CN113549822B

CN113549822B - High-performance steel plate for resisting marine atmospheric corrosion and production method thereof

Info

Publication number: CN113549822B
Application number: CN202110726233.XA
Authority: CN
Inventors: ***; 严玲; 李广龙; 王晓航; 张鹏; 韩鹏; 刘明; 渠秀娟; 王东旭; 陈华
Original assignee: Angang Steel Co Ltd
Current assignee: Angang Steel Co Ltd
Priority date: 2021-06-29
Filing date: 2021-06-29
Publication date: 2022-06-14
Anticipated expiration: 2041-06-29
Also published as: CN113549822A

Abstract

The invention discloses a high-performance steel plate for resisting marine atmospheric corrosion and a production method thereof, wherein the steel plate comprises the following chemical components in percentage by weight: c: 0.11-0.14%, Si: 0.51-0.80%, Mn: 0.50% -1.00%, P: 0.020% -0.040%, S: less than or equal to 0.005%, V: 0.055% -0.065%, Ti: 0.020-0.040%, Cr: 0.40-0.60%, Cu: 0.15% -0.35%, Sb: 0.03-0.05%, Zr: 0.02% -0.04%, Als: 0.015 to 0.045 percent. The temperature of a casting blank charging furnace is 700-800 ℃, and the temperature of a soaking section is 1200-1220 ℃; the initial rolling temperature of rough rolling is 1180-1200 ℃, the pass reduction rate is 15-25%, and the rough rolling speed is 1.0-1.2 m/s; when the thickness of the intermediate blank is 1.5-2 times of that of the finished product, the intermediate blank is heated, the secondary initial rolling temperature is 910-920 ℃, the final rolling temperature is 860-890 ℃, and after rolling, laminar cooling is carried out, the initial cooling temperature is 820-840 ℃, and the re-reddening temperature is 620-640 ℃. The seawater corrosion resistant rate of the steel plate is less than 0.10mm/a, the yield strength is 500-550 MPa, and the impact energy at-60 ℃ is more than or equal to 200J.

Description

High-performance steel plate for resisting marine atmospheric corrosion and production method thereof

Technical Field

The invention belongs to the technical field of metal materials, and particularly relates to a high-performance steel plate for resisting marine atmospheric corrosion and a production method thereof.

Background

Corrosion is a common failure problem in the service process of steel materials, and according to statistics, the economic loss caused by corrosion accounts for about 3 percent of the total domestic production value (GDP). The ocean with the surface area of about 71 percent of the earth is rich in resources, and with the increasing population of the world and the continuous consumption of land resources, the survival of human beings in the future depends on the ocean more and more, and the ocean becomes a main supply base of mineral products, energy and food resources. For this reason, ocean development is listed as one of the key targets for future world development. The seawater contains a large amount of NaCl-based salts, accounting for 88.7% of the total salt content. Because they are easy to ionize, the content of chloride ions in seawater is increased, the metal surface in seawater is difficult to maintain stable passive state, electrochemical corrosion is easy to occur, and deterioration and damage are easy to occur. At present, the marine pollution tends to be serious, and the marine environment is more complex, so that the corrosion problem of the steel material for the marine engineering is more prominent. Corrosion of large oceanographic engineering structures in the marine environment is generally divided into 4 zones: atmosphere zone, splash zone, tidal range zone, and total immersion zone. The conventional corrosion prevention methods for steel materials can be roughly classified into 4 types: coating method; second, long effective method; protecting the cathode; fourthly, stainless steel with self corrosion resistance is adopted. However, the environmental pollution, energy consumption and investment caused by the large-scale use of preventive measures are large, the cost is high and cannot be borne, and the mechanical property and the welding property of the stainless steel cannot meet the requirements of various projects, so that the corrosion condition of the steel material is not fundamentally controlled. Research shows that a compact protective layer containing a specific structure and having an ion selection characteristic can be formed on the surface of steel by adding trace alloy elements, so that the steel has corrosion resistance and maintains excellent comprehensive mechanical properties and service performance.

Patent application of Baoshan Steel works Ltd: a seawater corrosion resistant steel and a manufacturing method thereof, which are applied to (patent): CN201811580228.7 discloses seawater corrosion resistant steel which has good seawater corrosion resistance and excellent mechanical properties. But the chemical elements thereof contain Cr: 2.5% -5.5%, Ni: 0.05-0.15%, Mo: 0.15 to 0.35 percent of the Cr content is noble metal elements, which can affect the production cost of the steel, and the excessive Cr content can accelerate the corrosion of the steel.

Patent application of iron corporation of kawasaki, japan: the seawater corrosion resistant steel suitable for high temperature and humid environment and its production method apply (patent) No: CN 94115981.7; designed aiming at high-temperature and high-humidity corrosive environment and used for ship components (such as ballast tanks), the chemical components (weight percentage) of the high-temperature and high-humidity corrosive environment are as follows: less than 0.1 percent of C, less than 0.50 percent of Si, less than 1.5 percent of Mn, less than 1.5 percent of Ni, 0.5 to 3.5 percent of Cr0.8 percent of Mo, 0.005 to 0.05 percent of Nb0.005, 0.005 to 0.05 percent of Ti0.005, 0.005 to 0.050 percent of AlT0, and 0.002 to 0.012 percent of N; the patent adopts the design of no alloy element Cu, which affects the generation of protective rust layer, and is unfavorable for improving the corrosion resistance of steel, in addition, the highest Cr content reaches 3.5 percent, which not only improves the cost of steel, but also accelerates the corrosion of steel due to overhigh Cr content.

South yang han metallurgical special steel limited application for patent: a corrosion-resistant steel plate for an ocean platform and a production method thereof are disclosed in the application (patent) No.: CN201910524927.8, and through reasonable combination of chemical components and weight percentage, through KR molten iron pretreatment, converter smelting, argon station argon blowing and aluminum wire adding, LF furnace refining, VD vacuum refining, continuous casting, heating, controlled rolling and controlled cooling, stacking cooling, quenching, tempering and other steps, the corrosion-resistant steel plate for the ocean platform is prepared. The produced steel plate has excellent corrosion resistance, good low-temperature impact toughness and excellent comprehensive performance, and is particularly suitable for being used in cold weather and under seawater corrosion conditions. But the chemical elements thereof contain P: more than 0.07 percent to 0.075 percent, P is the most effective element for improving the corrosion resistance, but the P can simultaneously deteriorate the toughness and the welding performance of the steel, and the content of the P is generally required to be not more than 0.04 percent; in addition, the alloy also contains noble elements Mo: 0.47% -0.52%, Ni: 0.78% -0.83%, will raise the steel cost.

Patent applied by Nanjing Steel works Ltd: a low-alloy corrosion-resistant steel plate for an ocean splash zone and a production method thereof are disclosed in the application (patent) No.: CN 201310031557.7. Smelting in a vacuum induction furnace, performing TMCP controlled rolling and controlled cooling process, and then performing low-temperature tempering heat treatment, wherein the tempering temperature is 180-250 ℃. The obtained steel plate has good conventional mechanical properties which are equivalent to the Q500E grade, has stronger corrosion resistance, and has the characteristics of batch production conditions, stable production process, strong operability and the like. But it contains Ni: 0.90% -1.30%, Cr: 0.30% -0.60%, Mo: 0.40 to 0.60 percent of the steel is a noble metal element, and the surface of the casting blank of the high-nickel steel has thick oxide skin and strong adhesiveness, the surface needs to be polished, and the coating treatment needs to be carried out before heating, so that thick iron scale is prevented from being generated again in the heating process, and the production period and the cost of the process need to be increased.

Patent applied by iron and steel research institute: a seawater corrosion resistant steel plate and a manufacturing method thereof, which are disclosed in (patent) nos.: CN 201410713688.8; the process flow comprises the following steps: molten iron desulphurization → converter top and bottom combined blowing → external refining → continuous casting → hot continuous rolling → coiling → finishing → inspection and warehousing. The main technical parameters controlled in the process are that the heating temperature is 1210-1240 ℃; the finishing temperature is 810-850 ℃, and the coiling temperature is 500-540 ℃. The method has the advantages of economy, practicality and low cost. Belongs to the technical field of corrosion-resistant low alloy steel. The highest Cr content is 1.80-2.10%, which not only increases the cost of steel, but also accelerates the corrosion of steel due to too high Cr content.

As can be seen from the above comparative patents, the corrosion resistant steel plate or plywood for ship at present has the following disadvantages:

1. more noble metal elements Cr, Ni and Mo are added;

2. the comprehensive mechanical property and the corrosion resistance of the steel plate are not suitable for the application environment.

Disclosure of Invention

Aiming at the defects of the prior art, the invention aims to provide a high-performance steel plate for resisting marine atmospheric corrosion and a production method thereof. The marine atmosphere corrosion resistance of the steel plate is more stable and excellent (the corrosion rate is less than 0.10mm/a), and the steel plate has high strength and excellent low-temperature toughness. The problems of fluctuation of corrosion resistance, low strength, poor low-temperature impact toughness and small steel plate thickness specification are solved.

The technical scheme of the invention is as follows:

the corrosion-resistant steel plate with excellent marine atmospheric corrosion performance is basically characterized in that the steel plate comprises the following chemical components (Wt%): c: 0.11-0.14%, Si: 0.51-0.80%, Mn: 0.50% -1.00%, P: 0.02% -0.040%, S: less than or equal to 0.005%, V: 0.055% -0.065%, Ti: 0.02% -0.04%, Cr: 0.40-0.60%, Cu: 0.15% -0.35%, Sb: 0.03-0.05%, Zr: 0.02% -0.04%, Als: 0.015 to 0.045 percent, and the balance of Fe and inevitable impurities.

The invention selects the above alloy element types and contents because of the function of each element in marine corrosion resistance:

c: carbon is a key element influencing the structural performance of the steel plate, the variation range of the carbon is large, different matching relations between hardness and toughness can be obtained due to different carbon contents, the carbon is an element which can effectively improve the strength of the steel plate, and when the content of the carbon is lower than 0.02%, the strength of the steel plate can be greatly reduced, but the carbon is unfavorable for the corrosion resistance and the low-temperature impact toughness of the steel plate; therefore, the content of C in the invention is selected to be 0.11-0.14%.

Si: silicon is an essential element for steelmaking deoxidation, has a certain solid solution strengthening effect, can also inhibit the first class of temper brittleness, improves the tempering stability of martensite, increases the tempering temperature and obtains better performance. Silicon can improve the strength of the steel sheet by a solid solution strengthening effect, but at the same time, deteriorates low-temperature toughness and weldability. Certain Si content can effectively improve the marine corrosion resistance of the steel. The content of Si in the invention is controlled to be 0.51-0.80%.

Mn: manganese is a main element for improving the strength and the toughness, can obviously improve the hardenability of steel, has low cost, is a main additive element in the steel, and can reduce the ductility of the steel due to excessively high Mn. When the content of C is lower, the higher content of Mn can effectively improve the hardenability of steel, and the strength of the steel plate is improved by structure refinement and bainite transformation promotion; however, too high Mn content is disadvantageous to the weldability of steel and may deteriorate center segregation, but on the other hand, higher Mn content is advantageous to seawater corrosion resistance, and the Mn content of the present invention is selected to be 0.50% to 1.00%.

P: phosphorus is the cheapest element for improving the corrosion resistance, and the corrosion resistance can be obviously improved when the content of the phosphorus is more than or equal to 0.02 percent; on the other hand, if the content of the impurity element is more than 0.04%, the low-temperature toughness of the base material and the toughness of the weld heat affected zone are adversely affected, and therefore the content should be controlled as reasonable as possible. The content of the invention is controlled to be 0.02-0.04%.

S: the sulfur inclusion-forming elements form inclusions such as MnS, which lower the ductility of the steel product, and the vicinity of the inclusions become sources of corrosion, which are detrimental to the corrosion performance of the steel sheet. The content of the invention is controlled to be less than or equal to 0.005 percent.

V: vanadium has strong affinity with carbon, nitrogen and oxygen, and forms corresponding stable compounds with the vanadium. Vanadium is mainly present in steel in the form of carbides. The main function of the steel is to refine the structure and the crystal grains of the steel and reduce the strength and the toughness of the steel. When the solid solution is dissolved at high temperature, the hardenability is increased; conversely, if present in the carbide form, the hardenability is reduced. Vanadium increases the temper stability of the quenched steel and produces a secondary hardening effect. V can improve the solid solution amount of rare earth in steel, thereby improving the corrosion resistance of the steel, and the content of the invention is controlled to be 0.55-0.65%.

Ti: titanium has a very strong affinity for nitrogen, oxygen and carbon, and a stronger affinity for sulfur than for iron. Therefore, it is a good deoxidizing and degassing agent and an effective element for fixing nitrogen and carbon. Titanium, although a strong carbide-forming element, does not combine with other elements to form a composite compound. Titanium carbide has strong binding force, is stable and not easy to decompose, and can be slowly dissolved in solid solution only by heating to more than 1000 ℃ in steel. The titanium carbide fine particles have an effect of preventing the growth of the crystal grains before the dissolution. The plasticity and impact toughness of the steel are significantly improved as titanium fixes nitrogen and sulfur and forms titanium carbide. Ti can improve the solid solution amount of rare earth in steel, thereby improving the corrosion resistance of the steel, and the content of the Ti is controlled to be 0.02-0.04 percent.

Cr: chromium is an element that improves the corrosion resistance of steel. However, the corrosion resistance is sometimes reduced by adding Cr alone, even the corrosion resistance is worse than that of ordinary carbon steel, and the corrosion resistance is obviously improved by using Cr alone in combination with other corrosion-resistant alloy elements such as Cu, P, Si and the like. The content of the invention is controlled between 0.40 percent and 0.60 percent.

Cu: copper is the most predominant, most commonly used alloying element in corrosion resistant steels. The Cu can activate the cathode and promote the anode passivation, and the copper is enriched in the rust layer, so that the performances of marine atmospheric corrosion resistance and seawater corrosion resistance can be obviously improved; in the case where Ni is not added, too high Cu content affects the surface quality of the cast slab and thus the yield. Therefore, the content is controlled to be 0.15-0.35%.

Al: aluminum is mainly used to deoxidize and refine grains. Aluminum can inhibit aging of low-carbon steel and improve toughness of the steel at low temperature. When the content is high, the oxidation resistance of steel can be improved, and the oxidation resistance is improved under the conditions of oxidizing acid and H₂The corrosion resistance in S gas, if the amount of aluminum is too large, causes abnormal structure in the steel and tends to promote graphitization of the steel, and when the amount of aluminum is high in ferritic and pearlitic steels, the high temperature strength and toughness of the steels are reduced, and several difficulties are caused in smelting, casting, and the like. The content of the invention is controlled to be 0.015-0.045%.

Sb: antimony (Sb) in the steel is precipitated at the MnS inclusion and along the prior austenite grain boundary at the austenite temperature, so that the MnS inclusion is inhibited from being enriched and precipitated on the grain boundary, the antimony can also refine the size of secondary recrystallization grains, the structure of the steel is refined, the toughness is improved, and the corrosion resistance of the steel is improved. The content of the invention is controlled between 0.30 percent and 0.50 percent.

Zr: zirconium is a strong carbide forming element, and the addition of a small amount of zirconium has the effects of degassing, purifying and refining grains, thereby being beneficial to the low-temperature performance of steel and improving the corrosion resistance. The content of the invention is controlled to be 0.02-0.04%.

The content range and the function of various elements are added, and the manufacturing method of the corrosion-resistant steel plate with marine atmospheric corrosion performance comprises the following steps:

the steelmaking process is characterized in that:

carrying out vacuum treatment by adopting RH, wherein the RH cycle time is 20-25 min, and [ H ] and [ O ] in the steel are controlled to be below 2ppm and below 20 ppm; the target superheat degree of the tundish is 20-25 ℃; the whole process is protected and poured, and before the steel ladle is mounted, the static argon blowing time of the steel ladle is ensured to be 5-10 min; and stacking the casting blank and the hot blank for slow cooling after the casting blank is off the line, wherein the slow cooling time is 24-30 hours.

Characteristic of rolling process

When charging, the furnace temperature is required to be controlled between 700 and 800 ℃, and the temperature of a soaking section is controlled between 1200 and 1220 ℃; descaling the upper surface and the lower surface of the billet before rolling to ensure that foreign matters on the upper surface of the billet are removed completely; the initial rolling temperature of rough rolling is 1180-1200 ℃, low-speed large reduction is adopted during rolling, pass reduction rate is controlled to be 15-25%, and the rolling speed of rough rolling is controlled to be 1.0-1.2 m/s; and (3) when the thickness of the rolled intermediate blank is 1.5-2 times of that of the finished product, carrying out temperature waiting, controlling the secondary initial rolling temperature to be 910-920 ℃, controlling the final rolling temperature to be 860-890 ℃, carrying out laminar cooling after rolling, controlling the initial cooling temperature to be 820-840 ℃, and controlling the re-reddening temperature to be 620-640 ℃.

The marine atmospheric corrosion resistant high-performance steel plate produced according to the scheme has the following beneficial effects:

1. provides the corrosion-resistant steel which does not contain Ni and Mo and contains a small amount of Cr element, and reduces the segregation of the P element and greatly improves the corrosion resistance of the steel plate by controlling the content of the P element reasonably and adding a small amount of Zr and Sb compositely. The seawater corrosion resistance is more stable and excellent (the corrosion rate is less than 0.10 mm/a);

2. the composite material has good comprehensive mechanical properties, and the yield strength is 500-550 MPa, and the impact energy at-60 ℃ is more than or equal to 200J;

3. the range of producible thickness specifications is large, and the maximum thickness can reach 80 mm.

Detailed Description

According to the chemical components and the production process, the actual smelting components are shown in the table 1, the actual smelting and continuous casting process parameters are shown in the table 2, the rolling process parameters are shown in the table 3, and the physical properties are shown in the table 4.

TABLE 1 melting composition, Wt%

Numbering	C	Si	Mn	P	S	V	Ti	Cr	Cu	Sb	Zr	Als
													1	0.11	0.80	0.50	0.025	0.005	0.065	0.030	0.40	0.35	0.03	0.02	0.020
2	0.14	0.51	1.00	0.035	0.003	0.055	0.040	0.60	0.15	0.05	0.04	0.025
													3	0.12	0.65	0.60	0.036	0.004	0.060	0.020	0.50	0.30	0.04	0.03	0.015
4	0.13	0.74	0.90	0.040	0.005	0.055	0.025	0.40	0.20	0.03	0.02	0.045
													5	0.12	0.72	0.80	0.020	0.005	0.056	0.025	0.40	0.30	0.03	0.02	0.030
6	0.11	0.67	0.70	0.025	0.004	0.065	0.022	0.60	0.25	0.05	0.04	0.025

TABLE 2 smelting and continuous casting Process parameters

TABLE 3 Rolling Process parameters

TABLE 4 Properties of the materials

Claims

1. The high-performance steel plate for resisting marine atmospheric corrosion is characterized by comprising the following chemical components in percentage by weight: c: 0.11% -0.14%, Si: 0.51-0.80%, Mn: 0.50% -1.00%, P: 0.020% to 0.040%, S: less than or equal to 0.005%, V: 0.055% -0.065%, Ti: 0.020-0.040%, Cr: 0.40% -0.60%, Cu: 0.15% -0.35%, Sb: 0.03% -0.05%, Zr: 0.02% -0.04%, Als: 0.015-0.045%, and the balance of Fe and inevitable impurities; the production method of the high-performance steel plate for resisting marine atmospheric corrosion comprises smelting, continuous casting and rolling, wherein the temperature of a casting blank in a furnace before rolling is 700-800 ℃, and the temperature of a soaking section is 1200-1220 ℃; the initial rolling temperature of rough rolling is 1180-1200 ℃, the rolling is performed at a low speed and a large reduction, the pass reduction is 15% -25%, and the rolling speed of the rough rolling is 1.0-1.2 m/s; and (3) when the thickness of the rolled intermediate blank is 1.5-2 times of that of the finished product, carrying out temperature waiting, wherein the secondary initial rolling temperature is 910-920 ℃, the final rolling temperature is 860-890 ℃, carrying out laminar cooling after rolling, and carrying out initial cooling at 820-840 ℃ and re-reddening at 620-640 ℃.

2. The high-performance steel plate for resisting marine atmospheric corrosion according to claim 1, wherein the marine atmospheric corrosion resistance rate of the steel plate is less than 0.10 mm/a.

3. The high-performance steel plate for resisting marine atmospheric corrosion according to claim 1, wherein the yield strength of the steel plate is 500-550 MPa, and the impact energy at-60 ℃ is not less than 200J.

4. The high-performance steel sheet for resisting marine atmospheric corrosion according to claim 1, wherein the thickness of the steel sheet is 10 to 80 mm.

5. The high-performance steel plate for resisting marine atmospheric corrosion according to claim 1, wherein the smelting comprises RH vacuum treatment, RH cycle time is 20-25 min, and [ H ] and [ O ] in the steel are controlled to be less than 2ppm and less than 20 ppm; the superheat degree of the tundish is 20-25 ℃.

6. The marine atmospheric corrosion resistant high-performance steel plate according to claim 1, wherein the continuous casting adopts full-process protective casting, and the static argon blowing time of the steel ladle is ensured for 5-10 min before the steel ladle is mounted on a machine; and stacking the casting blank and the hot blank for slow cooling after the casting blank is off the line, wherein the slow cooling time is 24-30 hours.

7. The marine atmospheric corrosion resistant high-performance steel sheet as claimed in claim 1, wherein the upper and lower surfaces of the slab are descaled before rough rolling of the cast slab.