WO2023138372A1 - 一种带钢及其制造方法 - Google Patents

一种带钢及其制造方法 Download PDF

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WO2023138372A1
WO2023138372A1 PCT/CN2023/070391 CN2023070391W WO2023138372A1 WO 2023138372 A1 WO2023138372 A1 WO 2023138372A1 CN 2023070391 W CN2023070391 W CN 2023070391W WO 2023138372 A1 WO2023138372 A1 WO 2023138372A1
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steel
phosphating
stearate
spraying
strip steel
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PCT/CN2023/070391
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English (en)
French (fr)
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赵艳亮
魏星
戴毅刚
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宝山钢铁股份有限公司
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    • 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
    • C22C38/04—Ferrous alloys, e.g. steel alloys containing manganese
    • 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
    • C22C38/22—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
    • C22C38/34—Ferrous alloys, e.g. steel alloys containing chromium with more than 1.5% by weight of 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
    • C22C38/18—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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process
    • C23C22/76—Applying the liquid by spraying
    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/78—Pretreatment of the material to be coated
    • 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
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/82—After-treatment
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
    • Y02P70/10—Greenhouse gas [GHG] capture, material saving, heat recovery or other energy efficient measures, e.g. motor control, characterised by manufacturing processes, e.g. for rolling metal or metal working

Definitions

  • the invention relates to the field of metal material processing, in particular to an oil-free strip steel with excellent processability and anti-corrosion performance and a manufacturing method thereof.
  • the main process types include: (1) forming a micron-scale or submicron organic coating on the surface of the steel plate by means of roller coating + baking curing in the continuous manufacturing process, such as described in Chinese patents CN104451638, CN103289569, and CN105463436; mentioned.
  • Chinese patent CN103289569 discloses "a self-lubricating passivation solution and a hot-dip galvanized self-lubricating steel plate coated with it", mainly through the addition of nano- MoS2 and modified nano-polytetrafluoroethylene particles in the treatment agent to play the role of solid lubrication of the coating.
  • a lubricating coating with an adhesion amount of 800 to 1200mg/ m2 is formed on the surface of the steel plate by rolling coating + baking curing.
  • the product of this invention is mainly suitable for the stamping needs of home appliances and micro-motor shell materials, but it cannot meet the large deformation stamping of high-precision components in the automotive and mechanical fields, and is not suitable for surface treatment of ordinary cold-rolled sheets.
  • Chinese patent CN111349867 discloses "a coating-friendly pre-phosphating electro-galvanized automobile outer panel and its preparation method".
  • a kind of Nb-containing ultra-low carbon steel plate is designed.
  • a pre-phosphating layer of 1.0 to 2.0 g/ m2 is formed by double-sided spraying at a phosphating temperature of 50 to 60 ° C.
  • a product that meets the stamping lubrication and corrosion resistance requirements of automobile body materials is formed. It can be well applied in the body production line, but it cannot meet the large deformation stamping requirements of high-precision components in the automotive and mechanical fields, and cannot realize the manufacturing requirements of double-sided differential lubrication functions.
  • Chinese patent CN105018920A discloses "a phosphorus saponification production process", which relates to a drum-type continuous phosphating/saponification process for processing small parts, mainly including: cylinder entry ⁇ degreasing ⁇ primary cleaning ⁇ phosphating ⁇ secondary cleaning ⁇ surface adjustment ⁇ saponification ⁇ cylinder discharge, 8 technological processes, wherein the phosphating temperature is 60 to 85 ° C, the immersion time is 3 to 10 minutes, the saponification temperature is 55 to 80 ° C, and the immersion time is 0.5 to 5 minutes. This process mainly realizes the surface lubrication function of finished parts through high-temperature phosphating + saponification treatment, but it is not suitable for continuous manufacturing of strip steel.
  • Chinese patent CN105296997A discloses "a phosphating-saponification treatment process for 27SiMn steel", which provides a surface lubrication treatment method suitable for high-precision cold-drawn steel pipes, including: pickling 27SiMn steel parts ⁇ high-temperature phosphating (70 ° C) ⁇ saponification treatment. Likewise, the application adopts double-sided non-differentiation treatment, and is not suitable for continuous manufacturing of strip steel.
  • the object of the present invention is to provide an oil-free steel strip with excellent processability and anti-corrosion performance and a manufacturing method thereof.
  • the two surfaces of the steel strip in the thickness direction have differentiated functions: the surface roughness R a of the upper surface (that is, the surface with the phosphating layer and the stearate lubricating layer) is 0.6 to 1.8 ⁇ m and the R z is 6 to 16 ⁇ m, which has good surface lubrication performance during the extension process; the surface roughness of the lower surface (that is, the surface with only the stearate lubricating layer) is R a ⁇ 0.3 ⁇ m and R z ⁇ 2 ⁇ m, which has good lubricity and high surface cleanliness.
  • the steel strip provided by the present invention can meet the requirements of the continuous and efficient stamping process in the processing of high-precision, large-deformation shell parts, eliminating the need for conventional steel plates in the stamping process of high-precision, large-deformation shell parts, coating, oiling, and cleaning after forming.
  • the invention provides a kind of strip steel, described strip steel comprises substrate and the phosphating layer and the stearate lubricating layer that are arranged on the substrate; On the thickness direction of described substrate, on the upper surface of described substrate, be provided with phosphating layer and stearate lubricating layer successively from inside to outside, the lower surface of described substrate is provided with stearate lubricating layer; a ⁇ 0.3 ⁇ m and R z ⁇ 2 ⁇ m .
  • the substrate includes, in addition to Fe and unavoidable impurities, the following chemical elements in wt %: C: 0.1-0.7%, 0.2% ⁇ Si ⁇ 2%, 0.2% ⁇ Mn ⁇ 2%, Cr: 0.2-1.4%, 0.01% ⁇ Al ⁇ 0.06%, Mo: 0.05-0.2%; among unavoidable impurities, P ⁇ 0.04%, S ⁇ 0.05%.
  • upper surface and “lower surface” are used in this application to distinguish the two surfaces (or both sides) of the substrate or steel strip in the thickness direction.
  • the surface or side with phosphating layer and stearate lubricating layer is referred to as “upper surface” or “upper side”
  • only the surface or side with stearate lubricating layer is called “lower surface” or “lower side”.
  • inside to outside refers to the direction from the side close to the substrate to the side away from the substrate.
  • inside-out refers to a direction from bottom to top.
  • the substrate contains the following chemical elements in wt %: C: 0.1-0.7%, 0.2% ⁇ Si ⁇ 2%, 0.2% ⁇ Mn ⁇ 2%, Cr: 0.2-1.4%, 0.01% ⁇ Al ⁇ 0.06%, Mo: 0.05-0.2%, the balance is Fe and inevitable impurities; among the inevitable impurities, P ⁇ 0.04%, S ⁇ 0.05%.
  • the content of element C is controlled in the range of 0.1% to 0.7%.
  • element Si can effectively improve the formability of materials under high-strength conditions. However, if the Si content is too high (>2%), it will be selectively oxidized and precipitated during the heat treatment process, and the precipitates will be enriched on the surface, affecting the subsequent phosphating and passivation film-forming reaction performance. Therefore, the content of the element Si is controlled to be in the range of 0.2% to 2%.
  • the element Mn can play a role in ensuring the strength and hardness of the material. However, if the Mn content is too high (>2%), it will also be selectively oxidized and precipitated during the heat treatment process, and the precipitates will be enriched on the surface, affecting the subsequent phosphating and passivation film-forming reaction performance. Therefore, the content of the element Mn is controlled to be in the range of 0.2% to 2%.
  • Unavoidable impurities include elements P and S. If the content of P and S is too high, it will affect the toughness of the material and cannot meet the requirements of large deformation forming performance. Therefore, the contents of impurity elements P and S are controlled to be no more than 0.04% and no more than 0.05%, respectively.
  • the substrate has a thickness of 1.0 to 6.0 mm.
  • the "thickness of the substrate” does not include the thickness of one phosphating layer and two stearate lubricating layers on the upper and lower surfaces of the substrate. If the thickness of the substrate is less than 1 mm, the shell wall of the component is likely to be too thin to meet the load-bearing performance requirements after large deformation and deep drawing. If the thickness of the substrate is greater than 6 mm, the cold-rolled product manufacturing line cannot realize effective manufacturing.
  • the steel strip of the present invention is suitable for processing high-precision, large-deformation shell parts.
  • the grain size (ie, the maximum length of the grain) in the phosphating layer is 8 to 20 ⁇ m.
  • the crystal grains are elongated, and the grain size thereof is measured according to the standard GB/T 38933-2020.
  • the phosphating layer ie, phosphating film
  • the phosphating layer has a weight of 1 to 3 g/m 2 , which is measured according to the standard GB/T 38933-2020.
  • the phosphating layer of the present invention is a non-dense phosphating film with coarse crystals, which can effectively reduce the amount of wear debris in the stamping process, thereby improving the life of the mold.
  • the upper surface of the steel strip in the present invention includes a phosphating layer and a stearate lubricating layer sequentially from inside to outside, that is, the upper surface adopts a structural design of a phosphating layer+stearate coating.
  • Both the phosphating film and the stearate saponification film have a lubricating function, and the combination of the two can effectively improve the lubrication stability during the tensile deformation process.
  • the surface roughness Ra is 0.6 to 1.8 ⁇ m and R z is 6 to 16 ⁇ m, which can ensure that the surface of the strip has good surface lubrication performance during the elongation process.
  • the lower surface of the steel strip in the present invention is a stearate lubricating layer.
  • Stearate is a material processing lubricant with both internal and external lubrication functions. It has good thermal stability and excellent mold release performance during continuous rapid stamping (avoids adhesion and accumulation on the surface of the mold), avoids the influence of abnormal grinding particles on the inner surface of the formed part, and achieves lubricity and high surface cleanliness on the surface.
  • the upper and lower surfaces of the steel strip in the present invention have a structural design with differentiated functions, which can provide personalized functional requirements in the high-efficiency and high-precision forming and stamping process.
  • the strip steel surface of the present invention that contacts the die during the forming process is a phosphating layer and a stearate lubricating layer.
  • the surface has good surface lubrication performance during the extension process, and the surface roughness Ra : 0.6 to 1.8 ⁇ m, R z : 6 to 16 ⁇ m.
  • the surface of the steel strip in contact with the punch during the strip forming process of the present invention is a stearate lubricating layer, which has good lubricity and high surface cleanliness.
  • the surface roughness is R a ⁇ 0.3 ⁇ m and R z ⁇ 2 ⁇ m.
  • the surface of the strip steel in contact with the punch is the inner surface of the forming part.
  • the smoother surface design can meet the high dimensional accuracy requirements of the forming part. When the surface roughness in contact with the punch is too high, that is, Ra > 0.3 or R z > 2, the risk of poor dimensional accuracy and smoothness of the inner surface of the molded part increases.
  • the upper and lower surfaces of the steel strip described in the present invention are designed with differentiated functions, wherein the surface of the steel strip in contact with the punch has good lubricity and high surface cleanliness, and the surface of the steel strip in contact with the die has good surface lubrication performance during the stretching process, which meets the requirements of continuous and efficient stamping process during the processing of high-precision, large-deformation shell parts, and eliminates the need for coating and oiling operations of conventional steel plates during the stamping process of high-precision, large-deformation shell parts.
  • both the upper and lower surfaces of the strip have stearate. After the stearate is formed into a film, it has an excellent corrosion medium barrier function at room temperature, which can effectively improve the anti-rust and anti-corrosion performance of the strip surface. The parts produced with this strip do not need to be coated with anti-rust oil.
  • the present invention provides a method of manufacturing steel strip, such as the steel strip described above, comprising the steps of:
  • the steel material enters the degreasing tank equipped with alkaline degreasing agent through the tension roller, and the steel material is degreased at a degreasing temperature of 30 to 60°C; the oil stain on the surface of the steel material can be cleaned by using the alkaline degreasing agent;
  • the rinsing water is industrial pure water with a conductivity of ⁇ 10us/cm, or the rinsing water is tap water+0.2 to 1.1wt% corrosion inhibitor;
  • Spraying a surface conditioner on the upper surface of the rinsed steel to activate the upper surface of the steel wherein the spray pressure is 0.4 to 1.2 bar, and the spray direction is at an angle of 90 to 135° to the running direction of the steel; the lower surface of the steel is coated with a passivation treatment agent with a phosphating barrier function to passivate the lower surface of the steel;
  • Phosphating treatment is carried out on the upper surface of the activated steel through high-pressure spraying phosphating agent, wherein, the phosphating treatment time is 6 to 12s, and the spraying pressure is 5 to 8bar; the spraying direction and the running direction of the steel form an angle of 90 to 135°;
  • step 2) the steel surface is rinsed by spraying, and the spraying pressure is 2 to 4 bar.
  • the corrosion inhibitor is selected from one or more of sodium phosphate, sodium nitrite, sodium benzoate and sodium silicate.
  • the surface regulator is selected from colloidal titanium salt system surface regulators, such as commercially available Pacase PL-Z or similar products.
  • the passivation treatment agent with phosphating barrier function is a Zrate-based passivation treatment agent or a Crate-based passivation treatment agent.
  • the phosphating agent is selected from the phosphating solution of the zinc-manganese-nickel ternary system, such as commercially available Pacaseline PB-181 or similar products.
  • the spraying direction and the running direction of the steel form an included angle of 100 to 120°.
  • step 5 the steel surface is rinsed by spraying, the spraying pressure is 1 to 4 bar, and the spraying direction and the running direction of the steel form an included angle of 90 to 120°.
  • the stearate treatment agent is applied by spraying.
  • the stearate in the stearate treating agent is C18 or C16 stearate.
  • the stearate treatment agent comprises one or more of sodium stearate, magnesium stearate and zinc stearate.
  • movable baffles are respectively provided at 2 to 6 cm, preferably 3 to 5 cm, from both sides of the steel in the width direction of the steel.
  • the movable baffle is roughly on the same plane as the steel, and perpendicular to the length direction of the steel (ie running direction), and the gap between the movable baffle and the edge of the steel is 2 to 6 cm, preferably 3 to 5 cm.
  • the running speed of the steel is 40 to 80 m/min.
  • the main purpose of degreasing is to effectively clean the dirt on the steel surface.
  • the temperature of the degreasing agent is controlled at 30 to 60°C. If the temperature is too low ( ⁇ 30°C), the cleaning ability will be significantly reduced, and the surface cleaning effect will be difficult to guarantee, or a large amount of cleaning aids will be added, which is not environmentally friendly; if the temperature is too high (>60°C), the energy consumption will be too large to meet the requirements of low-carbon production.
  • the first rinse removes the residual degreasing agent on the steel surface, and the cleaning effect of the surface oil is confirmed through the continuous state of the surface water film.
  • Corrosion problems are prone to occur during the first rinsing process, which can be effectively avoided mainly through rinsing water quality and corrosion inhibition technology.
  • the corrosion process of metal materials in water is mainly electrochemical reaction, and the conductivity of water directly affects the difficulty of corrosion reaction.
  • the conductivity of water is affected by the number of anions and cations of impurities in it, and it is mainly characterized by conductivity.
  • the surface of fresh metal materials after degreasing is prone to rust.
  • the rinsing process uses industrial pure water with a conductivity of ⁇ 10us/cm, which can effectively control the occurrence of corrosion problems.
  • the rinsing water uses tap water + 0.2 to 1.1wt% corrosion inhibitor, which can effectively reduce the risk of surface corrosion during the washing process while the surface is fully cleaned.
  • the added corrosion inhibitor is selected from one or more of sodium phosphate, sodium nitrite, sodium benzoate and sodium silicate.
  • the surface conditioner is sprayed on the upper surface of the steel to form a surface adjustment activation layer that promotes the uniform nucleation of phosphating; on the other hand, a passivation treatment agent with a phosphating barrier function is coated on the lower surface of the steel to form a rust-proof passivation layer with a phosphating barrier function.
  • the spray pressure is controlled at 0.4 to 1.2 bar. When the pressure is too low, less than 0.4bar, the spraying amount of the surface conditioner is insufficient and the activation is insufficient.
  • the spraying direction and the running direction of the steel form an included angle of 90 to 135°, preferably 100 to 120°, which can better avoid the influence of the surface conditioner on the lower surface.
  • the passivation treatment agent with phosphating barrier function on the steel surface can be applied by spraying, roller coating, brushing, etc.
  • spraying it is necessary to control the angle range between the spraying direction and the running direction of the steel, which can reduce the interaction between the upper and lower surface treatment agents caused by spray splashing.
  • movable baffles In order to avoid the interference between the two surfaces during the spraying process, it is preferable to set movable baffles at a distance of 2 to 6 cm from the edges on both sides of the steel.
  • the main purpose is to avoid the mutual contamination of the two surface treatment agents during the spraying process.
  • the gap between the steel and the movable baffle is too large (>6cm), different treatment agents on the upper and lower surfaces will significantly affect each other during the spraying process; when the gap between the steel and the movable baffle is too small ( ⁇ 2cm), there is a greater risk of steel edge collision during normal production.
  • the gap between the steel material and the movable baffle is preferably 3 to 5 cm.
  • the main purpose of phosphating is to quickly form evenly distributed phosphating crystal particles on one side of the steel to form a film quickly, uniformly, and non-densely (see Figure 1).
  • a phosphating film is formed within 6 to 12 seconds. It is a non-dense phosphating film composed of elongated plate-like phosphating crystal particles. The size and length of the crystal particles are 8 to 20 ⁇ m.
  • the phosphating film layer can better provide a three-dimensional space for the subsequent stearate film formation, effectively increasing the storage capacity of the stearate lubricant on the product surface; on the other hand, it can better ensure the uniform distribution of the lubricant during the deformation process, and use its own good friction and lubrication characteristics to provide further lubrication functions.
  • the design of non-dense phosphating film with coarse crystals can effectively reduce the amount of wear debris in the stamping process, thereby improving the life of the die.
  • Conventional continuous steel phosphating treatment generally takes more than 15s.
  • the present invention can control the effective surface phosphating treatment in 6 to 12s by controlling the spraying pressure at 4 to 10bar through high-pressure spraying, which greatly improves the phosphating efficiency.
  • the spray pressure is low ( ⁇ 4bar)
  • the phosphating efficiency in the continuous manufacturing process does not meet the requirements of fast (6 to 12s) phosphating treatment, and the phosphating crystal size produced is too small (particle size length ⁇ 8 ⁇ m), which cannot meet the surface requirements of continuous steel production products.
  • the spray pressure is too high (>10bar)
  • excessive splashing will occur, which will easily affect the lower surface, and adversely affect the stability of the phosphating effect and the uniform distribution of phosphating crystals.
  • the spraying direction and the running direction of the steel form an included angle of 90 to 135°, preferably 100 to 120°.
  • the second rinse the main function is to effectively clean the phosphating treatment agent remaining on the surface. Due to the effect of the phosphating film and the surface passivation film on the steel surface, the risk of corrosion in this process is significantly reduced, and no special anti-rust control is required.
  • the surface of the steel is rinsed with industrial pure water with a conductivity of ⁇ 10us/cm.
  • the temperature of the rinsing water is room temperature
  • the spray pressure is 1 to 4bar
  • the spray direction and the running direction of the steel are at an angle of 90 to 120°.
  • Stearate treatment (saponification treatment): Apply stearate liquid at 70 to 90°C to the surface of the steel by spraying, and use a wiping roller to treat the surface film evenly.
  • the stearate is C18 or C16 stearate.
  • the stearate treating agent is formulated from one or more of sodium stearate, magnesium stearate and zinc stearate. After the liquid stearate is sprayed onto the surface of the steel, it is blown by compressed air, and the surface film is evenly treated by the wiping roller.
  • the steel coil manufactured by the above method has excellent anti-rust and anti-corrosion properties, and does not need to be coated with anti-rust oil during storage and transportation.
  • the present invention obtains a steel strip with differentiated functions on both sides, wherein only the surface with the stearate lubricating layer has good lubricity and high surface cleanliness, and the surface with the phosphating layer and the stearate lubricating layer has good surface lubricity during the extension process, which meets the requirements of continuous and efficient stamping process during the processing of high-precision, large-deformation shell parts; while traditional steel plates need to be coated and oiled during the stamping process of high-precision, large-deformation shell parts, and the parts need to be cleaned after being processed into parts.
  • the steel strip described in the present invention can be used for direct punching and processing of high-precision and large-deformation housing parts.
  • the two surfaces of the substrate are activated and passivated respectively, and the parameters in the process are controlled to prevent interference in the two surface treatment processes, and then the single-side phosphating spray process + double-side saponification process is adopted to realize the continuous production of strip steel with differentiated functions on the two surfaces.
  • the present invention adopts the phosphating process of high-pressure spraying, which greatly reduces the effective processing time under the condition of appropriate equipment length, and the overall running speed of the strip can be controlled at 40 to 80 m/min, which meets the requirements of high-efficiency manufacturing of conventional strip steel, so that the method can be directly connected to the existing continuous annealing and smoothing process of cold-rolled strip steel, and can also be used as a separate strip surface treatment method to realize continuous production of strip steel with two different surface functions.
  • Fig. 1 is a structural schematic diagram of strip steel in the present invention.
  • Fig. 1 it shows the structure of steel strip of the embodiment of the present invention, and described oil-free steel strip comprises substrate, and the A face of described substrate comprises phosphating layer 1 and stearate lubricating layer 2 successively from inside to outside, and the B face of substrate is stearate lubricating layer 2.
  • Table 1 for the substrate composition of the examples and comparative examples of the present invention, and the balance is Fe and unavoidable impurities except P and S.
  • Table 2 is the manufacturing process parameter of embodiment and comparative example. The evaluation results of the process implementation effect of the embodiment of the present invention and the comparative example are shown in Table 3. Two kinds of surface roughness R a ("contour arithmetic mean deviation") and R z ("micro-roughness ten-point height") of the strip steel were measured by using the Mahr MARSURF PS 10 mobile roughness measuring instrument in Germany (measuring reference standard GB/T 1031).
  • the degreasing and cleaning effect on the strip surface was evaluated by the continuous state of the water film on the surface during the water washing process after degreasing. Visually observe the state of the water film on the washed surface after degreasing:
  • the surface water film is uniform and continuous, with a coverage rate of 100%;
  • ⁇ The water film on the surface is obviously discontinuous, and the coverage is less than 100%.
  • ⁇ There are rust spots on the surface, and the rust area is more than 0%.
  • the phosphating crystal size on the upper surface is 8 to 20 ⁇ m, and the crystals are evenly distributed, 1g/m 2 ⁇ phosphating film weight ⁇ 3g/m 2 ;
  • the phosphating crystal size on the upper surface is 8 to 20 ⁇ m, but the local distribution of crystals is uneven, 1g/m 2 ⁇ phosphating film weight ⁇ 3g/m 2 ;
  • the phosphating crystal size on the upper surface is ⁇ 8 ⁇ m or >20 ⁇ m, and the weight of the phosphating film is ⁇ 1 g/m 2 or the weight of the phosphating film is >3 g/m 2 ;
  • embodiment 1-6 is processed according to the procedure described in the present invention, and the strip steel technological effect that obtains all shows excellent, and the lower surface of strip steel is a stearate lubricating layer, and its surface roughness R a ⁇ 0.3 ⁇ m and R z ⁇ 2 ⁇ m, has good lubricity and high surface cleanliness; m, the surface has good surface lubricity during the extension process, realizes the differential functional design of the two surfaces of the strip steel, and meets the continuous and efficient stamping process requirements in the processing of high-precision, large-deformation shell parts.
  • Comparative Example 1 the phosphating barrier treatment process was not adopted in the phosphating process, resulting in the formation of obvious phosphating crystals on the lower surface partially affected by phosphating.
  • Comparative Example 2 the degreasing temperature was close to room temperature, which could not satisfy the effective cleaning of the surface. At the same time, due to the short phosphating time and too low spray pressure, no significant phosphating crystals were formed on the upper surface.
  • Comparative Example 3 since the tap water with relatively high conductivity was used as the rinse water 1, the washing process after degreasing was obviously rusted, which had a negative impact on the subsequent phosphating.
  • the strip steel that the embodiment of the present invention obtains carries out neutral salt spray test on the strip steel surface with reference to ASTM B117 standard, and strip steel surface 24h does not have corrosion to produce, and its corrosion resistance is obviously better than conventional oiled steel plate (neutral salt spray test surface appears corrosion time is about 12h), illustrates that the strip steel obtained by the present invention has good antirust and anticorrosion performance, can satisfy the corrosion resistance requirement of 4 months storage and transportation strip steel surface without corrosion.
  • Example 1 0.1 0.2 1.22 1.02 0.04 0.05 0.02 0.015
  • Example 2 0.5 1.2 0.8 0.23 0.06 0.11 0.04 0.04
  • Example 3 0.2 0.8 1.7 0.61 0.01 0.15 0.02 0.01
  • Example 4 0.7 1.8 0.2 1.4 0.05 0.20 0.03 0.05
  • Example 5 0.3 2.0 0.3 0.82 0.03 0.08 0.015 0.03
  • Example 6 0.4 1.0 2.0 0.74 0.02 0.06 0.02 0.022 Comparative example 1 0.4 1.1 0.9 1.3 0.03 0.06 0.03 0.02 Comparative example 2 0.1 0.2 1.22 1.02 0.04 0.05 0.02 0.015 Comparative example 3 0.3 2.0 0.3 0.82 0.03 0.08 0.015 0.03

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Abstract

一种具有优良加工性和防腐性能的免涂油带钢及其制造方法，所述带钢具有基板以及设置在基板上的磷化层和硬脂酸盐润滑层；所述带钢的上表面由内至外依次包括磷化层和硬脂酸盐润滑层，其表面粗糙度R a为0.6至1.8μm且R z为6至16μm，该表面在延展过程中具有良好的表面润滑性；所述带钢的下表面为硬脂酸盐润滑层，其表面粗糙度R a≤0.3μm且R z≤2μm，具有良好的润滑性和高表面清洁度。用本发明所述两个表面差异化功能设计的带钢可直接冲压加工高精度、大变形量壳体零件，省去了采用传统钢板制造高精度、大变形量壳体零件冲压过程中的覆膜、涂油及成型后清洗等操作，大幅提升零件制造效率；且带钢具有良好的防锈和防腐蚀性能，在仓储运输过程中表面无需进行涂油处理。

Description

一种带钢及其制造方法 技术领域
本发明涉及金属材料加工领域，特别涉及一种具有优良加工性和防腐性能的免涂油带钢及其制造方法。
背景技术
在金属材料加工领域，以高精度、高复杂度、环保要求为特征的连续高效加工技术，被广泛应用于汽车和机械零件加工。经过理论分析、大量的实验室科学研究和应用实践调研发现，高精度大变形壳体类零件在冲压过程中，与凹模接触的钢板表面承受了主要的变形摩擦力；与凸膜接触的钢板表面相对而言变形摩擦力较小，主要保障内表面尺寸精度。因此，与凹模接触的钢板表面需要在变形过程中能够提供充分的润滑功能，与凸模接触的钢板表面则不需要太高的润滑性能，但是需要超高的表面光洁度。为保证获得高尺寸精度/高表面质量的壳体类零件，要求材料两面具备不同的润滑功能。
材料供应商JFE、日新、POSCO等主要关注力学性能优异的产品的开发。在冲压用材料开发研究领域，主要关注带钢双面涂层处理(例如涂覆具有润滑功能的涂层)，例如如日本专利JP05076347B2、日本专利JP8295985A、韩国专利KR376927B1中所述。
针对带钢表面双面涂层处理，主要工艺类型包括：(1)连续制造过程中通过辊涂+烘烤固化的方式在钢板表面形成微米级或亚微米的有机涂层，例如如中国专利CN104451638、CN103289569、CN105463436中所述；(2)连续制造过程中通过喷淋方式在钢板表面形成磷化层/钝化层，例如如中国专利CN111349867A中所述。
中国专利CN103289569公开了“一种自润滑钝化液及用其涂敷的热镀锌自润滑钢板”，主要通过纳米MoS 2和改性纳米聚四氟乙烯粒子在处理剂中的添加起到涂层固体润滑的功能。通过辊涂+烘烤固化的方式在钢板表面形成附着量800至1200mg/m 2的润滑涂层。该发明产品主要适用于家电和微电机壳体材料的冲压需求，尚不能满足汽车和机械领域高精度要求部件的大变形冲压，且不适用于普通冷轧板表面处理。
中国专利CN111349867公开了“一种涂装友好的预磷化电镀锌汽车外板及其制备方法”，设计了一种含Nb超低碳钢板，通过重力法电镀工艺在钢板表面形成连续镀层后，采用双面喷淋的方式在磷化温度50至60℃条件下形成1.0至2.0g/m 2的预磷化层， 经过涂油处理后形成满足汽车车身材料冲压润滑和耐蚀要求的产品。在车身产线可以良好应用，但不能满足汽车和机械领域高精度要求部件的大变形冲压要求，同时无法实现双面差异化润滑功能制造要求。
中国专利CN105018920A公开了“一种磷皂化生产工艺”，涉及一种加工小型部件的滚筒式连续磷化/皂化工艺，主要包括：入筒→脱脂→一次清洗→磷化→二次清洗→表调→皂化→出筒8个工艺流程，其中磷化温度为60至85℃，浸渍时间为3至10分钟，皂化温度为55至80℃，浸渍时间为0.5至5分钟。该工艺主要通过高温磷化+皂化处理的方式来实现成品零件表面润滑功能，但其不适用于进行带钢连续制造。
中国专利CN105296997A公开了“一种27SiMn钢的磷化-皂化处理工艺”，提供了一种适用于高精度冷拔钢管的表面润滑处理方法，包括：对27SiMn钢部件进行酸洗→高温磷化(70℃)→皂化处理。同样，该申请中采用双面无差别化处理，且不适用于进行带钢连续制造。
可以看出，高精度大变形壳体类零件要求材料两面具有不同的润滑功能。传统工艺通过在冲压工序对钢板凸模接触表面进行覆膜(塑料润滑膜)或涂敷润滑油来实现钢板的双面差异化，但这种方式不能满足在高效和环保方面的要求。针对冲压过程中的涂敷，目前的现有技术主要关注润滑装置、润滑油涂敷方法及精冲用润滑剂组合物的研究。随着对高精度大变形壳体类零件的需求增加，简化零件的加工、生产工艺，生产出性价比更具市场竞争力的产品将成为整个行业的要求。因此，需要提供一种具有优异性能(例如加工性和防腐性能)、高效率且环保(例如免涂油)的带钢及其制造方法。
发明内容
本发明的目的在于提供一种具有优良加工性和防腐性能的免涂油带钢及其制造方法。该带钢在厚度方向上的两个表面具有差异化功能：上表面(即具有磷化层和硬脂酸盐润滑层的表面)的表面粗糙度R a为0.6至1.8μm且R z为6至16μm，在延展过程中具有良好的表面润滑性能；下表面(即仅具有硬脂酸盐润滑层的表面)的表面粗糙度R a≤0.3μm且R z≤2μm，具有良好的润滑性和高表面清洁度。因此，本发明提供的带钢可以满足高精度、大变形量壳体零件加工过程中连续高效冲压工艺要求，省去了常规钢板在加工高精度、大变形壳体零件冲压过程中的覆膜、涂油及成型后的清洗操作，生产的零件可直接包装出厂，大幅提升零件制造效率；且带钢具有良好的防锈和防腐蚀性能，生产的零件在仓储运输过程中无需进行防锈油的涂敷。
在一方面，本发明提供了一种带钢，所述带钢包括基板以及设置在基板上的磷化 层和硬脂酸盐润滑层；在所述基板的厚度方向上，所述基板的上表面上由内至外依次设置有磷化层和硬脂酸盐润滑层，所述基板的下表面上设置有硬脂酸盐润滑层；所述带钢的上表面的表面粗糙度R a为0.6至1.8μm且R z为6至16μm，所述带钢的下表面的表面粗糙度R a≤0.3μm且R z≤2μm。
优选地，所述基板除包含Fe和不可避免的杂质之外，还包含以wt％计的如下化学元素：C：0.1-0.7％，0.2％≤Si≤2％，0.2％≤Mn≤2％，Cr：0.2-1.4％，0.01％≤Al≤0.06％，Mo：0.05-0.2％；在不可避免的杂质中，P≤0.04％，S≤0.05％。
需要注意的是，为了更清楚地描述本发明，本申请中采用“上表面”和“下表面”(或“上侧”和“下侧”)对基板或带钢在厚度方向上的两个表面(或两侧)进行区分。具体地，在本文中，具有磷化层和硬脂酸盐润滑层的表面或一侧被称为“上表面”或“上侧”，仅具有硬脂酸盐润滑层的表面或一侧被称为“下表面”或“下侧”。然而，此种描述并不意在对本发明构成不当限定，因为本领域技术人员了解：术语“上”和“下”是一种相对性描述，其显然将随该制品的摆放方向而发生变化。
在本文中，当描述基板的上表面上的磷化层和硬脂酸盐润滑层的相对位置关系时，“由内至外”是指从靠近基板侧到远离基板侧的方向。例如，在图1中，“由内至外”是指从下至上的方向。
优选地，所述基板包含以wt％计的如下化学元素：C：0.1-0.7％，0.2％≤Si≤2％，0.2％≤Mn≤2％，Cr：0.2-1.4％，0.01％≤Al≤0.06％，Mo：0.05-0.2％，余量为Fe和不可避免的杂质；在不可避免的杂质中，P≤0.04％，S≤0.05％。
在本发明所述带钢的基板中，各元素含量的设计原理如下：
C：若元素C含量低于0.1％，则强度不足。若元素C含量高于0.7％，会降低材料的表面化学反应性，进而影响到表面磷化和钝化成膜性能，材料成型稳定性容易出现不足。因此，元素C的含量控制在0.1％至0.7％的范围内。
Si：元素Si可以有效改善材料高强度条件下的成型性能。但是，若Si含量过高(＞2％)，会在热处理过程中被选择性氧化析出，析出物会富集到表面，影响后续的磷化和钝化成膜反应性能。因此，元素Si的含量控制为在0.2％至2％的范围内。
Mn：元素Mn可以起到保障材料强度和硬度的作用。但是，若Mn含量过高(＞2％)，同样也会由于在热处理过程中被选择性氧化析出，析出物会富集到表面，影响后续的磷化和钝化成膜反应性能。因此，元素Mn的含量控制为在0.2％至2％的范围内。
Cr、Al和Mo：这些元素主要起到细化结晶的作用。若含量过低，则不能充分实现上述作用。若过量添加，则不利于产品制造经济性。因此，元素Cr、Al和Mo的含 量分别控制在0.2％至1.4％、0.01％至0.06％和0.05％至0.2％的范围内。
不可避免的杂质包括元素P和S。若P和S含量过高，会影响材料韧性，不能满足大变形量成型性能要求。因此，杂质元素P和S的含量分别控制为不超过0.04％和不超过0.05％。
优选地，所述基板的厚度为1.0至6.0mm。在本文中，“基板的厚度”不包括基板的上下表面上的一层磷化层和两层硬脂酸盐润滑层的厚度。若基板的厚度＜1mm，则经过大变形、深拉延，部件易发生壳壁过薄而无法满足承载性能的要求。若基板的厚度＞6mm，则冷轧产品制造产线无法实现有效制造。通过使基板厚度为1.0至6.0mm，本发明的带钢适合用于加工高精度、大变形壳体零部件。
优选地，所述磷化层中晶粒尺寸(即晶粒的最大长度)为8至20μm。在所述磷化层中，晶体颗粒呈长条形，其晶粒尺寸根据标准GB/T 38933-2020进行测量。
优选地，所述磷化层(即磷化膜)的重量为1至3g/m 2，其根据标准GB/T 38933-2020进行测量。
通过使磷化层中晶粒尺寸为8至20μm和/或磷化层重量为1至3g/m 2，一方面可以更好地为后续硬脂酸盐成膜提供立体空间，有效增加产品表面硬脂酸盐润滑剂的存储量；另一方面在变形过程中更好地保障润滑剂均匀分布，利用自身良好的摩擦润滑特性提供进一步的润滑功能。本发明的磷化层是一种具有粗大结晶的非致密磷化膜，可以起到有效降低冲压过程磨屑量的作用，进而提升模具寿命。
本发明所述带钢的上表面由内至外依次包括磷化层和硬脂酸盐润滑层，即上表面采用磷化层+硬脂酸盐涂层的结构设计。磷化膜和硬脂酸盐皂化膜均有润滑功能，两者相结合可以有效提升拉伸变形过程的润滑稳定性，其表面粗糙度R a为0.6至1.8μm且R z为6至16μm，可以保证带钢表面在延展过程中具有良好的表面润滑性能。
本发明所述带钢下表面为硬脂酸盐润滑层。硬脂酸盐是一种兼顾内润滑和外润滑功能的材料加工润滑剂，在连续快速冲压过程中具备良好的热稳定性和优良的脱模性能(避免在模具表面黏附堆积)，避免成型零件内表面异常磨削颗粒污染影响，实现该表面的润滑性和高表面清洁度，其表面粗糙度R a≤0.3μm且R z≤2μm。
本发明所述带钢的上下两个表面具有差异化功能的结构设计，可以在高效率、高精度的成型冲压过程中提供个性化的功能需求。
本发明带钢在成型过程中与凹模接触的带钢表面为磷化层和硬脂酸盐润滑层，该表面在延展过程中具有良好的表面润滑性能，表面粗糙度R a：0.6至1.8μm，R z：6至16μm。当与凹模接触的带钢表面粗糙度偏低，即R a＜0.6或R z＜6时，表面润滑组分在变形延展过程快速流失，易出现润滑性能不足，导致材料表面拉毛进而损伤模具；当 其粗糙度过高，即R a＞1.8或R z＞16时，变形延展过程的润滑性充足，连续冲压过程中易出现磨屑物过多的情况，影响模具寿命。
本发明带钢成型过程中与凸模接触的带钢表面为硬脂酸盐润滑层，该表面具有良好的润滑性和高表面清洁度，表面粗糙度R a≤0.3μm且R z≤2μm，与凸模接触的带钢表面是成型部件内表面，更加平滑的表面设计可以满足成型部件的高尺寸精度要求，同时该表面在成型过程全程与模具紧密接触，适当的表层润滑组分会在成型过程中充分发挥润滑作用。当与凸模接触表面粗糙度过高即R a＞0.3或R z＞2时，成型部件内表面尺寸精度和平滑度不良风险加大。
本发明所述带钢的上下两个表面采用差异化功能设计，其中与凸模接触的带钢表面具有良好的润滑性和高表面清洁度，与凹模接触的带钢表面在延展过程中具有良好的表面润滑性能，满足高精度、大变形量壳体零件加工过程中连续高效冲压工艺要求，省去了常规钢板在加工高精度、大变形壳体零件冲压过程中的覆膜、涂油操作，生产的产品可直接包装出厂，省去用户端成型后的清洗工序，大幅提升产品制造效率。
同时，带钢的上下两个表面均具有硬脂酸盐，硬脂酸盐成膜后在室温环境下具备优良的腐蚀介质阻隔功能，可以有效提升带钢表面的防锈、防腐蚀性能，用该带钢生产的零件，不需要再进行防锈油的涂敷。
在另一方面，本发明提供了一种制造带钢(例如上述带钢)的方法，其包括如下步骤：
1)脱脂
钢材经张力辊进入装有碱性脱脂剂的脱脂槽，在30至60℃的脱脂温度下对钢材进行脱脂；利用碱性脱脂剂，可以将钢材表面的油污清洗干净；
2)第一次漂洗
采用漂洗水对脱脂后的钢材表面进行漂洗，所述漂洗水为电导率≤10us/cm的工业纯水，或者所述漂洗水为自来水+0.2至1.1wt％的缓蚀剂；
3)活化和钝化
向漂洗后的钢材的上表面喷淋表面调整剂，以使钢材的上表面活化，其中，喷淋压力为0.4至1.2bar，喷淋方向与钢材运行方向呈90至135°夹角；向钢材的下表面涂敷具有磷化阻隔功能的钝化处理剂，以使钢材的下表面钝化；
4)磷化
通过高压喷淋磷化剂，对活化后的钢材上表面进行磷化处理，其中，磷化处理时间6至12s，喷淋压力5至8bar；喷淋方向与钢材运行方向呈90至135°夹角；
5)第二次漂洗
采用电导率≤10us/cm的工业纯水对钢材表面进行漂洗，漂洗后进行表面挤干处理；
6)皂化
向钢材的上表面和下表面涂敷硬脂酸盐处理剂，采用压缩空气对钢材表面进行吹扫、擦拭辊处理，其中，涂敷温度为70至90℃。
优选地，步骤2)中，采用喷淋的方式对钢材表面进行漂洗，喷淋压力为2至4bar。
优选地，步骤2)中，所述缓蚀剂选自磷酸钠、亚硝酸钠、苯甲酸钠和硅酸钠中的一种或多种。
优选地，步骤3)中，所述表面调整剂选自胶体钛盐体系的表调剂，例如可商购获得的帕卡濑精的PL-Z或同类产品。
优选地，步骤3)中，所述具有磷化阻隔功能的钝化处理剂为Zr酸盐系钝化处理剂或Cr酸盐系钝化处理剂。
优选地，步骤4)中，所述磷化剂选自锌锰镍三元体系的磷化液，例如可商购获得的帕卡濑精PB-181或同类产品。
优选地，步骤4)中，喷淋方向与钢材运行方向呈100至120°夹角。
优选地，步骤5)中，采用喷淋的方式钢材表面进行漂洗，喷淋压力为1至4bar，喷淋方向与钢材运行方向呈90至120°夹角。
优选地，步骤6)中，采用喷淋的方式涂敷硬脂酸盐处理剂。
优选地，步骤6)中，所述硬脂酸盐处理剂中硬脂酸盐为C18或C16的硬脂酸盐。
优选地，步骤6)中，所述硬脂酸盐处理剂包含由硬脂酸钠、硬脂酸镁和硬脂酸锌中的一种或多种。
优选地，步骤3)和/或步骤4)中，在所述钢材的宽度方向上，在距离钢材两侧边缘2至6cm、优选3至5cm处各自设置有活动挡板。换言之，活动挡板大致和钢材在同一平面上，且垂直于钢材的长度方向(即运行方向)，并且活动挡板与钢材边缘之间的间隙为2至6cm、优选3至5cm。
优选地，步骤3)和/或步骤4)中，所述钢材运行速度为40至80m/min。
在本发明所述的制造方法中：
脱脂主要目的是对钢材表面脏污进行有效清洗。脱脂剂的温度控制在30至60℃。若温度过低(＜30℃)，则清洗能力显著下降表面清洗效果难以保障，或者需要大量清洗助剂添加不环保；若温度过高(＞60℃)，则能耗过大不满足低碳生产要求。
第一次漂洗将钢材表面残留脱脂剂冲洗去除，通过表面水膜的连续状态来确认表面油污的清洗效果。在第一次漂洗过程中易出现锈蚀问题，主要通过漂洗水水质和缓蚀技术来有效避免。金属材料腐蚀在水中的腐蚀过程主要为电化学反应，水的导电性 直接影响锈蚀反应的难易程度。水的导电受其中杂质的阴阳离子数量影响，主要通过电导率进行表征，脱脂后新鲜的金属材料表面及易发生锈蚀现象，漂洗过程采用采用电导率≤10us/cm的工业纯水，可以有效控制锈蚀问题的发生。
漂洗水采用自来水+0.2至1.1wt％的缓蚀剂，在表面充分清洗的同时能够有效降低水洗过程表面锈蚀风险。缓蚀剂添加量过低＜0.2wt％时，无法起到有效的缓蚀效果；当添加剂过量＞1.1wt％时，不符合经济环保要求。所添加的缓蚀剂选自磷酸钠、亚硝酸钠、苯甲酸钠和硅酸钠中的一种或多种。
活化&钝化：一方面，在钢材上表面喷淋表面调整剂，形成促进磷化均匀形核的表调活化层；另一方面，在钢材的下表面涂敷具有磷化阻隔功能的钝化处理剂，形成具有磷化阻隔功能的防锈钝化层。活化&钝化处理过程中需要有效控制上下表面处理过程中的相互干扰问题。优选地，喷淋表面调整剂过程中，喷淋压力控制在0.4至1.2bar。当压力过低、小于0.4bar时，表面调整剂喷淋量不足，活化不充分。当喷淋压力过高、大于1.2bar时，同样会影响表面调整剂的吸附量，进而导致产品磷化处理不充分。喷淋方向与钢材运行方向呈90至135°、优选100至120°的夹角，可以更好地避免表面调整剂对下表面的影响。
钢材表面具有磷化阻隔功能的钝化处理剂的涂敷方式可以采用喷淋、辊涂、刷涂等，采用喷淋方式进行涂敷时，需要控制喷淋方向与钢材运行方向夹角范围，可降低喷淋飞溅引发的上下表面处理剂的相互影响。
为避免喷淋过程中两个表面之间的干扰问题，优选在距离钢材两侧边缘2至6cm处各自设置活动挡板，主要目的是避免喷淋过程出现两个表面处理剂相互污染的问题。当钢材与活动挡板之间的间隙过大(＞6cm)时，会造成上下表面不同处理剂在喷淋过程相互显著影响；当钢材与活动挡板之间的间隙过小(＜2cm)时，在正常生产过程中存在较大的钢材边部碰撞风险。钢材与活动挡板之间的间隙优选为3至5cm。
磷化的主要目的是在钢材单面快速形成均匀分布的磷化结晶颗粒，以快速、均匀、非致密地成膜(参见图1)。通过高压喷淋磷化剂，在6至12s时间内形成磷化膜，其是由长条形的片状磷化结晶颗粒构成的非致密磷化膜，结晶颗粒尺寸长度为8至20μm，磷化膜重(即，磷化层重量)为1至3g/m 2。该磷化膜层一方面可以更好地为后续硬脂酸盐成膜提供立体空间，有效增加产品表面硬脂酸盐润滑剂的存储量；另一方面在变形过程中更好地保障润滑剂均匀分布，利用自身良好的摩擦润滑特性提供进一步的润滑功能。粗大结晶的非致密磷化膜的设计，可以起到有效降低冲压过程磨屑量的作用，进而提升模具寿命。
常规连续钢材磷化处理时间一般需要15s以上，本发明通过高压喷淋，通过控制 喷淋压力在4至10bar，可以控制在6至12s完成有效的表面磷化处理，大幅提升了磷化效率。当喷淋压力偏低(＜4bar)时，连续制造过程磷化效率不满足快速(6至12s)磷化处理要求，产生的磷化结晶尺寸偏小(颗粒尺寸长度＜8μm)，无法满足连续钢材生产产品表面要求。当喷淋压力过大(＞10bar)时，会产生过度飞溅，易对下表面产生影响，且对磷化效果稳定性和磷化结晶分布的均匀产生不良影响。喷淋方向与钢材运行方向呈90至135°、优选100至120°的夹角。
第二次漂洗：主要作用是对表面残留的磷化处理剂进行有效清洗，由于钢材表面磷化膜和表面钝化膜的作用显著降低了该过程的锈蚀风险，无需进行特殊的防锈控制。钢材表面均采用电导率≤10us/cm的工业纯水进行漂洗，漂洗水温度为室温，喷淋压力为1至4bar，喷淋方向与钢材运行方向呈90至120°夹角。如果直接采用高电导率的自来水会在表面形成电解质残留，在后工序直接包覆在硬脂酸润滑膜下，影响产品储运过程的防锈性能。漂洗后进行表面挤干处理(例如采用挤干辊或挤干机)，有效降低表面水量。
硬脂酸盐处理(皂化处理)：采用喷淋方式，将70至90℃的硬脂酸盐液体涂敷至钢材表面，利用擦拭辊将表面膜层处理均匀。优选地，硬脂酸盐采用C18或C16的硬脂酸盐。优选地，硬脂酸盐处理剂由硬脂酸钠、硬脂酸镁和硬脂酸锌中的一种或多种配制而成。液态硬脂酸盐喷淋至钢材表面后，通过压缩空气进行吹扫，经过擦拭辊将表面膜层处理均匀。
完成上述工序后通过卷曲机将钢材进行卷曲后包装出厂。通过如上方法制造的钢卷具有优良的防锈和防腐蚀性能，在仓储运输过程中不需要再进行防锈油的涂敷。
本发明的有益效果：
1、本发明获得两面具有差异化功能的带钢，其中仅具有硬脂酸盐润滑层的表面具有良好的润滑性和高表面清洁度，具有磷化层和硬脂酸盐润滑层的表面在延展过程中具有良好的表面润滑性，满足高精度、大变形量壳体零件加工过程中连续高效冲压工艺要求；而传统的钢板在加工高精度、大变形壳体零件冲压过程中需要进行覆膜、涂油操作，加工成零件后还需要对零件进行清洗。用本发明所述带钢可以直接冲压加工高精度、大变形量壳体零件，与利用常规的钢板相比，省去了覆膜、涂油及成型后清洗等操作，可直接包装出厂，大幅提升零件制造效率；且带钢两个表面均涂敷硬脂酸盐，硬脂酸盐成膜后有效提升带钢表面的防锈和防腐蚀性能，带钢在仓储运输过程中不需要再进行防锈油的涂敷。
2、本发明提供的制造方法，基板进行脱脂和漂洗后，分别对基板两个表面进行活化和钝化处理，并控制过程中的参数，防止两个表面处理过程中的干扰，后续采用单 面磷化喷淋工艺+双面皂化工艺，实现两个表面差异化功能带钢的连续制造。
3、本发明采用高压喷淋的磷化工艺，在适当的装备长度条件下大幅降低了有效处理时间，带钢整体运行速度可以控制在40至80m/min，满足常规带钢高效制造的需求，使该方法可以直接连接于现有冷轧带钢连退平整工艺之后，也可以作为单独的带钢表面处理方式，实现两个表面差异化功能带钢的连续制造。
附图说明
图1为本发明带钢的结构示意图。
具体实施方式
下面通过附图和列举实施例和比较例对本发明进行具体说明，但本发明的范围并非通过这些实施例进行限定。
参见图1，其所示为本发明实施例带钢的结构，所述免涂油带钢包括基板，所述基板的A面由内至外依次包括磷化层1和硬脂酸盐润滑层2，基板的B面为硬脂酸盐润滑层2。
本发明实施例及比较例的基板成分参见表1，余量为Fe和除P、S之外的不可避免杂质。表2为实施例及比较例的制造工艺参数。本发明实施例和比较例工艺实施效果评价结果如表3所示。采用德国马尔Mahr MARSURF PS 10移动式粗糙度测量仪，对带钢的两种表面粗糙度R a(“轮廓算术平均偏差”)和R z(“微观不平度十点高度”)进行测量(测量参照标准GB/T 1031)。
本发明工艺实施效果评价标准：
(1)工艺过程——脱脂效果评估
通过脱脂后水洗过程表面水膜的连续状态对带钢表面脱脂清洗效果进行评价。目视观察脱脂后水洗表面水膜状态：
◎：表面水膜均匀连续，覆盖率100％；
×：表面水膜明显不连续，覆盖率小于100％。
(2)工艺过程——漂洗1后锈蚀现象
目视观察第一次漂洗后活化&钝化前带钢表面锈蚀情况：
◎：表面无锈蚀，锈蚀面积0％；
×：表面有锈点，锈蚀面积大于0％。
(3)工艺过程——磷化效果
磷化后取样通过SEM观察进行磷化处理的带钢上表面的磷化结晶尺寸：
◎：上表面磷化结晶尺寸8至20μm，结晶均匀分布，1g/m 2≤磷化膜重≤3g/m 2；
○：上表面磷化结晶尺寸8至20μm，但结晶局部分布不均，1g/m 2≤磷化膜重≤3g/m 2；
△：上表面磷化结晶尺寸＜8μm或＞20μm，磷化膜重＜1g/m 2或磷化膜重＞3g/m 2；
×：上表面无显著磷化结晶。
(4)工艺过程——清洁效果
磷化后取样通过SEM观察没有进行磷化处理的带钢下表面：
◎：无磷化结晶；
○：局部区域存在轻微磷化，无明显磷化结晶；
△：表面轻微磷化结晶；
×：表面明显磷化结晶。
由表3所示可知，实施例1-6按照本发明所述工序处理，获得的带钢工艺效果均表现优异，带钢的下表面为硬脂酸盐润滑层，其表面粗糙度R a≤0.3μm且R z≤2μm，具有良好的润滑性和高表面清洁度；带钢的上表面由内至外依次包括磷化层和硬脂酸盐润滑层，其表面粗糙度R a为0.6至1.8μm且R z为6至16μm，表面在延展过程中具有良好的表面润滑性，实现带钢两个表面的差异化功能设计，满足高精度、大变形量壳体零件加工过程中连续高效冲压工艺要求。
比较例1中磷化中未采用磷化阻隔处理工艺，导致下表面局部受到磷化影响形成明显磷化结晶。比较例2脱脂温度接近室温无法满足表面有效清洗，同时由于磷化时间短且喷淋压力过低导致上表面未形成显著磷化结晶。比较例3由于漂洗水1采用了电导率偏高的自来水导致，脱脂后水洗过程明显锈蚀现象，对后续磷化产生不良影响。
本发明实施例获得的带钢，参照ASTM B117标准对带钢表面进行中性盐雾实验，带钢表面24h无锈蚀产生，其耐蚀性明显优于常规涂油钢板(中性盐雾实验表面出现锈蚀时间约为12h)，说明本发明获得的带钢具有良好的防锈和防腐蚀性能，可以满足4个月储运带钢表面无锈蚀的耐蚀性要求。
表1
编号 C Si Mn Cr Al Mo P S
实施例1 0.1 0.2 1.22 1.02 0.04 0.05 0.02 0.015
实施例2 0.5 1.2 0.8 0.23 0.06 0.11 0.04 0.04
实施例3 0.2 0.8 1.7 0.61 0.01 0.15 0.02 0.01
实施例4 0.7 1.8 0.2 1.4 0.05 0.20 0.03 0.05
实施例5 0.3 2.0 0.3 0.82 0.03 0.08 0.015 0.03
实施例6 0.4 1.0 2.0 0.74 0.02 0.06 0.02 0.022
比较例1 0.4 1.1 0.9 1.3 0.03 0.06 0.03 0.02
比较例2 0.1 0.2 1.22 1.02 0.04 0.05 0.02 0.015
比较例3 0.3 2.0 0.3 0.82 0.03 0.08 0.015 0.03
表2
Figure PCTCN2023070391-appb-000001
表3
Figure PCTCN2023070391-appb-000002

Claims (13)

  1. 一种带钢，其中，所述带钢包括基板以及设置在基板上的磷化层和硬脂酸盐润滑层；
    在所述基板的厚度方向上，所述基板的上表面上由内至外依次设置有磷化层和硬脂酸盐润滑层，所述基板的下表面上设置有硬脂酸盐润滑层；
    所述带钢的上表面的表面粗糙度R a为0.6至1.8μm且R z为6至16μm，所述带钢的下表面的表面粗糙度R a≤0.3μm且R z≤2μm。
  2. 根据权利要求1所述的带钢，其中，所述基板除包含Fe和不可避免的杂质之外，还包含以wt％计的如下化学元素：C：0.1-0.7％，0.2％≤Si≤2％，0.2％≤Mn≤2％，Cr：0.2-1.4％，0.01％≤Al≤0.06％，Mo：0.05-0.2％；在不可避免的杂质中，P≤0.04％，S≤0.05％。
  3. 根据权利要求1或2所述的带钢，其中，所述基板包含以wt％计的如下化学元素：C：0.1-0.7％，0.2％≤Si≤2％，0.2％≤Mn≤2％，Cr：0.2-1.4％，0.01％≤Al≤0.06％，Mo：0.05-0.2％，余量为Fe和不可避免的杂质；在不可避免的杂质中，P≤0.04％，S≤0.05％。
  4. 根据权利要求1至3中任一项所述的带钢，其中，所述基板的厚度为1.0至6.0mm；优选地，所述磷化层中晶粒尺寸为8至20μm，和/或所述磷化层的重量为1至3g/m 2。
  5. 一种制造权利要求1至4中任一项所述的带钢的方法，包括如下步骤：
    1)脱脂
    钢材经张力辊进入装有碱性脱脂剂的脱脂槽，在30至60℃的脱脂温度下对钢材进行脱脂；
    2)第一次漂洗
    采用漂洗水对脱脂后的钢材表面进行漂洗，所述漂洗水为电导率≤10us/cm的工业纯水，或者所述漂洗水为自来水+0.2至1.1wt％的缓蚀剂；
    3)活化和钝化
    向漂洗后的钢材的上表面喷淋表面调整剂，以使钢材的上表面活化，其中，喷淋压力为0.4至1.2bar，喷淋方向与钢材运行方向呈90至135°夹角；向钢材的下表面涂敷具有磷化阻隔功能的钝化处理剂，以使钢材的下表面钝化；
    4)磷化
    通过高压喷淋磷化剂，对活化后的钢材上表面进行磷化处理，其中，磷化处 理时间6至12s，喷淋压力5至8bar，喷淋方向与钢材运行方向呈90至135°、优选100至120°的夹角；
    5)第二次漂洗
    采用电导率≤10us/cm的工业纯水对钢材表面进行漂洗，漂洗后进行表面挤干处理；
    6)皂化
    向钢材的上表面和下表面涂敷硬脂酸盐处理剂，采用压缩空气对钢材表面进行吹扫、擦拭辊处理，其中，涂敷温度为70至90℃。
  6. 根据权利要求5所述的方法，其中，步骤2)中，采用喷淋的方式对钢材表面进行漂洗，喷淋压力为2至4bar。
  7. 根据权利要求5所述的方法，其中，步骤2)中，所述缓蚀剂选自磷酸钠、亚硝酸钠、苯甲酸钠和硅酸钠中的一种或多种。
  8. 根据权利要求5所述的方法，其中，步骤3)中，所述钝化处理剂为Zr酸盐系钝化处理剂或Cr酸盐系钝化处理剂；优选地，通过喷淋、辊涂和刷涂中的一种或多种来涂覆钝化处理剂。
  9. 根据权利要求5所述的方法，其中，步骤5)中，采用喷淋方式对钢材表面进行漂洗，喷淋压力为1至4bar，喷淋方向与钢材运行方向呈90至120°夹角。
  10. 根据权利要求5所述的方法，其中，步骤6)中，采用喷淋方式涂敷硬脂酸盐处理剂。
  11. 根据权利要求5所述的方法，其中，步骤6)中，所述硬脂酸盐处理剂中的硬脂酸盐为C18或C16的硬脂酸盐；优选地，所述硬脂酸盐处理剂包含硬脂酸钠、硬脂酸镁和硬脂酸锌中的一种或多种。
  12. 根据权利要求5所述的方法，其中，步骤3)和/或步骤4)中，在所述钢材的宽度方向上，在距离钢材两侧边缘2至6cm、优选3至5cm处各自设置有活动挡板。
  13. 根据权利要求5所述的方法，其中，步骤3)和/或步骤4)中，所述钢材运行速度为40至80m/min。
PCT/CN2023/070391 2022-01-19 2023-01-04 一种带钢及其制造方法 WO2023138372A1 (zh)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1754009A (zh) * 2002-12-24 2006-03-29 坎梅陶尔股份有限公司 在金属表面上提供薄腐蚀抑制涂层的方法
CN106947963A (zh) * 2017-03-28 2017-07-14 东北大学 一种在超低碳钢表面制备超疏水膜的方法
CN109679420A (zh) * 2018-12-27 2019-04-26 武汉材料保护研究所有限公司 一种预涂覆于冲压成形加工板材表面的双层固体膜及其制备方法
CN111893276A (zh) * 2020-08-03 2020-11-06 宝钢金属有限公司 一种环保耐热高温合金钢丝制备方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN1754009A (zh) * 2002-12-24 2006-03-29 坎梅陶尔股份有限公司 在金属表面上提供薄腐蚀抑制涂层的方法
CN106947963A (zh) * 2017-03-28 2017-07-14 东北大学 一种在超低碳钢表面制备超疏水膜的方法
CN109679420A (zh) * 2018-12-27 2019-04-26 武汉材料保护研究所有限公司 一种预涂覆于冲压成形加工板材表面的双层固体膜及其制备方法
CN111893276A (zh) * 2020-08-03 2020-11-06 宝钢金属有限公司 一种环保耐热高温合金钢丝制备方法

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