions from corroding a steel bar matrix and reduce the corrosion rate; the P element is oxidized to form PO 4 3- in the corrosion process, and the P element is enriched in the rust layer in the form of phosphate, so that the reinforcing steel bar matrix can be protected. If the content of the P element is more than 0.03%, brittleness of the steel bar increases and ductility thereof decreases. In some embodiments, the P content may be 0.015%, 0.018%, 0.02%, 0.025%, or 0.028%.
For V element, 0.01-0.02 mass percent of V element is added to further refine the structure grains of the steel bar and improve the strength and toughness of the steel bar. In some embodiments, the V element content may be 0.012%, 0.015%, 0.017%, or 0.019%.
The reinforcement bars described herein ensure the resistance to chloride corrosion of corrosion resistant reinforcement bars by the addition of a reasonable and small amount of Cr, ni, mo, cu, P, V elements and the synergistic effect between the elements.
For the carbon equivalent, by controlling the carbon equivalent Ceq to be not more than 0.58, the content of Mn, cr, V, mo, cu and Ni elements can be limited so as to ensure good corrosion resistance, and meanwhile, the steel bar has good welding performance, and brittle failure of the corrosion-resistant steel bar in the welding process is avoided.
Further, the chemical components of the steel bar are 1.98-2.00% of Cr+Mo+Ni+Cu by mass percent. Cr+Mo+Ni+Cu is a main corrosion-resistant alloy element, and by controlling Cr+Mo+Ni+Cu to be 1.98-2.00%, the yield strength of the steel bar is more than 600MPa, the tensile strength is more than or equal to 750MPa, the strength-to-flex ratio is more than or equal to 1.5, the elongation after break is more than or equal to 15%, the total elongation under the maximum force is more than or equal to 8%, and the corrosion resistance is good, so that the production cost of the steel bar can be further saved. In some embodiments, cr+mo+ni+cu may be 1.99%, mn+p+si may be 1.52% or mn+p+si may be 1.55% or mn+p+si may be 1.58% or mn+p+si may be 1.60% or mn+p+si may be 1.63%.
Further, the tensile strength of the steel bar is more than or equal to 750MPa, the strength-to-deflection ratio is more than or equal to 1.5, the elongation after breaking is more than or equal to 15%, and the total elongation under the maximum force is more than or equal to 8%. In some embodiments, the tensile strength is equal to or greater than 780MPa or the tensile strength is equal to or greater than 790MPa or the tensile strength is equal to or greater than 800MPa, the dorsiflexion ratio is equal to or greater than 1.5 or the dorsiflexion ratio is equal to or greater than 1.7 or the dorsiflexion ratio is equal to or greater than 1.9 or the dorsiflexion ratio is equal to or greater than 2.0, the elongation after break is equal to or greater than 15% or greater than 17% or greater than 18% or greater than 20% or greater than 21% or greater than after break, the total elongation at maximum force is equal to or greater than 8% or greater than 8.5% or greater than 8.9% or greater than 9.5% at maximum force.
Further, 600MPa grade corrosion resistant tendons described herein have excellent corrosion resistance. The average corrosion rate of the steel bars can be 4.23-4.31 g/m 2.h. For example, the average corrosion rate may be 3.2g/m 2·h、3.8g/m2·h、4.27g/m2. Multidot.h or 4.3g/m 2. Multidot.h. The average corrosion rate is obtained by carrying out a 72-hour peri-immersion corrosion test according to the method recorded in YB/T4367 steel bar corrosion test method in chloride ion environment, and the parameters of the peri-immersion corrosion test are as follows: placing the treated sample into a peri-immersion test box, wherein the test solution is NaCl solution with the mass fraction of 2%; the test temperature is: 45 ℃ +/-2 ℃; test environment humidity: 70% ± 5RH; total duration of the test: 72 hours; test single cycle setup: 60 min/cycle, infiltration time 12 min/cycle, drying time 48 min/cycle, continuous test and average corrosion rate of 72 hours were obtained.
In addition, in the 72-hour cycle immersion corrosion test, according to the description of "corrosion resistant reinforcing bar for reinforced concrete" and "method of corrosion test of YB/T4367 reinforcing bar in chloride ion environment", the reinforcing bar described herein has a relative corrosion rate of less than 70%, for example, less than 69% or less than 68% or less than 67% compared with the reinforcing bar under the trade name HRB 600E.
In the water solution with the NaCl mass fraction of 3.5 percent for simulating the seawater environment, the self-corrosion potential E corr of the steel bar is-0.564 to-0.576V, the self-corrosion current density I corr is 23.7-24.9 mu A cm -2, compared with the corrosion-resistant steel bar with the brand HRB600E, the self-corrosion potential forward movement range exceeds 0.4V, the self-corrosion current density Icorr is more than 5 mu A cm -2, and the corrosion resistance is stronger than that of the common steel bar. For example, the self-corrosion potential of the steel bar may be-0.575V and the self-corrosion current density may be 24.9 μA cm -2. The specific method for the electrochemical corrosion test comprises the following steps: the electrochemical test is carried out according to GB/T24196-2009 'constant potential and potentiodynamic polarization measurement guide of corrosion electrochemical test method of metals and alloys', a three-electrode system is adopted, a reference electrode is a saturated calomel electrode, an auxiliary electrode is a Pt sheet, and a test solution is a NaCl solution with mass fraction of 3.5% to simulate a seawater environment; the test scanning range of the polarization curve is-300-600 mV relative to the self-corrosion potential of the sample, and the scanning frequency is 1mV/s; the scanning frequency range of the electrochemical impedance test is 10 5～10-2 Hz, and the amplitude of the alternating current excitation signal is +/-5 mV.
Further, the microstructure of the corrosion-resistant steel bar is bainite and ferrite.
The invention further provides a preparation method of the 600 MPa-level corrosion-resistant reinforcing steel bar. In an exemplary embodiment of the 600 MPa-grade corrosion-resistant tendon preparation method of the present invention, the preparation method may include a molten iron pretreatment (e.g., molten iron pre-desulfurization) process, a converter smelting process, a molten steel refining process (e.g., LF furnace refining process), a Fang Pei continuous casting process, a hot continuous rolling process, and a temperature-controlled cooling process.
Further, the molten iron pretreatment process is known to those skilled in the art, and the molten iron is pretreated in a conventional manner in the art.
Further, in the converter smelting process, the molten steel at the end point of converter smelting contains more than or equal to 0.05% of elements in mass percent and less than or equal to 0.02% of P. For example, the endpoint of converter smelting may be C greater than 0.07% and P no greater than 0.015%.
Further, in the converter smelting process, alloy with the following components and content can be added into the deoxidization and alloying of molten steel, wherein the alloy comprises 2.5 kg/t-2.85 kg/t of ferrosilicon, 15.12 kg/t-19.34 kg/t of ferrochrome, 11.21 kg/t-15.35 kg/t of ferrosilicon, 5.10 kg/t-5.97 kg/t of copper plate, 6.21 kg/t-8.12 kg/t of nickel plate, 3.11 kg/t-5.17 kg/t of ferrovanadium and 3.85 kg/t-4.78 kg/t of ferromolybdenum. For example, in some embodiments, 2.59kg/t to 2.75kg/t ferrosilicon, 15.86kg/t to 18.34kg/t ferrochromium, 12.21kg/t to 15.12kg/t ferrosilicon, 5.31kg/t to 5.67kg/t copper plate, 6.38kg/t to 7.83kg/t nickel plate, 3.17kg/t to 4.85kg/t ferrovanadium, 3.97kg/t to 4.68kg/t ferromolybdenum may be included. For example, ferrosilicon 2.67kg/t, ferrochromium 17.27kg/t, ferrosilicon 13.57kg/t, copper plate 5.56kg/t, nickel plate 7.10kg/t, ferrovanadium 4.21kg/t, ferromolybdenum 4.25kg/t.
The alloy can be added according to the sequence of ferrosilicon-silicomanganese-ferrochromium when tapping 1/4, copper plate and nickel plate scrap steel are put into a converter, the scrap steel loading amount is correspondingly reduced, and ferromolybdenum and ferrovanadium are added in the molten steel refining process. It should be appreciated that in certain embodiments, the alloy may be added in other ways.
Further, in the molten steel refining process, argon is introduced after molten steel smelted by a converter reaches the refining process, and the gas quantity is regulated. After the ladle is opened to a refining station, adding 200-400kg of lime and 0-100kg of fluorite into the slag, electrifying to remove slag for 8-15 minutes, and measuring the temperature and sampling; adding deoxidizer to make white slag. And adding alloy for component fine adjustment according to the LF sampling analysis result. After the component temperature reaches the target, feeding pure calcium wires for 0-100m, and soft argon blowing time is more than or equal to 6min.
Further, in the process of Fang Pei continuous casting, the casting can be protected in the whole process, the argon seal of the large ladle long nozzle is realized, the liquid level of the long nozzle inserted into the long nozzle is more than or equal to 150mm, and the liquid level of the ladle in normal casting is more than or equal to 500mm.
Further, the temperature control and cooling are carried out in the hot continuous rolling process, 24 passes are adopted in the rolling process, the initial rolling temperature can be 1140+/-50 ℃, the intermediate rolling temperature can be 950-970 ℃, and the final rolling temperature can be 1080-1100 ℃. The mechanical properties of the steel bars produced after rolling are all satisfied with various indexes of the hot rolled ribbed steel bars for 600MPa level anti-seismic steel bars in the 2 nd part of GB/T1499.2-2018 steel for reinforced concrete. For example, the rolling process is performed in 24 passes, the initial rolling temperature may be 1170 ℃, the intermediate rolling temperature may be 960 ℃, and the final rolling temperature may be 1090 ℃.
For a better understanding of the present invention, the content of the present invention is further elucidated below in connection with the specific examples, but the content of the present invention is not limited to the examples below.
Example 1
The steel bars of example 1 and comparative example 1 shown in table 1 are subjected to molten iron pretreatment, converter smelting, LF furnace refining, square billet continuous casting, inspection, finishing, cold feeding and hot continuous rolling, the rolling process adopts 24 passes for rolling, and the rolling temperature is started: 1180 ℃, intermediate process rolling temperature: 960 ℃, final rolling temperature: 1090 ℃, and rolling into a threaded reinforcing steel bar with phi of 12mm, wherein the mechanical properties of the reinforcing steel bar of example 1 are shown in table 2.
TABLE 1 composition of reinforcing bar components
The micro-morphology of the corrosion-resistant steel bar of example 1 is shown in fig. 1 to 4, wherein (a) in fig. 4 is 2000 times the micro-morphology, (b) is 5000 times the micro-morphology, (c) is 10000 times the micro-morphology, and (d) is 20000 times the micro-morphology. As can be seen from the figure, the microstructure of the steel bar is composed of ferrite and bainite.
Table 2 mechanical properties of example 1 and comparative example 1 reinforcing bars
The types of test solutions, the solution temperature, the environment humidity, the test time and the infiltration period time are set according to the corrosion-resistant steel bar for reinforced concrete of GB/T33953-2017 and the corrosion test method of YB/T4367 in chloride ion environment, and the infiltration experiment design of 72-hour period is as follows:
Test sample configuration: example 1 steel bar parallel test sample 5, numbered 1 through 5, labeled example 1-1, example 1-2, example 1-3, example 1-4, and example 1-5, respectively; the comparative example bars were 5 in parallel and numbered 1 to 5, and were labeled example 1-1, example 1-2, example 1-3, example 1-4 and example 1-5, respectively, for a total of 10.
Test sample specification: the test sample adopts a uniform specification test sample, and the specification is phi 9mm multiplied by 50mm.
Test solution types: naCl solution.
The NaCl concentration in the test solution was: mass fraction 2%.
The replenishment solution during the test was: ultrapure water.
Test temperature: 45 ℃ +/-2 ℃; test environment humidity: 70% ± 5RH; total duration of the test: 72 hours; test single cycle setup: 60 min/period, soaking time 12 min/period, and drying time 48 min/period.
After 72-hour period immersion test, the corrosion loss of the steel bars is shown in tables 3 and 5 (in FIG. 5, curve A represents the corrosion loss of examples 1-1 to 1-5, curve B represents the corrosion loss of comparative examples 1-1 to 1-5), the corrosion rates are shown in tables 4 and 6 (in FIG. 6, curve A represents the corrosion rates of examples 1-1 to 1-5, curve B represents the corrosion rates of comparative examples 1-1 to 1-5), and the relative corrosion rates are shown in Table 5.
TABLE 3 weight loss by corrosion of steel bars
TABLE 4 Rebar Corrosion Rate
TABLE 5 relative Corrosion Rate
As can be seen from table 3 and fig. 5, the corrosion loss of the steel bar of example 1 is smaller than that of the steel bar of comparative example 1, and the corrosion rate of the steel bar is also smaller, and the relative corrosion rate is 69%.
Examples 2 to 6
The rebar compositions of examples 2 and 5 are shown in table 6.
Table 6 reinforcing bar composition of examples 2 to 6
Examples 2 to 6 were tested according to the method described in example 1, and the mechanical properties, corrosion rates, and relative corrosion rates are shown in table 7.
Table 7 examples 2 to 6 various properties of the reinforcing bars
As can be seen from tables 2,4, 5 and 7, the rebars of examples 1 to 6 are significantly superior to comparative example 1 in corrosion resistance. The average corrosion rate of the corrosion-resistant reinforcing steel bar can reach 4.23-4.31 g/m 2 & h, the relative corrosion rate is not more than 69%, and the corrosion-resistant reinforcing steel bar has excellent corrosion resistance.
Although the present invention has been described above by way of the combination of the exemplary embodiments, it should be apparent to those skilled in the art that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined in the appended claims.
Claims (4)
1. The 600MPa grade corrosion-resistant steel bar is characterized by comprising the following chemical components in percentage by mass, wherein the balance of Cr:1.00～1.10％、Mo:0.15～0.30％、Ni:0.45～0.50％、Cu:0.50～0.55％、V:0.01～0.02％、P:0.01～0.03％、C:0.10～0.13％、Si:0.30～0.40％、Mn:0.80～1.60％、S:0.001～0.025％, is iron and unavoidable impurities, and the carbon equivalent Ceq is not more than 0.58, and the microstructure of the corrosion-resistant steel bar is bainite and ferrite; the tensile strength of the steel bar is more than or equal to 750MPa, the strength-to-deflection ratio is more than or equal to 1.5, the elongation after breaking is more than or equal to 15%, and the total elongation under the maximum force is more than or equal to 8%; the preparation method comprises the following steps: molten iron pretreatment, converter smelting, molten steel refining, billet continuous casting, hot continuous rolling and temperature control and cooling control procedures, wherein the temperature control and cooling control procedures comprise:
After the continuous casting of the square billets is finished, the heating temperature is controlled to 1150+/-50 ℃, the hot continuous rolling is carried out after the heat preservation is carried out for 30-50 minutes, the initial rolling temperature is 1140+/-50 ℃, the intermediate rolling temperature is 950-970 ℃, and the final rolling temperature is 1080-1100 ℃;
The water penetrating treatment is not carried out in the rolling process, the temperature of the upper cooling bed is 840-870 ℃, the cooling is carried out after the rolling, and the cooling rate is controlled at 1 ℃/s;
At the smelting end point of the converter, the mass percentage of C in the molten steel is more than or equal to 0.05 percent, and the mass percentage of P is less than or equal to 0.02 percent.
2. A 600MPa grade corrosion resistant steel according to claim 1 wherein the average corrosion rate is 4.23-4.31 g/(m 2 h) for 72 hours dip corrosion.
3. A 600MPa grade corrosion resistant steel according to claim 1 or claim 2 wherein the relative corrosion rate is no more than 69% by 72 hours of dip corrosion.
4. A 600MPa grade corrosion resistant steel according to claim 1 or 2 wherein the steel has a self-corrosion potential of-0.564 to-0.576V and a self-corrosion current density of 23.7 to 24.9 μa cm -2 in an aqueous solution of 3.5% naci by mass.
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| CN114032449A (en) * | 2021-08-04 | 2022-02-11 | 敬业钢铁有限公司 | Niobium-free rare earth-free high-strength corrosion-resistant reinforcing steel bar with yield strength of 600MPa and production method thereof |
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| CN114032449A (en) * | 2021-08-04 | 2022-02-11 | 敬业钢铁有限公司 | Niobium-free rare earth-free high-strength corrosion-resistant reinforcing steel bar with yield strength of 600MPa and production method thereof |
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