CN102716905B - A kind of production method of cold-rolled sheet for surface coating plated substrate - Google Patents

Abstract

The invention discloses a method for producing a cold-rolled sheet for a surface coating and plating base plate. A steel billet comprises the following compositions by weight percentage: at most 0.12 percent of C, at most 0.05 percent of Si, at most 0.60 percent of Mn, at most 0.04 percent of P, at most 0.04 percent of S, and the balance of Fe. The steel billet comprising the compositions is sequentially subjected to hot rolling, acid washing and cold rolling to obtain a cold-rolled steel coil, and then the cold-rolled steel coil is made into the cold-rolled sheet for the surface coating and plating base plate through a continuous annealing or galvanizing method. Continuous annealing coating and plating bases plate and galvanizing coating and plating base plates produced through the method for producing the cold-rolled sheet for the surface coating and plating base plate have a good formability, meanwhile also have a good surface quality and paintability, and can be used as base plates of high-grade electric galvanized sheets, prepainted steel sheets, tinning sheets and aluminized steel sheets.

Description

A kind of production method of cold-rolled sheet for surface coating plated substrate

technical field

The invention relates to the field of metal material processing, in particular to a production method of a cold-rolled sheet for a surface-coated substrate

Background technique

Cold-rolled coated substrates are used as raw materials for electro-galvanized, aluminum-plated, color-coated, tin-plated and other products. There are mainly two kinds of cold-rolled coated substrates: continuous strip coating substrate and galvanized coating substrate. Continuous strip coating substrate is generally used for electrogalvanizing, color coating, tin plating, aluminum plating, etc. Prepainted. Because the customer needs to coat a layer of other metals or substances on the surface of the strip during the subsequent processing of the coated substrate, if the coating is relatively thick, it can cover up some defects on the substrate, if the coating is relatively thin , which in most cases will amplify some defects on the substrate. The actual situation is mostly the latter. In the subsequent coating process of most customers, the coating layer is relatively thin (especially electro-galvanized), so the chromatic aberration, roller printing, scratches, and zinc flow marks on the surface of the substrate will be affected. and other defects magnified. Customers have high requirements on the surface quality of the final product (especially when used for home appliance panels), so the surface quality of the raw substrate must be strictly controlled. However, when traditional cold-rolled coated substrates are cold-rolled, continuously annealed, and galvanized, the work rolls of the rolling mill, the work rolls of the continuous annealing mill, and the work rolls of the galvanizing skin pass machine all use ordinary Cr3 or Cr5 rolls, and the surface quality is relatively low. Poor, mainly due to defects such as chromatic aberration, roller printing, scratches, light and dark stripes, zinc flow lines, etc., which cannot meet the requirements of high-end customers.

Contents of the invention

The technical problem to be solved by the present invention is to provide a method for producing a cold-rolled thin plate for surface-coated substrates with high surface quality and meeting the requirements of high-end customers.

In order to solve the above technical problems, the invention provides a method for producing a cold-rolled sheet for a surface-coated substrate, comprising the steps of:

1) Steel billets are produced by steelmaking;

2) hot-rolling, pickling, and cold-rolling the billets to obtain cold-rolled steel coils;

3) The cold-rolled steel coil is produced through a continuous annealing production process or a galvanizing production process to obtain a cold-rolled sheet for a surface-coated substrate, wherein the continuous annealing production process is alkali cleaning, annealing and smoothing; Annealing, galvanizing and skin pass;

The technical parameter control in the production technology that described billet makes cold-rolled steel coil is as follows:

In the hot rolling process, the exit temperature is 1250±30°C, the exit temperature of rough rolling is 1100±10°C, the final rolling temperature is 930±20°C, and the coiling temperature is 730±20°C;

In the pickling process, the free acid concentration of the 1# acid tank is controlled at 50-55g/L, the pickling temperature is 75-90°C, and the pickling speed is 140-200m/min;

In the cold rolling process, the work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls, and the surface roughness of the work rolls of the rolling mill is controlled to be 0.7-0.8 μm for stands 1 and 2, and Ra for stands 3 and 4. 0.6～0.7μm, 5 frame roughness Ra is 3.0μm; emulsion concentration is 1～4 frame emulsion concentration is 2.5～4.5%, 5 frame emulsion concentration is 0.5～1.5%; The rate is controlled within the range of 60-85%;

The technical parameters are controlled as follows in the described continuous annealing production process:

In the alkaline cleaning process, the conductivity of the NaOH solution in the 1# alkali immersion tank and scrubbing tank and 2# alkali immersion tank and scrubbing tank is controlled at 30000-50000us/cm, and the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 50000-80000us/cm cm, use more than 10 brush rollers in the cleaning section;

The heating temperature of the continuous annealing furnace is 750-790°C;

The working roll of the tempering machine adopts chrome-plated roll, the surface roughness is 2.4μm, the Pc value is ≥ 80, the leveling elongation is controlled within the range of 0.6-1.5%, and the roll period is controlled within 150km;

Technical parameter control is as follows in the described galvanizing production process:

In the alkali cleaning process, the conductivity of the NaOH solution in the alkali immersion tank and brushing tank is controlled at 30000-50000us/cm, the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 50000-80000us/cm, and more than 8 brush rollers are used in the cleaning section;

The heating temperature of the continuous annealing furnace is 750-790°C, and the annealing time is 40-100s;

In the galvanizing process, the temperature of the zinc liquid is 460±5°C, the temperature of the strip steel is controlled at 450-470°C before entering the zinc pot, the galvanizing time is 5-20s, and the air knife sprays N ₂ ;

The working roll of the skin pass machine adopts chrome-plated roll, the surface roughness is 2.4μm, the Pc value is ≥ 80, the skin pass elongation is controlled within the range of 0.5-1.4%, the roll period is controlled within 120km, and the process speed is controlled within 100-150m/min within range.

Further, the mass percent of the chemical composition of the billet is: C≤0.12%, Si≤0.05%, Mn≤0.60%, P≤0.04%, S≤0.04%, and the balance is Fe.

Further, the mass percent of the chemical composition of the billet is: C≤0.10%, Si≤0.040%, Mn≤0.40%, P≤0.030%, S≤0.030%, and the balance is Fe.

Further, the mass percentage of the chemical composition of the billet is: C≤0.08%, Si≤0.050%, Mn≤0.40%, P≤0.020%, S≤0.025%, and the balance is Fe.

The invention provides a method for producing cold-rolled thin plates for surface-coated substrates. The cold-rolled coated substrates produced, no matter whether they are continuously stripped coated substrates or galvanized coated substrates, have a bright and clean surface, and the surface quality can reach FC Above grade, it not only has excellent formability, but also has excellent surface quality and coating performance, and can be used as a substrate for high-grade electro-galvanized sheets, color-coated sheets, tin-plated sheets, and aluminum-coated sheets.

Description of drawings

FIG. 1 is a metallographic structure diagram of a surface continuous decoating substrate provided in Example 1 of the present invention.

Detailed ways

The present invention provides a cold-rolled thin plate for surface-coated substrates. The mass percentage of the chemical composition of the billet obtained from steelmaking is: C≤0.12%, Si≤0.05%, Mn≤0.60%, P≤0.04%, S≤0.04% , the balance being Fe. Depending on the end use of the product, such as for ordinary stamping, stamping, and deep drawing, the components of the steel billet can be further optimized into the following three types, and the specific chemical composition mass percentages are shown in Table 1 (the balance is Fe):

Table 1 Chemical composition of billets for surface coating substrates

C≤ Si≤ Mn≤ P≤ S≤ Preferred 1 0.12 0.050 0.60 0.040 0.04 Preferred 2 0.10 0.040 0.40 0.030 0.030 Preferred 3 0.08 0.050 0.40 0.020 0.025

The steel slabs with the above-mentioned chemical composition mass percentages are hot-rolled, pickled and cold-rolled successively to obtain cold-rolled steel coils. Obtain a cold-rolled thin plate for a surface-coated substrate; when producing a galvanized surface-coated substrate, the obtained cold-rolled steel coil is then subjected to alkali washing, continuous annealing, galvanizing, and smoothing to obtain a cold-rolled thin plate for a surface-coated substrate.

The production methods of continuous annealing coated substrates and galvanized coated substrates are the same in steelmaking, hot rolling, pickling and cold rolling processes:

In the hot rolling step, the heating temperature of the billet during hot rolling is 1280±20°C, the final rolling temperature is 910±20°C, the coiling temperature is 710±20°C, and the surface quality level of the hot-rolled coil is controlled to be 1-2. Control the surface quality of the strip from the source to ensure that the final cold-rolled coated substrate meets the high-level surface quality requirements.

In the pickling step, the free acid in the 1# acid tank is controlled at 50-55g/L, the pickling temperature is 75-90°C, and the pickling speed is 140-200m/min. By strictly controlling the acid concentration, temperature and pickling speed, Ensure that the iron oxide scale, iron powder and other impurities on the surface of the strip are cleaned, keep the pickling speed stable during production, and avoid under-pickling and over-pickling.

In the cold rolling step, the work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls; the surface roughness control of the work rolls of the rolling mill: the surface roughness of the work rolls of stands 1 and 2 is 0.7-0.8 μm, and that of stands 3 and 4 The surface roughness Ra of the work roll is 0.6-0.7 μm, and the surface roughness Ra of the 5-stand work roll is 3.0 μm; the concentration of the emulsion: the concentration of the emulsion of 1-4 stands is 2.5-4.5%, and the concentration of the emulsion of the 5-stand is 0.5-1.5%; the reduction rate of cold rolling is controlled within the range of 60-85%. Compared with ordinary rollers, chrome-plated rollers have higher hardness, smoothness, wear resistance and scraping performance, can effectively eliminate or reduce surface defects such as color difference, roller marks, scratches, zinc flow lines, etc., and have a longer service life . The cold rolling process strictly controls the surface roughness of the work rolls of each stand and the concentration of the emulsion, which can ensure the stability of the rolling process, reduce the slippage of the strip, avoid scratches and scratches on the surface of the strip, and ensure that the surface of the strip is clean.

When producing surface continuous decoating and plating substrates, in the alkali cleaning step, the conductivity of the NaOH solution in the 1# alkali immersion tank and brushing tank, 2# alkali immersion tank and brushing tank is controlled at 30000-50000us/cm, and the NaOH solution in the electrolytic cleaning tank The conductivity is controlled at 50000-80000us/cm, and more than 10 (including 10) brush rollers in the cleaning section must be put into use to ensure that the residual emulsion, iron powder and other sundries on the surface of the strip are cleaned. In the continuous annealing step, the annealing heating temperature is controlled within the range of 750-790°C. In the leveling step, the working rolls of the tempering machine are chrome-plated rolls, the surface roughness is 2.4 μm, the Pc value is ≥ 80, the leveling elongation is controlled within the range of 0.6-1.5%, and the roll period is controlled within 150km.

When producing surface galvanized and coated substrates, in the alkali cleaning step, the conductivity of the NaOH solution in the alkali immersion tank and brushing tank is controlled at 30000-50000us/cm, and the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 50000-80000us/cm. Section brush rollers must ensure that more than 8 (including 8) are put into use to ensure that the residual emulsion, iron powder and other sundries on the surface of the strip are cleaned. In the continuous annealing step, the annealing heating temperature is controlled within the range of 750-790° C., and the annealing time is controlled within the range of 40-100 s. In the galvanizing step, the temperature of the zinc liquid is 460±5°C, the temperature of the strip steel before entering the zinc pot is controlled at 450-470°C, the galvanizing time is controlled at 5-20s, and nitrogen N ₂ is injected by the air knife to ensure that the surface of the zinc pot The liquid and strip zinc layer are not oxidized to cause zinc slag defects, thereby ensuring the surface quality of the final product. In the skin-passing step, the working rolls of the skin-passing machine are chrome-plated rolls, the surface roughness is 2.4 μm, the Pc value is ≥ 80, the skinning elongation is controlled within the range of 0.5-1.4%, and the roll period is controlled within 120km. The speed of the process section is controlled within the range of 100-150m/min to keep the tension and speed stable and avoid defects such as scratches on the strip surface caused by the production process.

The following examples illustrate the production method of the cold-rolled sheet for surface-coated substrates provided by the present invention.

Example 1:

The mass percentages of steel billets used are: C, 0.12%; Si, 0.050%; Mn, 0.60%; P, 0.040%; S, 0.04%;

The tapping temperature is 1280°C, the exit temperature of rough rolling is 1200°C, the final rolling temperature is 950°C, and the coiling temperature is 750°C.

The free acid in pickling 1# acid tank is controlled at 55g/L, the pickling temperature is 90°C, and the pickling speed is 200m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified liquid is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 85%.

The subsequent process adopts the continuous annealing process to produce the surface coated substrate.

Alkali cleaning 1# alkali immersion tank and brushing tank, 2# alkali immersion tank and brushing tank NaOH solution conductivity is controlled at 50000us/cm, electrolytic cleaning tank NaOH solution conductivity is controlled at 80000us/cm, and 11 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 790°C.

The working rolls of the tempering machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 90, the leveling elongation is controlled at 1.5%, the rolling period of the working rolls of the tempering machine is controlled within 140-145km, and the thickness of the finished product is 2.4mm.

The metallographic structure of the obtained surface continuous strip coating substrate is shown in Figure 1, and the physical properties and surface quality of the product are shown in Table 2.

Example 2:

The mass percentages of steel billets used are: C, 0.11%; Si, 0.040%; Mn, 0.50%; P, 0.035%; S, 0.036%, and the balance is Fe.

The tapping temperature is 1220°C, the exit temperature of rough rolling is 1090°C, the final rolling temperature is 910°C, and the coiling temperature is 710°C.

Pickling 1# acid tank free acid concentration 5g/L, pickling temperature 75°C, pickling speed 140m/min.

The work rolls of stands 1, 2, and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.7 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.6 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified solution is 2.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 0.5%. Cold rolling reduction rate is controlled at 60%.

The subsequent process adopts the continuous annealing process to produce the surface coated substrate.

Alkali cleaning 1# alkali immersion tank and brushing tank, 2# alkali immersion tank and brushing tank, the conductivity of NaOH solution is controlled at 30000us/cm, the conductivity of electrolytic cleaning tank NaOH solution is controlled at 50000us/cm, and 10 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 750°C.

The working rolls of the tempering machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 80, the tempering elongation is controlled at 0.6%, and the rolling period of the tempering machine working rolls is controlled within 10-15km. Finished product thickness is 0.5mm.

The physical performance and surface quality of the product are shown in Table 2.

Example 3:

The mass percentages of steel billets used are: C, 0.09%; Si, 0.040%; Mn, 0.40%; P, 0.030%; S, 0.03%, and the balance is Fe.

The tapping temperature is 1250°C, the exit temperature of rough rolling is 1105°C, the final rolling temperature is 935°C, and the coiling temperature is 734°C.

The free acid in pickling 1# acid tank is controlled at 53g/L, the pickling temperature is 80°C, and the pickling speed is 180m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified liquid is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 81%.

The subsequent process adopts the continuous annealing process to produce the surface coated substrate.

Alkali cleaning 1# alkali immersion tank and brushing tank, 2# alkali immersion tank and brushing tank NaOH solution conductivity is controlled at 45000us/cm, electrolytic cleaning tank NaOH solution conductivity is controlled at 77000us/cm, and 11 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 780°C.

The working rolls of the tempering machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 90, the tempering elongation is controlled at 1.2%, and the rolling period of the tempering machine working rolls is controlled within 140-145km. The thickness of the finished product is 1.0mm.

The physical performance and surface quality of the product are shown in Table 2.

Example 4:

The mass percentages of steel billets used are: C, 0.08%; Si, 0.045%; Mn, 0.35%; P, 0.020%; S, 0.02%, and the balance is Fe.

The tapping temperature is 1252°C, the exit temperature of rough rolling is 1108°C, the final rolling temperature is 933°C, and the coiling temperature is 732°C.

The free acid in pickling 1# acid tank is controlled at 53g/L, the pickling temperature is 80°C, and the pickling speed is 180m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified liquid is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 81%.

The subsequent process adopts the continuous annealing process to produce the surface coated substrate.

Alkali cleaning 1# alkali immersion tank and brushing tank, 2# alkali immersion tank and brushing tank NaOH solution conductivity is controlled at 45000us/cm, electrolytic cleaning tank NaOH solution conductivity is controlled at 77000us/cm, and 11 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 780°C.

The working rolls of the tempering machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 90, the tempering elongation is controlled at 1.2%, and the rolling period of the tempering machine working rolls is controlled within 140-145km. The thickness of the finished product is 1.0mm.

The physical performance and surface quality of the product are shown in Table 2.

Example 5:

The mass percentages of steel billets used are: C, 0.12%; Si, 0.050%; Mn, 0.60%; P, 0.040%; S, 0.04%, and the balance is Fe.

The tapping temperature is 1280°C, the exit temperature of rough rolling is 1200°C, the final rolling temperature is 950°C, and the coiling temperature is 750°C.

The free acid in pickling 1# acid tank is controlled at 55g/L, the pickling temperature is 90°C, and the pickling speed is 200m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified liquid is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 85%.

The subsequent process adopts the galvanizing process to produce the surface-coated substrate.

The conductivity of the NaOH solution in the alkaline washing tank and scrubbing tank is controlled at 50000us/cm, the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 80000us/cm, and 9 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 790°C, and the annealing time is 100s.

Galvanizing process: the temperature of the zinc solution is 465°C, the temperature of the strip steel before entering the zinc pot is 470°C, the galvanizing time is 20s, and the air knife sprays N ₂ .

The working rolls of the skin pass machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 90, the skin pass elongation is controlled at 1.4%, and the roll period of the skin pass machine work rolls is controlled within 120km. The thickness of the finished product is 2.4mm.

The process speed is controlled at about 150m/min.

The physical performance and surface quality of the product are shown in Table 2.

Embodiment 6:

The mass percentages of steel billets used are: C, 0.11%; Si, 0.040%; Mn, 0.50%; P, 0.035%; S, 0.036%, and the balance is Fe.

The tapping temperature is 1220°C, the exit temperature of rough rolling is 1090°C, the final rolling temperature is 910°C, and the coiling temperature is 710°C.

The free acid concentration of pickling 1# acid tank is 50g/L, the pickling temperature is 75°C, and the pickling speed is 140m/min.

The work rolls of stands 1, 2, and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.7 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.6 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified solution is 2.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 0.5%. Cold rolling reduction rate is controlled at 60%.

The subsequent process adopts the galvanizing process to produce the surface-coated substrate.

The conductivity of the NaOH solution in the alkali immersion tank and scrubbing tank is controlled at 30000us/cm, the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 50000us/cm, and 8 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 750°C.

The working rolls of the skin pass machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 80, the skin pass elongation is controlled at 0.5%, and the roll period of the skin pass machine work rolls is controlled within 10-15km. The finished product thickness is 0.5mm.

The process speed is controlled at about 100m/min.

The physical performance and surface quality of the product are shown in Table 2.

Embodiment 7:

The mass percentages of steel billets used are: C, 0.09%; Si, 0.040%; Mn, 0.40%; P, 0.030%; S, 0.030%, and the balance is Fe.

The tapping temperature is 1250°C, the exit temperature of rough rolling is 1105°C, the final rolling temperature is 935°C, and the coiling temperature is 734°C.

The free acid in pickling 1# acid tank is controlled at 53g/L, the pickling temperature is 80°C, and the pickling speed is 180m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified solution is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 81%.

The subsequent process adopts the galvanizing process to produce the surface-coated substrate.

The conductivity of the NaOH solution in the alkaline washing tank and brushing tank is controlled at 45000us/cm, the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 77000us/cm, and 8 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 780°C.

The working rolls of the skin pass machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 85, the skin pass elongation is controlled at 1.2%, and the roll period of the skin pass machine work rolls is controlled within 10-15km. The thickness of the finished product is 1.0mm.

The process speed is controlled at about 120m/min.

The physical performance and surface quality of the product are shown in Table 2.

Embodiment 8:

The mass percentages of steel billets used are: C, 0.08%; Si, 0.045%; Mn, 0.35%; P, 0.020%; S, 0.020%, and the balance is Fe.

The tapping temperature is 1252°C, the exit temperature of rough rolling is 1108°C, the final rolling temperature is 933°C, and the coiling temperature is 732°C.

The free acid in pickling 1# acid tank is controlled at 53g/L, the pickling temperature is 80°C, and the pickling speed is 180m/min.

The work rolls of stands 1, 2 and 5 of the rolling mill use chrome-plated rolls. The surface roughness Ra of the work rolls of stands 1 and 2 is 0.8 μm, the surface roughness of the work rolls of stands 3 and 4 is 0.7 μm, and the surface roughness of the work rolls of stand 5 is The roughness Ra is 3.0 μm; the concentration of the emulsified solution is 4.5% for racks 1 to 4, and the concentration of the emulsified liquid for racks 5 is 1.5%. Cold rolling reduction rate is controlled at 81%.

The subsequent process adopts the galvanizing process to produce the surface-coated substrate.

The conductivity of the NaOH solution in the alkaline washing tank and brushing tank is controlled at 45000us/cm, the conductivity of the NaOH solution in the electrolytic cleaning tank is controlled at 77000us/cm, and 8 brush rollers are put into the cleaning section.

The heating temperature of the continuous annealing furnace is 780°C.

The working rolls of the skin pass machine are chrome-plated rolls, the surface roughness is 2.4μm, the Pc value is 85, the skin pass elongation is controlled at 1.2%, and the roll period of the skin pass machine work rolls is controlled within 10-15km. The thickness of the finished product is 1.0mm.

The process speed is controlled at about 150m/min.

The physical performance and surface quality of the product are shown in Table 2.

Table 2 Physical performance and surface quality of the product

Finally, it should be noted that the above specific embodiments are only used to illustrate the technical solutions of the present invention without limitation, although the present invention has been described in detail with reference to examples, those of ordinary skill in the art should understand that the technical solutions of the present invention can be carried out Modifications or equivalent replacements without departing from the spirit and scope of the technical solution of the present invention shall be covered by the claims of the present invention.

Claims (3)

1. a production method for flat cold-rolled sheet for Coating substrate, comprises the steps:

1) steel-making makes steel billet;

2) steel billet is made to cold-rolled steel coils by hot rolling, pickling and cold-rolling production process;

3) cold-rolled steel coils is moved back to production technology by company or zinc-plated production technology makes Coating substrate flat cold-rolled sheet, wherein, connect that to move back production technology be alkali cleaning, annealing and smooth, zinc-plated production technology is alkali cleaning, annealing, zinc-plated and polishing;

It is characterized in that,

Described steel billet chemical composition mass percent is: C≤0.12%, and Si≤0.05%, Mn≤0.60%, P≤0.04%, S≤0.04%, surplus is Fe;

It is as follows that described steel billet makes in the production technology of cold-rolled steel coils technical parameter control:

In hot rolling technology, tapping temperature is 1250 ± 30 DEG C, and roughing outlet temperature is 1100 ± 10 DEG C, and finishing temperature is 930 ± 20 DEG C, and coiling temperature is 730 ± 20 DEG C;

In acid cleaning process, 1# acid tank free acid concentration is controlled at 50～55g/L, 75～90 DEG C of pickling temperatures, pickling speed 140～200m/min;

In cold-rolling process, milling train 1,2,5 frame working rolls use chrome-plated roller, and operation roll of mill Roughness Surface on Control is that 1,2 frame roughness Ras are 0.7～0.8 μ m, and 3,4 frame roughness Ras are 0.6～0.7 μ m, and 5 frame roughness Ras are 3.0 μ m; Concentration of emulsion used is that 1～4 frame concentration of emulsion used is that 2.5～4.5%, 5 frame concentration of emulsion used are 0.5～1.5%; Cold rolling reduction ratio is controlled within the scope of 60-85%;

It is as follows that technical parameter control is moved back in production technology by described company:

In alkali washing process, 1# alkali immersion trough and scrub groove and 2# alkali immersion trough and the NaOH electrical conductivity of solution of scrubbing groove are controlled at 30000-50000us/cm, the NaOH electrical conductivity of solution of electrolytic cleaning tank is controlled at 50000-80000us/cm, and cleaning section brush roll uses more than 10;

Continuous annealing furnace heating-up temperature is 750～790 DEG C;

Planisher working roll adopts chrome-plated roller, surface roughness 2.4 μ m, and Pc value >=80, smooth elongation control is in 0.6～1.5% scope, within the roller phase is controlled at 150km;

In described zinc-plated production technology, technical parameter control is as follows:

In alkali washing process, alkali immersion trough and scrub groove NaOH electrical conductivity of solution and be controlled at 30000-50000us/cm, electrolytic cleaning tank NaOH electrical conductivity of solution is controlled at 50000-80000us/cm, and cleaning section brush roll uses more than 8;

750～790 DEG C of continuous annealing furnace heating-up temperatures, annealing time 40～100s;

In zincincation, 460 ± 5 DEG C of zinc liquid temperatures, before band steel enters zinc pot, temperature is controlled at 450～470 DEG C, zinc-plated time 5～20s, air knife winding-up N ₂;

Polishing machine working roll adopts chrome-plated roller, surface roughness 2.4 μ m, and Pc value >=80, polishing elongation control is in 0.5～1.4% scope, and within the roller phase is controlled at 120km, process speed is controlled within the scope of 100～150m/min.

2. the production method of flat cold-rolled sheet for Coating substrate according to claim 1, is characterized in that, described steel billet chemical composition mass percent is: C≤0.10%, Si≤0.040%, Mn≤0.40%, P≤0.030%, S≤0.030%, surplus is Fe.

3. the production method of flat cold-rolled sheet for Coating substrate according to claim 2, is characterized in that, described steel billet chemical composition mass percent is: C≤0.08%, Si≤0.050%, Mn≤0.40%, P≤0.020%, S≤0.025%, surplus is Fe.