CN108220799B - Cold-rolled low-carbon enamel steel for household appliances - Google Patents

Cold-rolled low-carbon enamel steel for household appliances Download PDF

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CN108220799B
CN108220799B CN201711440368.XA CN201711440368A CN108220799B CN 108220799 B CN108220799 B CN 108220799B CN 201711440368 A CN201711440368 A CN 201711440368A CN 108220799 B CN108220799 B CN 108220799B
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steel
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CN108220799A (en
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杨跃标
邓深
樊雷
陈海
叶姜
刘崇林
袁勤攀
蒋才灵
张广川
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Liuzhou Iron and Steel Co Ltd
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Priority to CN202010284599.1A priority patent/CN111424215B/en
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    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/06Ferrous alloys, e.g. steel alloys containing aluminium
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0205Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0226Hot rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0221Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
    • C21D8/0236Cold rolling
    • CCHEMISTRY; METALLURGY
    • C21METALLURGY OF IRON
    • C21DMODIFYING 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
    • C21D8/00Modifying the physical properties by deformation combined with, or followed by, heat treatment
    • C21D8/02Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
    • C21D8/0247Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
    • C21D8/0273Final recrystallisation annealing
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C33/00Making ferrous alloys
    • C22C33/04Making ferrous alloys by melting
    • C22C33/06Making ferrous alloys by melting using master alloys
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/001Ferrous alloys, e.g. steel alloys containing N
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/02Ferrous alloys, e.g. steel alloys containing silicon
    • CCHEMISTRY; METALLURGY
    • C22METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
    • C22CALLOYS
    • C22C38/00Ferrous alloys, e.g. steel alloys
    • C22C38/04Ferrous alloys, e.g. steel alloys containing manganese

Abstract

The invention provides cold-rolled low-carbon enamel steel for household appliances. The cold-rolled low-carbon enamel steel for the household appliances comprises the following chemical components in percentage by weight: 0.03-0.08 Wt%, Si is less than or equal to 0.03Wt%, Mn: 0.25-0.60 Wt%, P is less than or equal to 0.020Wt%, S: 0.015-0.040 Wt%, Als (acid-melted aluminum): 0.015-0.040 Wt%, N: 0.0050-0.0120 Wt%, Ti less than or equal to 0.020Wt%, and Mn/S more than or equal to 15. The invention realizes the stable production of the product, and the product has excellent scale explosion resistance, adherence, high-temperature deformation resistance and formability.

Description

Cold-rolled low-carbon enamel steel for household appliances
Technical Field
The invention relates to the field of metallurgical steel rolling, in particular to cold-rolled low-carbon enamel steel for household appliances, such as water heaters, oven ovens and the like.
Background
The enamel product has the characteristics of corrosion resistance, abrasion resistance, high temperature resistance, long service life, beautiful appearance, easy cleaning, safety, no toxicity and the like, thereby being widely applied to various fields of household appliance production and the like. An enamel product is generally formed by stamping a steel sheet to form a blank, and then enameling and sintering the blank to form an enamel on the surface of the blank, so that the enamel product is required to have good stamping performance, fishscaling resistance, adhesion performance and high-temperature deformation resistance.
Most of enamel products in the field of traditional household appliance production, such as water heaters, oven ovens and the like, are produced by taking common steel plates as raw materials, although the common steel plates can ensure the stamping performance and the high-temperature deformation resistance, the defects of scale explosion, poor adhesion and the like are often generated in the enamel process, and the defects seriously restrict the quality of the enamel products. With the continuous expansion of the application range of enamel products, the requirement on the enamel quality is higher and higher, the high requirement on the enamel quality cannot be met by a common steel plate, and only special steel for enamel with excellent enamel coating performance can completely meet the development requirement of the enamel industry.
The common production process of cold-rolled enamel steel for home and abroad appliances at present comprises the following steps: 1) a titanium (Ti) microalloying process mainly utilizes second phase precipitates such as TiN, TiS, Ti4C2S2 and Ti (C, N) in steel as hydrogen traps to improve the fish scaling resistance of a steel plate. The main problems of the process are that the precipitated phase in the steel is complex, the process control window of the type and the size of the precipitated phase of Ti in the hot rolling and cold rolling annealing processes is strict, and the process control accuracy requirement on a production site is high; in addition, the Ti microalloying process is mainly suitable for ultra-low carbon steel, and the enamel adherence and the scale explosion performance of the steel are deteriorated to a certain extent by adopting the process for common cold-rolled low carbon steel. 2) The Re microalloying process is mainly characterized by adding a certain amount of rare earth elements into steel to obtain fine and dispersedly distributed Re second-phase precipitates in the steel and simultaneously denature inclusions such as Al2O3 in the steel to be fine and uniform so as to improve the fishscaling resistance of a steel plate. The main problems of the steel technology are that the Re element is too active and has large atom density, the alloying technology and the stable control of the element content are difficult, and large-scale modified inclusion has large density and is difficult to float upwards. 3) The high oxygen (O) process mainly controls the O content in steel in a higher range, generally more than 100ppm, and improves the fish scaling resistance of a steel plate by using oxides in the steel as hydrogen traps. The main problems of the steel technology are that the oxygen content control technology in the smelting process is difficult, the continuous casting production technology is also difficult to control, and the probability of the existence of air hole defects on the surface of the steel plate is high. 4) The boron (B) process is mainly characterized by adding a certain trace amount of B element into steel, and using boron compounds such as BN in the steel as hydrogen traps to improve the fish scaling resistance of the steel plate. The main problem of the steel technology is that the B microalloyed continuous casting billet is easy to generate a surface transverse crack defect which can be inherited to the surface of a subsequent steel plate to influence the enameling performance.
In summary, the following problems exist in the prior art: the cold-rolled enamel steel for household appliances has high production cost and complex process.
Disclosure of Invention
The invention provides cold-rolled low-carbon enamel steel for household appliances, which solves the problems of high production cost and complex process of the cold-rolled enamel steel for the household appliances.
Therefore, the invention provides cold-rolled low-carbon enamel steel for household appliances, which comprises the following chemical components in percentage by weight: 0.03-0.08 Wt%, Si is less than or equal to 0.03Wt%, Mn: 0.25-0.60 Wt%, P is less than or equal to 0.020Wt%, S: 0.015-0.040 Wt%, Als (acid-melted aluminum): 0.015-0.040 Wt%, N: 0.0050-0.0120 Wt% and the balance of Fe and inevitable trace elements.
Furthermore, in the chemical components of the cold-rolled low-carbon enamel steel for household appliances, the weight percentage of Ti is less than or equal to 0.020Wt%, and the Mn/S is greater than or equal to 15.
Further, the cold-rolled low-carbon enamel steel for the household appliances comprises the following chemical components in percentage by weight: 0.06 Wt%, Si: 0.02 Wt%, Mn: 0.30 Wt%, P: 0.013 Wt%, S: 0.018 Wt%, Als: 0.029 Wt%, N: 0.0061 Wt%, Ti less than or equal to 0.020Wt%, Mn/S more than or equal to 15, and the balance of Fe and inevitable trace elements.
Further, the cold-rolled low-carbon enamel steel for the household appliances comprises the following chemical components in percentage by weight: 0.05 Wt%, Si: 0.02 Wt%, Mn: 0.53 Wt%, P: 0.010 Wt%, S: 0.033 Wt%, Als: 0.018 Wt%, N: 0.0114 Wt%, Ti less than or equal to 0.020Wt%, Mn/S more than or equal to 15, and the balance of Fe and inevitable trace elements.
Further, the cold-rolled low-carbon enamel steel for the household appliances comprises the following chemical components in percentage by weight: 0.05 Wt%, Si: 0.02 Wt%, Mn: 0.53 Wt%, P: 0.010 Wt%, S: 0.033 Wt%, Als: 0.018 Wt%, N: 0.0114 Wt%, Ti less than or equal to 0.020Wt%, Mn/S more than or equal to 15, and the balance of Fe and inevitable trace elements.
The cold-rolled low-carbon enamel steel for producing household appliances adopts the following manufacturing method, and the manufacturing method comprises the following process steps in sequence: smelting blast furnace molten iron, desulfurizing pretreatment of molten iron, smelting converter molten steel, refining molten steel, continuously casting plate blanks, continuously rolling hot, pickling and continuously rolling cold, annealing and leveling;
wherein, in the converter molten steel smelting step: controlling S to be less than or equal to 0.040Wt% in molten iron; the whole process of bottom blowing nitrogen is adopted in the smelting process;
the molten steel refining treatment step comprises: and (2) carrying out deoxidation and alloying processes of Al, Mn, N and S, wherein the N microalloying is carried out by adding ferro-manganese nitride alloy, the S alloying process is carried out by adding ferro-sulphur or feeding a sulphur wire, the molten steel is subjected to Ca treatment, the Ca treatment is controlled according to the condition that [ Ca ]/[ Als ] is0.10-0.14, the soft argon blowing is carried out on the ladle for 8-15 min after the Ca treatment is finished, and the molten steel sedation time of the ladle between the soft argon blowing end and the continuous casting ladle casting is controlled to be 15-30 min.
Further, in the slab continuous casting step: the automatic slag discharging detection and control of the ladle is carried out, the superheat degree of pouring of the tundish is 10-30 ℃, the alkali covering agent is used in the tundish, the low-carbon steel covering slag is used, the casting blank drawing speed is 1.20-1.60 m/min, the liquid level fluctuation of the crystallizer is automatically controlled, and the fluctuation range is controlled to be +/-3 mm.
Further, in the hot continuous rolling step: controlling the heating temperature of the casting blank to be 1100-1250 ℃; controlling the finishing temperature to be 850-950 ℃; the coiling temperature is 600-700 ℃.
Further, in the step of pickling and cold continuous rolling: and the cold rolling reduction rate is 65-80%.
Furthermore, in the annealing step, cover type annealing or continuous annealing is adopted;
wherein, cover annealing: purging with full hydrogen; the annealing heat preservation temperature is 660-730 ℃, the annealing heat preservation time is 11-14 h, the cooling rate is controlled to be less than or equal to 20 ℃/h, the cooling is controlled to be 380 ℃, and the tapping temperature is less than or equal to 80 ℃;
and (3) continuous annealing: the temperature of the soaking section is 780-870 ℃, the heat preservation time is 50-170 s, the slow cooling end point temperature is 640-690 ℃, the fast cooling end point temperature is 320-450 ℃, the temperature of the overaging section is 360-450 ℃, and the time is 200-350 s.
Further, in the leveling step: the leveling elongation is controlled according to the thickness of different strip steels and is 0.7-1.6%.
The invention realizes the stable production of the product by reasonable component design and process control, without adding Ti, Re and B and controlling the high O content in steel, and only by controlling the proper contents of C, Mn, Als, S and N and by optimized smelting, continuous casting, hot rolling, cold rolling and annealing processes, and the product has excellent fish scaling resistance, adherence, high-temperature deformation resistance and formability. The yield strength of the cold-rolled low-carbon enamel steel is Rp0.2 and is 170-260 MPa, the tensile strength Rm is 280-370 MPa, the elongation A80mm is more than or equal to 34%, n90 is more than or equal to 0.16, and r90 is more than or equal to 1.4. The invention meets the requirements of double-sided enameling and two-time enameling processes in household appliance production, and is also suitable for wet and dry enameling processes.
Detailed Description
The present invention will now be described in order to more clearly understand the technical features, objects, and effects of the present invention.
The invention relates to cold-rolled low-carbon enamel steel for household appliances, which comprises the following chemical components in percentage by weight: 0.03-0.08 Wt%, Si is less than or equal to 0.03Wt%, Mn: 0.25-0.60 Wt%, P is less than or equal to 0.020Wt%, S: 0.015-0.040 Wt%, Als: 0.015-0.040 Wt%, N: 0.0050-0.0120 Wt%, Ti less than or equal to 0.020Wt%, Mn/S more than or equal to 15, and the balance of Fe and inevitable trace elements. The invention controls the chemical components as follows:
c of the present invention: 0.03% -0.08%, C in the steel can promote the precipitation of cementite, pearlite and other carbides as hydrogen traps to improve the anti-scaling performance of the steel; while C is one of the most effective strengthening elements in steel, it increases the strength of steel but also decreases the plasticity of steel, so the C content is generally less than 0.10 Wt%. For the cold-rolled enamel steel, the content of C is increased as much as possible on the premise of ensuring no problem of forming performance in order to ensure the scale explosion resistance and the high-temperature enamel firing strength.
According to the invention, Si is less than or equal to 0.03%, Si is a harmful element in the enamel steel, the enamel performance is damaged due to the high Si content, and oxide inclusions with poor ductility are formed to reduce the plasticity of the steel, so that the lower the Si content is, the better the control is.
Mn of the present invention: 0.25% -0.60%, S: 0.015 to 0.040 percent. Mn can play a role in refining grains in steel, and meanwhile Mn reacts with S to generate MnS plastic inclusions to play a role in hydrogen traps to improve the anti-fishscaling performance. However, the Fe element in the steel is easy to produce FeS with low melting point due to the excessively high S content, so that the problem of edge surface defects of the steel plate is caused, and therefore, the Mn/S in the steel is required to be more than or equal to 15. According to the invention, a certain amount of MnS inclusions are generated in the steel by improving the Mn content and the S content in the steel, and the purpose of improving the anti-fishscale performance is achieved by refining grains to a certain degree.
Als (acid-fusible aluminum) of the present invention: 0.015 to 0.040%, N: 0.0050-0.0150%. Al can play a role in refining grains in steel, and Al generated by the reaction of Al with O (oxygen) and N2O3And AlN can improve the fishscaling resistance as a hydrogen trap in the steel, but Al2O3 inclusions in the steel deteriorate the plasticity of the steel too much. The invention achieves the purpose of improving the anti-fishscaling performance by improving the Als content and the N content in the steel, generating a certain amount of AlN in the steel and refining grains to a certain degree.
P is less than or equal to 0.020%, P is a harmful element, and is easy to segregate on a crystal boundary in steel, bubbles and black spots are easy to generate during enameling burning, the surface quality of enamel is influenced, and therefore the lower the control is, the better the control is.
The manufacturing method of the invention comprises the following process routes: blast furnace molten iron smelting → molten iron desulphurization pretreatment → converter molten steel smelting → LF molten steel refining treatment (or RH molten steel refining treatment) → slab continuous casting → hot continuous rolling → acid pickling cold continuous rolling → bell-type furnace annealing (or continuous annealing) → leveling → inspection, packaging and warehousing; wherein, the process characteristics of each stage are as follows:
smelting molten steel in a converter: controlling S to be less than or equal to 0.040Wt% in molten iron; the whole process of bottom blowing nitrogen is adopted in the smelting process;
LF molten steel refining treatment (or RH molten steel refining treatment): and (2) carrying out deoxidation and alloying processes such as Al, Mn, N, S and the like, wherein the N microalloying is carried out by adding nitride alloys such as ferromanganese nitride and the like, the S alloying process is carried out by adding ferrosulfur or feeding a sulfur wire, the molten steel is subjected to Ca treatment, the Ca treatment is controlled according to the condition that [ Ca ]/[ Als ] is0.10-0.14, the soft argon blowing is carried out on the ladle for 8-15 min after the Ca treatment is finished, and the steel ladle molten steel calming time between the soft argon blowing end and the continuous casting ladle casting is controlled to be 15-30 min.
Slab continuous casting: the automatic slag discharging detection control of the ladle is required, the superheat degree of pouring of the tundish is 10-30 ℃, the alkali covering agent is used in the tundish, the low-carbon steel covering slag is used, the casting blank drawing speed is 1.20-1.60 m/min, the liquid level fluctuation of the crystallizer is automatically controlled, and the fluctuation range is controlled to be +/-3 mm.
Hot continuous rolling: controlling the heating temperature of the casting blank to be 1100-1250 ℃, so that the steel blank is fully austenitized and most alloying elements are fully dissolved, and preparing for obtaining a uniformly refined structure; the final rolling temperature is controlled to be 850-950 ℃, enough deformation in an austenite low-temperature region is ensured, and mixed crystals are prevented from being obtained by deformation in a two-phase region, so that a hot rolled plate obtains a uniformly refined structure; the coiling temperature is 600-700 ℃, cementite of the steel is fully precipitated, and meanwhile, the structure refinement is guaranteed as much as possible.
Acid pickling and cold continuous rolling: the cold rolling reduction rate is 65-80%, and the large cold deformation degree can enable the steel plate to obtain fine grain size and smaller dispersed cementite in the subsequent annealing process, and simultaneously improve the dislocation density, thereby improving the number of hydrogen traps and the fish scaling resistance.
Annealing process: the proper annealing process parameters can ensure that the steel plate is fully recrystallized, crystal grains are equiaxial, and cementite is dispersed and precipitated, so that the steel plate has good mechanical property and anti-fishscaling property. The annealing process is mainly divided into hood annealing and continuous annealing. 1) Cover annealing: the cleaning of the atmosphere in the furnace and the cleaning of the surface of the strip steel are realized by adopting full hydrogen purging; the annealing heat preservation temperature is 660-730 ℃, the annealing heat preservation time is 11-14 h, the cooling rate is controlled to be less than or equal to 20 ℃/h, the cooling is controlled to be 380 ℃, and the tapping temperature is controlled to be less than or equal to 80 ℃. 2) And (3) continuous annealing: the temperature of the soaking section is 780-870 ℃, the heat preservation time is 50-170 s, the slow cooling end point temperature is 640-690 ℃, the fast cooling end point temperature is 320-450 ℃, the temperature of the overaging section is 360-450 ℃, and the time is 200-350 s.
The flattening process comprises the following steps: the flat elongation is controlled according to the thickness of different strip steels and is 0.7-1.6%, and the flat elongation is mainly used for eliminating a tensile yield platform of the strip steels after recrystallization annealing, eliminating wave shapes and improving the surface quality.
The yield strength of the cold-rolled low-carbon enamel steel is Rp0.2 and is 170-260 MPa, the tensile strength Rm is 280-370 MPa, the elongation A80mm is more than or equal to 34%, n90 is more than or equal to 0.16, and r90 is more than or equal to 1.4. The invention realizes the stable production of the product by reasonable component design and process control, without adding Ti, Re and B and controlling the high O content in steel, and only by controlling the proper contents of C, Mn, Als, S and N and by optimized smelting, continuous casting, hot rolling, cold rolling and annealing processes, and the product has excellent fish scaling resistance, adherence, high-temperature deformation resistance and formability. The invention meets the requirements of double-sided enameling and two-time enameling processes in household appliance production, and is also suitable for wet and dry enameling processes.
The production method of the cold-rolled low-carbon enamel steel for household appliances adopts the following component proportion and specific process. Wherein, Table 1 shows the compositions (in weight%) of the steels of the respective examples. Table 2 is the process parameters corresponding to the examples described in table 1. Table 3 shows the overall properties corresponding to the examples of Table 1.
TABLE 1 product chemistry (wt%)
Examples of the invention C Si Mn P S Als N
Example 1 0.06 0.02 0.30 0.013 0.018 0.029 0.0061
Example 2 0.07 0.02 0.41 0.014 0.024 0.021 0.0082
Example 3 0.05 0.03 0.53 0.010 0.033 0.018 0.0114
Example 4 0.08 0.03 0.32 0.009 0.017 0.020 0.0055
Example 5 0.06 0.01 0.43 0.011 0.025 0.034 0.0073
Example 6 0.04 0.02 0.52 0.015 0.034 0.026 0.0128
TABLE 2 specific Process parameters for the examples
Figure GDA0001604631840000061
Table 3 the cold rolled low carbon enamel obtained in each example has the combination of properties rp0.2 meaning yield strength, Rm tensile strength, a80mm elongation, n90 strain hardening index and r90 plastic strain ratio.
Figure GDA0001604631840000071
The above description is only an exemplary embodiment of the present invention, and is not intended to limit the scope of the present invention. In order that the components of the present invention may be combined without conflict, it is intended that all equivalent changes and modifications made by those skilled in the art without departing from the spirit and principles of the present invention shall fall within the protection scope of the present invention.

Claims (3)

1. The cold-rolled low-carbon enamel steel for the household appliances is characterized by comprising the following chemical components in percentage by weight: 0.08Wt%, Si: 0.03Wt%, Mn: 0.32Wt%, P: 0.009Wt%, S: 0.017Wt%, Als: 0.020Wt%, N: 0.0055 Wt%, the balance Fe and inevitable trace elements;
the cold-rolled low-carbon enamel steel for the household appliances adopts the following process steps which are carried out in sequence: smelting blast furnace molten iron, desulfurizing pretreatment of molten iron, smelting converter molten steel, refining molten steel, continuously casting plate blanks, continuously rolling hot, pickling and continuously rolling cold, annealing and leveling;
wherein, in the converter molten steel smelting step: controlling S to be less than or equal to 0.040Wt% in molten iron; the whole process of bottom blowing nitrogen is adopted in the smelting process;
the molten steel refining treatment step comprises: carrying out deoxidation and an alloying process of Al, Mn, N and S, wherein the N microalloying is carried out by adding ferro-manganese nitride alloy, the S alloying process is carried out by adding ferro-sulphur or feeding a sulphur wire, the molten steel is subjected to Ca treatment, the control is carried out according to the condition that [ Ca ]/[ Als ] = 0.10-0.14, the soft argon blowing is carried out on the ladle after the Ca treatment is finished for 8-15 min, and the steel ladle molten steel calming time between the soft argon blowing end and the continuous casting ladle casting is controlled to be 15-30 min;
the cold-rolled low-carbon enamel steel has the yield strength Rp0.2 of 211 MPa, the tensile strength Rm of 319 MPa, the elongation A80mm of 44 percent, the strain hardening index n90 of 0.22 and the plastic strain ratio r90 of 2.2, and has the advantages of non-scale explosion and good adherence of the scale explosion resistance of dry-process enameling, wet-process enameling, double-surface enameling and twice enameling.
2. The cold-rolled low-carbon enamel steel for household appliances according to claim 1, wherein the cold-rolled low-carbon enamel steel for household appliances comprises the chemical components with the weight percentage of Mn/S being more than or equal to 15 and Ti being less than or equal to 0.020 Wt%.
3. The cold-rolled low-carbon enamel steel for home appliances claimed in claim 1, wherein in the annealing step, hood annealing or continuous annealing is adopted;
wherein, cover annealing: purging with full hydrogen; the annealing heat preservation temperature is 660-730 ℃, the annealing heat preservation time is 11-14 h, the cooling rate is controlled to be less than or equal to 20 ℃/h, the cooling is controlled to be 380 ℃, and the tapping temperature is less than or equal to 80 ℃;
and (3) continuous annealing: the temperature of the soaking section is 780-870 ℃, the heat preservation time is 50-170 s, the slow cooling end point temperature is 640-690 ℃, the fast cooling end point temperature is 320-450 ℃, the temperature of the overaging section is 360-450 ℃, and the time is 200-350 s.
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