Manufacturing method of composite steel plate with single surface uniformly attached with inorganic oxide

Abstract

According to the manufacturing method of the composite steel plate with the inorganic oxide evenly attached to the single face, attachment of steel and inorganic matter is achieved in the steel plate production process, conventional steel plate surface treatment is conducted after the steel plate is formed, steel plate rolling production and finished steel plate surface treatment can be completed at the same time, separate operation is not needed, and production efficiency is improved. The steps are simplified, the production efficiency is improved, and the production cost is reduced. According to the composite steel plate with the surface compounded with the inorganic oxide, the thickness of the inorganic oxide layer on the surface can reach about 100 microns, the thickness and the adherence of the obtained inorganic oxide are equivalent to those of enamel steel, but the enamel steel needs to be repeatedly coated with glaze and heated on the surface of steel, so that a compact enamel layer can be formed, the power consumption is very high, and the efficiency is relatively low.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of steel plate surface treatment, and particularly relates to a manufacturing method of a composite steel plate with inorganic oxide uniformly attached to one side. BACKGROUND

[0002] In order to increase the corrosion resistance of carbon steel in service, many applications of combining steel with inorganic and organic substances have been developed, such as enamel steel, glass-lined steel, plastic-coated steel, coated steel, painted steel, and the like. These combined methods take into account the advantages of two or three materials, increase the surface corrosion resistance of the steel under the condition that the basic steel material does not change much, and form a relatively wide application market. They belong to the deep processing and value-added processing process after the purchase of steel, and the main process is finished steel plate-surface treatment-coating inorganic or organic substances-service. The enamel steel or glass-lined steel with better surface quality has a relatively complex process, which needs to repeatedly apply glaze to the steel and heat to form a relatively dense enamel layer, and the power consumption is very high and the efficiency is low. The other types of steel combined with organic or inorganic substances are relatively easy to peel off. The plastic-coated steel and painted steel are coated by hot coating or cold coating, and the adhesion is not good, which causes the steel and plastic to peel off when colliding or changing in temperature; the coated steel has a relatively thin surface coating (such as tin-plated plate and zinc-plated plate), and is also easy to produce peeling pits in the case of collision, and has relatively general corrosion resistance.

[0003] The current common enamel method is to spray the surface of the steel plate or steel part after sandblasting, and then put it into an oven for electrostatic adsorption or glaze application, and finally bake. For example, US10017667B2 discloses a glass-coated cast iron product and a method for manufacturing such a product; Chinese patent CN110615615B discloses a high and low temperature corrosion resistant enamel material, a preparation method thereof, an application and a high temperature boiling grate device; Japanese patent JP4210728B2 discloses a method for manufacturing a porcelain enamel and an enamel slurry; Japanese patent JP57190679A discloses a porcelain enamel frit and a two-layer or multi-layer one-time firing porcelain enamel method; the above patents mainly innovate in product plate firing or glaze.

[0004] Chinese patent CN116897214A discloses a steel plate and a plated steel plate; it provides a high-strength steel plate and a plated steel plate with high plating property, LME resistance and hydrogen brittleness resistance, which mainly improves the strength of the plating layer and increases the bonding force of zinc plating and tin plating.

[0005] Chinese patent CN116529068A discloses a plated steel plate for pre-coated steel plate, a pre-coated plated steel plate and a shaped product; it mainly uses an aluminum-magnesium mixed surface plating layer to play a corrosion protection role.

[0006] European Patent Publication No. EP1634932A1 discloses a high corrosion-resistant surface-treated steel sheet and a method for producing the same, having a zinc-based plated steel sheet, a surface-treatment coating layer being formed on the surface of the zinc-based by applying and drying a coating composition on the surface of the steel sheet. SUMMARY

[0007] The present application aims to provide a method for manufacturing a composite steel sheet with inorganic oxide uniformly attached to one side, which realizes the attachment of steel and inorganic oxide during the production of the steel sheet, and which can complete the rolling production of the steel sheet and the surface treatment of the finished steel sheet at the same time, without separate operations, thereby simplifying the steps, improving the production efficiency, and reducing the production cost.

[0008] To achieve the above object, the technical solution of the present application is as follows:

[0009] A method for manufacturing a composite steel sheet with inorganic oxide uniformly attached to one side, comprising the following steps:

[0010] 1) Surface treatment

[0011] Removing the iron oxide scale on the surface of the billet;

[0012] 2) Grouping

[0013] Stacking the surface-treated billets together, with a layer of inorganic oxide uniformly filled between the billets, the added amount of inorganic oxide being Wm, in kg / m 2 , Wm = 2 * ε * a * r a * ρ;

[0014] Wherein:

[0015] ε is the loss coefficient, with a value range of 1.1-1.5, dimensionless;

[0016] a is the thickness of the inorganic oxide layer, with a value range of 80-200 μm;

[0017] ρ is the density of inorganic oxide, in kg / m 3 ;

[0018] r a is the compression ratio, r a = H s / h p , H s is the thickness of the billet before rolling, and h p is the thickness of the billet after rolling, in mm;

[0019] 3) Welding

[0020] Welding the combined billets around, leaving a breathing hole during the welding process, the welding depth is 5-50mm, forming a combined billet;

[0021] 4) Breathing

[0022] Through the breathing hole, the air in the combined billet is extracted, and a certain amount of oxygen is input, the oxygen input per unit area is 0.01-0.03L / mm 2 ;

[0023] 5) Rolling

[0024] The opening rolling temperature is 1000-1300℃; the pass reduction rate of the first 5 passes is controlled at 1-5% respectively;

[0025] 6) Post-processing

[0026] After cooling, the welded part around the combined billet is cut off to obtain a composite steel plate with a surface composite inorganic oxide.

[0027] Preferably, the main components of the inorganic oxide include: SiO2, B2O3, Al2O3, Na2O, K2O, Li2O, CaO and MgO, wherein the content of SiO2 is 60-80wt%, and preferably, the softening point of the inorganic oxide is 420-630℃.

[0028] Preferably, the inorganic oxide is in the form of powder, granules or blocks.

[0029] Preferably, the thickness of the billets can be the same or different, the thickness of the billet is ≥20mm, the thickness of the combined billet is ≥80mm, and preferably, the width tolerance and length tolerance between the billets are not more than 10mm.

[0030] Preferably, the method for removing the iron oxide scale on the surface of the billet includes one or more of sandblasting, polishing, milling, and laser cleaning.

[0031] Preferably, in step 3), laser welding, arc welding or electron beam welding is used.

[0032] Preferably, in step 4), the total amount of oxygen input V o is 0.01-0.03L, unit L; Vo=β*L s *W s , wherein β is the oxygen input per unit area, unit L / mm 2 ; L s is the length of the combined billet, unit mm; W s is the width of the combined billet, unit mm.

[0033] Preferably, the heating temperature in step 5) is 1000-1300℃, and the heating time is 180-380℃.

[0034] Preferably, the final rolling temperature is ≥780℃.

[0035] Preferably, in step 6), the cutting is performed by fire cutting or saw cutting.

[0036] The present application fills a layer of inorganic oxide between two billets, then welds the four sides of the steel plate together, first vacuum, then fill oxygen, then heat and roll, so that the inorganic oxide adheres to the surface of the steel plate, and finally obtains a composite steel plate composed of inorganic oxide and steel plate.

[0037] Before treatment, the surface of the billet needs to remove the surface scale, expose the metal color. The treatment method includes but is not limited to sand blasting, polishing, milling, laser cleaning, etc.

[0038] The thickness of the combined billets can be the same or different, the billet thickness is ≥20mm, the combined billet thickness is ≥80mm, preferably, the width tolerance and length tolerance between the billets are not more than 10mm. The thickness control is mainly to consider that it is too thin to enter the heating furnace, in addition, the single layer also cannot be too thin, otherwise it will cause poor welding quality.

[0039] The added amount of inorganic oxide Wm=2×ε×a×r a ×ρ, unit, kg / m 2 , wherein ε is the loss coefficient, the value range is 1.1-1.5, dimensionless, a is the thickness of inorganic oxide, ρ is the density of inorganic matter (unit kg / m 3 ), r a is the compression ratio, r a =H s / h p , H s is the thickness of single-layer plate billet (unit mm), h p is the thickness of the final steel plate (unit mm). The added amount of inorganic oxide per unit area mainly considers that the solid inorganic oxide can reach the surface of the steel plate in a molten state at high temperature. The initial plate billet state surface area is small, the surface becomes large after rolling, and the inorganic oxide attached to the surface needs to extend to the new surface, r aThe ratio of the surface expansion is a key control point, and is the basis for achieving uniform inorganic oxide adhesion on the surface of the billet. Since inorganic oxide needs to be adhered to the upper and lower surfaces of the billet, the amount of inorganic oxide added per unit area needs to be multiplied by 2. The loss coefficient is mainly considered in the rolling process, in which part of the inorganic oxide is squeezed into the edge, and part of the reaction occurs, resulting in a certain loss. a is the thickness of the inorganic oxide, and the value range is 80-200 μm. The thicker the thickness of the composite steel plate obtained finally, the larger a is, and the thinner the thickness, the smaller a is.

[0040] The four sides of the billet are welded together to form a combined billet, and the welding method includes but is not limited to laser welding, arc welding, electron beam welding, etc., and a ventilation hole is left after welding; the weld depth is controlled to be 5-50 mm, and the weld depth ensures that the combined billet will not crack during subsequent heating and rolling.

[0041] Then use the air treatment equipment to extract the air in the middle cavity of the combined billet, and then input a certain amount of oxygen, and the combined billet enters the heating furnace for heating to 1000-1300℃, and the effect of filling oxygen is to react with Fe to obtain FeO, the reaction formula is 2Fe+O2(high temperature)=2FeO, and a dense oxide layer is generated on the surface of the billet. The divalent iron oxide in the oxide layer will mix with the inorganic oxide at high temperature, penetrate each other, form a molten salt state, and be compacted and homogenized during subsequent rolling to realize the combination of steel and inorganic oxide. The input amount of oxygen per unit area is controlled to be 0.010-0.03 L / mm 2 , and the total input amount of oxygen V o (L) is proportional to the surface area of the cavity (the length L s * the width W s of the combined billet), V o =β*L s *W s , β is the input amount of oxygen per unit area, unit L / mm 2 , and the oxygen is filled in order to generate a certain amount of FeO on the surface of the steel plate. FeO can increase the adhesion between the steel plate and the inorganic mixture, but the input of oxygen cannot be too much. If the oxygen is too much, Fe2O3 will be formed, which will cause the steel plate surface to be unable to adhere to the inorganic substance.

[0042] The reduction rate (reduction amount / billet thickness) needs to be controlled at the beginning of rolling, and the single-pass reduction rate needs to be controlled at 1-5% in the first 1-5 passes to prevent the intermediate molten salt state inorganic oxide mixture from being excessively concentrated at the head and tail of the rolling, and to prevent the inorganic oxide mixture from being distributed on the surface of the billet. The reduction rate of the subsequent passes does not need to be controlled.

[0043] The main components of the inorganic oxide of the present application include: SiO2, B2O3, Al2O3, Na2O, K2O, Li2O, CaO and MgO, wherein the content of SiO2 is 60-80wt%. The inorganic oxide of the present application is mainly composed of silicon oxide (SiO2), and is divided into a base agent and a solubilizer. The FeO formed on the surface of the steel plate at high temperature can play a close bonding role between the steel plate and the oxide. Among them, the silicon dioxide (SiO2) plays a key role in forming a low-melting-point mixture with iron oxide at high temperature and is the key substance for finally realizing corrosion resistance. At high temperature, it is affected by other oxides to form a molten salt-like substance, and the mixture is fully wrapped.

[0044] The boron oxide (B2O3) plays a role in improving the fusion between substances in the mixture, reducing the melting point of the mixture, and having no negative impact on thermal expansion and chemical durability.

[0045] The aluminum oxide (Al2O3) plays a role in increasing the thermal conductivity of the molten salt mixture at high temperature.

[0046] The sodium oxide, potassium oxide and lithium oxide (Na2O, K2O, Li2O) play a role in improving the viscosity of the mixture to ensure that the molten salt-like substance will not be excessively concentrated due to extrusion during rolling.

[0047] The calcium oxide (CaO) plays a role in reducing the softening point of the mixture, reducing the melting point, and improving the adhesion of the inorganic mixture to the steel;

[0048] The magnesium oxide (MgO) plays a role in reducing the melting point of the mixture and increasing its thermal conductivity, and maintaining the gel-like state of the molten salt-like mixture.

[0049] The softening point of the inorganic oxide of the present application is controlled at 420-630℃. On the one hand, the inorganic oxide reaches the softening point at this temperature during the heating process to closely adhere to the surface of the steel blank, increasing the contact area with the steel blank, and then fully mixing with FeO at high temperature. On the other hand, after rolling is completed, the lower softening temperature can ensure that the inorganic oxide attached to the steel plate will not burst open when the steel plate is slightly deformed.

[0050] After rolling, the combined blank gradually cools down, and the material cools down inconsistently. The steel blank separates from the inorganic oxide layer from top to bottom at the center, and after cutting off the welded parts around, a composite steel plate composed of inorganic oxide and steel is obtained. The cutting of the welded parts around the steel plate needs to avoid using the scissors cutting method, and needs to use the fire cutting (including laser and plasma cutting) and saw cutting (including mechanical saw blade and water jet cutting) cutting methods. If the scissors cutting method is used, the inorganic oxide at the cutting site will be partially peeled off.

[0051] Compared with the prior art, the present application has the following advantages:

[0052] The application provides a new method for compounding inorganic matter and steel, which realizes the compounding of inorganic oxide on the surface of the steel plate during the production of the steel plate, and the inorganic oxide does not need to be processed after the forming.

[0053] The method for compounding inorganic oxide on the surface of the steel plate increases the corrosion resistance of the steel, the thickness of the inorganic oxide layer on the surface of the steel plate can reach about 100 microns, the adhesion reaches level two or above, the thickness and adhesion of the inorganic oxide obtained are equivalent to those of enamel steel, but the enamel steel needs to be repeatedly coated with glaze and heated on the surface of the steel to form a relatively dense enamel layer, and the power consumption is very high and the efficiency is relatively low. BRIEF DESCRIPTION OF DRAWINGS

[0054] Figure 1 The figure is a schematic diagram of the cross section of the combined blank in the embodiment of the application.

[0055] Figure 2 The figure is a schematic diagram of the surface of the combined steel plate obtained in the embodiment of the application.

[0056] Figure 3 The figure is a schematic diagram of the side of the combined steel plate obtained in the embodiment of the application under a microscope.

[0057] Figure 4 The figure is a schematic diagram of the surface of the steel plate obtained in the comparative example. DETAILED DESCRIPTION

[0058] The application will be further described below in combination with the embodiments and the drawings.

[0059] These embodiments are only descriptions of the best embodiments of the application, and do not have any limitation on the scope of the application.

[0060] The components of the inorganic oxide in the embodiment of the application are shown in Table 1; the steel blanks and process control parameters used in the embodiment of the application and the comparative example are shown in Table 2; the thickness of the inorganic oxide layer on the combined steel plate obtained in the embodiment of the application and the comparative example is shown in Table 3.

[0061] Referring to Figure 1 The figure is a schematic diagram of the cross section of the combined blank in the embodiment of the application, wherein the inorganic oxide 3 is uniformly distributed between the upper steel blank 1 and the lower steel blank 2, and the steel plate is welded together through the weld 4 around the steel plate.

[0062] Figure 2 The figure is a picture of the inorganic oxide layer on the surface of the combined steel plate obtained in the embodiment of the application, Figure 3The schematic diagram of the composite steel plate side surface obtained by the embodiment of the present application under a microscope can be seen from the picture. It can be seen that the inorganic oxide layer finally obtained on the steel plate surface is uniformly distributed, and the inorganic oxide layer is tightly combined with the steel plate, and the adhesion reaches level two and above.

[0063] The adhesion evaluation standard is as follows:

[0064] 1. Level one: the coating has strong bonding force with the steel plate substrate, less microcracks, the coating surface is flat, the color is consistent, and there are no defects such as bubbles.

[0065] 2. Level two: the coating has strong bonding force with the steel plate substrate, there are some microcracks, the coating surface is basically flat, the color is basically consistent, and there are defects such as local slight bubbles.

[0066] 3. Level three: the coating has general bonding force with the steel plate substrate, there are some obvious microcracks, the coating surface is slightly blistering, the color is not completely consistent, and there are defects such as a small amount of bubbles.

[0067] 4. Level four: the coating has poor bonding force with the steel plate substrate, there are a large number of microcracks, the coating surface is obviously blistering, the color is obviously inconsistent, and there are defects such as bubbles and holes.

[0068] In the comparative example, after the steel billets are combined together, the operation of vacuumizing and inputting oxygen is not performed, and in addition, the slab billets are not welded to completely close the cavity. Figure 4 It can be seen that the oxide adhesion on the surface of the steel plate finally obtained in the comparative example is very poor.

[0069]

[0070]

[0071]

Claims

1. A method for manufacturing a composite steel plate with uniformly deposited inorganic oxides on one side, characterized in that, The method comprises the following steps: 1) surface treatment Removing the oxide scale on the surface of the steel billet; 2) grouping The surface treated steel billets are stacked together, and a layer of inorganic oxide is evenly filled between the steel billets, the added amount of the inorganic oxide is Wm, unit kg / m 2 , Wm = 2 * ε * a * r a * ρ; Wherein: ε is the loss coefficient, 1.1-1.5, dimensionless; a is the thickness of the inorganic oxide layer, ranging from 80 to 200 μm; p is the density of the inorganic oxide in kg / m3 3 ; r a For the compression ratio, r a = H s / h p , H s is the thickness of the steel billet before rolling, h p is the thickness of the steel billet after rolling, in mm; 3) welding Welding the combined steel billet around the perimeter in step 2), leaving a ventilation hole during the welding process, the weld depth is 5-50 mm, forming a combined billet; 4) ventilation The air in the combined blank is extracted through the venting hole, and a certain amount of oxygen is input, and the oxygen input amount per unit area is 0.01-0.03 L / mm 2 ; 5) rolling The open rolling temperature is 1000-1300℃, and the pass reduction rate of the first 5 passes is controlled at 1-5%; 6) post-processing After cooling, the combined billet is cut around the perimeter of the welding part to obtain a composite steel plate with a composite inorganic oxide on the surface.

2. The production method according to claim 1, wherein The main components of the inorganic oxide include: SiO2, B2O3, Al2O3, Na2O, K2O, Li2O, CaO and MgO, wherein the content of SiO2 is 60-80wt%, preferably, the softening point of the inorganic oxide is 420-630℃.

3. The method of claim 1 or 2, wherein the inorganic oxide is uniformly adhered to the surface of the steel sheet. The inorganic oxide is in the form of powder, granules or blocks.

4. The production method according to claim 1, wherein The thickness of the steel billet can be the same or different, the thickness of the steel billet is ≥20mm, the thickness of the combined billet is ≥80mm, preferably, the width tolerance and length tolerance between the steel billets are not more than 10mm.

5. The production method according to claim 1, wherein The method for removing the oxide scale on the surface of the steel billet includes one or more of sandblasting, polishing, milling, and laser cleaning.

6. The production method according to claim 1, wherein In step 3), laser welding, arc welding or electron beam welding is used.

7. The production method according to claim 1, wherein In step 4), the total oxygen input V o , unit L; V o = β * L s * W s , wherein β is the oxygen input per unit area, unit L / mm 2 ; L s L is the length of the combined blank, in mm; W s W is the width of the combined blank, in mm.

8. The production method according to claim 1, wherein In step 5), the heating temperature is 1000-1300℃, and the heating time is 180-380℃.

9. The production method according to claim 1, wherein In step 5), the final rolling temperature is ≥780℃.

10. The production method according to claim 1, wherein In step 6), cutting is performed by fire cutting or sawing.

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