CN114934248A - Production method of hot-base galvanized plate for refrigerator slide rail - Google Patents
Production method of hot-base galvanized plate for refrigerator slide rail Download PDFInfo
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- CN114934248A CN114934248A CN202210328971.3A CN202210328971A CN114934248A CN 114934248 A CN114934248 A CN 114934248A CN 202210328971 A CN202210328971 A CN 202210328971A CN 114934248 A CN114934248 A CN 114934248A
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- 238000004519 manufacturing process Methods 0.000 title claims abstract description 38
- 238000005096 rolling process Methods 0.000 claims abstract description 58
- 238000005246 galvanizing Methods 0.000 claims abstract description 35
- 238000000034 method Methods 0.000 claims abstract description 35
- 238000005554 pickling Methods 0.000 claims abstract description 25
- 229910000831 Steel Inorganic materials 0.000 claims abstract description 23
- 239000010959 steel Substances 0.000 claims abstract description 23
- 239000002253 acid Substances 0.000 claims abstract description 22
- 238000010438 heat treatment Methods 0.000 claims abstract description 21
- 238000009749 continuous casting Methods 0.000 claims abstract description 19
- 230000008569 process Effects 0.000 claims abstract description 18
- 238000009628 steelmaking Methods 0.000 claims abstract description 8
- 238000005406 washing Methods 0.000 claims abstract description 8
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims abstract description 5
- 238000007747 plating Methods 0.000 claims description 18
- 238000005498 polishing Methods 0.000 claims description 13
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims description 12
- 239000011701 zinc Substances 0.000 claims description 12
- 229910052725 zinc Inorganic materials 0.000 claims description 12
- 230000006698 induction Effects 0.000 claims description 10
- 238000002161 passivation Methods 0.000 claims description 6
- 238000002791 soaking Methods 0.000 claims description 6
- 239000000758 substrate Substances 0.000 claims description 6
- 238000010583 slow cooling Methods 0.000 claims description 5
- 238000003723 Smelting Methods 0.000 claims description 4
- 239000012535 impurity Substances 0.000 claims description 4
- 238000005461 lubrication Methods 0.000 claims description 3
- 229910052698 phosphorus Inorganic materials 0.000 abstract description 3
- 239000011574 phosphorus Substances 0.000 abstract description 3
- 229910052799 carbon Inorganic materials 0.000 description 11
- 239000000047 product Substances 0.000 description 10
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 8
- 239000010936 titanium Substances 0.000 description 7
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 6
- 238000005098 hot rolling Methods 0.000 description 6
- 229910052760 oxygen Inorganic materials 0.000 description 6
- 239000001301 oxygen Substances 0.000 description 6
- 238000001556 precipitation Methods 0.000 description 6
- 230000009467 reduction Effects 0.000 description 6
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 5
- 238000001816 cooling Methods 0.000 description 5
- 230000007547 defect Effects 0.000 description 5
- 239000002994 raw material Substances 0.000 description 5
- 239000006104 solid solution Substances 0.000 description 5
- 230000003746 surface roughness Effects 0.000 description 5
- 125000004429 atom Chemical group 0.000 description 4
- 238000007664 blowing Methods 0.000 description 4
- 238000005266 casting Methods 0.000 description 4
- 238000005728 strengthening Methods 0.000 description 4
- 230000032683 aging Effects 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 239000007788 liquid Substances 0.000 description 3
- 238000010079 rubber tapping Methods 0.000 description 3
- 229910052719 titanium Inorganic materials 0.000 description 3
- 229910052782 aluminium Inorganic materials 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000009286 beneficial effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 230000004907 flux Effects 0.000 description 2
- 238000009489 vacuum treatment Methods 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 1
- 229910000997 High-speed steel Inorganic materials 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- ATJFFYVFTNAWJD-UHFFFAOYSA-N Tin Chemical compound [Sn] ATJFFYVFTNAWJD-UHFFFAOYSA-N 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive effect Effects 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 229910001566 austenite Inorganic materials 0.000 description 1
- 230000008901 benefit Effects 0.000 description 1
- 230000005540 biological transmission Effects 0.000 description 1
- 238000005097 cold rolling Methods 0.000 description 1
- 230000000052 comparative effect Effects 0.000 description 1
- 238000010924 continuous production Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000005261 decarburization Methods 0.000 description 1
- 230000002500 effect on skin Effects 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000004134 energy conservation Methods 0.000 description 1
- 239000012467 final product Substances 0.000 description 1
- 239000008397 galvanized steel Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000004615 ingredient Substances 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 150000004767 nitrides Chemical class 0.000 description 1
- 229910052757 nitrogen Inorganic materials 0.000 description 1
- 125000004433 nitrogen atom Chemical group N* 0.000 description 1
- 238000005457 optimization Methods 0.000 description 1
- 230000008520 organization Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000003908 quality control method Methods 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000007670 refining Methods 0.000 description 1
- 239000008237 rinsing water Substances 0.000 description 1
- 239000002893 slag Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 230000035882 stress Effects 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 239000011135 tin Substances 0.000 description 1
- 238000003466 welding Methods 0.000 description 1
Classifications
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/04—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the coating material
- C23C2/06—Zinc or cadmium or alloys based thereon
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B22—CASTING; POWDER METALLURGY
- B22D—CASTING OF METALS; CASTING OF OTHER SUBSTANCES BY THE SAME PROCESSES OR DEVICES
- B22D11/00—Continuous casting of metals, i.e. casting in indefinite lengths
- B22D11/001—Continuous casting of metals, i.e. casting in indefinite lengths of specific alloys
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C18/00—Alloys based on zinc
- C22C18/04—Alloys based on zinc with aluminium as the next major constituent
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C33/00—Making ferrous alloys
- C22C33/04—Making ferrous alloys by melting
-
- 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
- C22C38/004—Very low carbon steels, i.e. having a carbon content of less than 0,01%
-
- 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
- C22C38/14—Ferrous alloys, e.g. steel alloys containing titanium or zirconium
-
- 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
- C23C2/00—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor
- C23C2/34—Hot-dipping or immersion processes for applying the coating material in the molten state without affecting the shape; Apparatus therefor characterised by the shape of the material to be treated
- C23C2/36—Elongated material
- C23C2/40—Plates; Strips
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Coating With Molten Metal (AREA)
Abstract
The invention discloses a method for producing a hot-base galvanized plate for a refrigerator slide rail, which belongs to the technical field of steel production and comprises the following process flow routes: steel making → continuous casting → hot continuous rolling → continuous pickling and galvanizing; continuous acid pickling and galvanizing: comprises the steps of straightening and phosphorus breaking, acid washing, rinsing, heating, galvanizing, finishing, passivating and straightening. The galvanized product has the performance yield strength of less than or equal to 290MPa, the tensile strength of less than or equal to 400MPa and the elongation of more than or equal to 31 percent, and meets the requirement of stamping and forming a refrigerator slide rail.
Description
Technical Field
The invention relates to the technical field of steel production, in particular to a production method of a hot-base galvanized plate suitable for a refrigerator slide rail.
Background
The refrigerator slide rail is divided into an outer rail, a middle rail and an inner rail, and a galvanized plate with the thickness of 1.0-2.0mm and the thickness tolerance of +/-0.04 mm is mainly used. The surface quality requirement is high, and the galvanized surface cannot have the defects of zinc flow marks, color difference, scratches and the like; the ball type slide rail reduces the noise requirement, and the surface roughness is less than 1.0 mu; the yield strength is 260-300MPa, the tensile strength is 360-420MPa, the elongation is 30-39%, and the hardness requirement is 66-73HRB, so that the requirements of slide rail forming and wear resistance are met.
At present, cold-base zinc plating is generally adopted in the industry to prepare the slide rail, but based on the initial purpose of energy conservation and emission reduction, the use of hot-base zinc-plated plates in the slide rail field to replace cold-base zinc plating is continuously explored in recent years. As reported by the same company, the method for manufacturing 500 MPa-grade seat slide rail steel based on a continuous casting and rolling line (CN202110116290.6) is used for producing a hot base plate with the thickness of 1.5-3.0mm, and can realize the thin specification of 2.0mm or less. But the method can only produce the automobile seat slide rail, the yield strength is more than or equal to 500MPa, the tensile strength is more than or equal to 600MPa, and the elongation A80 after fracture is 17-19%; a process for producing galvanized sheet without zinc flower (CN202010246403.X) with 1.2-4.0mm grid features that the yield strength of product is greater than or equal to 350MPa, the tension strength is greater than or equal to 420MPa, and the elongation is greater than or equal to 14%. The reason is that a recrystallization annealing process is not needed in the production process of hot-base galvanizing, and the galvanizing process has the factors of precipitation strengthening, dislocation strengthening and the like, so that the strength is higher after galvanizing, the yield strength cannot be reduced to be below 300Mpa, the elongation is generally less than 30%, the surface roughness is 0.8-1.2 mu, the processing performance deviation is caused, the surface after galvanizing has color difference and bright spots, the surface is poorer than that of cold-base galvanizing, and the performance and surface parameters cannot be applied to refrigerator slide rails in the household appliance industry. And the thickness tolerance is poor in stability due to +/-0.09 mm of the thickness tolerance, so that the mass production cannot be realized.
Disclosure of Invention
The technical task of the invention is to provide a production method of a hot-base galvanized plate for a refrigerator slide rail aiming at the defects of the prior art, aiming at hot-base galvanized products with the thickness of 2.0mm and below, by optimizing the component design of a base plate and hot rolling and galvanizing processes, controlling aging, organization and precipitation strengthening, realizing the production of hot-galvanized products with common stamping level, meeting the requirements of the forming and surface quality of the galvanized stamped plate for the refrigerator slide rail, and replacing cold-base products in the household electrical slide rail industry, thereby realizing cost reduction and consumption reduction.
The technical scheme for solving the technical problem is as follows: a production method of a hot-base galvanized plate for a refrigerator slide rail comprises the following process flow routes: steel making → continuous casting → hot continuous rolling → continuous pickling and galvanizing; the method is characterized by comprising the following specific process steps:
s1: steel making;
s2: continuous casting: smelting to obtain molten steel with required components;
s3: hot continuous rolling: comprises rough rolling → induction heating → high pressure descaling → finish rolling; wherein the finish rolling adopts polishing rack rolling and lubrication rolling, and the finish rolling temperature is 870-910 ℃;
s4, continuous acid pickling and galvanizing: comprises straightening, breaking phosphorus, pickling, rinsing, heating, galvanizing, finishing, passivating and straightening; wherein, the substrate is in an over-acid-washing state in the acid-washing process; in the heating process, the temperature after induction heating is 530 ℃ plus 550 ℃, the plate temperature after soaking and slow cooling is 485 ℃ plus 490 ℃, and the plate temperature after zinc pot is 462 ℃ plus 467 ℃; 0.2-0.4% of elongation percentage of a tension straightening descaler, 0.7-0.9% of elongation percentage of a polished machine after plating, 0.2-0.3% of elongation percentage of the tension straightening machine and 1.4 +/-0.2% of total elongation percentage.
Further, the continuous casting tundish molten steel comprises the following components: c is less than or equal to 0.008 percent, Si: 0.04-0.05%; mn: 0.06-0.10%; s: less than or equal to 0.003 percent; p: less than or equal to 0.015 percent; ti: 0.015-0.020%; n: less than or equal to 0.003 percent, and the balance of Fe element and inevitable impurities.
Further, the polishing stand rolling is specifically finish rolling changed from a 5-stand rolling mill to a 4-stand rolling mill.
Furthermore, the over-pickling parameters in the pickling process are that the free acid concentration of the acid tank is 90g/L-100g/L, and the pickling temperature is 80-95 ℃.
Furthermore, the sum of the elongation of the polishing machine and the withdrawal and straightening machine after plating is 0.9-1.3%.
Furthermore, the sum of the elongation of the above-mentioned post-plating finisher and withdrawal and straightening unit is 1.1 +/-0.1%.
Furthermore, the above-mentioned polishing roller after plating is a smooth surface roller.
Furthermore, the original roughness of the roller surface of the smooth roller is 0.3-0.5 mu.
Further, the passivation adopts chromium-free acid passivation.
Compared with the prior art, the invention has the following outstanding beneficial effects:
1. the production method for producing the hot-base galvanized sheet for the refrigerator slide rail by the continuous pickling galvanizing production line is provided, the coating has excellent binding force, the surface quality is equivalent to that of cold-base galvanizing, the surface roughness of a smooth galvanized product is 0.3-0.6 mu, and the surface quality of the product is good;
2. the strength of the hot-base galvanized sheet is reduced, the elongation of the hot-base galvanized sheet is improved, the yield strength of the galvanized product is less than or equal to 290MPa, the tensile strength is less than or equal to 400MPa, the elongation is more than or equal to 31 percent, and the requirement of stamping and forming a refrigerator slide rail is met;
3. the steel for the refrigerator sliding rail with the thickness specification of 1.0mm-2.0mm is produced, the performance and the dimensional deviation are stable, and the thickness tolerance is controlled to be +/-0.03 mm.
Detailed Description
The present invention will be further described with reference to the following embodiments.
The invention provides a production method of a hot-base galvanized sheet for a refrigerator slide rail, which adopts a continuous pickling and galvanizing combined unit to produce the hot-base galvanized sheet for the refrigerator slide rail. The method can also be disassembled into two steps, firstly, hot-base galvanizing raw materials produced on the basis of a continuous hot rolling production line are put into a galvanizing procedure for production, and finally, the hot-base galvanized sheet for the refrigerator slide rail is obtained.
The technical scheme of the invention comprises the following molten iron components in percentage by weight: c is less than or equal to 0.008 percent, Si: 0.04-0.05%; mn: 0.06-0.10%; s: less than or equal to 0.003 percent; p: less than or equal to 0.015 percent; ti: 0.015-0.020%; n: less than or equal to 0.003 percent. The balance of Fe element and inevitable impurities.
Key ingredient control C, Ti control description of the invention:
c: carbon element can be dissolved in steel to form solid solution, which can play a role in solid solution strengthening, but the plasticity and the welding performance are reduced along with the increase of the carbon content; conversely, reducing the carbon content may increase the plasticity of the steel. To obtain the hypoeutectoid steel with higher elongation. In the invention, the content of C is controlled to be less than or equal to 0.008 percent. The content of C is controlled to be less than or equal to 0.008 percent and exceeds the expectation, and the combination of the end point C of the converter and the tapping temperature control, the RH furnace vacuum treatment, the LF furnace nondestructive electrode application and the temperature control is required.
Ti: titanium is a strong carbonitride forming element in steel, and TiN and Ti occur in the continuous casting and cooling stages 4 C 2 S 2 Liquid precipitation and solid precipitation of particles; in the rolling stage, the deformation of TiC in austenite is induced and precipitated; precipitation of TiC also occurs during the cooling and coiling stages. The addition of Ti content can effectively inhibit the aging change of the steel. The Ti content is controlled to be 0.015-0.020%.
The relationship for the amount of C, Ti in the present invention has the requirement: ti strong carbon and nitride forming elements are added to ensure that most of carbon and nitrogen atoms in the steel are fixed into carbonitride so as to ensure the stamping performance of the steel plate, and when the C is more than or equal to 0.01, the rest part of TiC is easy to precipitate and strengthen, thus being not beneficial to reducing the strength and the stamping formability of the steel plate.
The invention relates to a process mode for producing hot-base galvanized raw materials by adopting a continuous casting and rolling mode, which comprises the following steps: steel making → continuous casting → rough rolling → induction heating → high pressure descaling → finish rolling → laminar cooling → coiling. Finally obtaining the hot-base galvanizing raw material with the thickness of 1.0-2.0 mm.
The process comprises the following steps:
s1: making steel
The method specifically comprises the following steps: converter → LF furnace treatment → RH vacuum furnace treatment.
Converter: the end point C is 0.030-0.060 percent, the tapping oxygen is 550-800ppm, and the tapping temperature is more than or equal to 1630 ℃;
and (4) LF furnace: checking the electrode before LF treatment, using a crack-free and breakage-free electrode, controlling the power transmission time to be less than or equal to 20min, and controlling the temperature: the LF refining is controlled at 1640-1650 ℃.
RH vacuum furnace treatment: RH arrival temperature: not less than 1635 ℃; the thickness of the slag arriving at the station is less than or equal to 200 mm. And (3) starting oxygen blowing and decarburization after vacuum circulation for 3min, calculating oxygen blowing amount according to the station sample C, finishing oxygen blowing once, and determining oxygen 3min after oxygen blowing starts. The vacuum degree is less than or equal to 2mbar (pressure behind a vacuum valve), and the holding time is more than or equal to 6 min; vacuum treatment time: not less than 20 min. Before aluminum addition and deoxidation: [C] less than or equal to 20ppm, and [ O ] is 200 and 350 ppm.
S2: continuous casting
Continuous casting tundish covering agent: the lower layer adopts a high-alkalinity low-carbon covering agent, (FeO + MnO) is less than or equal to 3 percent; crystallizer mold flux: and (4) low-carbon mold flux. Molten steel with required components is obtained through smelting, and the continuous casting tundish comprises the following components in percentage by weight: c is less than or equal to 0.008 percent, Si: 0.04-0.05%; mn: 0.06 to 0.10 percent; s: less than or equal to 0.003 percent; p: less than or equal to 0.015 percent; ti: 0.015-0.020%; n: less than or equal to 0.003 percent. The balance of Fe element and inevitable impurities.
The pouring speed is high, the efficiency is one of the main characteristics of a short-flow production line, the pulling speed is too high, the rolling line temperature is high, and the surface oxidation control difficulty is high; the casting and drawing speed is slow, the temperature drop in the production process is large, the rolling load is increased, and the finish rolling temperature is difficult to ensure. Therefore, the casting and pulling speed is controlled to be 5.3-5.6 m/min.
Molten steel obtained by smelting enters a continuous casting machine to obtain a casting blank;
s3: hot continuous rolling
The method specifically comprises the following steps: rough rolling → induction heating → high pressure descaling → finish rolling.
Rough rolling: the casting blank is directly hot rolled without being heated by a soaking pit furnace, the inlet temperature of the hot rolling rough rolling is increased to 990-.
Finish rolling:
(1) adopting a polishing frame for rolling, specifically, changing a 5-frame rolling mill into a 4-frame rolling mill (F5 is removed) for finish rolling;
(2) the actual finish rolling temperature (F4 outlet) is 870-910 ℃. Compared with the conventional endless rolling, the finishing temperature is increased by 40-50 ℃, and the purpose is to avoid two-phase region rolling;
(3) the working roll of the hot-rolling finishing mill adopts a high-speed steel roll, the rolling kilometer number is less than or equal to 110KM, and the surface of the control substrate has no bright spots and color difference;
(4) by adopting rolling lubrication, the average rolling force of thin gauge below 1.2mm is reduced from 25000KN to 21000KN, the average rolling force of 1.0-2.0mm is reduced from 15-20%, and the rolling force load of a thin gauge finishing mill is controlled in headless rolling.
S4: cold layer coiling
Laminar cooling is changed into back-end cooling, high-temperature coiling is carried out to ensure the full growth of crystal grains and the precipitation of solid solution after finish rolling, the toughness of the product is further improved, the aging is reduced, and the coiling temperature is 700-.
The hot rolled strip steel as the galvanized base material is required to be 1.0-2.0mm, the straightness is less than or equal to 200I, and the defects of scale pits and the like cannot exist. Then the hot-base galvanizing raw material enters a galvanizing procedure for production, and finally the hot-base galvanized sheet with the thickness of 1.0-2.0mm for the refrigerator slide rail is obtained.
The other mode of the invention is to directly produce the hot-base galvanized plate for the refrigerator slide rail by adopting a continuous casting and rolling production line and a continuous pickling and galvanizing combined unit (PGL), and mainly utilizes steel making → continuous casting → continuous rolling → PGL galvanization. PGL galvanizing comprises the steps of straightening, phosphor breaking, pickling, rinsing, heating, galvanizing, finishing, passivating, straightening and coiling to produce the hot galvanizing coil through a continuous pickling galvanizing production line. The hot galvanizing production can be directly carried out by the hot rolling target thickness without cold rolling and continuous annealing processes, so that the hot rolling instead of cold is realized, and the method has considerable economic benefit and great social significance.
S1, steel making: as above.
S2, continuous casting: as above.
S3, hot continuous rolling: as above.
S4 continuous acid pickling galvanization
And (3) putting the strip steel obtained in the step (S3) into a PGL acid plating continuous production line, and performing straightening, phosphorus breaking, acid pickling, rinsing, heating, galvanizing, finishing, passivating, straightening and coiling to obtain the hot-base galvanized coil.
In the acid washing process, the concentration of free acid in the acid tank is 90-100 g/L, and the acid washing temperature is 80-95 ℃; the rinsing water temperature is 45-55 ℃, and the conductivity is 30-50 ms/cm. Compared with the conventional pickling method, the concentration of free acid is increased by 15-30g/L, the pickling temperature is 15-30 ℃, and the substrate is in an over-pickling state.
In the heating process, the temperature after induction heating is 530 ℃ plus 550 ℃, the plate temperature after soaking and slow cooling is 485 plus 490 ℃, the plate temperature after zinc pot is 462 ℃ plus 467 ℃, and the dew point of the induction heating furnace: -50 ℃ or below, oven pressure: 0.4-1.0mbar, hydrogen content > 9%, ensuring full reduction of the substrate before plating. The induction heating has skin effect, the heating hot base galvanizing of the invention is improved by 30 ℃, the soaking slow cooling process is added, the temperature of the base plate is uniform, the full reduction of the base plate before plating is ensured, the surface quality of the base plate and the adhesive force of the galvanized layer after plating are ensured, the soaking slow cooling process is added, the full reduction of the base plate before plating is ensured, and the temperature of the plate entering a zinc pot needs to be controlled at a lower level.
The production line adopts a single-leveling and double-straightening process, and scale breaking before acid pickling provides a good interface for acid liquor to clean off iron scales; and (4) straightening before coiling to obtain a good plate shape. The specific parameters are as follows: 0.2-0.4% of elongation of a tension leveler (scale breaking) machine, 0.7-0.9% of elongation of a polished machine after plating, 0.2-0.3% of elongation of the tension leveler and 1.4 +/-0.2% of total elongation. The leveling procedure is positioned before induction heating, the dislocation density is leveled and increased, and in the heating process, solid solution interstitial atoms at interstitial positions are activated at a higher temperature, the movement capacity is greatly improved, and the solid solution interstitial atoms are gathered at the defect position under the action of a dislocation stress field. Since the movement of the mobile dislocations is hindered, a greater force must be applied to move the mobile dislocations free from pinning of interstitial atoms or dragging interstitial atoms with them, which macroscopically manifests as an increase in yield strength. Therefore, the polishing pad is flat before polishing and heating, and can control the performance change caused by baking and hardening. The elongation of the polishing and withdrawal and straightening machine after plating is 0.9-1.3%, the optimization scheme is 1.1 +/-0.1%, the pinning effect of the galvanized steel plate C, N is destroyed, the yield strength is reduced, and simultaneously the requirements of the rolling force of the polishing surface roller of 1000-1200KN and the plate shape control are obtained.
In the galvanizing process, the zinc liquid in a zinc pot comprises the following components: zn > 99%, Al: 0.20-0.30%, Sb is less than or equal to 0.02%, Fe is less than or equal to 0.03%, others are less than or equal to 0.015%, the temperature of zinc liquid is as follows: 460 ℃ plus or minus 2 ℃.
The surface finishing roller is a smooth surface roller after plating, the original roughness of the roller surface is 0.3-0.5 mu, and the customized requirements of the surface roughness in the refrigerator slide rail industry can be realized.
The passivation adopts chromium-free acid passivation, and meets the environment-friendly requirement of household appliances.
To better compare the present application with the prior art, comparative tests were performed.
Examples 1 to 3 are the present invention and the present invention provide a technique for directly producing a hot-base galvanized sheet for a refrigerator slide rail. Example 4 a hot-based galvanized feedstock, rather than the final product, was produced using a continuous casting and rolling mill model.
The control group adopts molten steel component design in a 300 MPa-grade low-carbon hot rolled steel production method without transverse fracture defects (CN 202011195998.7); combines the production process in a zinc flower-free hot galvanized plate process (CN202010246403. X).
1. Designing the components of each group of galvanized substrates:
| element(s) | C | Si | Mn | P | S | Ti | N | B |
| Example 1 | 0.0078 | 0.045 | 0.076 | 0.012 | 0.003 | 0.016 | 0.0013 | - |
| Example 2 | 0.0067 | 0.050 | 0.085 | 0.008 | 0.001 | 0.0180 | 0.0024 | - |
| Example 3 | 0.0080 | 0.043 | 0.068 | 0.015 | 0.001 | 0.0172 | 0.0030 | - |
| Example 4 | 0.0059 | 0.040 | 0.098 | 0.013 | 0.002 | 0.0168 | 0.0017 | - |
| Control group | 0.012 | 0.10 | 0.18 | 0.009 | 0.002 | - | 0.0050 | 0.002 |
2. See table below for various sets of production parameter control:
3. for control of parameters in extension for each group see table below: examples 1 to 3 are single leveling + double straightening processes, and the control group is a double leveling setting:
the comparison results are shown in the following table:
from the above results, it can be seen that in examples 1-3, when the method of the present invention is used to directly produce the hot-base galvanized sheet for the refrigerator slide rail, the coating has excellent binding force and good surface quality, the yield strength of the galvanized product is less than or equal to 290MPa, the tensile strength is less than or equal to 400MPa, and the elongation is greater than or equal to 31%; the surface quality is equivalent to that of cold-base galvanizing, and the surface roughness of a smooth-surface galvanized product is 0.3-0.6 mu; stable performance and size deviation and excellent plating binding force. The hot-base galvanized raw material with the thickness of 1.2mm obtained in the embodiment 4 enters a traditional pickling and galvanizing production line, and the hot-base galvanized plate which meets the use specification of the refrigerator slide rail cannot be produced, wherein the yield strength is 290-350MPa, the tensile strength is 360-420MPa, and the elongation is 23-32%.
And the comparison group obtained by combining the low-strength component design and the sheet galvanizing method in the prior art cannot stably produce the hot-base galvanized sheet with the thickness specification of 1.2mm, the size deviation is unstable, and the thickness tolerance reaches +/-0.06 mm. And the yield strength is 339MPa, the elongation is 27%, the sliding rail is manufactured and punched to be formed, the part with larger deformation is easy to crack, the surface quality control result is unqualified, and the sliding rail cannot be used as the sliding rail of the refrigerator for production.
It should be noted that while the invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various obvious changes can be made therein without departing from the spirit and scope of the invention.
Claims (9)
1. A production method of a hot-base galvanized plate for a refrigerator slide rail comprises the following process flow routes: steel making → continuous casting → hot continuous rolling → continuous pickling and galvanizing; the method is characterized by comprising the following specific process steps:
s1: steel making;
s2: continuous casting: smelting to obtain molten steel with required components;
s3: hot continuous rolling: comprises rough rolling → induction heating → high pressure descaling → finish rolling; wherein the finish rolling adopts polishing frame rolling and lubrication rolling, and the finish rolling temperature is 870-910 ℃;
s4, continuous acid pickling and galvanizing: comprises straightening, phosphor breaking, acid washing, rinsing, heating, galvanizing, finishing, passivating and straightening; wherein, the substrate is in an over-acid-washing state in the acid-washing process; in the heating process, the temperature after induction heating is 530 ℃ plus 550 ℃, the plate temperature after soaking and slow cooling is 485 ℃ plus 490 ℃, and the plate temperature after zinc pot is 462 ℃ plus 467 ℃; 0.2-0.4% of elongation percentage of a tension straightening and descaling machine, 0.7-0.9% of elongation percentage of a polished machine after plating, 0.2-0.3% of elongation percentage of the tension straightening machine and 1.4 +/-0.2% of total elongation percentage.
2. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 1, characterized in that: the molten steel of the continuous casting tundish comprises the following components: c is less than or equal to 0.008 percent, Si: 0.04-0.05%; mn: 0.06-0.10%; s: less than or equal to 0.003 percent; p: less than or equal to 0.015 percent; ti: 0.015-0.020%; n: less than or equal to 0.003 percent, and the balance of Fe element and inevitable impurities.
3. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 1, characterized in that: the polishing rack rolling is specifically finish rolling changed from a 5-frame rolling mill to a 4-frame rolling mill.
4. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 1, characterized in that: the over-pickling parameters in the pickling process are that the free acid concentration of the acid tank is 90g/L-100g/L, and the pickling temperature is 80-95 ℃.
5. The method for producing a hot-base galvanized sheet for refrigerator sliding rails according to claim 1, characterized in that: the sum of the elongation of the plated finishing and withdrawal and straightening machines is 0.9-1.3%.
6. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 5, characterized in that: the sum of the elongation of the polishing machine and the withdrawal and straightening machine after plating is 1.1 +/-0.1 percent.
7. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 1, characterized in that: the polishing roller after plating is a smooth surface roller.
8. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 7, characterized in that: the original roughness of the roller surface of the smooth roller is 0.3-0.5 mu.
9. The method for producing the hot-base galvanized sheet for the refrigerator slide rail according to claim 1, characterized in that: the passivation adopts chromium-free acid passivation.
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