WO2023088294A1 - Hot-rolled steel for enameling having enameling and firing strengthening property, and manufacturing method therefor - Google Patents

Hot-rolled steel for enameling having enameling and firing strengthening property, and manufacturing method therefor Download PDF

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WO2023088294A1
WO2023088294A1 PCT/CN2022/132223 CN2022132223W WO2023088294A1 WO 2023088294 A1 WO2023088294 A1 WO 2023088294A1 CN 2022132223 W CN2022132223 W CN 2022132223W WO 2023088294 A1 WO2023088294 A1 WO 2023088294A1
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hot
steel
rolled
enamelling
enameling
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PCT/CN2022/132223
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French (fr)
Chinese (zh)
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王双成
孙全社
陶孝勇
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宝山钢铁股份有限公司
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    • 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
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226—Hot rolling
    • 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
    • C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0263—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment following hot rolling
    • C—CHEMISTRY; METALLURGY
    • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22C—ALLOYS
    • C22C33/00—Making ferrous alloys
    • C22C33/04—Making ferrous alloys by melting
    • 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
    • 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
    • C22C38/20—Ferrous alloys, e.g. steel alloys containing chromium 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
    • C22C38/22—Ferrous alloys, e.g. steel alloys containing chromium with molybdenum or tungsten
    • 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
    • C22C38/24—Ferrous alloys, e.g. steel alloys containing chromium with vanadium
    • 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
    • C22C38/28—Ferrous alloys, e.g. steel alloys containing chromium with titanium or zirconium
    • 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
    • C22C38/38—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of manganese
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23D—ENAMELLING OF, OR APPLYING A VITREOUS LAYER TO, METALS
    • C23D5/00—Coating with enamels or vitreous layers

Definitions

  • the invention relates to a steel material and a manufacturing method thereof, in particular to a hot-rolled steel plate for enameling and a manufacturing method thereof.
  • Hot-rolled enamelled steel is a composite material made by applying enamel to the surface of a pretreated hot-rolled steel plate and sintering at high temperature. It combines the strength and toughness of hot-rolled steel plate with the corrosion resistance and easy cleaning of enamel. characteristic.
  • the relatively mature theory believes that the scale explosion defect is mainly caused by hydrogen, and hydrogen is mainly in pickling (dissolving metal in acid to generate hydrogen) and enamel firing (crystal water contained in enamel grinding or furnace atmosphere) The water vapor and the like react with the metal to form hydrogen) into the steel plate; as the temperature drops, the solubility of hydrogen in the steel decreases and reaches a supersaturated state, causing hydrogen to accumulate in the form of gas between the steel plate and the enamel layer. Then a certain pressure is formed, and when the pressure increases to a certain critical value, the scale explosion defect will be caused.
  • the final strength of the enamel product depends on the strength of the steel used for enamel after high-temperature enamel firing. Under normal circumstances, the strength of the steel plate will decrease significantly after such high-temperature heat treatment. These changes lead to the simultaneous weakening of dislocation strengthening, fine grain strengthening and precipitation strengthening. How to improve the strength of the steel plate after high-temperature enamel firing has always been a key research topic in the field of enameling steel development, and it also has important practical application value.
  • the existing patented technology on hot-rolled enamelled steel mostly adopts the design of adding Ti element in the composition, through which it forms TiC, Ti(C, N) and other precipitated phases with C and N, and exerts the storage capacity. Hydrogen trapping and precipitation strengthening.
  • the publication number is CN101812630A
  • the publication date is August 25, 2010, and the Chinese patent document titled "Hot-rolled high-strength enamelled steel sheet for deep drawing and its manufacturing method” publicly introduces a hot-rolled high-strength enamelled steel sheet for deep drawing.
  • Strength enamel steel plate and its manufacturing method, the components used in it are C: 0.02-0.10%, Si ⁇ 0.10%, Mn: 0.05-1.00%, P ⁇ 0.05%, S: 0.005-0.035%, Al: 0.01-0.10% , N ⁇ 0.015%, Ti ⁇ 0.10%, and the balance is iron and unavoidable impurities.
  • the publication number is CN103540845A
  • the publication date is January 29, 2014
  • the publication number is CN102181805A
  • the publication date is September 14, 2011, and the Chinese patent document titled "a thin slab continuous casting and rolling line produces steel plates and methods for enamelling water heater inner tanks” discloses a Thin slab continuous casting and rolling line produces steel plate for water heater liner enamel and method, the components used in it are carbon 0.03-0.10, manganese 0.15-0.40, silicon ⁇ 0.06, sulfur 0.004-0.040, phosphorus ⁇ 0.15, aluminum 0.03-0.05, Nitrogen 0.002-0.008, titanium 0.02-0.10, and the rest are iron and unavoidable impurities.
  • the present invention expects to obtain a new hot-rolled steel for enamelling with enamel strengthening, which has lower strength and good Excellent formability, after high-temperature enamel firing, its yield strength will not decrease but will increase, which can effectively improve the strength of the final enamel product.
  • One of the objectives of the present invention is to provide a hot-rolled steel for enamelling with enamel strengthening, which has lower strength and good formability in the hot-rolled state, and it has high-temperature enameling Finally, through the mechanism of phase transformation strengthening, the yield strength can be increased instead of falling, thereby improving the strength of the final enamel product and prolonging the service life of the enamel product.
  • the hot-rolled enamelling steel can be used to prepare large-volume water heater inner tanks, water heater accessories, barbecue ovens and other products with high enamelling temperature and high yield strength performance requirements after enamelling, and has very significant application value.
  • the present invention proposes a hot-rolled enamelling steel with enamel strengthening, which also contains the following chemical elements in mass percentage except Fe and unavoidable impurities:
  • the mass percentage content of each chemical element is:
  • each chemical element design principle is as follows:
  • element C is an important strengthening element in steel, which can be dissolved in ferrite or form pearlite structure under certain conditions, thereby strengthening the matrix structure The effect of increasing the yield strength of the steel plate.
  • C element can also combine with strong carbide-forming elements such as Ti and V to form precipitates of a certain size and quantity. These precipitates can improve the hydrogen storage performance of the steel plate, thereby exerting the effect of enamel anti-scale explosion.
  • the C element in the steel should not be too high.
  • the mass percentage content of the element C is limited between 0.03% and 0.07%.
  • Si element exists as a residual element in the steel.
  • the content of Si element in the steel is too high, it will cause the plasticity of the steel to deteriorate; in addition, especially when using In the process of enamel and enamel, the higher content of Si element will also affect the adhesion between the steel plate and the enamel. Therefore, considering the adverse effect of Si element on the properties of steel, in the hot-rolled steel for enameling according to the present invention, the mass percentage content of Si element is controlled to satisfy: Si ⁇ 0.05%. In some embodiments, the content of Si is 0.005-0.05%.
  • Mn, Cr In the hot-rolled steel for enamelling according to the present invention, Mn and Cr elements are important elements to ensure that the high-strength performance of the steel material is obtained after high-temperature enamelling. The combination of these two elements can make the steel plate undergo bainite transformation at a lower cooling rate, thereby improving the strength of the matrix structure. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of Mn element is limited between 1.5-2.5%, and the mass percentage content of Cr element is limited between 0.25-0.65%.
  • the Mo element in the hot-rolled enamel steel described in the present invention, can be solid-dissolved in ferrite, austenite and carbide, which plays a role of solid-solution strengthening and can also improve the stability of carbide. Reduce the coarsening of carbide precipitates caused by high-temperature sintering, thereby improving the high-temperature stability of steel.
  • adding an appropriate amount of Mo element to the steel can also promote the phase transformation of the steel plate under air-cooling conditions after high-temperature sintering. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percent content of the Mo element is limited between 0.01% and 0.10%.
  • adding the above-mentioned Mn, Mo and Cr elements can significantly improve the stability of the supercooled austenite, when the steel plate is fired at high temperature and air-cooled to In the process of room temperature, the combination of these three elements can make the steel plate undergo bainite transformation at a lower cooling rate, thereby obtaining high strength properties.
  • Al is a strong deoxidizing element, and it is often necessary to use Al element for deoxidation in medium and low carbon steels to ensure that the O content in the steel is kept at a low value. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of the Al element is limited between 0.01-0.05%.
  • the addition of an appropriate amount of Cu element in the steel is beneficial to surface deposition, improves the adhesion performance between the steel and the enamel, and then improves the anti-scaling performance of the steel. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of Cu element is limited between 0.02-0.20%.
  • Ti, V In the hot-rolled steel for enamel described in the present invention, the compound addition of Ti and V elements is the main element to make the steel obtain good hydrogen storage performance, and they can form fine, dispersed TiC and VC precipitates, these precipitates can effectively improve the hydrogen storage performance of the steel plate as irreversible hydrogen storage traps, and then play the role of enamel anti-scale explosion. Therefore, comprehensively considering the mechanical properties and cost factors of the steel, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of the Ti element is limited between 0.01% and 0.08%, and the mass percentage content of the V element It is limited between 0.01 and 0.10%.
  • the steel for hot-rolled enameling according to the present invention, it further contains B: 0.0006-0.003%.
  • B In the steel for hot-rolled enamel described in the present invention, the solubility of B in the steel is very low, and it can mainly be combined with the residual nitrogen in the steel and precipitated in the form of BN, which can be used as a hydrogen storage trap to play a role Enamel anti-scale explosion effect. Therefore, in order to exert the beneficial effect of the B element, in the hot-rolled steel for enameling according to the present invention, the mass percentage content of the B element is controlled between 0.0006-0.003%.
  • each chemical element also satisfies: (C-Ti/4-V/4.25) ⁇ (Mn+Cr)>0.05; wherein, C, Ti, V, Cr and Mn represent the numerical values of the mass percentages of the corresponding elements, respectively.
  • the hot-rolled steel for enamelling of the present invention can preferably control C, Ti, V, Cr and Mn elements to satisfy the formula while controlling the mass percentage content of a single chemical element: (C-Ti/4-V/4.25 ) ⁇ (Mn+Cr)>0.05.
  • the hot-rolled steel for enameling according to the present invention, its microstructure is ferrite+pearlite. Further, in the microstructure, the proportion of pearlite is 10-45% in terms of area ratio.
  • the ferrite grain size is 8-10 grades.
  • the thickness thereof is 1.5-3.5 mm.
  • the yield strength of the hot-rolled steel is 345-389 MPa, and the yield strength is 402-439 MPa after high-temperature enamelling in the temperature range of 870-950°C.
  • the yield strength of the hot-rolled enamelling steel according to the present invention is 340-400 MPa, the tensile strength is 550-630 MPa, and the elongation A 50 is 25-35%. In some embodiments, the yield strength of the hot-rolled enamelling steel according to the present invention is 345-390 MPa, the tensile strength is 550-630 MPa, and the elongation A 50 is 28-35%.
  • the present invention provides an enamelled steel comprising a substrate and an enamel layer on one or both surfaces of the substrate, wherein the elemental composition of the substrate is the same as that described in any embodiment of the present invention.
  • Fire-strengthened hot-rolled enamelling steels have the same elemental composition.
  • the enamelled steel has a yield strength of 400-450 MPa, a tensile strength of 610-660 MPa, and an elongation A 50 ⁇ 18% (eg, 18-25%).
  • the microstructure of the substrate is a ferrite+bainite structure.
  • the proportion of bainite is 10-40% in terms of area ratio.
  • the material used for the enamel layer may be enamel glaze known in the art.
  • An exemplary material is Flow EMP6515 high temperature glaze.
  • another object of the present invention is to provide the above-mentioned manufacturing method of hot-rolled enameling steel, the manufacturing method has simple production process, and the hot-rolled enameling steel prepared by this manufacturing method has lower strength in hot-rolled state And good formability, after high-temperature sintering, it can increase its yield strength instead of falling through the mechanism of phase transformation strengthening.
  • the present invention proposes the manufacturing method of above-mentioned hot-rolled enamelling steel, and it comprises steps:
  • Hot rolling control the rough rolling temperature to be greater than 850°C, the finish rolling start temperature to be 900-1050°C, and the finish rolling finish temperature to be 840-900°C;
  • the present invention in order to obtain suitable hot-rolled state structure, make the steel product of hot-rolled state have lower strength, higher formability, the present invention is to the hot-rolled process parameter of step (3) and step ( 4)
  • the laminar flow cooling parameters are strictly controlled, which can ensure the performance of the hot-rolled enameling steel of the present invention through controlled rolling and controlled cooling.
  • the present invention first rough-rolls the heated cast slab into an intermediate slab, then performs finish rolling on the obtained intermediate slab, and finally finish-rolls the required slab.
  • the rough rolling temperature is controlled to be greater than 850°C
  • the finish rolling start temperature is controlled to be 900-1050°C
  • the finish rolling finish rolling temperature is controlled to be 840-900°C.
  • the rough rolling temperature is controlled to be 850-1080°C or 880-1080°C.
  • step (4) of the present invention water cooling is carried out at a cooling rate of 10-35°C/s to the coiling temperature, and then air-cooling to room temperature.
  • the invention adopts such a controlled rolling and controlled cooling process, which is beneficial to obtain fine ferrite and pearlite grain structure, so that the steel plate has good processing and forming performance.
  • the hot-rolled steel for enameling prepared by the above manufacturing method can be further used for single-side or double-side enamelling to obtain enameling products.
  • step (1) of the present invention continuous casting or mold casting can be used for casting, which can ensure uniform internal composition and good surface quality of the slab.
  • die casting may also be used, and the die cast steel ingot needs to be rolled into a billet through a blooming mill.
  • the heating temperature is 1150-1260°C.
  • step (5) the coiling temperature is controlled to be 550-680°C.
  • the coiling temperature can preferably be controlled at 550-680°C.
  • the coiling temperature range it is not only beneficial to the refinement of ferrite grains, but also beneficial to the precipitation of TiC and VC in the steel. Homogenization to obtain hot-rolled steel for enamelling with excellent mechanical properties and anti-scale explosion performance.
  • the present invention also provides a method for preparing enamelled steel, which includes the step of preparing the hot-rolled enamelled steel by the method described in any embodiment herein, and preparing the prepared hot-rolled enamelled steel The steps of enamelling and firing of steel.
  • the hot-rolled steel for enameling is subjected to shot blasting and other treatments.
  • the enamelling treatment is performed using a one-enameling-one-firing process or a two-enameling-two-firing process.
  • the manufacturing method of the hot-rolled steel for enamelling of the present invention has the following advantages and beneficial effects:
  • the present invention not only rationally designs the chemical composition, but also combines and optimizes the controlled rolling and controlled cooling process of rapid cooling after rolling, and then can effectively prepare hot-rolled enamelled steel with excellent performance in the hot-rolled state.
  • the production process is simple, and the The prepared hot-rolled enamelled steel has low strength and good formability in the hot-rolled state.
  • the hot-rolled enamelled steel can make its own yield strength not decrease but reverse through the mechanism of phase transformation strengthening. It can not only improve the strength of enamel products, but also prolong the service life of enamel products.
  • the yield strength of the hot-rolled enamel steel in the hot-rolled state is 345-389 MPa, and after high-temperature enamel firing in the temperature range of 870-950 ° C, its yield strength can be increased to 402-439 MPa, which can be used to prepare large-volume Water heater liners, water heater accessories, barbecue ovens and other products with high firing temperature and high yield strength performance requirements after firing, have very significant application value.
  • Figure 1 shows the influence of different sintering temperatures on the yield strength properties of the steels of Example 1 and Comparative Example 1 of the present invention after sintering.
  • Fig. 2 is a photograph of the metallographic structure of the hot-rolled enamelling steel of Example 1 in a hot-rolled state.
  • Fig. 3 is the metallographic structure photograph of the hot-rolled enamelling steel of Example 1 after being fired at a high temperature of 870° C. and kept for 10 minutes and then air-cooled.
  • the manufacturing method of the hot-rolled enameling steel of embodiment 1-7 and the contrast steel of comparative example 1-2 adopts the following steps to make:
  • Hot rolling control the rough rolling temperature to be greater than 850°C, control the finish rolling start temperature to be 900-1050°C, and control the finish rolling finish rolling temperature to be 840-900°C.
  • Laminar flow cooling carry out laminar flow water cooling, and control the cooling rate to 10-35°C/s.
  • the hot-rolled enameling steels of Examples 1-7 of the present invention are all prepared by the above steps, and their chemical composition and related process parameters all meet the control requirements of the design specification of the present invention.
  • the comparative example steel of the comparative example 1-2 also adopts the step flow process of the above-mentioned steps (1)-step (5), its chemical There are parameters that do not meet the design requirements of the present invention in the elemental components.
  • Table 1 lists the mass percentages of each chemical element in the hot-rolled enameling steels of Examples 1-7 and the comparative steels of Comparative Examples 1-2.
  • M* (C-Ti/4-V/4.25) ⁇ (Mn+Cr); where, C, Ti, V, Cr and Mn represent the numerical values of the mass percentages of the corresponding elements.
  • Table 2 lists the specific process parameters of the above-mentioned manufacturing of the hot-rolled steel for enamelling of Examples 1-7 and the comparison steel of Comparative Examples 1-2.
  • Tensile test According to GB/T 228.1-2010 "Metallic Materials Tensile Test Method at Room Temperature", use SCL233 room temperature tensile testing machine for testing, the tensile speed is 3mm/min, and the tensile sample is JIS5 tensile sample. The yield strength, tensile strength and elongation A 50 of the hot-rolled steel corresponding to Examples 1-7 and Comparative Examples 1-2 were obtained.
  • the hot-rolled enamelling steels of Examples 1-7 all have lower yield strength and good formability in the hot-rolled state, and the yield strength is between 345-389MPa , its tensile strength is between 558-625MPa, and its elongation A 50 is between 28-32%.
  • the lower yield strength is beneficial to the stamping and cold-bending processing of the steel plate during the user's use.
  • it can avoid the springback after cold bending and rolling, which is beneficial to the welding process.
  • the yield strength of the comparative steel in Comparative Example 1-2 is higher, which is not conducive to the user's use of the processing process.
  • the double-sided wet enamel treatment of the steel plates of the examples and the comparative examples was carried out with Flow EMP6515 high-temperature glaze, and the controlled enamel firing process was as follows: control the enamel firing temperature to 870-950°C, keep it warm for 10 minutes, and then air-cool to obtain enameled The steel plates of Examples 1-7 and Comparative Examples 1-2.
  • control examples 1-7 and comparative examples 1-2 were all fired at a high temperature in the temperature range of 870-950°C and kept warm for 10 minutes; in the present invention, each example and The specific high-temperature sintering temperatures of the comparative examples are listed in Table 4 below.
  • Table 5 lists the mechanical properties and enameling properties of the hot-rolled enameling steels of Examples 1-7 and the comparative steels of Comparative Examples 1-2 after enameling.
  • the thickness range of the hot-rolled enameling steel in Examples 1-7 can be between 1.5-3.5 mm, and it can be enamelled at a high temperature in the temperature range of 870-950°C.
  • the strength of the steel plates in Examples 1-7 did not decrease but increased, the yield strength increased to 402-439MPa, the tensile strength increased to 610-660MPa, and the elongation A50 was between 18-439MPa. 22% between.
  • the performance of the comparative steel plate of Comparative Example 1-2 is obviously inferior to that of the hot-rolled enameling steel of Example 1-7.
  • the yield strength of the steel in Comparative Example 1-2 has a very large decrease.
  • the large decrease in the yield strength of the steel plate before and after sintering will lead to problems such as bending and deformation of the steel plate, which is not conducive to users. processing use.
  • scale burst defects appeared in Comparative Example 2 after double-sided enamel, which could not meet the anti-scale burst performance requirements of double-sided enamel.
  • Figure 1 shows the influence of different sintering temperatures on the yield strength properties of the steels of Example 1 and Comparative Example 1 of the present invention after sintering.
  • the yield strength of the steel in Example 1 shows an upward trend as the sintering temperature increases.
  • the yield strength can reach 425 MPa;
  • the yield strength of the steel in Comparative Example 1 showed a downward trend, and when the sintering temperature was 930° C., the yield strength of the steel in Comparative Example 1 decreased to 289 MPa.
  • Fig. 2 is a photograph of the metallographic structure of the hot-rolled enamelling steel of Example 1 in a hot-rolled state.
  • Fig. 3 is the metallographic structure photograph of the hot-rolled enamelling steel of Example 1 after being fired at a high temperature of 870° C. and kept for 10 minutes and then air-cooled.
  • the microstructure of the hot-rolled steel for enameling in Example 1 in the hot-rolled state is ferrite+pearlite, which transforms into ferrite after high-temperature sintering +Bainite structure.

Abstract

Disclosed is a hot-rolled steel for enameling having an enameling and firing strengthening property, comprising, in addition to Fe and inevitable impurities, the following chemical elements in mass percent: C: 0.03-0.07%, Si≤0.05%, Mn: 1.5-2.5%, Al: 0.01-0.05%, Cr: 0.25-0.65%, Cu: 0.02-0.20%, Ti: 0.01-0.08%, V: 0.01-0.10%, and Mo: 0.01-0.10%. Accordingly, further disclosed is a manufacturing method for the hot-rolled steel for enameling, comprising the steps of: (1) smelting and casting; (2) heating; (3) hot rolling, the temperature of rough rolling being controlled to be greater than 850°C, the start temperature of finish rolling being controlled to be 900-1050°C, and the final temperature of finish rolling being controlled to be 840-900°C; (4) laminar cooling, the cooling speed being controlled to be 10-35°C/s; and (5) coiling. The hot-rolled steel for enameling provided by the present invention has low strength and good formability in a hot-rolled state, and after high-temperature enameling and firing, the yield strength of the hot-rolled steel for enameling is not decreased but increased, such that the strength of a final enamel product can be effectively improved.

Description

一种具有搪烧强化性的热轧搪瓷用钢及其制造方法A hot-rolled enamelling steel with enamel strengthening and its manufacturing method 技术领域technical field
本发明涉及一种钢材及其制造方法，尤其涉及一种搪瓷用热轧钢板及其制造方法。The invention relates to a steel material and a manufacturing method thereof, in particular to a hot-rolled steel plate for enameling and a manufacturing method thereof.
背景技术Background technique
热轧搪瓷钢是一种将瓷釉施加于经过预处理的热轧钢板表面并配合高温烧结而成的复合材料，它兼具热轧钢板的强度、韧性和瓷釉的耐腐蚀、易清洁等优良的特性。Hot-rolled enamelled steel is a composite material made by applying enamel to the surface of a pretreated hot-rolled steel plate and sintering at high temperature. It combines the strength and toughness of hot-rolled steel plate with the corrosion resistance and easy cleaning of enamel. characteristic.
当然，不是所有的钢板都适用于搪瓷用途，作为基材的钢板直接影响着搪瓷钢制品的质量，鱼鳞爆是搪瓷钢制品最常见也是最可怕的缺陷之一。Of course, not all steel plates are suitable for enamel use. The steel plate used as the base material directly affects the quality of enamelled steel products. Fish scale cracking is one of the most common and most terrible defects of enameled steel products.
目前比较成熟的理论认为，鳞爆缺陷主要是由氢造成的，氢主要是在酸洗(金属溶解于酸中产生氢)和搪烧(瓷釉磨加物中含的结晶水或炉内气氛中的水蒸气等与金属反应生成氢)过程中进入钢板的；随着温度的下降，氢在钢中的溶解度下降并达到过饱和状态，造成氢以气体的形式在钢板和搪瓷层之间积聚，进而形成一定压力，当压力增大一定的临界值，便造成鳞爆缺陷。At present, the relatively mature theory believes that the scale explosion defect is mainly caused by hydrogen, and hydrogen is mainly in pickling (dissolving metal in acid to generate hydrogen) and enamel firing (crystal water contained in enamel grinding or furnace atmosphere) The water vapor and the like react with the metal to form hydrogen) into the steel plate; as the temperature drops, the solubility of hydrogen in the steel decreases and reaches a supersaturated state, causing hydrogen to accumulate in the form of gas between the steel plate and the enamel layer. Then a certain pressure is formed, and when the pressure increases to a certain critical value, the scale explosion defect will be caused.
因此，除了改进搪瓷工艺外，还需要改善钢板本身的贮氢性能；当钢板贮氢能力强时，氢在钢板中的扩散就慢，在相同的搪瓷工艺下进入钢板中的氢就少，并且搪瓷结束后钢板容纳氢的能力也强，这将有利于防止搪瓷制品的鳞爆。钢中的晶界、位错、空穴、夹杂物和析出相等都是良好的贮氢陷阱，因此对于搪瓷钢，需要针对不同的搪瓷用途，调整钢的成分和生产工艺，以保证钢中有足够的贮氢陷阱,实现良好的抗鳞爆性能。Therefore, in addition to improving the enamel process, it is also necessary to improve the hydrogen storage performance of the steel plate itself; when the hydrogen storage capacity of the steel plate is strong, the diffusion of hydrogen in the steel plate is slow, and the hydrogen entering the steel plate is less under the same enamel process, and After the enamel is finished, the ability of the steel plate to accommodate hydrogen is also strong, which will help prevent the scale explosion of the enamel products. Grain boundaries, dislocations, cavities, inclusions and precipitations in steel are all good traps for hydrogen storage. Therefore, for enamelled steel, it is necessary to adjust the composition and production process of the steel for different enamel applications to ensure that there is hydrogen in the steel. Sufficient hydrogen storage traps to achieve good anti-scale explosion performance.
另外，因为搪瓷烧结过程通常要在820℃以上的高温下保温一段时间来完成，因此，搪瓷制品最终的强度取决于搪瓷用钢经高温搪烧后的强度。在通常情况下，钢板经这样的高温热处理后强度会明显下降，这是因为高温热处理过程中钢板的微观组织会经历位错密度的降低、铁素体晶粒的长大、纳米析出相的粗化等，这些变化导致位错强化、细晶强化、析出强化作用同时减弱。如何提高钢板经高温搪烧后的 强度一直是搪瓷用钢开发领域的重点研究课题，也具有重要的实际应用价值。In addition, because the enamel sintering process is usually completed at a high temperature above 820°C for a period of time, the final strength of the enamel product depends on the strength of the steel used for enamel after high-temperature enamel firing. Under normal circumstances, the strength of the steel plate will decrease significantly after such high-temperature heat treatment. These changes lead to the simultaneous weakening of dislocation strengthening, fine grain strengthening and precipitation strengthening. How to improve the strength of the steel plate after high-temperature enamel firing has always been a key research topic in the field of enameling steel development, and it also has important practical application value.
在现有技术中，现有的关于热轧搪瓷用钢的专利技术在成分上多采用加Ti元素的设计，通过它与C、N形成TiC、Ti(C、N)等析出相，发挥贮氢陷阱以及析出强化等作用。In the existing technology, the existing patented technology on hot-rolled enamelled steel mostly adopts the design of adding Ti element in the composition, through which it forms TiC, Ti(C, N) and other precipitated phases with C and N, and exerts the storage capacity. Hydrogen trapping and precipitation strengthening.
例如：公开号为CN101812630A，公开日为2010年8月25日，名称为“深冲用热轧高强度搪瓷钢板及其制造方法”的中国专利文献，公开介绍了一种深冲用热轧高强度搪瓷钢板及其制造方法，它采用的成分为C：0.02～0.10％、Si≤0.10％、Mn：0.05～1.00％、P≤0.05％、S：0.005～0.035％、Al：0.01～0.10％、N≤0.015％、Ti＜0.10％、余量为铁和不可避免杂质。For example: the publication number is CN101812630A, the publication date is August 25, 2010, and the Chinese patent document titled "Hot-rolled high-strength enamelled steel sheet for deep drawing and its manufacturing method" publicly introduces a hot-rolled high-strength enamelled steel sheet for deep drawing. Strength enamel steel plate and its manufacturing method, the components used in it are C: 0.02-0.10%, Si≤0.10%, Mn: 0.05-1.00%, P≤0.05%, S: 0.005-0.035%, Al: 0.01-0.10% , N≤0.015%, Ti<0.10%, and the balance is iron and unavoidable impurities.
又例如：公开号为CN103540845A，公开日为2014年1月29日，名称为“屈服强度为330MPa级的热轧薄板搪瓷钢及制造方法”的中国专利文献，也公开介绍了一种热轧薄板搪瓷钢，它采用的成分为C：0.02～0.07％，Si≤0.05％，Mn：0.10～0.50％，P≤0.020％，S≤0.010％，Ti：0.04～0.10％，Al：0.02～0.08％，N≤0.008％，其余为Fe及不可避免的夹杂，且Ti/C＝1.0～1.5。Another example: the publication number is CN103540845A, the publication date is January 29, 2014, and the Chinese patent document titled "Hot-rolled thin-plate enamelled steel with a yield strength of 330MPa and its manufacturing method" also discloses a hot-rolled thin-plate Enamel steel, the composition of which is C: 0.02～0.07%, Si≤0.05%, Mn: 0.10～0.50%, P≤0.020%, S≤0.010%, Ti: 0.04～0.10%, Al: 0.02～0.08% , N≤0.008%, the rest is Fe and unavoidable inclusions, and Ti/C=1.0～1.5.
再例如：公开号为CN102181805A，公开日为2011年9月14日，名称为“一种薄板坯连铸连轧线生产热水器内胆搪瓷用钢板及方法”的中国专利文献，公开介绍了一种薄板坯连铸连轧线生产热水器内胆搪瓷用钢板及方法，它采用的成分为碳0.03-0.10，锰0.15-0.40，硅≤0.06，硫0.004-0.040，磷≤0.15，铝0.03-0.05，氮0.002-0.008，钛0.02-0.10，其余为铁和不可避免的杂质。Another example: the publication number is CN102181805A, the publication date is September 14, 2011, and the Chinese patent document titled "a thin slab continuous casting and rolling line produces steel plates and methods for enamelling water heater inner tanks" discloses a Thin slab continuous casting and rolling line produces steel plate for water heater liner enamel and method, the components used in it are carbon 0.03-0.10, manganese 0.15-0.40, silicon ≤ 0.06, sulfur 0.004-0.040, phosphorus ≤ 0.15, aluminum 0.03-0.05, Nitrogen 0.002-0.008, titanium 0.02-0.10, and the rest are iron and unavoidable impurities.
但需要注意的是，上述的这几种技术方案均存在一个共同的缺点，它们公开获得的搪瓷钢经高温搪烧后的屈服强度都低于热轧态的屈服强度。However, it should be noted that the above-mentioned several technical solutions all have a common shortcoming. The yield strength of the enamel steels publicly obtained after high-temperature enamel firing is lower than that of the hot-rolled state.
基于此，针对上述现有技术中的缺陷，本发明期望获得一种新的具有搪烧强化性的热轧搪瓷用钢，该热轧搪瓷用钢在热轧态时具有较低的强度和良好的成型性能，在经高温搪烧后，其屈服强度不会下降反而会升高，可以有效提高最终搪瓷制品的强度。Based on this, aiming at the defects in the above-mentioned prior art, the present invention expects to obtain a new hot-rolled steel for enamelling with enamel strengthening, which has lower strength and good Excellent formability, after high-temperature enamel firing, its yield strength will not decrease but will increase, which can effectively improve the strength of the final enamel product.
发明内容Contents of the invention
本发明的目的之一在于提供一种具有搪烧强化性的热轧搪瓷用钢，该热轧搪瓷用钢在热轧态时具有较低的强度和良好的成型性能，其在经高温搪烧后，能够通过相变强化的机制使自身屈服强度不降反升，进而提高最终搪瓷制品的强度，延长搪 瓷制品的使用寿命。One of the objectives of the present invention is to provide a hot-rolled steel for enamelling with enamel strengthening, which has lower strength and good formability in the hot-rolled state, and it has high-temperature enameling Finally, through the mechanism of phase transformation strengthening, the yield strength can be increased instead of falling, thereby improving the strength of the final enamel product and prolonging the service life of the enamel product.
该热轧搪瓷用钢可以用于制备大容积热水器内胆、热水器附件、烧烤炉等搪烧温度较高，且对搪烧后有高屈服强度性能要求的产品，其具有十分显著的应用价值。The hot-rolled enamelling steel can be used to prepare large-volume water heater inner tanks, water heater accessories, barbecue ovens and other products with high enamelling temperature and high yield strength performance requirements after enamelling, and has very significant application value.
为了实现上述目的，本发明提出了一种具有搪烧强化性的热轧搪瓷用钢，其除了Fe和不可避免的杂质以外还含有质量百分含量如下的下述各化学元素：In order to achieve the above object, the present invention proposes a hot-rolled enamelling steel with enamel strengthening, which also contains the following chemical elements in mass percentage except Fe and unavoidable impurities:
C：0.03～0.07％，Si≤0.05％，Mn：1.5～2.5％，Al：0.01～0.05％，Cr：0.25～0.65％，Cu：0.02～0.20％，Ti：0.01～0.08％，V：0.01～0.10％，Mo：0.01～0.10％。C: 0.03～0.07%, Si≤0.05%, Mn: 1.5～2.5%, Al: 0.01～0.05%, Cr: 0.25～0.65%, Cu: 0.02～0.20%, Ti: 0.01～0.08%, V: 0.01 ~0.10%, Mo: 0.01~0.10%.
进一步地，在本发明所述的热轧搪瓷用钢中，其各化学元素质量百分含量为：Further, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of each chemical element is:
C：0.03～0.07％，Si≤0.05％，Mn：1.5～2.5％，Al：0.01～0.05％，Cr：0.25～0.65％，Cu：0.02～0.20％，Ti：0.01～0.08％，V：0.01～0.10％，Mo：0.01～0.10％，余量为Fe和其他不可避免的杂质。C: 0.03～0.07%, Si≤0.05%, Mn: 1.5～2.5%, Al: 0.01～0.05%, Cr: 0.25～0.65%, Cu: 0.02～0.20%, Ti: 0.01～0.08%, V: 0.01 ～0.10%, Mo: 0.01～0.10%, the balance is Fe and other unavoidable impurities.
在本发明所述的热轧搪瓷用钢中，各化学元素设计原理如下所述：In the steel for hot-rolled enamel of the present invention, each chemical element design principle is as follows:
C：在本发明所述的热轧搪瓷用钢中，C元素是钢中重要的强化元素，其能够固溶在铁素体中或在一定条件下形成珠光体组织，从而起到强化基体组织的作用，提高钢板的屈服强度。同时，C元素还可以和Ti、V等强碳化物形成元素结合，形成一定尺寸和数量的析出相，这些析出相可以提高钢板的贮氢性能，从而发挥出搪瓷抗鳞爆的作用。但是，钢中C元素不宜过高，当钢中C元素含量过高，钢中的固溶碳或珠光体组织比例过高时，在搪瓷烧成时会产生大量的CO等气体，造成搪瓷层气泡结构不良，进而产生针孔、气泡等缺陷，影响搪瓷表面质量。因此，在本发明所述的热轧搪瓷用钢中，将C元素的质量百分含量限定在0.03～0.07％之间。C: In the hot-rolled enamel steel described in the present invention, element C is an important strengthening element in steel, which can be dissolved in ferrite or form pearlite structure under certain conditions, thereby strengthening the matrix structure The effect of increasing the yield strength of the steel plate. At the same time, C element can also combine with strong carbide-forming elements such as Ti and V to form precipitates of a certain size and quantity. These precipitates can improve the hydrogen storage performance of the steel plate, thereby exerting the effect of enamel anti-scale explosion. However, the C element in the steel should not be too high. When the C element content in the steel is too high, and the proportion of solid solution carbon or pearlite structure in the steel is too high, a large amount of CO and other gases will be produced when the enamel is fired, causing the enamel layer Poor structure of air bubbles will cause defects such as pinholes and air bubbles, which will affect the surface quality of enamel. Therefore, in the hot-rolled steel for enamelling of the present invention, the mass percentage content of the element C is limited between 0.03% and 0.07%.
Si：在本发明所述的热轧搪瓷用钢中，Si元素在钢中做为残余元素存在，当钢中Si元素含量过高时，会导致钢材的塑性变差；另外，特别是当采用一搪一烧搪瓷工艺时，较高的Si元素含量还会影响钢板与瓷釉间的密着性能。因此，考虑到Si元素对于钢材性能的不利影响，在本发明所述的热轧搪瓷用钢中，控制Si元素的质量百分含量满足：Si≤0.05％。在一些实施方案中，Si的含量为0.005～0.05％。Si: In the hot-rolled enamel steel of the present invention, Si element exists as a residual element in the steel. When the content of Si element in the steel is too high, it will cause the plasticity of the steel to deteriorate; in addition, especially when using In the process of enamel and enamel, the higher content of Si element will also affect the adhesion between the steel plate and the enamel. Therefore, considering the adverse effect of Si element on the properties of steel, in the hot-rolled steel for enameling according to the present invention, the mass percentage content of Si element is controlled to satisfy: Si≤0.05%. In some embodiments, the content of Si is 0.005-0.05%.
Mn、Cr：在本发明所述的热轧搪瓷用钢中，Mn和Cr元素是确保钢材在经过高温搪烧后获得高强度性能的重要元素。这两种元素的组合可以使钢板在较低的冷却速度下发生贝氏体相变，从而提高基体组织的强度。因此，在本发明所述的热轧搪瓷用钢中，将Mn元素的质量百分含量限定在1.5～2.5％之间，将Cr元素的质量百分含量限定在0.25～0.65％之间。Mn, Cr: In the hot-rolled steel for enamelling according to the present invention, Mn and Cr elements are important elements to ensure that the high-strength performance of the steel material is obtained after high-temperature enamelling. The combination of these two elements can make the steel plate undergo bainite transformation at a lower cooling rate, thereby improving the strength of the matrix structure. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of Mn element is limited between 1.5-2.5%, and the mass percentage content of Cr element is limited between 0.25-0.65%.
Mo：在本发明所述的热轧搪瓷用钢中，Mo元素可固溶于铁素体、奥氏体和碳化物中，起到固溶强化作用，同时还能提高碳化物的稳定性，减小因高温搪烧而导致的碳化物析出相粗化现象，从而提高钢的高温稳定性。另外，钢中添加适量的Mo元素对于钢板经高温搪烧后空冷条件下发生相变也有促进作用。因此，在本发明所述的热轧搪瓷用钢中，将Mo元素的质量百分含量限定在0.01～0.10％之间。Mo: In the hot-rolled enamel steel described in the present invention, the Mo element can be solid-dissolved in ferrite, austenite and carbide, which plays a role of solid-solution strengthening and can also improve the stability of carbide. Reduce the coarsening of carbide precipitates caused by high-temperature sintering, thereby improving the high-temperature stability of steel. In addition, adding an appropriate amount of Mo element to the steel can also promote the phase transformation of the steel plate under air-cooling conditions after high-temperature sintering. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percent content of the Mo element is limited between 0.01% and 0.10%.
需要说明的是，在本发明所述的热轧搪瓷用钢中，添加上述的Mn、Mo和Cr元素可以显著的提高过冷奥氏体的稳定性，当钢板在高温搪烧后并空冷至室温的过程中，这三种元素的组合可以使钢板在较低的冷速下发生贝氏体相变，从而获得高强度性能。It should be noted that in the hot-rolled steel for enamelling of the present invention, adding the above-mentioned Mn, Mo and Cr elements can significantly improve the stability of the supercooled austenite, when the steel plate is fired at high temperature and air-cooled to In the process of room temperature, the combination of these three elements can make the steel plate undergo bainite transformation at a lower cooling rate, thereby obtaining high strength properties.
Al：在本发明所述的热轧搪瓷用钢中，Al为强脱氧元素，中低碳钢中常常需要采用Al元素进行脱氧，以确保钢中的O含量保持在较低的值。因此，在本发明所述的热轧搪瓷用钢中，将Al元素的质量百分含量限定在0.01～0.05％之间。Al: In the hot-rolled steel for enamelling of the present invention, Al is a strong deoxidizing element, and it is often necessary to use Al element for deoxidation in medium and low carbon steels to ensure that the O content in the steel is kept at a low value. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of the Al element is limited between 0.01-0.05%.
Cu：在本发明所述的热轧搪瓷用钢中，钢中添加适量的Cu元素均有利于表面沉积，提高钢与瓷釉间的密着性能，进而改善钢材的抗鳞爆性能。因此，在本发明所述的热轧搪瓷用钢中，将Cu元素的质量百分含量限定在0.02～0.20％之间。Cu: In the steel for hot-rolled enamel according to the present invention, the addition of an appropriate amount of Cu element in the steel is beneficial to surface deposition, improves the adhesion performance between the steel and the enamel, and then improves the anti-scaling performance of the steel. Therefore, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of Cu element is limited between 0.02-0.20%.
Ti、V：在本发明所述的热轧搪瓷用钢中，Ti和V元素的复合添加是使钢获得良好贮氢性能的主要元素，它们在适当的控制控冷工艺下可以形成细小、弥散的TiC、VC析出相，这些析出相作为不可逆的贮氢陷阱可以有效提高钢板的贮氢性能，进而发挥搪瓷抗鳞爆作用。因此，综合考虑钢的力学性能和成本因素，在本发明所述的热轧搪瓷用钢中，将Ti元素的质量百分含量限定在0.01～0.08％之间，将V元素的质量百分含量限定在0.01～0.10％之间。Ti, V: In the hot-rolled steel for enamel described in the present invention, the compound addition of Ti and V elements is the main element to make the steel obtain good hydrogen storage performance, and they can form fine, dispersed TiC and VC precipitates, these precipitates can effectively improve the hydrogen storage performance of the steel plate as irreversible hydrogen storage traps, and then play the role of enamel anti-scale explosion. Therefore, comprehensively considering the mechanical properties and cost factors of the steel, in the hot-rolled steel for enamelling according to the present invention, the mass percentage content of the Ti element is limited between 0.01% and 0.08%, and the mass percentage content of the V element It is limited between 0.01 and 0.10%.
进一步地，在本发明所述的热轧搪瓷用钢中，其还含有B：0.0006～0.003％。Furthermore, in the steel for hot-rolled enameling according to the present invention, it further contains B: 0.0006-0.003%.
在本发明上述技术方案中，为了获得更优的实施效果，还可以优选地向热轧搪瓷用钢中添加适量的B元素。In the above technical solution of the present invention, in order to obtain a better implementation effect, it is also preferable to add an appropriate amount of B element to the hot-rolled steel for enamelling.
B：在本发明所述的热轧搪瓷用钢中，B在钢中的溶解度很低，其主要可以与钢中的残留的氮结合，并以BN形式析出，可以作为贮氢陷阱，起到搪瓷抗鳞爆的作用。因此，为了发挥B元素的有益效果，在本发明所述的热轧搪瓷用钢中，将B元素的质量百分含量控制在0.0006～0.003％之间。B: In the steel for hot-rolled enamel described in the present invention, the solubility of B in the steel is very low, and it can mainly be combined with the residual nitrogen in the steel and precipitated in the form of BN, which can be used as a hydrogen storage trap to play a role Enamel anti-scale explosion effect. Therefore, in order to exert the beneficial effect of the B element, in the hot-rolled steel for enameling according to the present invention, the mass percentage content of the B element is controlled between 0.0006-0.003%.
进一步地，在本发明所述的热轧搪瓷用钢中，各化学元素还满足：(C-Ti/4-V/4.25)×(Mn+Cr)＞0.05；其中，C、Ti、V、Cr和Mn分别表示相应元素的质量百分比的 数值。Further, in the hot-rolled steel for enamelling according to the present invention, each chemical element also satisfies: (C-Ti/4-V/4.25)×(Mn+Cr)>0.05; wherein, C, Ti, V, Cr and Mn represent the numerical values of the mass percentages of the corresponding elements, respectively.
本发明所述的热轧搪瓷用钢在控制单一化学元素质量百分含量的同时，还可以优选地控制C、Ti、V、Cr和Mn元素满足公式：(C-Ti/4-V/4.25)×(Mn+Cr)＞0.05。The hot-rolled steel for enamelling of the present invention can preferably control C, Ti, V, Cr and Mn elements to satisfy the formula while controlling the mass percentage content of a single chemical element: (C-Ti/4-V/4.25 )×(Mn+Cr)>0.05.
发明人通过试验研究发现，当控制钢中的C、Ti、V、Cr和Mn元素含量满足上述关系式时，可以使钢板获得搪烧强化性能，即钢板在经过高温搪烧后的强度不但不下降，反而会升高。The inventor found through experimental research that when the content of C, Ti, V, Cr and Mn elements in the steel is controlled to satisfy the above relational formula, the steel plate can obtain sintering strengthening performance, that is, the strength of the steel plate after high-temperature sintering is not only reduced down, it will rise instead.
这是因为，当钢中这些元素满足此关系式时，在形成Ti和V的析出相以后剩余的C元素和钢中的Mn、Cr元素可以共同发挥作用，使钢板经过高温搪烧并空冷后，微观组织由铁素体+珠光体转变为铁素体+贝氏体组织，进而通过这种相变强化作用，使钢板获得相较于热轧态更高的强度性能，其为本发明成分设计的关键创新之一。This is because, when these elements in the steel satisfy this relational formula, the remaining C elements after the formation of Ti and V precipitates and the Mn and Cr elements in the steel can work together to make the steel plate go through high-temperature sintering and air-cooling. , the microstructure changes from ferrite + pearlite to ferrite + bainite structure, and then through this phase transformation strengthening effect, the steel plate can obtain higher strength properties than the hot-rolled state, which is the composition of the present invention One of the key innovations of the design.
进一步地，在本发明所述的热轧搪瓷用钢中，其微观组织为铁素体+珠光体。进一步地，所述微观组织中，以面积比计，珠光体的比例为10～45％。Furthermore, in the hot-rolled steel for enameling according to the present invention, its microstructure is ferrite+pearlite. Further, in the microstructure, the proportion of pearlite is 10-45% in terms of area ratio.
进一步地，在本发明所述的热轧搪瓷用钢中，铁素体的晶粒度为8～10级。Furthermore, in the hot-rolled steel for enamelling according to the present invention, the ferrite grain size is 8-10 grades.
进一步地，在本发明所述的热轧搪瓷用钢中，其厚度为1.5～3.5mm。Furthermore, in the hot-rolled steel for enameling according to the present invention, the thickness thereof is 1.5-3.5 mm.
进一步地，在本发明所述的热轧搪瓷用钢中，其热轧态屈服强度为345～389MPa，经870～950℃温度区间内高温搪烧后，屈服强度为402～439MPa。Furthermore, in the hot-rolled enamelling steel according to the present invention, the yield strength of the hot-rolled steel is 345-389 MPa, and the yield strength is 402-439 MPa after high-temperature enamelling in the temperature range of 870-950°C.
进一步地，本发明所述的热轧搪瓷用钢的屈服强度为340～400MPa，抗拉强度为550～630MPa，延伸率A 50为25～35％。在一些实施方案中，本发明所述的热轧搪瓷用钢的屈服强度为345～390MPa，抗拉强度为550～630MPa，延伸率A 50为28～35％。 Furthermore, the yield strength of the hot-rolled enamelling steel according to the present invention is 340-400 MPa, the tensile strength is 550-630 MPa, and the elongation A 50 is 25-35%. In some embodiments, the yield strength of the hot-rolled enamelling steel according to the present invention is 345-390 MPa, the tensile strength is 550-630 MPa, and the elongation A 50 is 28-35%.
在一些实施方案中，本发明提供一种搪瓷钢，包括基材和基材一个或两个表面上的搪瓷层，其中，该基材的元素组成与本发明任一实施方案所述的具有搪烧强化性的热轧搪瓷用钢的元素组成相同。在一些实施方案中，该搪瓷钢的屈服强度为400～450MPa，抗拉强度为610～660MPa，延伸率A 50≥18％(如18～25％)。在一些实施方案中，该基材的显微组织为铁素体+贝氏体组织。优选地，所述微观组织中，以面积比计，贝氏体的比例为10～40％。所述搪瓷层所用材料可以是本领域周知的搪瓷釉料。示例性的材料为福禄EMP6515型高温釉料。 In some embodiments, the present invention provides an enamelled steel comprising a substrate and an enamel layer on one or both surfaces of the substrate, wherein the elemental composition of the substrate is the same as that described in any embodiment of the present invention. Fire-strengthened hot-rolled enamelling steels have the same elemental composition. In some embodiments, the enamelled steel has a yield strength of 400-450 MPa, a tensile strength of 610-660 MPa, and an elongation A 50 ≥ 18% (eg, 18-25%). In some embodiments, the microstructure of the substrate is a ferrite+bainite structure. Preferably, in the microstructure, the proportion of bainite is 10-40% in terms of area ratio. The material used for the enamel layer may be enamel glaze known in the art. An exemplary material is Flow EMP6515 high temperature glaze.
相应地，本发明的又一目的在于提供上述的热轧搪瓷用钢的制造方法，该制造方法生产工艺简单，通过该制造方法制备的热轧搪瓷用钢在热轧态时具有较低的强度和良好的成形性能，其在经高温搪烧后，能够通过相变强化的机制使自身屈服强 度不降反升。Correspondingly, another object of the present invention is to provide the above-mentioned manufacturing method of hot-rolled enameling steel, the manufacturing method has simple production process, and the hot-rolled enameling steel prepared by this manufacturing method has lower strength in hot-rolled state And good formability, after high-temperature sintering, it can increase its yield strength instead of falling through the mechanism of phase transformation strengthening.
为了实现上述目的，本发明提出了上述的热轧搪瓷用钢的制造方法，其包括步骤：In order to achieve the above object, the present invention proposes the manufacturing method of above-mentioned hot-rolled enamelling steel, and it comprises steps:
(1)冶炼和铸造；(1) Smelting and casting;
(2)加热；(2) heating;
(3)热轧：控制粗轧温度大于850℃，精轧开轧温度为900～1050℃，精轧终轧温度为840～900℃；(3) Hot rolling: control the rough rolling temperature to be greater than 850°C, the finish rolling start temperature to be 900-1050°C, and the finish rolling finish temperature to be 840-900°C;
(4)层流冷却：控制冷却速度为10～35℃/s；(4) Laminar cooling: Control the cooling rate to 10-35°C/s;
(5)卷取。(5) coiling.
在本发明上述技术方案中，为了获得合适的热轧态组织，使热轧态的钢材具有较低的强度、较高的成形性能，本发明对步骤(3)的热轧工艺参数和步骤(4)的层流冷却参数进行了严格的控制，其通过控轧控冷可以确保本发明热轧搪瓷用钢的性能。In the above-mentioned technical scheme of the present invention, in order to obtain suitable hot-rolled state structure, make the steel product of hot-rolled state have lower strength, higher formability, the present invention is to the hot-rolled process parameter of step (3) and step ( 4) The laminar flow cooling parameters are strictly controlled, which can ensure the performance of the hot-rolled enameling steel of the present invention through controlled rolling and controlled cooling.
在上述步骤(3)的热轧过程中，本发明先将经过加热后的铸坯粗轧成中间坯，而后再对获得的中间坯进行精轧，最后精轧轧成所需板坯。其中，控制粗轧温度大于850℃，控制精轧开轧温度为900～1050℃，控制精轧终轧温度为840～900℃。在一些实施方案中，控制粗轧温度为850～1080℃或880～1080℃。In the hot rolling process of the above step (3), the present invention first rough-rolls the heated cast slab into an intermediate slab, then performs finish rolling on the obtained intermediate slab, and finally finish-rolls the required slab. Among them, the rough rolling temperature is controlled to be greater than 850°C, the finish rolling start temperature is controlled to be 900-1050°C, and the finish rolling finish rolling temperature is controlled to be 840-900°C. In some embodiments, the rough rolling temperature is controlled to be 850-1080°C or 880-1080°C.
相应地，在本发明步骤(4)的中，通过10～35℃/s的冷却速度水冷至卷取温度，然后空冷至室温。本发明采用这样的控轧控冷工艺，有利于获得细小的铁素体和珠光体晶粒组织，使钢板具有良好的加工成形性能。Correspondingly, in step (4) of the present invention, water cooling is carried out at a cooling rate of 10-35°C/s to the coiling temperature, and then air-cooling to room temperature. The invention adopts such a controlled rolling and controlled cooling process, which is beneficial to obtain fine ferrite and pearlite grain structure, so that the steel plate has good processing and forming performance.
采用上述制造方法制得的热轧搪瓷用钢可以进一步地用于单面搪瓷或双面搪瓷，以制得搪瓷用品。The hot-rolled steel for enameling prepared by the above manufacturing method can be further used for single-side or double-side enamelling to obtain enameling products.
需要说明的是，在本发明上述步骤(1)中，铸造可以采用连铸或模铸的方式，其可以保证铸坯内部成分均匀和表面质量良好。在一些其他实施方式中，也可以采用模铸的方式，模铸的钢锭还需经初轧机轧制成钢坯。It should be noted that in the above step (1) of the present invention, continuous casting or mold casting can be used for casting, which can ensure uniform internal composition and good surface quality of the slab. In some other embodiments, die casting may also be used, and the die cast steel ingot needs to be rolled into a billet through a blooming mill.
进一步地，在本发明所述的制造方法中，在步骤(2)中，加热温度为1150～1260℃。Furthermore, in the production method of the present invention, in step (2), the heating temperature is 1150-1260°C.
进一步地，在本发明所述的制造方法中，在步骤(5)中，控制卷取温度为550～680℃。Furthermore, in the manufacturing method of the present invention, in step (5), the coiling temperature is controlled to be 550-680°C.
在上述技术方案中，可以优选地控制卷取温度为550～680℃，在这一温度区间进行卷取时，不仅有利于细化铁素体晶粒，还有利于钢中TiC、VC析出相的均匀化， 以获得具有优异力学性能和抗鳞爆性能的热轧搪瓷用钢。In the above technical solution, the coiling temperature can preferably be controlled at 550-680°C. When coiling in this temperature range, it is not only beneficial to the refinement of ferrite grains, but also beneficial to the precipitation of TiC and VC in the steel. Homogenization to obtain hot-rolled steel for enamelling with excellent mechanical properties and anti-scale explosion performance.
在一些实施方案中，本发明还提供一种搪瓷钢的制备方法，其包括采用本文任一实施方案所述的方法制备所述热轧搪瓷用钢的步骤，以及将制备得到的热轧搪瓷用钢进行搪烧的步骤。在一些实施方案中，所述搪烧步骤中，在870～950℃搪烧5～15分钟。在一些实施方案中，搪烧步骤前还包括对该热轧搪瓷用钢进行抛丸等处理。在一些实施方案中，采用一次涂搪一次烧成工艺或两次涂搪两次烧成工艺进行搪烧处理。In some embodiments, the present invention also provides a method for preparing enamelled steel, which includes the step of preparing the hot-rolled enamelled steel by the method described in any embodiment herein, and preparing the prepared hot-rolled enamelled steel The steps of enamelling and firing of steel. In some embodiments, in the simmering step, simmering is carried out at 870-950° C. for 5-15 minutes. In some embodiments, before the sintering step, the hot-rolled steel for enameling is subjected to shot blasting and other treatments. In some embodiments, the enamelling treatment is performed using a one-enameling-one-firing process or a two-enameling-two-firing process.
相较于现有技术，本发明所述的热轧搪瓷用钢的制造方法具有如下所述的优点以及有益效果：Compared with the prior art, the manufacturing method of the hot-rolled steel for enamelling of the present invention has the following advantages and beneficial effects:
本发明在合理设计化学成分的同时，还结合优化了轧后快速冷却的控轧控冷工艺，进而可以有效制备在热轧态下具有优异性能的热轧搪瓷用钢，其生产工艺简单，所制备的热轧搪瓷用钢在热轧态时具有较低的强度和良好的成型性能，在经高温搪烧后，该热轧搪瓷用钢能够通过相变强化的机制使自身屈服强度不降反升，其不仅可以提高搪瓷制品的强度，还可以延长搪瓷制品的使用寿命。The present invention not only rationally designs the chemical composition, but also combines and optimizes the controlled rolling and controlled cooling process of rapid cooling after rolling, and then can effectively prepare hot-rolled enamelled steel with excellent performance in the hot-rolled state. The production process is simple, and the The prepared hot-rolled enamelled steel has low strength and good formability in the hot-rolled state. After high-temperature enamelling, the hot-rolled enamelled steel can make its own yield strength not decrease but reverse through the mechanism of phase transformation strengthening. It can not only improve the strength of enamel products, but also prolong the service life of enamel products.
该热轧搪瓷用钢在热轧态下的屈服强度为345～389MPa，经870～950℃温度区间内高温搪烧后，其屈服强度能够升高为402～439MPa，其可以用于制备大容积热水器内胆、热水器附件、烧烤炉等搪烧温度较高，且对搪烧后有高屈服强度性能要求的产品，具有十分显著的应用价值。The yield strength of the hot-rolled enamel steel in the hot-rolled state is 345-389 MPa, and after high-temperature enamel firing in the temperature range of 870-950 ° C, its yield strength can be increased to 402-439 MPa, which can be used to prepare large-volume Water heater liners, water heater accessories, barbecue ovens and other products with high firing temperature and high yield strength performance requirements after firing, have very significant application value.
附图说明Description of drawings
图1显示了不同搪烧温度对于本发明实施例1和对比例1的钢在搪烧后的屈服强度性能的影响。Figure 1 shows the influence of different sintering temperatures on the yield strength properties of the steels of Example 1 and Comparative Example 1 of the present invention after sintering.
图2为实施例1的热轧搪瓷用钢在热轧态下的金相组织照片。Fig. 2 is a photograph of the metallographic structure of the hot-rolled enamelling steel of Example 1 in a hot-rolled state.
图3为实施例1的热轧搪瓷用钢经870℃高温搪烧并保温10min后空冷的金相组织照片。Fig. 3 is the metallographic structure photograph of the hot-rolled enamelling steel of Example 1 after being fired at a high temperature of 870° C. and kept for 10 minutes and then air-cooled.
具体实施方式Detailed ways
下面将结合说明书附图和具体的实施例对本发明所述的热轧搪瓷用钢及其制造方法做进一步的解释和说明，然而该解释和说明并不对本发明的技术方案构成不当限定。The hot-rolled enamelled steel and its manufacturing method according to the present invention will be further explained and illustrated in conjunction with the accompanying drawings and specific examples. However, such explanations and illustrations do not constitute undue limitations on the technical solution of the present invention.
实施例1-7及对比例1-2Embodiment 1-7 and comparative example 1-2
实施例1-7的热轧搪瓷用钢以及对比例1-2的对比钢的制造方法采用以下步骤制得：The manufacturing method of the hot-rolled enameling steel of embodiment 1-7 and the contrast steel of comparative example 1-2 adopts the following steps to make:
(1)按照下述表1所示的化学成分进行冶炼和铸造：冶炼完成的钢水经真空脱气处理后进行连铸，得到连铸坯。(1) Smelting and casting are carried out according to the chemical composition shown in the following table 1: the molten steel after smelting is vacuum degassed and then continuously cast to obtain a continuous casting slab.
(2)加热：将所得连铸坯进行加热，并控制加热温度为1150～1260℃。(2) Heating: heating the obtained continuous cast slab, and controlling the heating temperature to be 1150-1260°C.
(3)热轧：控制粗轧温度大于850℃，控制精轧开轧温度为900～1050℃，控制精轧终轧温度为840～900℃。(3) Hot rolling: control the rough rolling temperature to be greater than 850°C, control the finish rolling start temperature to be 900-1050°C, and control the finish rolling finish rolling temperature to be 840-900°C.
(4)层流冷却：进行层流水冷，控制冷却速度为10～35℃/s。(4) Laminar flow cooling: carry out laminar flow water cooling, and control the cooling rate to 10-35°C/s.
(5)卷取：控制卷取温度为550～680℃。(5) Coiling: Control the coiling temperature to 550-680°C.
本发明所述的实施例1-7的热轧搪瓷用钢均采用以上步骤制得，且其化学成分及相关工艺参数均满足本发明设计规范控制要求。The hot-rolled enameling steels of Examples 1-7 of the present invention are all prepared by the above steps, and their chemical composition and related process parameters all meet the control requirements of the design specification of the present invention.
需要说明的是，不同于上述实施例1-7的热轧搪瓷用钢，对比例1-2的对比例钢虽然也采用上述步骤(1)-步骤(5)的步骤流程值得，但其化学元素成分中均存在不满足本发明设计要求的参数。It should be noted that, unlike the hot-rolled steel for enamelling of the above-mentioned examples 1-7, although the comparative example steel of the comparative example 1-2 also adopts the step flow process of the above-mentioned steps (1)-step (5), its chemical There are parameters that do not meet the design requirements of the present invention in the elemental components.
表1列出了实施例1-7的热轧搪瓷用钢以及对比例1-2的对比钢中各化学元素质量百分比。Table 1 lists the mass percentages of each chemical element in the hot-rolled enameling steels of Examples 1-7 and the comparative steels of Comparative Examples 1-2.
表1 (余量为Fe和其他不可避免的杂质)Table 1 (the balance is Fe and other unavoidable impurities)
Figure PCTCN2022132223-appb-000001
Figure PCTCN2022132223-appb-000001
注：M*＝(C-Ti/4-V/4.25)×(Mn+Cr)；其中，C、Ti、V、Cr和Mn分别表示 相应元素的质量百分比的数值。Note: M*=(C-Ti/4-V/4.25)×(Mn+Cr); where, C, Ti, V, Cr and Mn represent the numerical values of the mass percentages of the corresponding elements.
表2列出了实施例1-7的热轧搪瓷用钢以及对比例1-2的对比钢在上述制造的具体工艺参数。Table 2 lists the specific process parameters of the above-mentioned manufacturing of the hot-rolled steel for enamelling of Examples 1-7 and the comparison steel of Comparative Examples 1-2.
表2Table 2
Figure PCTCN2022132223-appb-000002
Figure PCTCN2022132223-appb-000002
将处于热轧态的实施例1-7的热轧搪瓷用钢和对比例1-2的对比钢分别取样，并对各实施例和对比例的热轧态钢的性能进行测试，所得的测试结果列于表3中，相关性能测试方法及手段如下所述：The hot-rolled enamel steel of embodiment 1-7 in hot-rolled state and the contrast steel of comparative example 1-2 are respectively sampled, and the performance of the hot-rolled state steel of each embodiment and comparative example is tested, the test of gained The results are listed in Table 3, and the relevant performance testing methods and means are as follows:
拉伸试验：按照GB/T 228.1-2010《金属材料室温拉伸试验方法》，利用SCL233常温拉伸试验机进行测试，拉伸速度为3mm/min，拉伸试样为JIS5拉伸试样，以获得实施例1-7和对比例1-2所对应的热轧态钢的屈服强度、抗拉强度和延伸率A 50。 Tensile test: According to GB/T 228.1-2010 "Metallic Materials Tensile Test Method at Room Temperature", use SCL233 room temperature tensile testing machine for testing, the tensile speed is 3mm/min, and the tensile sample is JIS5 tensile sample. The yield strength, tensile strength and elongation A 50 of the hot-rolled steel corresponding to Examples 1-7 and Comparative Examples 1-2 were obtained.
表3table 3
Figure PCTCN2022132223-appb-000003
Figure PCTCN2022132223-appb-000003
Figure PCTCN2022132223-appb-000004
Figure PCTCN2022132223-appb-000004
如图3所示，在本发明中，实施例1-7的热轧搪瓷用钢在热轧态时，均具有较低的屈服强度和良好的成形性能，其屈服强度在345-389MPa之间，其抗拉强度在558-625MPa之间，其延伸率A 50在28-32％之间。 As shown in Figure 3, in the present invention, the hot-rolled enamelling steels of Examples 1-7 all have lower yield strength and good formability in the hot-rolled state, and the yield strength is between 345-389MPa , its tensile strength is between 558-625MPa, and its elongation A 50 is between 28-32%.
较低的屈服强度有利于钢板在用户使用过程中的冲压和冷弯成形加工，例如，在加工热水器内胆筒身过程中，可以避免冷弯卷圆后的回弹，从而有利于焊接加工。相较于实施例1-7，对比例1-2的对比钢的屈服强度较高，则不利于用户使用加工过程。The lower yield strength is beneficial to the stamping and cold-bending processing of the steel plate during the user's use. For example, in the process of processing the water heater inner tank body, it can avoid the springback after cold bending and rolling, which is beneficial to the welding process. Compared with Examples 1-7, the yield strength of the comparative steel in Comparative Example 1-2 is higher, which is not conducive to the user's use of the processing process.
为了进一步地证明本发明所述的实施例1-7的热轧搪瓷用钢和对比例1-2的对比钢经过搪瓷后的性能，需要对各实施例和对比例的钢板进行搪瓷处理：In order to further prove the performance of the hot-rolled steel for enameling of Examples 1-7 of the present invention and the comparative steel of Comparative Example 1-2 after enamelling, it is necessary to carry out enameling treatment to the steel plates of each embodiment and comparative example:
采用福禄EMP6515型高温釉料对各实施例和对比例钢板进行双面湿法搪瓷处理，控制搪烧工艺为：控制搪烧温度为870～950℃，并保温10分钟，然后空冷获得经过搪瓷后实施例1-7和对比例1-2的钢板。The double-sided wet enamel treatment of the steel plates of the examples and the comparative examples was carried out with Flow EMP6515 high-temperature glaze, and the controlled enamel firing process was as follows: control the enamel firing temperature to 870-950°C, keep it warm for 10 minutes, and then air-cool to obtain enameled The steel plates of Examples 1-7 and Comparative Examples 1-2.
需要说明的是，在本实施方式中，控制实施例1-7和对比例1-2均在870～950℃温度区间内高温搪烧，并保温10分钟；在本发明中，各实施例和对比例的具体高温搪烧温度列于下述表4之中。It should be noted that, in this embodiment, the control examples 1-7 and comparative examples 1-2 were all fired at a high temperature in the temperature range of 870-950°C and kept warm for 10 minutes; in the present invention, each example and The specific high-temperature sintering temperatures of the comparative examples are listed in Table 4 below.
表4Table 4
Figure PCTCN2022132223-appb-000005
Figure PCTCN2022132223-appb-000005
Figure PCTCN2022132223-appb-000006
Figure PCTCN2022132223-appb-000006
在完成上述高温搪瓷后，再对已经过高温搪瓷处理的实施例1-7热轧搪瓷用钢以及对比例1-2的对比钢进行进一步地观察分析和试验验证：After the above-mentioned high-temperature enamel is completed, the steel for hot-rolled enamel of Example 1-7 and the comparative steel of Comparative Example 1-2 that have been treated with high-temperature enamel are further observed, analyzed and tested:
将实施例1-7和对比例1-2的钢板静置48小时后观察表面是否发生鳞爆现象；采用落锤实验验证钢板与瓷釉间的密着性能；采用拉伸试验确定搪瓷后各实施例和对比例钢板的屈服强度、抗拉强度和延伸率A 50，试验测试的结果列于表5中。 Put the steel plates of Examples 1-7 and Comparative Examples 1-2 to stand for 48 hours to observe whether scale explosion occurs on the surface; use a drop weight test to verify the adhesion between the steel plate and the enamel; use a tensile test to determine the enamel of each embodiment and the yield strength, tensile strength and elongation A 50 of the steel plate of the comparative example, the test results are listed in Table 5.
表5列出了搪瓷后实施例1-7的热轧搪瓷用钢以及对比例1-2的对比钢的力学性能和搪瓷性能。Table 5 lists the mechanical properties and enameling properties of the hot-rolled enameling steels of Examples 1-7 and the comparative steels of Comparative Examples 1-2 after enameling.
表5.table 5.
Figure PCTCN2022132223-appb-000007
Figure PCTCN2022132223-appb-000007
由表4可以看出，并结合表1-3可以看出，实施例1-7的热轧搪瓷用钢的厚度范围可以在1.5-3.5mm之间，经870～950℃温度区间内高温搪烧处理后，实施例1-7钢板的强度均不降反升，其屈服强度升高至402～439MPa之间，抗拉强度升高至610-660MPa之间，其延伸率A 50在18-22％之间。 It can be seen from Table 4, combined with Tables 1-3, that the thickness range of the hot-rolled enameling steel in Examples 1-7 can be between 1.5-3.5 mm, and it can be enamelled at a high temperature in the temperature range of 870-950°C. After the sintering treatment, the strength of the steel plates in Examples 1-7 did not decrease but increased, the yield strength increased to 402-439MPa, the tensile strength increased to 610-660MPa, and the elongation A50 was between 18-439MPa. 22% between.
最终获得的实施例1-7的搪瓷钢板经48小时以后观察搪瓷表面，均无鳞爆现象发生；经落锤实验测试，钢板与瓷层之间密着性能优良，完全满足用户使用要求。The finally obtained enamel steel plates of Examples 1-7 were observed after 48 hours, and no scaling phenomenon occurred on the enamel surface; the drop weight test showed that the adhesion between the steel plate and the porcelain layer was excellent, which fully met the user's requirements.
相应地，对比例1-2的对比钢板性能明显劣于实施例1-7的热轧搪瓷用钢。在对比例1-2中，经高温搪烧处理后，对比例1-2的钢材的屈服强度的下降幅度非常大，搪烧前后钢板屈服强度降幅大会导致钢板瓢曲变形等问题，不利于用户的加工使用。同时，对比例2经双面搪瓷后出现鳞爆缺陷，无法满足双面搪瓷抗鳞爆性能要求。Correspondingly, the performance of the comparative steel plate of Comparative Example 1-2 is obviously inferior to that of the hot-rolled enameling steel of Example 1-7. In Comparative Example 1-2, after the high-temperature sintering treatment, the yield strength of the steel in Comparative Example 1-2 has a very large decrease. The large decrease in the yield strength of the steel plate before and after sintering will lead to problems such as bending and deformation of the steel plate, which is not conducive to users. processing use. At the same time, scale burst defects appeared in Comparative Example 2 after double-sided enamel, which could not meet the anti-scale burst performance requirements of double-sided enamel.
图1显示了不同搪烧温度对于本发明实施例1和对比例1的钢在搪烧后的屈服强度性能的影响。Figure 1 shows the influence of different sintering temperatures on the yield strength properties of the steels of Example 1 and Comparative Example 1 of the present invention after sintering.
由图1可以看出，随着搪烧温度升高，实施例1的钢的屈服强度呈上升趋势，当搪烧温度为930℃时，屈服强度可达425MPa；而随着搪烧温度升高，对比例1的钢的屈服强度呈下降趋势，当搪烧温度为930℃时，对比例1的钢的屈服强度降低为289MPa。It can be seen from Figure 1 that the yield strength of the steel in Example 1 shows an upward trend as the sintering temperature increases. When the sintering temperature is 930 ° C, the yield strength can reach 425 MPa; , the yield strength of the steel in Comparative Example 1 showed a downward trend, and when the sintering temperature was 930° C., the yield strength of the steel in Comparative Example 1 decreased to 289 MPa.
图2为实施例1的热轧搪瓷用钢在热轧态下的金相组织照片。Fig. 2 is a photograph of the metallographic structure of the hot-rolled enamelling steel of Example 1 in a hot-rolled state.
图3为实施例1的热轧搪瓷用钢经870℃高温搪烧并保温10min后空冷的金相组织照片。Fig. 3 is the metallographic structure photograph of the hot-rolled enamelling steel of Example 1 after being fired at a high temperature of 870° C. and kept for 10 minutes and then air-cooled.
如图2和图3所示，在本发明中，实施例1的热轧搪瓷用钢在热轧态时的显微组织为铁素体+珠光体，经高温搪烧后转变为铁素体+贝氏体组织。As shown in Figure 2 and Figure 3, in the present invention, the microstructure of the hot-rolled steel for enameling in Example 1 in the hot-rolled state is ferrite+pearlite, which transforms into ferrite after high-temperature sintering +Bainite structure.
需要说明的是，本案中各技术特征的组合方式并不限本案权利要求中所记载的组合方式或是具体实施例所记载的组合方式，本案记载的所有技术特征可以以任何方式进行自由组合或结合，除非相互之间产生矛盾。It should be noted that the combination of the technical features in this case is not limited to the combination described in the claims of this case or the combination described in the specific examples. All the technical features recorded in this case can be freely combined or combined in any way. combined, unless contradictory to each other.
还需要注意的是，以上所列举的实施例仅为本发明的具体实施例。显然本发明不局限于以上实施例，随之做出的类似变化或变形是本领域技术人员能从本发明公开的内容直接得出或者很容易便联想到的，均应属于本发明的保护范围。It should also be noted that the above-mentioned embodiments are only specific embodiments of the present invention. Apparently, the present invention is not limited to the above embodiments, and the similar changes or deformations made thereupon can be directly obtained or easily thought of by those skilled in the art from the disclosed content of the present invention, and all should belong to the protection scope of the present invention .

Claims (15)

  1. 一种具有搪烧强化性的热轧搪瓷用钢，其特征在于，其除了Fe和不可避免的杂质以外还含有质量百分含量如下的下述各化学元素：A hot-rolled enamelling steel with enamel strengthening is characterized in that, in addition to Fe and unavoidable impurities, it also contains the following chemical elements in mass percentages as follows:
    C：0.03～0.07％，Si≤0.05％，Mn：1.5～2.5％，Al：0.01～0.05％，Cr：0.25～0.65％，Cu：0.02～0.20％，Ti：0.01～0.08％，V：0.01～0.10％，Mo：0.01～0.10％。C: 0.03～0.07%, Si≤0.05%, Mn: 1.5～2.5%, Al: 0.01～0.05%, Cr: 0.25～0.65%, Cu: 0.02～0.20%, Ti: 0.01～0.08%, V: 0.01 ~0.10%, Mo: 0.01~0.10%.
  2. 如权利要求1所述的热轧搪瓷用钢，其特征在于，其各化学元素质量百分含量为：The hot-rolled steel for enamelling as claimed in claim 1, wherein the mass percent content of each chemical element is:
    C：0.03～0.07％，Si≤0.05％，Mn：1.5～2.5％，Al：0.01～0.05％，Cr：0.25～0.65％，Cu：0.02～0.20％，Ti：0.01～0.08％，V：0.01～0.10％，Mo：0.01～0.10％，余量为Fe和其他不可避免的杂质。C: 0.03～0.07%, Si≤0.05%, Mn: 1.5～2.5%, Al: 0.01～0.05%, Cr: 0.25～0.65%, Cu: 0.02～0.20%, Ti: 0.01～0.08%, V: 0.01 ～0.10%, Mo: 0.01～0.10%, the balance is Fe and other unavoidable impurities.
  3. 如权利要求1或2所述的热轧搪瓷用钢，其特征在于，其还含有B：0.0006～0.003％。The hot-rolled steel for enameling according to claim 1 or 2, further comprising B: 0.0006 to 0.003%.
  4. 如权利要求1或2所述的热轧搪瓷用钢，其特征在于，各化学元素还满足：(C-Ti/4-V/4.25)×(Mn+Cr)＞0.05；其中，C、Ti、V、Cr和Mn分别表示相应元素的质量百分比的数值。The hot-rolled enamelling steel according to claim 1 or 2, wherein each chemical element also satisfies: (C-Ti/4-V/4.25)×(Mn+Cr)>0.05; wherein, C, Ti , V, Cr and Mn represent the numerical values of the mass percentages of the corresponding elements, respectively.
  5. 如权利要求1或2所述的热轧搪瓷用钢，其特征在于，其微观组织为铁素体+珠光体；优选地，以面积比计，珠光体的比例为10～45％。The hot-rolled enamelling steel according to claim 1 or 2, characterized in that its microstructure is ferrite+pearlite; preferably, the proportion of pearlite is 10-45% in terms of area ratio.
  6. 如权利要求5所述的热轧搪瓷用钢，其特征在于，铁素体的晶粒度为8～10级。The hot-rolled steel for enamelling according to claim 5, wherein the grain size of ferrite is 8-10 grades.
  7. 如权利要求1或2所述的热轧搪瓷用钢，其特征在于，其厚度为1.5-3.5mm。The hot-rolled steel for enamelling according to claim 1 or 2, characterized in that its thickness is 1.5-3.5 mm.
  8. 如权利要求1或2所述的热轧搪瓷用钢，其特征在于，其热轧态屈服强度为345～389MPa，经870～950℃温度区间内高温搪烧后，屈服强度为402～439MPa。The hot-rolled steel for enameling according to claim 1 or 2, characterized in that the yield strength of the hot-rolled state is 345-389 MPa, and the yield strength is 402-439 MPa after high-temperature enamelling in the temperature range of 870-950°C.
  9. 一种搪瓷钢，其特征在于，所述搪瓷钢包括基材和基材一个或两个表面上的搪瓷层，其中，该基材为权利要求1-8中任一项所述的热轧搪瓷用钢。An enamelled steel, characterized in that the enamelled steel comprises a substrate and an enamel layer on one or both surfaces of the substrate, wherein the substrate is the hot-rolled enamel according to any one of claims 1-8 Use steel.
  10. 如权利要求9所述的搪瓷钢，其特征在于，所述搪瓷钢的屈服强度为400～450MPa，抗拉强度为610～660MPa，延伸率A 50≥18％；和/或，所述基材的显微组织为铁素体+贝氏体组织；优选地，以面积比计，贝氏体的比例为 10～40％。 The enamelled steel according to claim 9, characterized in that, the enamelled steel has a yield strength of 400-450 MPa, a tensile strength of 610-660 MPa, and an elongation A 50 ≥ 18%; and/or, the base material The microstructure is ferrite + bainite; preferably, in terms of area ratio, the proportion of bainite is 10-40%.
  11. 如权利要求1-8中任意一项所述的热轧搪瓷用钢的制造方法，其特征在于，包括步骤：The method for manufacturing hot-rolled enamelled steel according to any one of claims 1-8, comprising the steps of:
    (1)冶炼和铸造；(1) Smelting and casting;
    (2)加热；(2) heating;
    (3)热轧：控制粗轧温度大于850℃，精轧开轧温度为900～1050℃，精轧终轧温度为840～900℃；(3) Hot rolling: control the rough rolling temperature to be greater than 850°C, the finish rolling start temperature to be 900-1050°C, and the finish rolling finish temperature to be 840-900°C;
    (4)层流冷却：控制冷却速度为10～35℃/s；(4) Laminar cooling: Control the cooling rate to 10-35°C/s;
    (5)卷取。(5) coiling.
  12. 如权利要求9所述的制造方法，其特征在于，在步骤(2)中，加热温度为1150～1260℃。The manufacturing method according to claim 9, characterized in that, in step (2), the heating temperature is 1150-1260°C.
  13. 如权利要求9所述的制造方法，其特征在于，在所述步骤(5)中，控制卷取温度为550～680℃。The manufacturing method according to claim 9, characterized in that, in the step (5), the coiling temperature is controlled to be 550-680°C.
  14. 权利要求9或10所述的搪瓷钢的制造方法，其特征在于，所述方法包括采用权利要求11-13中任一项所述的方法制备得到所述热轧搪瓷用钢，以及将所述热轧搪瓷用钢用作基材进行搪烧的步骤。The manufacturing method of enamelled steel according to claim 9 or 10, characterized in that the method comprises preparing the hot-rolled enamelled steel by the method according to any one of claims 11-13, and making the Hot-rolled steel for enameling is used as the base material for the enamelling step.
  15. 如权利要求14所述的制造方法，其特征在于，所述搪烧步骤中，在870～950℃搪烧5～15分钟；任选地，搪烧步骤前还包括对该热轧搪瓷用钢进行抛丸处理；优选地，采用一次涂搪一次烧成工艺或两次涂搪两次烧成工艺进行搪烧。The manufacturing method according to claim 14, characterized in that, in the sintering step, sintering at 870-950°C for 5-15 minutes; Shot blasting is carried out; preferably, enamelling is carried out by one-time enamelling and one-firing process or two-time enamelling and two-firing process.
PCT/CN2022/132223 2021-11-16 2022-11-16 Hot-rolled steel for enameling having enameling and firing strengthening property, and manufacturing method therefor WO2023088294A1 (en)

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