CN111945063B - Steel for high-strength corrosion-resistant fastener for ocean wind power and production method - Google Patents

Steel for high-strength corrosion-resistant fastener for ocean wind power and production method Download PDF

Info

Publication number
CN111945063B
CN111945063B CN202010731641.XA CN202010731641A CN111945063B CN 111945063 B CN111945063 B CN 111945063B CN 202010731641 A CN202010731641 A CN 202010731641A CN 111945063 B CN111945063 B CN 111945063B
Authority
CN
China
Prior art keywords
steel
wind power
corrosion
equal
strength
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010731641.XA
Other languages
Chinese (zh)
Other versions
CN111945063A (en
Inventor
姜婷
汪开忠
胡芳忠
于同仁
丁雷
许文喜
牟祖茂
石践
郝震宇
郭湛
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Maanshan Iron and Steel Co Ltd
Original Assignee
Maanshan Iron and Steel Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Maanshan Iron and Steel Co Ltd filed Critical Maanshan Iron and Steel Co Ltd
Priority to CN202010731641.XA priority Critical patent/CN111945063B/en
Publication of CN111945063A publication Critical patent/CN111945063A/en
Application granted granted Critical
Publication of CN111945063B publication Critical patent/CN111945063B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/06—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires
    • C21D8/065—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of rods or wires of ferrous alloys
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/001—Ferrous alloys, e.g. steel alloys containing N
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/002—Ferrous alloys, e.g. steel alloys containing In, Mg, or other elements not provided for in one single group C22C38/001 - C22C38/60
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/008—Ferrous alloys, e.g. steel alloys containing tin
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C38/00—Ferrous alloys, e.g. steel alloys
    • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
    • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
    • C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/002—Bainite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/005—Ferrite
    • C—CHEMISTRY; METALLURGY
    • C21—METALLURGY OF IRON
    • C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
    • C21D2211/00—Microstructure comprising significant phases
    • C21D2211/009—Pearlite

Abstract

The invention discloses steel for a high-strength corrosion-resistant fastener for ocean wind power and a production method, and belongs to the technical field of ocean wind power fastener materials. The steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following main chemical components in percentage by mass: c: 0.20-0.30%, Si: 0.60-0.80%, Mn: 0.40-0.60%, Cr: 1.20% -1.40%, Mo: 0.15% -0.30%, Ni: 0.30-0.50%, Cu: 0.20-0.40%, Sn: 0.10-0.20%, Al: 0.020% -0.037%, N: 0.010% -0.015%, Mg: 0.0015 to 0.0035 percent, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, and the balance of Fe and other inevitable impurities. The grain size of austenite of the steel is less than or equal to 11 mu m, the steel has high strength and high toughness, and the heat treatment mechanical property reaches more than 10.9 grade and KV at-80 DEG C2The impact toughness value is more than or equal to 65J, and the chloride ion corrosion resistance is more than 1.5 times of that of the steel for 10.9-grade wind power bolts commonly used in the market.

Description

Steel for high-strength corrosion-resistant fastener for ocean wind power and production method
Technical Field
The invention belongs to the technical field of marine wind power fastener materials, and particularly relates to high-strength steel for a corrosion-resistant fastener for marine wind power and a production method.
Background
The width of the country is wide, the coastline is long, and the wind energy resource is rich. However, the development time of wind turbine generators in China is not long, and the development of industrialization is not reached until the last ten years. In recent years, the wind power industry has been rapidly developed under the support of national policies, and the mainstream machine type has been shifted to a high-capacity unit above megawatt level. The key parts used around the ocean wind power need to be in service for more than 25 years in the environment of low temperature, humidity, corrosion and alternating load, the bolt connection at the key part must have higher reliability, and the high requirements on the obdurability, the chloride ion corrosion resistance and the like of the raw material steel are provided.
In the aspect of steel for marine wind power corrosion-resistant fasteners in China, the mainstream steel grades such as 42CrMo and 35CrMo in the market do not have corrosion resistance, and the development requirements of marine wind power units cannot be met. The development of novel high-strength corrosion-resistant fastener steel for ocean wind power is urgent.
The Chinese patent application numbers are: 201711442848.X, published as: 2018-06-19, namely 'a steel for high-through-quenching large-size wind power bolts and a manufacturing method thereof', wherein the steel comprises the following chemical components in percentage by weight: 0.35 to 0.45 percent of C, less than or equal to 0.20 percent of Si, 0.60 to 1.00 percent of Mn, less than or equal to 0.012 percent of P, less than or equal to 0.005 percent of S, 1.00 to 1.50 percent of Cr, 0.15 to 0.40 percent of Mo, 0.0005 to 0.003 percent of B, 0.03 to 0.08 percent of Ti, 0.02 to 0.05 percent of Als, less than or equal to 0.005 percent of N, and 0.0001 to 0.0003 percent of Ca. The method is mainly used for manufacturing 10.9-12.9-grade large-size wind power bolts with the size specification of 42-75 mm. The disadvantage is that the steel of the invention has no corrosion resistance.
The Chinese patent application numbers are: 201811431401.7, publication date is: 2019-03-01, and the preparation method of the high-purity wind power fastener comprises the following steps: (1) smelting in a converter: controlling the mass percentage content of C to be more than or equal to 0.06 percent or the oxygen level of the tapping TSO to be less than or equal to 400ppm at the end point, and controlling the tapping temperature to be more than or equal to 1560 ℃; (2) tapping by a converter: a. bottom stirring; b. discharging slag; (3) and (3) deoxidation alloying: adding a carburant for pre-deoxidation at the early stage of tapping, then sequentially adding an alloy, a deoxidizer and slag charge, and keeping argon blowing in the whole deoxidation alloying process; (4) and (3) LF treatment: controlling the mass percentage of inclusions in the steel: CaO is 50-60%, Al2O3 is 15-25%, the alkalinity of final slag is controlled at 3-6, SiC, aluminum particles, calcium silico-aluminum and a deoxidizing slag former are adopted in the power supply smelting process for composite diffusion deoxidation, and the total mass percentage content of TFe and MnO is ensured to be less than or equal to 1%; (5) RH treatment: controlling the vacuum degree below 2.5 mbar and keeping for 0-5min, keeping the high vacuum for more than or equal to 8min, feeding aluminum wire for 1-2min, performing calcium treatment, and soft-blowing for more than 10 min; (6) and (4) continuous casting. The invention mainly controls the purity of the steel for the wind power bolt from the aspect of steelmaking process, and does not relate to the performances of toughness, corrosion resistance and the like of the steel.
The Chinese patent application numbers are: 201710742979.3, publication date is: 2018-01-16, which is a high-strength and high-toughness bolt steel and a production method thereof, comprises the following components in percentage by weight: c: 0.25-0.33%, Si: 1.00-1.30%, Mn: 0.90-1.10%, P: less than or equal to 0.015 percent, S: less than or equal to 0.010 percent, Cr: 0.85-1.20%, V: 0.12-0.22%, B: 0.0005-0.0015%, and the balance of iron and inevitable impurities. The production method comprises the following steps: smelting; deoxidizing and alloying in a ladle furnace; carrying out vacuum treatment in an RH vacuum furnace, and carrying out continuous casting or die casting; conventionally heating a casting blank; rolling into a wire rod; cooling by stelmor mode. The invention ensures that the tensile strength is not lower than 1400MPa and the added expensive elements are relatively few, can ensure that the elongation A of the steel is not lower than 18 percent, the reduction of area Z is not lower than 60 percent, the impact energy Akv at normal temperature is not lower than 60J without modifying any equipment, has lower production cost and completely meets the requirements of automobiles and aviation on high-strength bolts. However, the hot rolled wire rod produced by the method is mainly used for processing automobile and aviation bolts, the wind power bolts are basically processed by adopting bars at present, and the invented steel does not have obvious corrosion resistance.
The Chinese patent application numbers are: 201711215120.3, publication date is: 2018-05-25, which is a 1040 MPa-grade weather-resistant bolt resistant to delayed fracture, and comprises the following chemical components in percentage by mass: c: 0.21 to 0.32, Si: 0.10 to 0.50, Mn: 0.60 to 1.00, P: 0.008 to 0.020, S: less than or equal to 0.005, Cr: 0.82 to 1.20, Ni: 0.25 to 0.50, Cu: 0.25 to 0.50, Mo: 0.05 to 0.20, Nb: 0.015 to 0.060, V: 0.015 to 0.090, Ti: 0.008-0.035, B: 0.0008 to 0.0035, Al: 0.015 to 0.040, Ca: 0.003 to 0.007, Zr: 0.015 to 0.045, Re: 0.010-0.045, and the balance of Fe and inevitable impurities; the preparation method of the bolt mainly adopts the conventional high-purity melting-continuous casting-rolling technology, and the manufactured bolt is resistant to delayed fracture and atmospheric corrosion. However, the invented steel only has atmospheric corrosion resistance, and does not show obvious marine environment chloride ion corrosion resistance.
Disclosure of Invention
1. Problems to be solved
Aiming at the problem of poor corrosion resistance of the existing marine wind power fastener, the invention provides the steel for the high-strength marine wind power corrosion-resistant fastener and the production method thereof, the grain size of austenite grain size of the steel is less than or equal to 11 mu m, the steel has high strength and high toughness, and the heat treatment mechanical property reaches more than 10.9 grade and KV at-80 DEG C2The impact toughness value is more than or equal to 65J, and the chloride ion corrosion resistance is more than 1.5 times of that of the steel for 10.9-grade wind power bolts commonly used in the market.
2. Technical scheme
In order to solve the problems, the technical scheme adopted by the invention is as follows:
the invention relates to a high-strength steel for a corrosion-resistant fastener for ocean wind power, which mainly comprises the following chemical components in percentage by mass: c: 0.20-0.30%, Si: 0.60-0.80%, Mn: 0.40-0.60%, Cr: 1.20% -1.40%, Mo: 0.15% -0.30%, Ni: 0.30-0.50%, Cu: 0.20-0.40%, Sn: 0.10-0.20%, Al: 0.020% -0.037%, N: 0.010% -0.015%, Mg: 0.0015 to 0.0035 percent, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, and the balance of Fe and other inevitable impurities.
As further illustration of the invention, the chemical composition satisfies the following Cl-corrosion resistance index A ≥ 7.0，A＝5.7Sn+15.5Cu+2.9Ni+1.6Cr+1.7Si-6.8Cu*Ni-23.4Cu2。
As a further explanation of the present invention, the chemical composition satisfies 2.0. ltoreq. B.ltoreq.2.5, and B ═ Al/N.
As a further illustration of the invention, the structure of the steel for the high-strength corrosion-resistant fastener for the marine wind power is ferrite + pearlite + a small amount of bainite.
The invention relates to a production method of steel for a high-strength corrosion-resistant fastener for ocean wind power, which comprises the following steps of:
s1, smelting in an electric furnace or a converter, determining oxygen before tapping, and reserving steel in the tapping process;
s2, refining in an LF furnace;
s3, RH vacuum degassing;
s4, square billet continuous casting;
s5, hot rolling round steel;
and S6, feeding the mixture to a cooling bed (opening a heat preservation cover for slow cooling).
In step S2, elements such as C, Si, Mn, Cr, Mo, Ni, Cu, and Sn are adjusted to target values.
As a further explanation of the invention, in the step S3, the pure degassing time is more than or equal to 15 minutes, and the content of [ H ] after vacuum treatment is less than or equal to 1.5 ppm.
In step S4, the target temperature of the molten steel in the tundish is controlled to be 10 to 40 ℃ above the liquidus temperature, and the billet is continuously cast.
As a further description of the present invention, the hot rolling of round steel in step S5 includes:
a. heating the square billet, and controlling the soaking temperature of a heating furnace to be 1100-1200 ℃;
b. rough and medium rolling;
c. and (3) finish rolling, wherein the finish rolling temperature is controlled to be 810-860 ℃.
In the step S6, the temperature of the upper cooling bed is controlled to be 760 to 810 ℃.
3. Advantageous effects
Compared with the prior art, the invention has the beneficial effects that:
(1) the high-strength corrosion-resistant fastener steel for the marine wind power has the advantages that the grain size of austenite grain size of the steel is less than or equal to 11 mu m, the steel has high strength and high toughness, the heat treatment mechanical property reaches more than 10.9 grade, and KV is achieved at-80 DEG C2The impact toughness value is more than or equal to 65J, and the chloride ion corrosion resistance is more than 1.5 times of that of the steel for the 10.9-grade wind power bolt commonly used in the market;
(2) the A value of the steel for the high-strength corrosion-resistant fastener for the marine wind power is the Cl resistance of Sn, Cu, Mn, Ni, Cr and Si to the steel-The indexes Sn, Cu, Mn, Ni, Cr and Si for evaluating the degree of influence of the corrosion performance and the influence degrees of the elements in a weighted and added mode are the indexes for improving the marine environment Cl resistance of the steel grade-Elements of corrosion performance;
(3) according to the high-strength corrosion-resistant fastener steel for the marine wind power, the ALN precipitated phase is formed by using Al and the N element of the steel type, so that the growth of crystal grains is inhibited, the B value is controlled to be 2.0-2.5, the two elements are completely combined into AlN, the inhibition effect of the crystal grain size is exerted to the maximum extent, and the austenite crystal grain size is controlled to be within 11 microns;
(4) according to the production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power, the soaking temperature of the heating furnace is controlled to be 1100-1200 ℃, and if the soaking temperature is lower than 1100 ℃, insoluble elements such as Ni and Cu cannot be dissolved in austenite, so that the steel is segregated at a grain boundary during rolling, and the steel is high in brittleness; if it is higher than 1200 ℃, austenite grains start to become coarse, and the decarburization tendency is greatly increased;
(5) the production method of the high-strength steel for the corrosion-resistant fastener for the marine wind power controls the temperature to be 810-860 ℃ before finish rolling, and controls the finish rolling temperature to be A by utilizing the severe thermal deformation of the austenite region under large reductionC3The transformation of the pro-eutectoid ferrite occurs in the temperature range of 20-60 ℃ above the point, and the obtained deformation induced ferrite transformation can refine grains by combining deformation, so that the steel has excellent plasticity and toughness. This effect cannot be achieved either above or below this temperature;
(6) the production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power, disclosed by the invention, has the advantages that the temperature of an upper cooling bed is controlled to be 760-810 ℃, meanwhile, a heat-insulating cover is used on the cooling bed, if the reduced diameter temperature is lower than 750 ℃, the steel enters a phase-change stage before entering a heat-insulating section of the cooling bed, and abnormal structures are possibly formed in the air; if the temperature is higher than 800 ℃, the phase transition temperature is not reached when the heat preservation cover enters, and the whole phase transition is difficult to complete on the cooling bed, so that a large amount of abnormal tissues are generated;
(7) the invention relates to a production method of steel for a high-strength corrosion-resistant fastener for ocean wind power, and the austenite grain size of the produced steel is less than or equal to 11 mu m. The steel adopts the following quenching and tempering heat treatment process: quenching at 870-920 ℃ and tempering at 550-600 ℃. The mechanical property of the heat treatment reaches more than 10.9 grade (R)m≥1040MPa，Rp0.2940MPa or more, 9% or more of A, 48% or more of Z and 0.8% or more of yield ratio at-80 deg.C2The impact toughness value is more than or equal to 65J, and the chloride ion corrosion resistance is more than 1.5 times of that of general comparative steel in the market.
Drawings
The technical solutions of the present invention will be described in further detail below with reference to the accompanying drawings and examples, but it should be understood that these drawings are designed for illustrative purposes only and thus do not limit the scope of the present invention. Furthermore, unless otherwise indicated, the drawings are intended to be illustrative of the structural configurations described herein and are not necessarily drawn to scale.
FIG. 1 is a graph of the A value versus the relative corrosion rate;
FIG. 2 is a schematic diagram of a hot-rolled structure of the steel for the corrosion-resistant fastener for the high-strength marine wind power.
Detailed Description
The following detailed description of exemplary embodiments of the invention refers to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration exemplary embodiments in which the invention may be practiced. Although these exemplary embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, it should be understood that other embodiments may be realized and that various changes to the invention may be made without departing from the spirit and scope of the present invention. The following more detailed description of the embodiments of the invention is not intended to limit the scope of the invention, as claimed, but is presented for purposes of illustration only and not limitation to describe the features and characteristics of the invention, to set forth the best mode of carrying out the invention, and to sufficiently enable one skilled in the art to practice the invention. Accordingly, the scope of the invention is to be limited only by the following claims.
The detailed description and exemplary embodiments of the invention will be better understood when read in conjunction with the appended drawings, where the elements and features of the invention are identified by reference numerals.
The steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following main chemical components in percentage by mass as shown in table 1:
TABLE 1 chemical compositions and weight percentages (mass%, balance Fe and unavoidable impurities) of examples and comparative examples
Figure BDA0002603378280000051
The contents of the elements in the above examples all satisfy the following ranges:
c: 0.20-0.30%, Si: 0.60-0.80%, Mn: 0.40-0.60%, Cr: 1.20% -1.40%, Mo: 0.15% -0.30%, Ni: 0.30-0.50%, Cu: 0.20-0.40%, Sn: 0.10-0.20%, Al: 0.020% -0.037%, N: 0.010% -0.015%, Mg: 0.0015 to 0.0035 percent, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, and the balance of Fe and other inevitable impurities.
The specific effects of the element composition in the scheme are as follows:
c: c is the most basic effective strengthening and hardenability element in steel, but too high a content of C reduces ductility and increases the risk of delayed fracture of the bolt. For the high-strength corrosion-resistant fastener steel for the marine wind power, the C content is controlled to be 0.20-0.30%.
Si: si is an important element for strengthening in steel, and the strength and hardness of the steel are improved through solid solution. Silicon is mainly enriched on the surface of steel, the stability of a rust layer is improved, and the corrosion resistance is improved, but the increase of the Si element can increase the diffusion of carbon in the steel, and the decarburization of the steel is aggravated. For the high-strength corrosion-resistant fastener steel for the marine wind power, the Si content is controlled to be 0.60-0.80%.
Mn: mn and Fe form a solid solution, so that the hardness and strength of ferrite and austenite in the steel are improved, and meanwhile, Mn is used for improving the stability of an austenite structure and remarkably improving the hardenability of the steel. However, excessive Mn can reduce the plasticity of the steel, and the excessive Mn content easily causes the problem of center segregation. For the high-strength steel for the corrosion-resistant fastener for the marine wind power, the Mn content is controlled to be 0.40-0.60%.
Cr: cr element remarkably improves toughness and heat strength in steel, precipitates in the form of carbide, increases hydrogen trapping points, improves delayed fracture resistance, and increases hardenability of steel, but excessive Cr increases the temper brittleness tendency of steel. For the high-strength steel for the corrosion-resistant fastener for the marine wind power, the Cr content is controlled to be 1.20-1.40%.
Mo: the function of Mo in steel is mainly to improve hardenability, improve tempering resistance and prevent tempering brittleness. In addition, the reasonable matching of the Mo element and the Cr element can obviously improve the hardenability and the tempering resistance, the effect is limited when the Mo content is too low, the effect is saturated when the Mo content is too high, and the cost of the steel is increased. The content of Mo in the steel for the high-strength corrosion-resistant fastener for the marine wind power is 0.15-0.30%.
Ni: ni can generate an infinitely miscible solid solution with Fe, has the function of enlarging a phase region, and does not form carbide. Nickel stabilizes austenite and enhances hardenability of steel. Ni is an effective element for reducing the ductile-brittle transition temperature and obviously improving the low-temperature toughness. The corrosion resistance of Ni is similar to that of Cr, and the addition of Cu and Ni can also accelerate the cathodic reduction of a rust layer and inhibit the anodic dissolution. The Ni element is a noble metal element, and excessive addition thereof results in excessive cost. For the high-strength corrosion-resistant fastener steel for the marine wind power, the Ni content is controlled to be 0.30-0.50%.
Cu: the prominent role of Cu in steel is to improve the corrosion resistance of steel. The cathode contact between the steel and the Cu secondarily precipitated on the surface can promote the anodization of the steel and form a rust layer with better protection. Copper also changes the moisture absorption of the rust layer, thereby increasing the critical humidity. But Cu produces high crack sensitivity in steel. For the high-strength corrosion-resistant fastener steel for the marine wind power, the Cu content is controlled to be 0.20-0.40%.
Sn: under the marine atmospheric environment, the Sn added into the steel can increase the corrosion potential of the rust layer, reduce the self-corrosion current density, inhibit the anodic dissolution of the corrosion-resistant steel, increase the resistance of the rust layer and the reaction resistance of the joint of the rust layer and the matrix, and enhance the protection of the rust layer on the matrix of the steel. Excessive Sn can be segregated in the grain boundary, the bonding force of the grain boundary is weakened, and the tempering brittleness of the steel is increased. For the high-strength steel for the corrosion-resistant fastener for the marine wind power, the Sn content is controlled to be 0.10-0.20%.
Al: al is a strong deoxidizing element, improves the oxidation resistance of the steel, and can refine crystal grains and improve the toughness of the steel. However, as the Al content increases, the amount of coarse carbonitride-based inclusions increases. For the high-strength steel for the corrosion-resistant fastener for the marine wind power, the Al content is controlled to be 0.020-0.037%.
N: n forms a fine precipitated phase with aluminum in the steel, so that crystal grains are refined, and the comprehensive performance of the steel is improved. However, excessive N precipitates Fe4N in the steel, and the diffusion rate is slow, resulting in aging of the steel, and N also degrades cold workability of the steel. The content of N in the steel for the high-strength corrosion-resistant fastener for the marine wind power is 0.010-0.015%.
Mg: mg not only has excellent affinity with oxygen and sulfur, but also has strong control capability on the shape and size of the inclusion. In the case of Al-deoxidized steel, the Mg treatment can reduce the dissolved oxygen in the steel and convert the Al2O3 inclusion in the steel into MgO. Al with a high melting point2O3Because the oxide inclusions exist in a solid state in molten steel and do not grow in a polymerization manner, the oxide inclusions are very fine in size and are dispersed in the steel, and the mechanical properties of the steel are basically not negatively influenced. For the present hairThe Mg content of the steel for the high-strength corrosion-resistant fastener for the marine wind power is controlled to be 0.0015-0.0035 percent.
S and P: sulphur readily forms MnS inclusions with manganese in steel; p is an element with a strong segregation tendency and usually also causes co-segregation of sulphur and manganese, which is detrimental to the homogeneity of the product structure and properties. For the steel for the high-strength corrosion-resistant fastener for the marine wind power, P is controlled to be less than or equal to 0.020%, and S is controlled to be less than or equal to 0.010%.
The above elements also need to satisfy the following:
cl resistance-The corrosion index A is not less than 7.0, wherein A is 5.7Sn +15.5Cu +2.9Ni +1.6Cr +1.7Si-6.8Cu Ni-23.4Cu2。
The A value is an index for evaluating the degree of influence of Sn, Cu, Mn, Ni, Cr, Si on the Cl-corrosion resistance of steel and the influence of each element in a weighted and added manner, and the index is mainly used for improving the Cl resistance in marine environment of the steel grade of the invention-Elements of corrosion performance.
The steel materials meeting the requirements of the A value and the B value are judged to have excellent marine environment Cl-ion corrosion resistance by taking 10.9-grade wind-power bolt steel 42CrMo which is commonly used in the current market as a comparison steel grade, simultaneously carrying out 890 ℃ quenching (oil cooling) +560 ℃ (tempering), then carrying out 72h salt solution environment Cl-ion corrosion resistance circumferential immersion test, and calculating the relative corrosion rate (relative to 42CrMo), wherein the result is shown in figure 1, and the standard is that the relative corrosion rate is not less than 66.7% (namely 1.5 times of corrosion resistance).
As can be seen from fig. 1: in order to ensure corrosion resistance 1.5 times or more higher than that of 42CrMo general-purpose steel, it is necessary to maintain the A value at 7.0 or more.
2.0 and less than or equal to B and less than or equal to 2.5, wherein the value of B is Al/N. Al and steel N elements are mainly utilized to form an AlN precipitated phase, so that the growth of crystal grains is inhibited, the B value is controlled to be 2.0-2.5, the two elements are favorably and completely combined into AlN, the inhibition effect of the crystal grain size is exerted to the maximum extent, and the austenite crystal grain size is controlled to be within 11 mu m.
The invention relates to a production method of steel for a high-strength corrosion-resistant fastener for ocean wind power, which comprises the following steps of:
s1, smelting in an electric furnace or a converter, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating a square billet, controlling the soaking temperature of a heating furnace to be 1100-1200 ℃, and if the soaking temperature is lower than 1100 ℃, Ni, Cu and other insoluble elements cannot be dissolved in austenite, so that steel is segregated at a grain boundary during rolling and has large brittleness; if it exceeds 1200 ℃, austenite grains start to become coarse, and the decarburization tendency is greatly increased.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. Finish rolling, wherein the temperature before finish rolling is controlled to be 810-860 ℃, and the finish rolling temperature is controlled to be AC by utilizing the severe thermal deformation of large reduction of an austenite region3The transformation of the pro-eutectoid ferrite occurs in the temperature range of 20-60 ℃ above the point, and the obtained deformation induced ferrite transformation can refine grains by combining deformation, so that the steel has excellent plasticity and toughness. Neither above nor below this temperature this effect is achieved.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); controlling the temperature of an upper cooling bed to be 760-810 ℃, simultaneously using a heat preservation cover on the cooling bed, and if the reduced diameter temperature is lower than 750 ℃, entering a phase change stage before entering a heat preservation section of the cooling bed, wherein abnormal structures are possibly formed in the air; if the temperature is higher than 800 ℃, the phase transition temperature is not reached when the temperature enters the heat-insulating cover, and the complete phase transition on the cooling bed is difficult to complete, so that a large number of abnormal tissues are generated.
As shown in fig. 2, the performance of the obtained steel for the corrosion-resistant fastener for high-strength marine wind power, which is the structure of the hot-rolled round steel, is measured as follows:
organizing: taking a test sample with the length of 15mm from the hot-rolled round steel, polishing the cross section, corroding by using 4% nitric acid alcohol, and performing organization evaluation according to GB/T13298 metal microscopic structure inspection method; whether the bar has excellent cold processing service performance in the subsequent processing can be judged through the structure.
Austenite grain size: the austenitizing heat treatment process comprises the following steps: 890 ℃ quenching, oil cooling, the temperature of quenching medium is 18-35 ℃, and metallographic phase sample preparation and austenite average grain size measurement are carried out after cooling.
Tensile properties after heat treatment: the following quenching and tempering heat treatment process is adopted: quenching at 870-920 ℃ and tempering at 550-600 ℃. After the heat treatment, standard tensile test pieces are processed, tensile test is carried out, and Rm, Rp0.2 and A, Z values are tested. The strength grade of the steel is judged by the tensile properties after heat treatment.
And (3) heat treatment of the structure: sampling, carrying out quenching and tempering heat treatment (the heat treatment process is the same as the above), processing the sample after the heat treatment, corroding the sample by adopting 4% nitric acid alcohol, and carrying out tissue evaluation according to GB/T13298 metal microstructure inspection method; whether the steel is fully quenched is judged by the heat treatment histology department.
-80 ℃ KV2 impact test: sampling and carrying out quenching and tempering heat treatment (the heat treatment process is the same as the above), processing the sample into a V-shaped impact sample with the thickness of 10mm multiplied by 55mm after the heat treatment, carrying out an impact test at-80 ℃ by adopting GB/T229 'metallic material Charpy pendulum impact test method', and obtaining an impact toughness value.
And (3) carrying out Cl-ion corrosion resistance weekly immersion test in a 72h salt solution environment: sampling on the square billet, carrying out quenching and tempering heat treatment (the heat treatment process is the same as the above), adopting a sodium chloride solution, carrying out a test according to a GB/T19746 'metal and alloy corrosion salt solution week leaching test' method, completing a 72-hour week leaching test, calculating corrosion weight loss rate, numbering 10 groups each, and calculating an average value. The comparison steel is K steel in No.11, namely 10.9 grade steel 42CrMo for wind-power bolts commonly used in the market at present, and the weight loss ratio of the test steel and the comparison steel is the relative corrosion ratio of the test steel. Wherein the corrosion weight loss ratio (W) is calculated according to the following formula:
Figure BDA0002603378280000081
in the formula: w-weight loss ratio, g/(m)2H); g0 — sample original weight, G; g1-the post-test weight of the sample, g; a-specimen length, mm; b-sample width, mm; c-specimen thickness, mm; t-test time, h.
Example 1
The main chemical component composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 1 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and soaking the square billet in a heating furnace at 1100 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (5) finish rolling, wherein the temperature is 810 ℃ before finish rolling.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the upper cooling bed temperature is 760 ℃.
The rod obtained in this example had a size of 16 mm.
Example 2
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 2 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in a converter, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and uniformly heating the square billet in a heating furnace at the temperature of 1200 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. Finish rolling, the temperature before finish rolling is 823 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 810 ℃.
The rod obtained in this example had a size of 78 mm.
Example 3
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 3 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and heating the square billet in a heating furnace at the soaking temperature of 1166 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (3) finish rolling, wherein the temperature before finish rolling is 860 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the upper cooling bed temperature is 776 ℃.
The rod obtained in this example had a size of 80 mm.
Example 4
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 4 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in a converter, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and heating the square billet in a heating furnace at the soaking temperature of 1158 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. Finish rolling, temperature before finish rolling 822 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 786 ℃.
The rod obtained in this example had a size of 46 mm.
Example 5
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 5 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in a converter, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. the square billet is heated, and the soaking temperature of the heating furnace is 1116 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (5) fine rolling, wherein the temperature before the fine rolling is 834 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 791 ℃.
The rod obtained in this example had a size of 45 mm.
Example 6
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 6 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and heating the square billet in a heating furnace at the soaking temperature of 1102 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (3) finish rolling, wherein the temperature is 821 ℃ before finish rolling.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 803 ℃.
The rod obtained in this example had a size of 40 mm.
Example 7
The main chemical composition and the mass percentage content of the steel for the high-strength corrosion-resistant fastener for the marine wind power are shown in example 7 in table 1.
The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power comprises the following steps based on the components of the embodiment:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and uniformly heating the square billet in a heating furnace at the temperature of 1123 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (5) finish rolling, wherein the temperature before finish rolling is 820 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 802 ℃.
The rod obtained in this example had a size of 30 mm.
Comparative example 1
The main chemical composition and the mass percentage content of the comparative example are shown in the comparative example 1 in the table 1.
The production method of this comparative example includes the following steps based on the components of this example:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, wherein the soaking temperature of the heating furnace is 1126 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (5) finish rolling, wherein the temperature before finish rolling is 831 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the upper cooling bed temperature is 780 ℃.
The rod obtained in this example had a size of 43 mm.
Comparative example 2
The main chemical composition and mass percentage content of the comparative example are shown in comparative example 2 in table 1.
The production method of this comparative example includes the following steps based on the components of this example:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and heating the square billet in a heating furnace at the soaking temperature of 1138 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. Finish rolling, the temperature before finish rolling is 811 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the upper cooling bed temperature is 792 ℃.
The rod obtained in this example had a size of 52 mm.
Comparative example 3
The main chemical composition and the mass percentage content of the comparative example are shown in the comparative example 3 in the table 1.
The production method of this comparative example includes the following steps based on the components of this example:
and S1, smelting in a converter, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and uniformly heating the square billet in a heating furnace at 1140 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. Finish rolling, the temperature before finish rolling is 819 ℃.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 788 ℃.
The rod obtained in this example had a size of 43 mm.
Comparative example 4
The main chemical composition and mass percentage content of the comparative example are shown in comparative example 4 in table 1.
The production method of this comparative example includes the following steps based on the components of this example:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, and uniformly heating the square billet in a heating furnace at the temperature of 1146 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (4) finish rolling, wherein the temperature is 826 ℃ before finish rolling.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 783 ℃.
The rod obtained in this example had a size of 46 mm.
Comparative example 5
The main chemical composition and the mass percentage content of the comparative example are shown in the comparative example 5 in the table 1.
The production method of this comparative example includes the following steps based on the components of this example:
and S1, smelting in an electric furnace, determining oxygen before tapping, and reserving steel in the tapping process.
S2, refining in an LF furnace; the elements of C, Si, Mn, Cr, Mo, Ni, Cu, Sn, etc. are adjusted to target values.
S3, RH vacuum degassing; the pure degassing time is more than or equal to 15 minutes, and the content of H after vacuum treatment is less than or equal to 1.5 ppm.
S4, square billet continuous casting; and controlling the target temperature of the molten steel of the tundish to be 10-40 ℃ above the liquidus temperature, and carrying out square billet continuous casting.
S5, hot rolling round steel; the round steel hot rolling comprises the following steps:
a. heating the square billet, wherein the soaking temperature of the heating furnace is 1255 ℃.
b. Rough and medium rolling; the diameter reduction is performed using a rolling mill.
c. And (3) finish rolling, wherein the temperature is 893 ℃ before finish rolling.
S6, feeding the cold bed (opening a heat preservation cover for slow cooling); the temperature of the upper cooling bed is 831 ℃.
The rod obtained in this example had a size of 46 mm.
The results of the performance tests performed in the above examples and comparative examples are shown in table 2:
TABLE 2 results of performance test of each example and comparative example
Figure BDA0002603378280000151
In the above examples and comparative examples:
examples 1 to 7 are examples in which the chemical composition and the production method are properly controlled, and the chemical composition ensures that the value of A is not less than 7.0, the value of B is not less than 2.0 and not more than 2.5, the steel has a strength grade of 10.9 grade and above, has high toughness at-80 ℃, has Cl-ion corrosion resistance more than 1.5 times that of 10.9 grade wind-power bolt steel 42CrMo which is generally used in the market, and the production method also ensures that the structure is ferrite, pearlite and a small amount of bainite, so that excellent service performance such as cold drawing performance and saw cutting performance in downstream bar processing is realized, and the method is suitable for manufacturing the high-strength corrosion-resistant fastener for marine wind power.
The production methods of comparative examples 1 and 2 are properly controlled, but the chemical components are in the required range, and the A value is low, so that the steel has certain corrosion resistance but is insufficient and difficult to serve in a marine environment for a long time; in addition, in comparative example 1, the lower B value results in a coarser grain size of the steel, and the steel is qualified in strength but poor in plasticity and toughness.
Comparative example 3 is an example with improper control of chemical composition, because enough C, Mo strengthening element is not added, the strength of the steel is low, and Mg element is not added for inclusion plasticizing treatment, and the B value is also improperly controlled, the plasticity and toughness of the steel are poor, and the requirements of the current high-strength steel for wind power bolts cannot be met.
Comparative example 4 is 10.9 grade wind power bolt steel 42CrMo on the market, has no Cl-ion corrosion resistance, and after long-term use in the marine wind power environment, surface treatment such as coating and the like is carried out, otherwise, the steel can be cracked due to corrosion.
Comparative example 5 is an example in which the chemical composition is properly controlled but the production method is not properly controlled, and since the soaking temperature in the heating furnace is too high, the crystal grains are coarse and the plasticity and toughness of the steel are reduced, and meanwhile, the rolling temperature and the cooling temperature are improperly controlled, bainite with high brittleness is mainly contained in the steel, the cold workability of the steel is deteriorated, and the use and processing of users are not facilitated.

Claims (8)

1. The steel for the high-strength corrosion-resistant fastener for the marine wind power is characterized by comprising the following chemical components in percentage by mass: c: 0.20-0.30%, Si: 0.60-0.80%, Mn: 0.40-0.60%, Cr: 1.20% -1.40%, Mo: 0.15% -0.30%, Ni: 0.30-0.50%, Cu: 0.20-0.40%, Sn: 0.10-0.20%, Al: 0.020% -0.037%, N: 0.010% -0.015%, Mg: 0.0015 to 0.0035 percent, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, and the balance of Fe and other inevitable impurities; the chemical composition satisfies the following Cl resistance-The corrosion index A is more than or equal to 7.0, and A is 5.7Sn +15.5Cu +2.9Ni +1.6Cr +1.7Si-6.8Cu Ni-23.4Cu2(ii) a The chemical components satisfy that B is more than or equal to 2.0 and less than or equal to 2.5, and B is Al/N;
the production method of the high-strength corrosion-resistant fastener steel for the marine wind power comprises the following steps:
s1, smelting in an electric furnace or a converter, determining oxygen before tapping, and reserving steel in the tapping process;
s2, refining in an LF furnace;
s3, RH vacuum degassing;
s4, square billet continuous casting;
s5, hot rolling round steel;
and S6, putting on a cooling bed.
2. The steel for the high-strength corrosion-resistant fastener for marine wind power according to claim 1, wherein the steel for the high-strength corrosion-resistant fastener for marine wind power has a structure of ferrite + pearlite + a small amount of bainite.
3. The production method of the steel for the high-strength corrosion-resistant fastener for the marine wind power is characterized by comprising the following chemical components in percentage by mass: c: 0.20-0.30%, Si: 0.60-0.80%, Mn: 0.40-0.60%, Cr: 1.20% -1.40%, Mo: 0.15% -0.30%, Ni: 0.30-0.50%, Cu: 0.20-0.40%, Sn: 0.10-0.20%, Al: 0.020% -0.037%, N: 0.010% -0.015%, Mg: 0.0015 to 0.0035 percent, less than or equal to 0.020 percent of P, less than or equal to 0.010 percent of S, and the balance of Fe and other inevitable impurities; the chemical composition satisfies the following Cl resistance-The corrosion index A is more than or equal to 7.0, and A is 5.7Sn +15.5Cu +2.9Ni +1.6Cr +1.7Si-6.8Cu Ni-23.4Cu2The method comprises the following steps:
s1, smelting in an electric furnace or a converter, determining oxygen before tapping, and reserving steel in the tapping process;
s2, refining in an LF furnace;
s3, RH vacuum degassing;
s4, square billet continuous casting;
s5, hot rolling round steel;
and S6, putting on a cooling bed.
4. The method for producing a steel for a corrosion-resistant fastener for high-strength marine wind power according to claim 3, wherein in step S2, C, Si, Mn, Cr, Mo, Ni, Cu, Sn elements are adjusted to target values.
5. The production method of the steel for the corrosion-resistant fastener for the high-strength marine wind power as claimed in claim 3, wherein in the step S3, the pure degassing time is more than or equal to 15 minutes, and the content of [ H ] after vacuum treatment is less than or equal to 1.5 ppm.
6. The method for producing the steel for the corrosion-resistant fastener for the high-strength marine wind power as claimed in claim 3, wherein in the step S4, the target temperature of the molten steel in the tundish is controlled to be 10-40 ℃ above the liquidus temperature, and square billet continuous casting is performed.
7. The method for producing the steel for the corrosion-resistant fastener for the high-strength marine wind power as claimed in claim 3, wherein the step S5, the hot rolling of the round steel comprises:
a. heating the square billet, and controlling the soaking temperature of a heating furnace to be 1100-1200 ℃;
b. rough and medium rolling;
c. and (3) finish rolling, wherein the finish rolling temperature is controlled to be 810-860 ℃.
8. The method for producing the steel for the corrosion-resistant fastener for the high-strength marine wind power as claimed in claim 3, wherein in the step S6, the temperature of the upper cooling bed is controlled to be 760-810 ℃.
CN202010731641.XA 2020-07-27 2020-07-27 Steel for high-strength corrosion-resistant fastener for ocean wind power and production method Active CN111945063B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010731641.XA CN111945063B (en) 2020-07-27 2020-07-27 Steel for high-strength corrosion-resistant fastener for ocean wind power and production method

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010731641.XA CN111945063B (en) 2020-07-27 2020-07-27 Steel for high-strength corrosion-resistant fastener for ocean wind power and production method

Publications (2)

Publication Number Publication Date
CN111945063A CN111945063A (en) 2020-11-17
CN111945063B true CN111945063B (en) 2022-02-08

Family

ID=73339627

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010731641.XA Active CN111945063B (en) 2020-07-27 2020-07-27 Steel for high-strength corrosion-resistant fastener for ocean wind power and production method

Country Status (1)

Country Link
CN (1) CN111945063B (en)

Families Citing this family (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN112359274A (en) * 2020-09-29 2021-02-12 江苏永钢集团有限公司 Round steel for high-strength wind power anchor bolt and manufacturing method thereof
CN113930753B (en) * 2021-09-17 2023-09-05 武汉钢铁有限公司 Stabilizing treatment agent and method for hot-rolled weather-resistant steel rust layer
CN115852241A (en) * 2021-09-24 2023-03-28 宝山钢铁股份有限公司 High-homogeneity high-hardenability wind power bolt steel, bar and manufacturing method thereof
CN116288060A (en) * 2023-03-14 2023-06-23 钢研晟华科技股份有限公司 800 MPa-grade high-strength corrosion-resistant steel bar and preparation method thereof

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62180036A (en) * 1986-02-03 1987-08-07 Daido Steel Co Ltd Precipitation hardening austenitic alloy
JP2012167371A (en) * 2012-02-22 2012-09-06 Jfe Steel Corp Corrosion resistant steel product for ship and method for producing the same
CN105132815A (en) * 2015-09-28 2015-12-09 邢台钢铁有限责任公司 Cold forging steel for high-strength large-dimension bolt and production method thereof
CN105543654A (en) * 2015-12-18 2016-05-04 马鞍山钢铁股份有限公司 Vanadium-contained 10.9-level steel for fastener for rail transit mobile equipment and heat treatment technology of steel
CN107429352A (en) * 2015-03-27 2017-12-01 株式会社神户制钢所 Delayed fracture resistance after pickling and Q-tempering excellent bolt wire rod and bolt
JP2017226878A (en) * 2016-06-22 2017-12-28 Ｊｆｅスチール株式会社 Steel for bolt
CN110438402A (en) * 2019-09-05 2019-11-12 首钢集团有限公司 A kind of 1000Mpa grades of resistant to sulfuric acid dew point corrosion bolting steel and preparation method thereof
CN110923546A (en) * 2019-12-09 2020-03-27 马鞍山钢铁股份有限公司 High-weather-resistance cold forging steel for 10.9-grade fastener and production method thereof

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN110938732A (en) * 2019-12-05 2020-03-31 马鞍山钢铁股份有限公司 Titanium-containing atmospheric corrosion-resistant 14.9-grade high-strength bolt steel and production method thereof

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS62180036A (en) * 1986-02-03 1987-08-07 Daido Steel Co Ltd Precipitation hardening austenitic alloy
JP2012167371A (en) * 2012-02-22 2012-09-06 Jfe Steel Corp Corrosion resistant steel product for ship and method for producing the same
CN107429352A (en) * 2015-03-27 2017-12-01 株式会社神户制钢所 Delayed fracture resistance after pickling and Q-tempering excellent bolt wire rod and bolt
CN105132815A (en) * 2015-09-28 2015-12-09 邢台钢铁有限责任公司 Cold forging steel for high-strength large-dimension bolt and production method thereof
CN105543654A (en) * 2015-12-18 2016-05-04 马鞍山钢铁股份有限公司 Vanadium-contained 10.9-level steel for fastener for rail transit mobile equipment and heat treatment technology of steel
JP2017226878A (en) * 2016-06-22 2017-12-28 Ｊｆｅスチール株式会社 Steel for bolt
CN110438402A (en) * 2019-09-05 2019-11-12 首钢集团有限公司 A kind of 1000Mpa grades of resistant to sulfuric acid dew point corrosion bolting steel and preparation method thereof
CN110923546A (en) * 2019-12-09 2020-03-27 马鞍山钢铁股份有限公司 High-weather-resistance cold forging steel for 10.9-grade fastener and production method thereof

Also Published As

Publication number Publication date
CN111945063A (en) 2020-11-17

Similar Documents

Publication Publication Date Title
CN111945063B (en) Steel for high-strength corrosion-resistant fastener for ocean wind power and production method
CN110923546B (en) High-weather-resistance cold forging steel for 10.9-grade fastener and production method thereof
CN111676423B (en) Steel for 12.9-grade large-size high-toughness wind power bolt and production method thereof
CN110923545B (en) High-weather-resistance cold forging steel for 12.9-grade fastener and production method thereof
CN106555123B (en) A kind of corrosion-resistant high yield ratio anti-seismic steel bar and its production method
CN110791715A (en) Niobium-titanium-containing atmospheric corrosion-resistant 14.9-grade high-strength bolt steel and production method thereof
CN111041356B (en) Niobium-containing atmospheric corrosion-resistant 14.9-grade high-strength bolt steel and production method thereof
CN110938732A (en) Titanium-containing atmospheric corrosion-resistant 14.9-grade high-strength bolt steel and production method thereof
CN108588570A (en) 600 DEG C of medium temperature acid corrosion-resistant pressure vessel steels of one kind and preparation method thereof
CN114107822B (en) 15.9-grade high-strength bolt steel and production method and heat treatment method thereof
CN111663084A (en) Round steel for titanium-containing 16.9-grade bolt and production method thereof
CN113493882B (en) Steel with excellent pitting corrosion resistance for spring with long fatigue life, and heat treatment method and production method thereof
EP3831973A1 (en) High-mn steel and method for producing same
RU2653954C2 (en) Method of manufacturing thick-sheet rolled stock for manufacturing of electrically welded gas-and-oil pipes of large diameter category x42-x56, resistant against hydrogen-induced cracking in h2s-containing media
CN110117759B (en) Manufacturing process of austenitic stainless steel for roll forming high-strength steel structural member
CN111690876A (en) High-strength wire rod for bolt and production method thereof
CN115466905B (en) Non-quenched and tempered steel with good corrosion resistance for 10.9-grade large-specification wind power bolts and production method thereof
CN114231703B (en) Production method of high-strength simplified annealed cold heading steel
CN111621714B (en) Round steel for bolt with excellent corrosion resistance and delayed fracture resistance and production method thereof
CN111321346B (en) Ultrahigh-strength spring steel with excellent hydrogen-induced delayed fracture resistance and production method thereof
JP4719067B2 (en) High strength steel plate with excellent stretch flangeability and method for producing the same
KR20230010244A (en) Precipitation hardening type martensitic stainless steel sheet with excellent fatigue resistance
JP5136174B2 (en) High strength steel for bolts with excellent weather resistance and delayed fracture resistance
CN109868423A (en) A kind of high-strength spring steel and its production method with excellent fatigue behaviour and corrosion resisting property
CN115261724B (en) Steel for ultrahigh-strength and high-toughness fastener, production method thereof and heat treatment process

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant