KR20240017008A - Hot rolled pickled enameled steel with excellent deep drawing properties and method for manufacturing the same - Google Patents

Abstract

Provides hot rolled pickled enamel steel with excellent deep drawing properties and a production method thereof. The chemical components of hot rolled pickled enamel steel with excellent deep drawing properties include C, N, S, Al, Mn, Si, P, Ti and the rest. Fe and inevitable impurities; Here, the weight percentages of C, N, S, Al and Ti are C: 0.001% to 0.006%, N≤0.004%, S≤0.0080%, Als: 0.015% to 0.040%, 4[C]+3.42[N] +3[S]≤[Ti]≤0.065%; The weight percentages of Si, Mn and P are Mn: 1.0% to 1.5%, Si: 0.001% to 0.03% and P≤0.015%, or Si: 0.4% to 0.6%, Mn: 0.15% to 0.3% and P≤ 0.015%, or Si: 0.001% to 0.03%, Mn: 0.15% to 0.3% and P: 0.035% to 0.055%. The yield strength of the enamel steel of the present invention is 210 MPa to 245 MPa, the tensile strength is ≥320 MPa, the elongation is ≥46%, the r value is ≥1.3, the n value is ≥0.3, and the TH value is ≥7.0. , It has excellent formability, especially excellent deep drawing properties, and relatively high tensile strength and fish scaling resistance.

Description

Hot rolled pickled enameled steel with excellent deep drawing properties and method for manufacturing the same

The present invention relates to the field of enamel steel production technology, and more specifically, to hot-rolled pickled enamel steel with excellent deep drawing properties and a method for producing the same.

Enamel is a type of composite material that is firmly bonded to metal by melting and solidifying an inorganic glassy material in a metal matrix. Enamel products not only have the inherent strength, toughness, and processability of metal materials, but also have the corrosion resistance, aging resistance, wear resistance, high temperature resistance, non-toxicity, and decorative properties of ceramic materials, so they have the advantages of both metal materials and ceramic materials. Enameled products using steel plates as metal substrates play a very important role in the national economy and are widely used in industries such as light industry, home appliances, metallurgy, chemical industry, and architecture.

There are several types of enameled steel sheets, and according to the production process, they are divided into hot-rolled pickling sheets, cold-rolled sheets and clad laminates, etc. Among them, hot-rolled sheets are increasingly used more and more widely due to their good economic efficiency, for example, water heater liners. Used for manufacturing, its thickness is generally 1.5 mm to 2.5 mm, and annual demand exceeds 500,000 tons.

Currently, water heater liners are commonly produced by rolling and welding, which results in low production efficiency and low yield. In order to improve production efficiency and yield, the water heater industry has begun to produce water heater liners by deep drawing process, which requires improving the tensile performance of enameled steel products.

When the process conditions are relatively stable, the deep drawing properties of hot rolled enameled steel are mainly related to the following several performance indicators:

(1) Plastic anisotropy r value: The higher the plastic anisotropy r value, the more advantageous it is for deep drawing molding.

(2) Hardening index n value: A large plate n value means that the material has excellent plastic deformation distribution uniformity, concentrated deformation does not easily occur, and plastic rupture is relatively small.

(3) Yield ratio: Generally, the lower the yield ratio, the more advantageous it is for deep drawing of the compressor housing.

(4) Elongation: High elongation is advantageous for unidirectional deep drawing deformation of parts, and generally, high elongation is an important factor in ensuring smooth forming of parts.

Chinese Patent No. CN201310547968.1 discloses "Hot-rolled thin-plate enameled steel with yield strength of 245 MPa class and manufacturing method thereof", the thickness of the enameled steel produced is 1.0 mm to 2.5 mm, and the chemical composition is C: 0.001% to 0.001%. 0.010%, Si≤0.05%, Mn: 0.10% to 0.50%, P≤0.020%, S≤0.010%, Ti: 0.04% to 0.10%, Als: 0.02% to 0.08%, N≤0.008%, yield strength The manufacturing process of hot-rolled thin enameled steel with a capacity of 245 MPa includes a heating temperature of 1230°C to 1270°C, a starting rolling temperature of 1100°C to 1150°C, a final rolling temperature of 860°C to 930°C, and a coiling temperature of 600°C. to 700°C. The product yield strength is 245 MPa to 330 MPa, the tensile strength is ≥300 MPa, and the elongation is 37% to 42%.

Chinese Patent No. CN2013105483 No. 10.2 discloses “Hot-rolled thin-plate enameled steel with yield strength of 330 MPa class and manufacturing method thereof”, the thickness of the produced enameled steel is 1.0 mm to 2.5 mm, and the chemical composition is C: 0.02% to 0.07. %, Si≤0.05%, Mn: 0.10% to 0.50%, P≤0.020%, S≤0.010%, Ti: 0.04% to 0.10%, Als: 0.02% to 0.08%, N≤0.008%, and the remainder is Fe. and unavoidable impurities, and Ti/C=1.0 to 1.5. In the manufacturing process of hot-rolled thin-plate enameled steel with a yield strength of 330 MPa, the heating temperature is 1200°C to 1250°C, the final rolling temperature is 860°C to 930°C, and the coiling temperature is 650°C to 700°C. The product yield strength is 330 MPa to 450 MPa, the tensile strength is ≥400 MPa, and the elongation is 38% to 41%.

Chinese Patent No. CN201510280022.2 discloses "Method for producing enameled steel with excellent fishscaling resistance and steel sheet thereof", and the chemical components in the steel are C: 0.04% to 0.10%, Si≤0.10% based on weight percentage. , Mn: 0.30% to 1.0%, Ti: 0.03% to 0.10%, P≤0.015%, S: 0.010% to 0.045%, N: 0.003% to 0.009%, Als: 0.005% to 0.050%, Cr: 0.05% to 0.25% and Ti/C: 0.5 to 1.2. Continuous casting slab heating temperature is 1180℃ to 1250℃, finish rolling start temperature is 980℃ to 1100℃, final rolling temperature is 880℃ to 950℃, adopt shear cooling method after rolling, ≥30℃ within 6 seconds It is rapidly cooled to 630 ℃ to 700 ℃ at a cooling rate of ℃/s and wound, the product yield strength is 390 MPa to 500 MPa, tensile strength is 476 MPa to 598 MPa, and elongation is 26% to 38%.

Chinese Patent No. 201510398485.9 discloses “Thin enameled steel for subway decoration and its manufacturing method”, the thickness of the enameled steel is 1.0 mm to 2.0 mm, and the weight percentage of its chemical composition is C: 0.001% to 0.003%, Si≤0.10%. , Mn: 0.05% to 0.10%, P≤0.010%, S≤0.005%, Als: 0.01% to 0.02%, Ti: 0.20% to 0.25%, N: 0.010% to 0.020%. The tapping temperature is 1100°C to 1150°C, the final rolling temperature is 800°C to 850°C, and the coiling temperature is 700°C to 750°C. The product yield strength is ≧460 MPa, the tensile strength is ≧550 MPa, the elongation is 38% to 42%, the r value is 1 to 1.5, and the n value is 0.1 to 0.3.

Chinese Patent No. 201810663362.7 discloses “Low-cost high-oxygen enamel steel produced by CSP process and method for manufacturing the same,” and the chemical composition weight percentage of low-cost high-oxygen enamel steel produced by CSP process is C≤0.01%, Mn: 0.10% to 1.00%, O≤0.0500%, Si≤0.01%, P≤0.020%, S≤0.030%, Als≤0.01%, and the remainder is Fe and inevitable impurities. The above patent increases the oxygen content of steel, forming a greater number of oxide inclusions, which act as traps for hydrogen storage, improving the steel sheet's fishscaling resistance. The manufacturing process of low-cost high-oxygen enamel steel produced by the CSP process has a tapping temperature of 1160°C to 1200°C, a final rolling temperature of 860°C to 900°C, a coiling temperature of 600°C to 640°C, and a yield strength of 151 MPa. to 214 MPa, the tensile strength is 256 MPa to 282 MPa, and the elongation is 35.2% to 45.4%.

Chinese Patent No. CN201910697103.0 discloses “260 MPa grade hot rolled pickled enamel steel and method for manufacturing the same”, and the chemical composition weight percentage of 260 MPa grade hot rolled pickled enamel steel is C: 0.030% to 0.060%, Si ≤0.030%, Mn: 0.30% to 0.60%, P≤0.020%, S≤0.010%, Als≤0.060%, B: 0.0015% to 0.0040%, N: 0.0040% to 0.0100%. The method for manufacturing 260 MPa hot rolled pickled enamel steel is to control the steel sheet heating temperature before rolling to 1132°C to 1212°C, control the final rolling temperature to 881°C to 890°C, and coil the coiling temperature to 687°C to 696°C. Controlled, the free acid concentration of the pickling solution is 105 g/L to 119 g/L, and the acid solution temperature is 71.4°C to 74°C. The product yield strength is ≧260 MPa, the tensile strength is ≧360 MPa, and the elongation is 33% to 34%.

Chinese Patent No. CN202010986947. , P≤0.030%, S≤0.015%, Ti: 0.01% to 0.08%, Al: 0.01% to 0.07%, N≤0.010%, 4≤Ti/N≤10, Ca: 0.0010% to 0.0040%, Ca/ S≤1.25. The method for manufacturing hot rolled enamel steel for deep processing includes a heating temperature of 1150°C to 1190°C, a final rolling temperature of 800°C to 900°C, a coiling temperature of 710°C to 760°C, and a hot rolling rough rolling cumulative strain of 70%. Controlled to the above, and the finish rolling cumulative strain is controlled to 70% or more. The temper rolling pressure is 700 to 900 tons, and the temper rolling elongation of the temper rolling is 7% to 12%. The yield strength of the product is 359 MPa to 402 MPa, the tensile strength is 447 MPa to 483 MPa, and the elongation is 30% to 41%.

Chinese Patent No. CN202010986956.9 discloses “Enameled steel and its manufacturing method and application,” and the component mass percentages of the enamel steel are C: 0.01% to 0.14%, Si≤0.10%, Mn: 0.20% to 1.6%, P ≤0.040%, S≤0.040%, Ti: 0.01% to 0.12%, Al: 0.01% to 0.07%, N≤0.010%, Mn/S≥30. In the method of manufacturing enameled steel, the heating temperature is 1200°C to 1350°C, the final rolling temperature is 810°C to 980°C, the coiling temperature is 500°C to 700°C, and the rough rolling cumulative strain rate of hot rolling is controlled to 70% or more. The final rolling cumulative strain of hot rolling is controlled to be more than 70%, the pressure of temper rolling is 450 to 650 tons, the temper rolling elongation is ≤6%, and during the shot blasting pickling process, the rotation of the shot blasting machine The speed is 1650 rpm to 1850 rpm, the particle size of the shot blasting is 0.18 mm to 0.85 mm, the hardness of the shot blasting is 40 HRC to 52 HRC, and the concentration of the pickling liquid is 5% to 20%. The product yield strength is ≥410 MPa, the tensile strength is 490 MPa, and the elongation is 25% to 43.5%.

In summary, the conventionally disclosed enameled steel has a relatively high yield strength, relatively low elongation, poor deep drawing properties, and is prone to quality problems such as galling and cracking during the deep drawing forming process. Therefore, the development of hot-rolled enamel steel with excellent deep drawing properties is of great significance in promoting the advancement of the water heater liner manufacturing industry and the green transition of the home appliance industry.

The purpose of the present invention is to provide a hot-rolled pickled enamel steel with excellent deep drawing properties and a method for manufacturing the same. The yield strength of the hot-rolled pickled enamel steel is 210 MPa to 245 MPa, and the tensile strength is ≥320 MPa. , elongation is ≥46%, n value is ≥0.3, r value is ≥1.3, TH value is ≥7.0, excellent formability, especially good deep drawing formability, strength and fishscaling resistance. Excellent, meeting the production needs of water heater liners.

In order to achieve the above object, the technical solution adopted in the present invention is as follows.

Hot rolled pickled enameled steel with excellent deep drawing properties has chemical composition weight percentages of C: 0.001% to 0.006%, N≤0.004%, S≤0.0080%, Als: 0.015% to 0.040%; When reinforced with Mn, Mn: 1.0% to 1.5%, Si: 0.001% to 0.03%, P≤0.015%; When strengthened with Si, Si: 0.4% to 0.6%, Mn: 0.15% to 0.3%, P≤0.015%; When reinforced with P, Si: 0.001% to 0.03%, Mn: 0.15% to 0.3%, P: 0.035% to 0.055%; It further contains Ti, 4[C]+3.42[N]+3[S]≤[Ti]≤0.065%, and the remainder is Fe and other inevitable impurities.

In some implementations, the Ti content is 0.025% to 0.065%.

In some embodiments, when strengthening with Mn, Mn: 1.0% to 1.5%, Si: 0.005% to 0.025%, P≤0.015%.

In some implementations, when reinforced with P, Si: 0.003% to 0.006%, Mn: 0.15% to 0.3%, P: 0.035% to 0.055%.

The microstructure of the hot-rolled pickled enamelled steel according to the present invention is a uniform polygonal ferrite grain with a {111} plane structure, and the grain size does not exceed grade 7.

The yield strength of the hot rolled pickled enamelled steel according to the present invention is 210 MPa to 245 MPa, the tensile strength is ≥320 MPa, the elongation is ≥46%, the r value is ≥1.3, the n value is ≥0.3, and TH The value is ≥7.0.

In some embodiments, the hot rolled pickled enameled steel according to the present invention has a yield strength of 210 MPa to 245 MPa, a tensile strength of 320 MPa to 450 MPa, an elongation of 46% to 52%, and an r value of 1.3 to 1.8. , the n value is 0.3 to 0.4, and the TH value is 7.0 to 8.5.

In some embodiments, no dissolved C and N interstitial atoms are present in the ferrite of the hot rolled pickled enamelled steel according to the present invention.

In some embodiments, the present invention provides a water heater liner, wherein the steel portion of the water heater liner is hot rolled pickled enameled steel with excellent deep drawing properties according to any embodiment of the present invention. In some embodiments, the water heater liner of the present invention is obtained by producing hot-rolled pickled enameled steel with excellent deep drawing properties according to any embodiment of the present invention by a deep drawing molding method.

The component design of the hot rolled pickled enameled steel according to the present invention is as follows.

C: Solved C can increase the yield strength and tensile strength of steel, but plasticity is lowered. At the same time, dissolved C does not help form {111} structure and reduces the r value of the product. Materials with relatively high ultimate deep drawing require low yield strength, high elongation, and high {111} structure strength, so the smaller the dissolved C, the better, but the lower the C content, the higher the refining cost required to lower the C content; The refining time also becomes longer. In order to balance mechanical performance and production cost, the C content of the present invention steel is controlled to 0.001% to 0.006%.

N: A strong solid solution strengthening element, which is not conducive to the formation of {111} structure. Production aging may affect the stamping quality of steel sheets, but if the N content is too low, production costs may increase, so consider comprehensively. Therefore, the N content in the steel of the present invention is controlled to 0.004% or less. In some implementations, the N content is 0.002% to 0.004%.

S: A harmful impurity element present in steel. S contained in steel is prone to forming segregation in steel, reducing the toughness and weldability of steel. S is easy to form calcined sulfides, dividing the steel sheet and improving steel sheet performance. Since it lowers the S content, the lower the S content, the better. Therefore, taking comprehensive consideration, the S content contained in the steel of the present invention is controlled to 0.008% or less.

Als: Al is a powerful deoxidizing agent, which reduces oxide inclusions in steel and makes steel pure. However, if the Al content is too high, grain refinement is likely to occur, which increases the yield strength and yield ratio. Therefore, considering comprehensively, the present invention In steel, Als is controlled to 0.015% to 0.040%.

Ti: Ti has a very strong affinity with C and N in steel, creating TiC and TiN to fix C and N interstitial atoms, reducing the dissolved C and N content in steel, forming {111} structure. It is advantageous to promote and improve the r value, and in addition, since the bonding force between Ti and S is greater than that between Ti and C, to ensure that Ti can remove the dissolved C atoms, TiC, TiN and Ti According to the mass percentage of ₄ C ₂ S ₂ , 4[C]+3.42[N]+3[S]≤[Ti]≤0.065% must be guaranteed. The formed TiC, TiN, and Ti ₄ C ₂ S ₂ can act as a trap for hydrogen storage and can improve the fish scaling resistance of the steel sheet.

Si, Mn, P: dissolved in ferrite and austenite, can improve strength, but at the same time reduce plasticity, so considering comprehensively, when strengthening with Mn, Mn content is 1.0% to 1.5%, Si≤0.03% Controlled with, for example 0.005% to 0.025%, P≤0.015%, for example 0.005% to 0.013%; When strengthening with Si, the Si content is controlled to 0.4% to 0.6%, the Mn content is controlled to 0.15% to 0.3%, and P≤0.015%, for example, 0.005 to 0.015%; When strengthening with P, the P content is controlled to 0.035% to 0.055%, Si≤0.03%, for example, ≤0.01%, and the Mn content is controlled to 0.15% to 0.3%.

The present invention adopts ultra-low C and microalloying (Ti addition) to ensure that C and N interstitial atoms dissolved in ferrite do not exist, and by lubricating rolling at low temperature and high pressure and high temperature winding, coarse and uniform size and {111 } By obtaining ferrite crystal grains with a planar structure, the deep drawing formability of the product is improved, and further, the tensile strength and elongation of the product are improved through solid solution strengthening of Si, Mn, and P. In addition, by controlling the component ratios of Ti, C, N, and S, coarse ferrite grains (TiC, TiN, and Ti ₄ C ₂ S ₂ ) are formed as traps for hydrogen storage, and the fish scaling resistance of the steel sheet is improved. , the product has a yield strength of 210 MPa to 245 MPa, tensile strength ≥320 MPa, elongation ≥46%, n value ≥0.3, r value ≥1.3, and TH value ≥7.0. The product has excellent formability, especially dip It has excellent drawing formability and at the same time has excellent tensile strength and fish scaling resistance.

The method for producing hot-rolled pickled enamel steel with excellent deep drawing properties according to the present invention includes the following steps.

1) Smelting, casting

Smelting, refining and continuous casting into slabs according to the above ingredients.

2) rolling

The final rolling temperature is 750°C to 800°C, the total reduction ratio at the rolling temperature ≤840°C is ≥60%, the lubricant liquid is added during the rolling process at the rolling temperature ≤840°C, and the oil-to-water ratio of the lubricant liquid is 1. % to 5%.

3) Cooling

The cooling rate is ≤6℃/s.

4) Winding

The coiling temperature is 720°C to 780°C.

5) Slow cooling

After winding the steel sheet, slow cooling is performed.

6) Pickling

After slow cooling, pickling is performed to remove scale from the surface of the steel sheet.

Preferably, in step 2), the final hot rolling temperature is 750°C to 780°C.

Preferably, in step 4), the coiling temperature is 730°C to 760°C.

Preferably, in step 5), the slow cooling is laminate slow cooling or insulating cover slow cooling, and hot coils are stacked around the laminate slow cooling.

In some implementations, in the rolling of step 2), the total reduction ratio at a rolling temperature ≤840°C is 60-85%.

In some implementations, the cooling rate in step 3) is from 1° C./s to 6° C./s.

The method for producing hot rolled pickled enameled steel according to the present invention is as follows.

Controlling the final rolling temperature to 750°C to 800°C during the rolling process can promote the formation of {111} structure, increase the r value of the product, and coarsen ferrite grains; When the final rolling temperature is higher than 800℃, the ferrite grains become finer, the {111} structure decreases, the product strength improves, and the elongation, n value, and r value all decrease; when the final rolling temperature is lower than 750℃, , the coiling temperature cannot be guaranteed to be ≥720°C, and if the deformed ferrite is not sufficiently recovered, the formability of the product may deteriorate.

The rolling process of the present invention adopts low-temperature lubricated rolling, the steel sheet undergoes ferrite rolling below 840°C, and the rolling temperature is controlled to control the total reduction rate to ≥60% in the ferrite phase region range, thereby promoting the formation of {111} structure. By promoting this, ferrite grains with a {111} plane structure are obtained and the r value of the product is improved. The purpose of performing lubrication rolling during the ferrite rolling process at a rolling temperature of ≤840℃ is to obtain a uniform {111} texture in the thickness direction, prevent {110} texture from being created on the surface, and improve the r value of the product. It's for the sake of it. During lubricated rolling, if the oil-to-water ratio of the lubricant is less than 1%, the coefficient of friction between the steel sheet and the rolling roll is relatively large, and it is easy to form a shear structure that is not helpful for forming, and the oil-to-water ratio exceeds 5%. Otherwise, it is easy to slip during the rolling process, rolling stability is reduced, and product yield is lowered. The oil used in the lubricating fluid of the present invention may be an oil commonly used for rolling in the art.

To promote sufficient recovery of ferrite, the cooling rate is controlled to ≤6°C/s.

High-temperature winding is adopted for winding, and the coiling temperature is 720℃ to 780℃, combined with slow cooling of the steel coil, so that the ferrite extending along the rolling direction is sufficiently recovered at the end of rolling, forming coarse and uniform ferrite crystal grains. Therefore, the required performance can be obtained. If the coiling temperature is less than 720°C, the deformed ferrite may not be sufficiently recovered, and the formability of the product may deteriorate. Under existing process equipment conditions, the temperature may be lowered during the cooling process. At the set final rolling temperature, 780°C is the highest temperature at which ferrite can be sufficiently recovered and coarse and uniform ferrite grains can be realized, so the coiling temperature is 780°C. If it is higher, it only increases the difficulty of implementation and has no significant effect on performance.

In some embodiments, the present invention provides a method for manufacturing a water heater liner, which method includes manufacturing and obtaining hot-rolled pickled enamel steel with excellent deep drawing properties by a method according to any embodiment of the present invention; and forming a water heater liner by deep drawing and forming hot rolled pickled enameled steel with excellent deep drawing properties. The water heater liner of the present invention can be manufactured by deep drawing methods known in the art.

The beneficial effects of the present invention are as follows:

1. The composition design of the present invention adopts ultra-low carbon and Ti microalloy chemical composition design, and through Si, Mn and P solid solution strengthening, realizes that C and N interstitial atoms dissolved in ferrite do not exist, and hot rolling acid The microstructure of the washed enamel steel is coarse, uniform in size, and polygonal ferrite grains with a {111} plane structure are obtained, thereby improving the deep drawing properties of the product. In addition, by controlling the component ratios of Ti, C, N, and S, irreversible hydrogen storage traps such as TiC, TiN, and Ti ₄ C ₂ S ₂ are formed, thereby reducing dissolved hydrogen in the matrix and reducing the risk of fishscaling. and improves the fishscaling resistance of the steel plate, so that the manufactured hot-rolled pickled enameled steel products have excellent formability. In particular, deep drawing formability is excellent, tensile strength is high, and fishscaling resistance is excellent.

2. Based on the component design of the present invention, in the rolling process, the rolling temperature is controlled so that the total reduction ratio is greater than 60% in the ferrite phase region range, and combined with lubricated rolling, ferrite grains with {111} plane structure are formed. is obtained, and subsequent slow cooling and high-temperature winding are performed to sufficiently recover the ferrite, forming coarse and uniform polygonal ferrite grains, and hot-rolled pickled enameled steel with a yield strength of 210 MPa to 245 MPa and a tensile strength ≥ Made with 320 MPa, elongation ≥46%, n value ≥ 0.3, and r value ≥ 1.3, the product not only has excellent deep drawing formability, but also has relatively high tensile strength, and in addition, TH value is ≥7.0, and fish scaling is possible. Resistance is excellent.

3. In the low-temperature ferrite rolling process of the present invention, lubricated rolling is adopted, and the oil-to-water ratio of the lubricating fluid is controlled to 1% to 5% to prevent the formation of a shear structure unfavorable to forming, and the ferrite phase has a constant reduction rate. accumulated to create a {111} plane structure conducive to stamping forming, and combined with subsequent slow cooling and high-temperature winding to form coarse and uniform ferrite grains, the required mechanical performance is achieved.

4. The hot-rolled pickled enameled steel obtained in the present invention has relatively excellent deep drawing properties, so it can be used to produce water heater liners by deep drawing forming method, which uses rolling and welding forming methods with low production efficiency and low yield. It can replace , and is of great significance in advancing the water heater liner manufacturing industry and promoting the green transition of the home appliance industry.

Hereinafter, the present invention will be described in more detail with reference to examples.

The specific components of the examples of the present invention are shown in Table 1, the process parameters of the examples are shown in Table 2, and the hot-rolled pickled enameled steel performance of each example is shown in Table 3.

After processing the sample to a standard size, the yield strength, tensile strength, n value, and r value were detected using a tensile test detector, referring to the EN10002 standard. The enamel fishscaling sensitivity TH value was detected using the hydrogen permeation test method, referring to the EN10209 standard.

The microstructure of the hot-rolled pickled enamel steel obtained in the present invention is coarse, uniform in size, polygonal ferrite grains with a {111} plane structure, its yield strength is 210 MPa to 245 MPa, and its tensile strength is ≥320 MPa. , elongation is ≥46%, n value is ≥0.3, r value is ≥1.3, TH value is ≥7.0, excellent formability, especially good deep drawing formability, tensile strength and fishscaling resistance This excellent, deep-drawing molding method can be used to produce water heater liners, which can replace the rolling and welding molding methods with low production efficiency and low yield, advancing the water heater liner manufacturing industry, and greening the home appliance industry. It is very important for promotion.

Claims (15)

A hot-rolled pickled enamelled steel with excellent deep drawing properties,
The chemical components of hot rolled pickled enamel steel with excellent deep drawing properties are C, N, S, Al, Mn, Si, P, Ti and the remaining Fe and inevitable impurities; Here, the weight percentages of C, N, S, Al and Ti are C: 0.001% to 0.006%, N≤0.004%, S≤0.0080%, Als: 0.015% to 0.040%, 4[C]+3.42[N] +3[S]≤[Ti]≤0.065%; The weight percentages of Si, Mn and P are Mn: 1.0% to 1.5%, Si: 0.001% to 0.03% and P≤0.015%, or Si: 0.4% to 0.6%, Mn: 0.15% to 0.3% and P≤ 0.015%, or Si: 0.001% to 0.03%, Mn: 0.15% to 0.3%, and P: 0.035% to 0.055%. A hot rolled pickled enamel steel with excellent deep drawing properties. According to paragraph 1,
A hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that the Ti content is 0.025% to 0.065%. According to paragraph 1,
A hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that the weight percentages of Si, Mn, and P satisfy Mn: 1.0% to 1.5%, Si: 0.005% to 0.025%, and P≤0.015%. According to paragraph 1,
Hot rolled pickled enamel with excellent deep drawing properties, characterized in that the weight percentages of Si, Mn, and P satisfy Si: 0.003% to 0.006%, Mn: 0.15% to 0.3%, and P: 0.035% to 0.055%. river. According to paragraph 1,
A hot rolled pickled enamel steel with excellent deep drawing properties, characterized in that the microstructure of the hot rolled pickled enamel steel is uniform polygonal ferrite crystal grains with a {111} plane structure, and the grain size does not exceed grade 7. According to any one of claims 1 to 5,
The yield strength of the hot rolled pickled enameled steel is 210 MPa to 245 MPa, the tensile strength is ≥320 MPa, the elongation is ≥46%, the r value is ≥1.3, the n value is ≥0.3, and the TH value is ≥ Hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that it is 7.0. According to clause 6,
The yield strength of the hot rolled pickled enamel steel is 210 MPa to 245 MPa, the tensile strength is 320 MPa to 450 MPa, the elongation is 46% to 52%, the r value is 1.3 to 1.8, and the n value is 0.3 to 0.4. and a TH value of 7.0 to 8.5. A hot-rolled pickled enamel steel with excellent deep drawing properties. A method for producing hot-rolled pickled enamel steel with excellent deep drawing properties according to any one of claims 1 to 7, comprising:
1) Smelting, casting
Smelting, refining and continuous casting into a slab according to the ingredients of any one of claims 1 to 4;
2) rolling
The final rolling temperature is 750°C to 800°C, the total reduction ratio at the rolling temperature ≤840°C is ≥60%, the lubricant fluid is added during the rolling process at the rolling temperature ≤840°C, and the oil-to-water ratio of the lubricant fluid is 1% to 5%;
3) Cooling
cooling rate ≤6°C/s;
4) Winding
The coiling temperature is 720°C to 780°C;
5) Slow cooling
performing slow cooling after winding the steel sheet; and
6) Pickling
A method for producing hot-rolled pickled enamel steel with excellent deep drawing properties, comprising the step of removing scale from the surface of the steel sheet by pickling after slow cooling. According to clause 8,
In step 2), a method for producing hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that the final rolling temperature is 750 ℃ to 780 ℃. According to clause 8,
In step 4), a method for producing hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that the coiling temperature is 730 ℃ to 760 ℃. According to clause 8,
In step 5), the slow cooling is lamination slow cooling or insulating cover slow cooling, and hot coils are stacked around the lamination slow cooling. A method for producing hot rolled pickled enamel steel with excellent deep drawing properties. According to clause 8,
A method for producing hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that in the rolling of step 2), the total reduction ratio at a rolling temperature ≤840°C is 60% to 85%. According to clause 8,
3) A method for producing hot-rolled pickled enamel steel with excellent deep drawing properties, characterized in that the cooling rate is 1°C/s to 6°C/s. As a water heater liner,
A water heater liner manufactured by producing the hot-rolled pickled enameled steel with excellent deep drawing properties according to any one of claims 1 to 7 by a deep drawing molding method. A method of manufacturing a water heater liner, comprising:
Manufacturing and obtaining the hot-rolled pickled enamel steel having excellent deep drawing properties by the method according to any one of claims 8 to 13; and forming the water heater liner by deep drawing and forming the hot rolled pickled enamel steel having excellent deep drawing properties.