Production process of TSPCC steel for barrel making

Abstract

The application discloses a production process of a TSPCC steel type for barrel production, and first designs the composition of the steel material: the content of C is 0.03%-0.08%, Si is less than or equal to 0.3%, Mn is 0.26%-0.33%, P is less than or equal to 0.018%, S is less than or equal to 0.015%, Al is 0.018%-0.04%, Ca is 0.0015%-0.0035%, and the balance is iron and impurities; slab continuous casting control and inspection requirements: the continuous casting adopts full-range argon protection pouring, adopts carbon-free protective slag and carbon-free ladle covering agent; a dam is installed on the tundish; the superheat of the tundish in the first furnace of the continuous casting is less than or equal to 45 DEG C, the superheat of the molten steel in the tundish of the continuous casting furnace is less than or equal to 35 DEG C, and the maximum casting speed of the continuous casting is less than or equal to 1.6 m / min; subsequently, cold rolling and pickling, conventional control of a rolling mill, process control of a bell-type annealing furnace, process parameters of a skin pass mill and color coating process parameters are adjusted and optimized; the steel type has good mechanical properties and outstanding rust prevention.

Description

TECHNICAL FIELD

[0001] The application relates to a production process of a TSPCC steel type for environment-friendly barrel manufacturing. BACKGROUND

[0002] At present, the planting area of tomato sauce is continuously expanded in Xinjiang, and the barrel steel for tomato sauce reaches more than 50,000 tons per year. However, with the continuous improvement, perfection and rapid promotion of the environmental protection regulations in China, barrel manufacturing companies begin to put forward new requirements for the steel plant under the pressure of environmental protection. Whether the cold-rolled color-coated commodity coil can be produced is required to have good mechanical properties and good anti-rust function of the color-coated coil. However, the steel plant faces the problem of how to ensure the good punching performance of the steel coil, ensure that the steel coil does not crack in the punching, edge rolling and edge rolling process, ensure that the steel barrel has sufficient strength, and ensure that the paint has good adhesion, so that the steel coil does not fall off and does not rust in the processing process. According to the literature: Research on diameter expansion cracking of cold-rolled barrel steel, by Han Jiyan, Di Yanjun and Luo Xiaoyang, the microstructure and microstructure of the heat-affected zone and base material at the weld are compared and analyzed through a metallographic microscope and SEM. The results show that the heat-affected zone has small grain size, no obvious directionality, dense dislocation and shallow toughness, and the heat-affected zone presents brittle fracture morphology, and the base material presents plastic fracture morphology. By adjusting the welding parameters, reducing the welding current speed, increasing the welding time and reducing the post-weld cooling speed, the diameter expansion cracking at the weld is controlled to a certain extent, but cannot be completely eliminated. Further comparison is made on the composition control of the barrel steel of other steel plants in the industry, the carbon equivalent and the cold crack sensitivity index are compared and analyzed, the composition of the cold-rolled barrel steel of the steel plant is further optimized, the Mn content is reduced, and the Si and Cr contents are increased, which is irrelevant to the content of the application. SUMMARY

[0003] The application aims to provide a production process of a TSPCC steel type for environment-friendly barrel manufacturing, which can reduce the paint spraying process of the tomato sauce barrel manufacturer, relieve the environmental protection pressure of the barrel manufacturing plant, has good mechanical properties and outstanding anti-rust function.

[0004] The technical scheme adopted by the application is a production process of a TSPCC steel type for environment-friendly barrel manufacturing,

[0005] 1) First, the composition of the steel material is designed: the C content is 0.03%-0.08%, the Si content is ≤0.3%, the Mn content is 0.26%-0.33%, the P content is ≤0.018%, the S content is ≤0.015%, the Al content is 0.018%-0.04%, the Ca content is 0.0015%-0.0035%, and the balance is iron and impurities;

[0006] 2) Slab continuous casting control and inspection requirements: continuous casting adopts full-range argon protection pouring, adopts carbon-free protective slag and carbon-free ladle covering agent; ladle is installed with a retaining wall; the first ladle of continuous casting has a superheat of ≤45℃, the ladle of continuous casting has a superheat of ≤35℃, the maximum casting speed is ≤1.6 m / min, the liquidus temperature of the steel mark AP1461C1 is 1530℃, the liquidus temperature is 1528℃; the conventional process control points of hot rolling are as follows: heating temperature 1125-1185℃, finishing temperature 870±20℃, cooling mode fast in the later stage, coiling temperature 640±20℃;

[0007] 3) Conventional control points of cold rolling and pickling: 1-4# tank hydrochloric acid temperature is controlled to 65-75℃, process section running speed is controlled to 60-130 m / min; the acid pickling unit is replaced with new acid 60-80 m 3 4 hours in advance before producing the TSPCC steel for the environmental protection barrel, ensuring that the HCL content of the 1# acid tank is ≥50 g / L, the iron ion content is ≤100 g / L, and the under-pickling phenomenon is eliminated; the 1# rinsing tank filter outlet temperature is 60-80℃, the 2# rinsing tank rinsing water conductivity is ≤100 μS / cm, the rinsing water make-up valve opening is increased by 25%-40% compared with the ordinary SPCC steel, the shape is controlled according to the micro-double-edge wave, and the middle wave is strictly prohibited, the shape instrument standard control curve A2 control coefficient is set to +4, the width is 930-1250 mm, all of which are suitable; before production, ensure that the end mill is normal, the surface of the strip steel is not allowed to have emulsion residue, the mill outlet blowing pressure is >0.6 MPa, the nozzle is not allowed to be missing or blocked, and the mill outlet portal condensate water cannot drop onto the strip steel surface; the surface of the cold hard coiled strip steel, the single-sided residual oil content is ≤300 mg / m 2 , the single-sided residual iron content of the strip steel surface is ≤120 mg / m 2 ; the roughness of the new work roll is kept below 0.7 μm;

[0008] 4) Process control design of bell-type annealing furnace: the process of bell-type annealing furnace is full hydrogen complete annealing, the coil outlet temperature of the furnace shall not be higher than 100℃, the accumulated dust and carbon black of the furnace table is cleaned before production; the hydrogen blowing amount of the 2nd and 3rd sections is controlled to 25-30 m 3h, to ensure that the emulsion residue is fully volatilized; when the steel coil is heated, a heating cover in good working condition is selected to ensure that the gas electric regulating valve operates normally without blockage; the number of burners in operation must be more than 6; when the reflectivity of the rolling mill unit is less than 50%, double platforms are used for annealing, and a 430°C holding platform is added for 2-3 hours, otherwise single platform annealing is used; the charging amount must be no less than 45 tons; when the charging amount is 45-55 tons, the temperature is controlled at 690°C, the heating time is 8h, the holding time is ≥7h, the waiting cover time is 2h, and the discharge temperature is 95°C; when the charging amount is 55-75 tons, the temperature is controlled at 690°C, the heating time is 9h, the holding time is ≥8h, the waiting cover time is 3h, and the discharge temperature is 100°C; when the charging amount is >75 tons, the temperature is controlled at 690°C, the heating time is 10h, the holding time is ≥9h, the waiting cover time is 5h, and the discharge temperature is 100°C; when the steel coil is discharged and cooled on the final cooling table, the cooling temperature is stopped after reaching 45°C, and the outside air suction port of the plant needs to be closed in rainy weather;

[0009] 5) Design of process parameters of the skin pass mill: the main purpose of the strip passing through the skin pass mill process is to level the strip shape and eliminate the yield platform inside the strip. The key process parameter of the skin pass mill is the setting of elongation. After different specifications of testing, the elongation parameter is set according to the incoming thickness in this process: the skin pass mill strictly controls the elongation, and the elongation deviation is controlled to ±0.1%. The details are as follows: incoming thickness 0.6-0.75mm, strip elongation set to 0.7%-0.9%; incoming thickness 0.751-0.85mm, strip elongation set to 0.8%-1.0%; incoming thickness 0.851-0.95mm, strip elongation set to 0.9%-1.1%; incoming thickness 0.951-1.05mm, strip elongation set to 1.0%-1.2%; the skin pass mill is controlled according to micro and medium waves, and edge wave defects are strictly prohibited; before production, the skin pass liquid nozzles are inspected, and the emulsion nozzles in the middle of the strip must not be blocked; when the skin pass liquid concentration is tested by a refractometer, the refractometer display value is increased from 1.5% to 2.5%, the skin pass liquid middle jet flow is increased by 10%-20% when producing this steel grade; the blowing jet pressure is >0.47MPa, and the blowing angle control value is 45°-60°; the skin pass liquid must be sprayed to the upper and lower work roll gap. Before producing the steel coil, the skin pass liquid nozzles are adjusted for 3-5 coils in advance to ensure the uniformity of the skin pass liquid spraying; the normal production speed must be no less than 500m / min to improve the strip surface cleanliness and reduce the occurrence of skin pass liquid stain defects; when producing this steel grade, the work roll roughness of the skin pass mill is controlled at 0.6-0.7μm, and the steel coil packaging temperature must be no more than 40°C;

[0010] 6) Design of process parameters of the color coating: the pretreatment 1# and 2# alkali liquid spraying and hot water rinsing temperature is controlled to 70±3°C when producing this steel grade; the alkali spraying alkali point is controlled to 6-10 mg / L when producing this steel grade, and 10m of overflow is required per shift3 The front treatment liquid ensures that the original plate carbon black can be fully discharged. When producing 2000 tons of TSPCC annealed plate, the degreasing section tank liquid is replaced and reconfigured. The passivation liquid chromium point of the ordinary zinc-based plate coating machine is controlled to 21-25 mg / L, and the Cr content of the passivated plate film is 15-30 mg / m 2 When producing this steel grade, the passivation liquid chromium point of the coating machine is controlled to 23-25 mg / L, and the Cr content of the passivated plate film is 25-30 mg / m 2 Within one hour after the shift, sampling is sent for inspection, and in the later stage, sampling is sent for inspection once every 3 hours. The PMT plate temperature after the coating oven is controlled to 70-80°C, and it is detected once every 4 hours using a temperature gun or temperature paper A / B. The coating drying requirements are: the passivation film is wiped with paper without obvious yellow spots, the steel strip surface is free of missed coating, the surface is free of pockmarks, passivation spots, and thick edges, and the edges are free of yellow spots. When producing 1000 tons or more of TSPCC barrel plates, the passivation liquid is replaced. The pressure adjustment of the coating roll and the suction roll of the coating machine makes the current value between the two rolls 30-80%. The roll speed ratio is set as follows: coating roll speed: machine speed = 1.1-1.5:1; suction roll speed: machine speed = 0.2-0.6:1. Before producing this steel grade, the brush hairs on the brush roll are inspected, and the brush roll height is adjusted. The brush roll working current is 10-20 A, and all brush rolls are in use. At the same time, the clogging of the alkali washing and rinsing nozzles in the pretreatment is checked and confirmed. The nozzle angle is controlled to 45-60° to ensure that the carbon black on the surface of the steel coil can be fully washed. The 6# and 7# squeezing rolls at the end of hot water rinsing rotate flexibly without jamming, and the roll surface is free of delamination. The 1# air knife angle is controlled to 45-60°. When producing this steel grade, the water quenching spray pipeline pressure is 0.05-0.4 MPa, and the water quenched plate temperature is ≤45°C. The steel strip is inspected once every shift. The inspection method is as follows: at the 5# deflection roll after the degreasing section, a large cloth is wrapped around a wooden stick, a force of 20 kg is applied, and the cloth is wiped on the running plate surface for 6-8 seconds. The white cloth is checked for no wetness, no obvious oil stains, and no black ash. The gap between the suction roll and the coating roll of the upper and lower roll systems is adjusted to 2-10 mm. The diluent addition amount is controlled at 5-15%, and the ratio will vary with the coating temperature and the original viscosity. The stirrer speed is 400-800 revolutions per minute, the stirring time is 20-40 minutes, and the coating temperature requirement is ≥0°C. The polyester front face finish: dry film ≥3 μm, viscosity: 40±5 seconds; polyester back face finish: dry film ≥6 μm, viscosity: 75±5 seconds; coating film thickness: front face finish film thickness ≥3 μm, back face finish film thickness ≥6 μm; the film thickness is the three-point average value, and the back face finish film thickness fluctuation value should not exceed 2 μm. Furnace temperature setting and plate temperature PMT: the furnace temperature setting uses the temperature rising and falling type: the second and third zone temperatures are the same, which is the highest temperature. The initial coating PMT is 216-232°C, and the fine coating PMT is 216-232°C. Each coil is checked and adjusted. The color coating unit pays attention to the cleaning effect of the leveling liquid, and all the brush rolls of the unit are in use.

[0011] Through this method, the one-time pass rate of the steel grade is currently improved from 50% in the early stage to 95.5%, customers have no quality complaints, the satisfaction degree is improved from 50% in the early stage to 100%, the steel coil is used well without paint peeling and rusting defects, and meets the use of various tomato sauce barrel factories. The invention is suitable for raw materials for batch production of tomato sauce barrels, and has a wide application range. DETAILED DESCRIPTION

[0012] A production process of an environmentally-friendly TSPCC steel for barrel making,

[0013] 1) First, the composition of the steel material is designed: C content 0.03%-0.08%, Si≤0.3%, Mn 0.26%-0.33%, P≤0.018%, S≤0.015%, Al 0.018%-0.04%, Ca 0.0015%-0.0035%, and the balance is iron and impurities;

[0014] 2) Slab continuous casting control and inspection requirements: full-process argon protection pouring is adopted, carbon-free protective slag and carbon-free ladle covering agent are adopted; a retaining wall is installed in the tundish; the tundish overheat degree of the first furnace is ≤45℃, the tundish overheat degree of the continuous casting furnace is ≤35℃, the maximum casting speed is ≤1.6 m / min, the liquidus temperature of the tapping mark AP1461C1 is 1530℃, the liquidus temperature is 1528℃, and the conventional process control points of hot rolling are as follows: heating temperature 1125-1185℃, finishing temperature 870±20℃, cooling mode fast in the later stage, and coiling temperature 640±20℃;

[0015] 3) Conventional control points of cold rolling and pickling: 1-4# tank hydrochloric acid temperature is controlled to 65-75℃, and the process section running speed is controlled to 60-130 m / min; the acid pickling unit is replaced with new acid 60-80 m 3 4 hours in advance before producing the steel grade to ensure that the HCL content of the 1# acid tank is ≥50 g / L, the iron ion content is ≤100 g / L, and the under-pickling phenomenon is eliminated; the 1# rinsing tank filter outlet temperature is 60-80℃, the 2# rinsing tank rinsing water conductivity is ≤100 μS / cm, the rinsing water replenishment valve opening degree is increased by 25%-40% than that of ordinary steel, the plate shape is controlled according to the micro double edge wave, and the middle wave is strictly prohibited, the plate shape instrument standard control curve A2 control coefficient is set to +4, the width is 930-1250 mm, and all are suitable; the end mill blowing device is ensured to be normal before production, the surface of the strip steel is not allowed to have emulsion residue, the mill outlet blowing pressure is >0.6 MPa, the nozzle is not allowed to be missing or blocked, the mill outlet gantry condensate water is not allowed to drop on the surface of the strip steel; the surface and single-side residual oil amount of the mill cold hard coiled strip steel is ≤300 mg / m 2 2, the single-side residual iron amount of the surface of the strip steel is ≤120 mg / m 2 ; and the new work roll roughness roll surface is kept below 0.7 μm.

[0016] 4) Process control design of batch annealing furnace: The process of batch annealing is full hydrogen complete annealing, the coil temperature out of the furnace should not be higher than 100℃, hydrogen has reducing property, it can reduce the oxide of coil when heating, when annealing, because the temperature is still high, hydrogen can reduce some oxidized metal. According to this principle, a set of process control points of oil drum steel of batch annealing furnace is formulated; before production, the accumulated ash and carbon black of furnace table is cleaned to no ash; the hydrogen blowing amount of 2nd and 3rd section is controlled at 25-30m 3 / h, to ensure that the residual emulsion is fully volatilized; when heating the coil, select the heating cover with good working condition, to ensure that the gas electric regulating valve operates normally without blockage; the number of burner operating should be more than 6; when the reflectivity of rolling mill unit is less than 50%, use double platform for annealing, add 430℃ holding platform for 2-3 hours, otherwise use single platform annealing; the loading amount should not be less than 45 tons; when the loading amount is 45-55 tons, control the temperature at 690℃, heating time 8h, holding time ≥7h, waiting cover time 2h, the temperature out of the furnace 95℃; when the loading amount is 55-75 tons, control the temperature at 690℃, heating time 9h, holding time ≥8h, waiting cover time 3h, the temperature out of the furnace 100℃; when the loading amount is more than 75 tons, control the temperature at 690℃, heating time 10h, holding time ≥9h, waiting cover time 5h, the temperature out of the furnace 100℃; when the coil is cooled on the final cooling platform, stop cooling after the cooling temperature reaches 45℃, close the outside suction port of the plant when it rains;

[0017] 5) Design of the process parameters of the skin pass mill: the main purpose of the strip passing through the skin pass mill process is to level the strip shape and eliminate the yield platform inside the strip. The key process parameter of the skin pass mill is the setting of the elongation rate. After testing different specifications, the elongation rate parameter is set according to the incoming thickness in this process: the skin pass mill strictly controls the elongation rate, and the elongation rate deviation is controlled to ±0.1%. The details are as follows: incoming thickness 0.6-0.75mm, strip elongation rate set to 0.7%-0.9%; incoming thickness 0.751-0.85mm, strip elongation rate set to 0.8%-1.0%; incoming thickness 0.851-0.95mm, strip elongation rate set to 0.9%-1.1%; incoming thickness 0.951-1.05mm, strip elongation rate set to 1.0%-1.2%; the skin pass mill is controlled according to the micro-medium wave, and edge wave defects are strictly prohibited; before production, the skin pass liquid nozzles are inspected, and the emulsion nozzles in the middle of the strip must not be blocked; the skin pass liquid concentration is controlled to 1.5% to 2.5% by the refractometer reading, and the middle jet flow of the skin pass liquid is increased by 10%-20% when producing this steel grade; the blowing jet pressure is >0.47MPa, and the blowing angle control value is 45°-60°. In order to further improve the blowing pressure, peak production can be staggered with the rolling mill, and the blowing pressure can be increased to 0.58-0.61MPa when producing the pickling commodity coil or the acid combined rolling is stopped; the skin pass liquid must be sprayed to the upper and lower work roll gap, and before producing this steel grade, the skin pass liquid nozzles are adjusted for 3-5 coils in advance to ensure the uniformity of the skin pass liquid spraying; the normal production speed must not be less than 500m / min to improve the strip surface cleanliness and reduce the occurrence of skin pass liquid stain defects; when producing this steel grade, the work roll roughness of the skin pass mill is controlled to 0.6-0.7μm, and the temperature of the steel coil during packaging must not be greater than 40℃.

[0018] 6) Design of the process parameters of the color coating: the pre-treatment 1# and 2# alkali liquid spraying and hot water rinsing temperature is 70±3℃ when producing this steel grade; the alkali spraying alkali point is controlled to 6-10mg / L when producing this steel grade, and 10m 3 of the pre-treatment liquid is overflowed every shift to ensure that the original plate carbon black can be fully discharged, and the degreasing section tank liquid is replaced and re-liquidized when producing 2000t of TSPCC annealed plate; the passivation liquid chromium point of the ordinary zinc-based coater is controlled to 21-25mg / L, and the Cr content of the passivation plate film is 15-30mg / m 2 ; the passivation liquid chromium point of the coater is controlled to 23-25mg / L when producing this steel grade, and the Cr content of the passivation plate film is 25-30mg / m 2, sampling and inspection within one hour after the shift, sampling and inspection every 3 hours later; PMT plate temperature control to 70-80℃ after the chemical coating oven, every 4 hours detected by temperature gun or temperature paper A / B, chemical coating drying requirements: passivation film with paper wiping no obvious yellow spot, steel strip surface no leakage, surface no pockmark, passivation spot, edge no yellow spot thick edge, production TSPCC barrel plate 1000 tons above, change passivation liquid; chemical coating machine coating roll and suction roll pressure adjustment makes the current value between the two rolls 30-80%, roll speed ratio setting: coating roll speed: machine group speed = 1.1-1.5:1; suction roll speed: machine group speed = 0.2-0.6:1; before production of the steel, check the brush on the brush roll, at the same time, adjust the brush roll height, brush roll working current is 10-20A, all brush rolls are put into use; at the same time, check and confirm the blockage of pretreatment alkali washing, rinsing nozzle, nozzle angle control to 45-60° to ensure that the steel coil surface carbon black can be fully washed; hot water rinsing end 6#, 7# squeeze roll rotates flexibly without jamming, roll surface without degumming, 1# air knife angle control to 45-60°; when producing the steel, water quenching spray pipeline pressure 0.05-0.4MPa, water quenching plate temperature ≤45℃; every shift, check the strip once, the checking method: at the 5# deflection roll after the degreasing section, wrap the large cloth on the wooden stick, apply 20kg force, press on the running plate surface, wipe for 6-8 seconds, check the white cloth without wet, no obvious oil stains, black ash; the gap between the upper and lower roll system suction roll and coating roll is adjusted to 2-10mm; diluent addition amount is controlled according to 5%-15%, the proportion will be different with the change of coating temperature, original viscosity; stirrer speed 400-800r / min, stirring time 20-40 minutes, coating use temperature requirement: ≥0℃; polyester front face paint: dry film ≥3μm, viscosity: 40±5 seconds; polyester back face paint: dry film ≥6μm, viscosity: 75±5 seconds; coating film thickness inspection standard: front paint film thickness ≥3μm, back paint film thickness ≥6μm; film thickness is three-point average value, back paint film thickness fluctuation value should not be more than 2μm; furnace temperature setting and plate temperature PMT (plate temperature monitor, Peak Metal Temperature), furnace temperature setting uses temperature rising and falling type: the second zone and the third zone temperature is the same, which is the highest temperature, initial coating PMT: 216-232℃; finishing PMT: 216-232℃, check and adjust every coil, the color coating unit pays attention to the leveling liquid cleaning effect, all brush rolls of the unit are put into use.

[0019] Example

[0020] 1-4# tank hydrochloric acid temperature control to 65-75℃, process section running speed control to 60-130m / min.

[0021] The pickling unit is replaced with new acid 60-80m³ 4 hours in advance to ensure that the HCL content of the acid in the 1# acid tank is ≥50g / L and the iron ion content is ≤100g / L to prevent the occurrence of under-pickling.

[0022] The temperature of the water outlet of the 1# rinsing tank filter is 60-80℃, the conductivity of the water in the 2# rinsing tank is ≤100μS / cm, the opening degree of the water supply valve of the 2# rinsing tank is increased by 25-40% compared to ordinary steel, all the wringing rollers must be in good condition and the roller surface must not have serious defects such as wear, sticking, scratches, peeling, and thermal damage, and the rollers must not be blocked during operation, and there must be no "water mark" defects at the outlet of the pickling dryer.

[0023] In addition to the conventional parameter control, the main control of the rolling mill unit is the residual emulsion on the surface of the strip, and sufficient preparation is made for the annealing of the bell-type furnace unit. The shape of the strip is controlled according to the micro-double-edge wave, and the presence of middle waves is strictly prohibited. The standard control curve A2 control coefficient is set to +4 (width 930-1250mm is applicable).

[0024] Before production, it is ensured that the blowing device of the last rolling mill is normal, and there is no emulsion residue on the surface of the strip. The blowing pressure at the outlet of the rolling mill is >0.6MPa. The nozzles must not be missing or blocked, and the condensate water at the outlet of the rolling mill must not drop onto the surface of the strip. The residual oil on the surface of the strip (single side) is ≤300mg / m 2 The residual iron on the surface of the strip (single side) is ≤120mg / m 2 .

[0025] After the rolling mill unit starts rolling production and the coil is produced, the reflectivity of the coil surface is measured. If the reflectivity is less than 50%, the production of this steel grade is strictly prohibited. If the reflectivity is greater than 60%, the normal scheme is executed. If the reflectivity is between 50% and 60%, the bell-type furnace is immediately notified to enter the production remediation plan, i.e. the temperature curve is increased by 430℃ platform for 3-4 hours, the hydrogen blowing amount is increased from 25m³ / h to 30m³ / h, and the hydrogen blowing time is extended by 3 hours. The loading amount of this steel grade must not be less than 45 tons. For loading amount of 45-55 tons, the control temperature is 690℃, the heating time is 8h, the holding time is ≥7h, the standby time is 2h, and the discharge temperature is 95℃. For loading amount of 55-75 tons, the control temperature is 690℃, the heating time is 9h, the holding time is ≥8h, the standby time is 3h, and the discharge temperature is 100℃. For loading amount >75 tons, the control temperature is 690℃, the heating time is 10h, the holding time is ≥9h, the standby time is 5h, and the discharge temperature is 100℃.

[0026] When the coil is discharged from the final cooling table, the cooling is stopped when the cooling temperature reaches 45℃. If it is raining, the outdoor suction port of the plant must be closed.

[0027] Before the leveling production, it is confirmed that the temperature of the coil is consistent with the ambient temperature.

[0028] The smooth unit adopts light bar production, the new work roll surface roughness should not be greater than 0.7 μm, and the strip surface roughness is controlled below 0.6 μm.

[0029] The liquid concentration of the smooth unit is controlled to 4.0%~6.0%, the production is carried out according to the micro and medium wave mode, and the edge wave is strictly prohibited. The wave shape observation station is located at the side of the coiler, the crane clamp is protected during the steel coil hoisting process, and a person is in charge. The steel coil end cannot be damaged.

[0030] The smooth blowing jet pressure is greater than 0.5 MPa, the blowing angle control value is 45°~60°, and the edge should not have residual smooth liquid spots.

[0031] Before the smooth production, the smooth liquid nozzle is checked, and the smooth liquid nozzle in the middle of the strip should not have a blockage. When the production width of the steel coil is less than 1000 mm, the upper roll edge 2 nozzles can be blocked to prevent the smooth liquid from leaking out of the strip edge roll gap and splashing onto the strip surface. The elongation of the smooth unit is strictly controlled, and the elongation deviation is controlled to ±0.1%. The details are as follows: the incoming thickness is 0.6-0.75 mm, the strip elongation is set to 0.7%-0.9%; the incoming thickness is 0.751-0.85 mm, the strip elongation is set to 0.8%-1.0%; the incoming thickness is 0.851-0.95 mm, the strip elongation is set to 0.9%-1.1%; and the incoming thickness is 0.951-1.05 mm, the strip elongation is set to 1.0%-1.2%.

[0032] The smooth liquid is uniformly and overlappedly sprayed to the roll gap, the inlet anti-wrinkle roll lifting angle must be kept in the direction of 190-200°, to ensure that the smooth liquid is uniformly applied on the surface of the strip. The middle 2 nozzles of the smooth liquid are replaced from φ1.5 mm to φ2.0 mm, to increase the smooth liquid flow. After the steel coil production is completed, the surface black ash can be easily washed clean.

[0033] The temperature of the 1# and 2# alkali liquid spraying and hot water rinsing in the pretreatment is controlled to 70±3℃ when producing this steel grade.

[0034] When producing this steel grade, the alkali spraying alkali point is controlled to 6-10 mg / L, and 10 m 3 Pretreatment liquid, to ensure that the original plate carbon black can be fully discharged, when producing 2000 t of TSPCC annealed plate, the degreasing section tank liquid is replaced, and the liquid is reconfigured.

[0035] When producing this steel grade, the passivation liquid chromium point of the chemical coating machine is controlled to 23~25 mg / L, and the Cr content of the passivation plate film is 25~30 mg / m 2The sample is taken and sent for inspection within one hour after the shift, and the sample is taken and sent for inspection once every 3 hours later; the PMT plate temperature is controlled to 70-80℃ after the chemical coating oven, and the temperature is detected once every 4 hours by using the temperature gun or temperature paper A / B, and the chemical coating drying requirements are that the passivation film is wiped by paper without obvious yellow spots, the steel strip surface is without missing coating, the surface is without pockmarks, passivation spots, and the edge is without yellow thick edge, and the production TSPCC barrel plate is more than 1000 tons, and the passivation liquid is replaced.

[0036] The pressure of the coating roll and the suction roll of the chemical coating machine of the color coating unit is adjusted to make the current value between the two rolls be 30-80%. The roll speed ratio is set as follows:

[0037] The coating roll speed: the unit speed = 1.1-1.5:1, and the suction roll speed: the unit speed = 0.2-0.6:1.

[0038] Before the production of the steel, the brush on the brush roll is checked, and the height of the brush roll is adjusted, the working current of the brush roll is 10-20A, and all the brush rolls are put into use; meanwhile, the blockage of the nozzle for the pretreatment alkali washing and rinsing is checked and confirmed, and the angle of the nozzle is controlled to 45-60° to ensure that the carbon black on the surface of the steel coil can be fully washed.

[0039] The 6# and 7# squeezing rolls at the end of the hot water rinsing are flexible and without jamming, and the roll surface is without degumming, and the angle of the 1# air knife is controlled to 45-60°.

[0040] When the steel is produced, the water quenching spray pipeline pressure is 0.05-0.4MPa, and the water quenching plate temperature is ≤45℃, the steel strip is checked once every shift, and the checking method is that at the 5# deflection roll after the degreasing section, the large cloth is wound on the wooden stick, 20kg force is applied, and the cloth is wiped on the running plate for 6-8 seconds, the white cloth should not be wet, and there should be no obvious oil stains, black ash and the like, the coating roll surface should not be damaged, and there should be no bulges and degumming and the like, and the gap between the upper and lower roll systems, the suction roll and the coating roll is adjusted to 2-10mm.

[0041] The diluent adding amount of the color coating unit is controlled to be 5-15%, and the ratio is different with the change of the coating temperature and the original viscosity.

[0042] The stirring speed is 400-800r / min, the stirring time is 20-40 minutes, and the coating use temperature requirement is ≥0℃.

[0043] The coating film thickness and the viscosity of the coating.

[0044] The polyester front face finish paint: dry film ≥3μm, viscosity: 40±5 seconds; the polyester back face finish paint: dry film ≥6μm, viscosity: 75±5 seconds; the coating film thickness: the front face paint film thickness ≥3μm, and the back face paint film thickness ≥6μm; the film thickness is the three-point average value, and the fluctuation value of the back face paint film thickness should not be more than 2μm.

[0045] Furnace temperature setting and plate temperature (PMT). The furnace temperature setting adopts the temperature rising and falling type: the second and third zones have the same temperature, which is the highest temperature.

[0046] Initial coating PMT: 216-232℃; fine coating PMT: 216-232℃. Inspection and adjustment are performed every roll. The cleaning effect of the leveling liquid is controlled before the color coating unit. All brush rollers of the unit are put into use.

[0047] The color difference of the finished product must be less than 1.2.

Claims

1. A production process for environmentally friendly TSPCC steel for barrel making, characterized by: 1) First, the composition of the steel material is designed: C content 0.03%-0.08%, Si≤0.3%, Mn0.26%-0.33%, P≤0.018%, S≤0.015%, Al 0.018%-0.04%, Ca0.0015%-0.0035%, and the balance is iron and impurities; 2) Slab continuous casting control and inspection requirements: Continuous casting shall be conducted using argon protection throughout the casting process, with carbon-free mold slag and carbon-free ladle covering agent used; retaining walls shall be installed on the tundish; the superheat of the tundish in the first continuous casting furnace shall be ≤45°C, the superheat of the molten steel in the tundish in the continuous pouring furnace shall be ≤35°C, the maximum continuous casting speed shall be ≤1.6m / min, the liquidus temperature for the tapping mark AP1461C1 shall be 1530°C, and the liquidus temperature shall be 1528°C; conventional process control points for hot rolling shall include: heating temperature 1125-1185°C, finishing rolling temperature 870±20°C, rapid cooling mode in the latter part, and coiling temperature 640±20°C; 3) Key points for conventional control of cold rolling pickling and rolling mills: The hydrochloric acid temperature of tanks 1-4 is controlled to 65-75°C, and the operating speed of the process section is controlled to 60-130m / min; before the pickling unit produces the environmentally friendly TSPCC steel for barrel making as specified in the application, the new acid is replaced 4 hours in advance for 60-80m 3 , ensure that the HCl content of the acid in the 1# acid tank is ≥50g / L, the iron ion content is ≤100g / L, and the phenomenon of insufficient pickling is eliminated; the outlet temperature of the filter in the 1# rinsing tank is 60℃~80℃, the conductivity of the rinse water in the 2# rinsing tank is ≤100μS / cm, the opening of the rinse water supply valve station is 25%~40% higher than that of ordinary SPCC steel grades, the plate shape is controlled according to micro-double-sided waves, and medium waves are strictly prohibited. The control coefficient of the standard control curve A2 of the plate shape meter is set to +4, and the width is 930 to 1250㎜ for all adaptations; before production, ensure that the purge device of the last stand rolling mill is normal, no emulsion residue is allowed on the surface of the strip, the purge pressure at the mill outlet is greater than 0.6MPa, the nozzle is not allowed to be missing or blocked, and the condensation water at the mill outlet arch shall not drip onto the strip plate surface; the residual oil content on the surface and single side of the cold-hardened coil of the rolling mill is ≤300mg / m 2 , Residual iron content on one side of the strip surface ≤ 120mg / m 2 ;The roughness of the new working roll surface is kept below 0.7μm; 4) Process control design of bell-type annealing furnace: The bell-type furnace annealing process adopts full hydrogen annealing. The temperature of the steel coil out of the furnace shall not be higher than 100℃. Before production, the ash and carbon black on the furnace table shall be cleaned until there is no ash. The hydrogen blowing volume in the second and third sections shall be controlled at 25-30m 3 / h, ensure that the residual emulsion is fully evaporated; when heating the steel coil, use a heating hood in good working condition and ensure that the gas electric regulating valve operates normally without obstruction; the number of burners in operation must reach 6 or more; when the reflectivity of the rolling mill unit is lower than 50%, use a double platform for annealing, and add a 430℃ holding platform for 2-3 hours, otherwise use a single platform for annealing; the furnace load shall not be less than 45 tons; for a furnace load of 45-55 tons, control the temperature at 690℃, heating time 8h, holding time ≥7h, waiting for hood time 2h, and furnace discharge temperature 95℃; for a furnace load of 55-75 tons, control the temperature at 690℃, heating time 9h, holding time ≥8h, waiting for hood time 3h, and furnace discharge temperature 100℃; for a furnace load greater than 75 tons, control the temperature at 690℃ , heating time is 10h, holding time is ≥9h, waiting time is 5h, and furnace temperature is 100℃; when the steel coil is cooled on the final cooling table after leaving the furnace, cooling is stopped after the cooling temperature reaches 45℃. In case of rainy days, the air intake outside the factory building must be closed; 5) Design of the process parameters of the leveler: The main purpose of the leveler is to level the strip shape and eliminate the yield platform inside the strip. The key process parameter of the leveler is the setting of the elongation. After testing different specifications, the elongation parameters are set according to the thickness of the incoming material in this process: the leveler unit strictly controls the elongation, and the elongation deviation is controlled to ± 0.1%. The details are as follows: incoming material thickness 0.6-0.75 mm, the strip elongation is set to 0.7%-0.9%; incoming material thickness 0.751-0.85 mm, the strip elongation is set to 0.8%-1.0%; incoming material thickness 0.851-0.95 mm, the strip elongation is set to 0.9%-1.1%; incoming material thickness 0.951-1.05 mm, the strip elongation is set to 1.0%-1.0% .2%; the leveling mill is controlled according to micro-medium wave, and edge wave defects are strictly prohibited; the leveling fluid nozzle must be inspected before production, and the emulsion nozzle in the middle of the strip must not be clogged; when the leveling fluid concentration is tested with a refractometer, the refractometer display value is increased from 1.5% to 2.5%. When producing this steel grade, the leveling fluid center injection flow rate is increased by 10%-20%; the purge jet pressure is greater than 0.47MPa, and the purge angle is controlled at 45°~60°; the leveling fluid must be sprayed into the gap between the upper and lower working rolls. Before producing this steel grade, the leveling fluid nozzle must be adjusted 3-5 rolls in advance to ensure uniformity of the leveling fluid injection; the normal production speed must not be less than 500m / min to improve the cleanliness of the strip surface and reduce the occurrence of leveling fluid spot defects; when producing this steel grade, the roughness of the working roll of the leveling mill is controlled at 0.6~0.7μm; the temperature of the steel coils during packaging must not exceed 40℃; 6) Design of color coating process parameters: Pre-treatment 1# and 2# alkali solution spraying and hot water rinsing temperature, when producing this steel type, the temperature is controlled to 70±3℃; when producing this steel type, the alkali spraying alkali point is controlled to 6-10mg / L, and the overflow is 10m per shift. 3 Pretreatment liquid, to ensure that the original plate carbon black can be fully discharged, when producing TSPCC annealing plate 2000t, replace the degreasing section tank liquid, re-liquid; when producing this steel grade, the chromium point of the passivation liquid of the chemical coating machine is controlled to 23-25 ​​mg / L, and the Cr content of the passivation plate film is 25-30 mg / m 2 , take samples for inspection within one hour after taking over, and take samples for inspection once every 3 hours in the later period; the PMT plate temperature after the chemical coating oven is controlled to 70-80℃, and is tested once every 4 hours with a temperature gun or temperature measuring paper A / B. Chemical coating drying requirements: there is no obvious yellow spot when the passivation film is wiped with paper, there is no missing coating on the steel strip surface, no pitting or passivation spots on the surface, and no yellow spots or thick edges on the edges. The passivation liquid should be replaced when producing more than 1,000 tons of TSPCC barrel board; the pressure of the coating roller and the suction roller of the chemical coating machine is adjusted so that the current value between the two rollers is 30-80%, and the roller speed ratio is set as follows: coating roller speed: unit speed = 1.1-1.5:1; suction roller speed: unit speed = 0 .2~0.6:1; before producing this type of steel, check the bristles on the brush roller and adjust the height of the brush roller. The working current of the brush roller is 10~20A, and all brush rollers are put into use. At the same time, check and confirm the blockage of the pre-treatment alkali cleaning and rinsing nozzles. The nozzle angle is controlled to 45-60° to ensure that the carbon black on the surface of the steel coil can be fully cleaned; the 6# and 7# squeeze rollers at the end of the hot water rinsing rotate flexibly without obstruction and the roller surface is not debonded. The angle of the 1# air knife is controlled to 45-60°; when producing this type of steel, the water quenching spray pipeline pressure is 0.05-0.4MPa, and the water quenching plate temperature is ≤45℃; the strip steel is inspected once per shift, Inspection method: Wrap a large cloth around a wooden stick at the 5# turning roller after the degreasing section, apply 20kg of force to press, and wipe the running board surface for 6 to 8 seconds. Check that the white cloth is not wet and there is no obvious oil or black ash. Adjust the gap between the upper and lower rollers and the coating roller to 2 to 10mm. Control the amount of thinner added at 5%-15%, and its proportion will vary with the temperature and original viscosity of the paint. The stirrer speed is 400-800 rpm, and the stirring time is 20-40 minutes. The paint use temperature requirement is: ≥0℃; polyester front topcoat: dry film ≥3 μm, viscosity: 40±5 seconds; polyester back topcoat: dry film ≥6 μm, viscosity: 75±5 seconds. seconds; coating film thickness inspection standard: front paint film thickness ≥3μm, back paint film thickness ≥6μm; film thickness is the average of three points, and the fluctuation value of the back paint film thickness shall not exceed 2μm; furnace temperature setting and plate temperature PMT, furnace temperature setting adopts ramping type: the temperature of the second zone and the third zone is the same, which is the highest temperature, initial coating PMT: 216-232℃; fine coating PMT: 216-232℃. Each roll is checked and adjusted. The color coating unit pays attention to the cleaning effect of the leveling liquid, and all brush rollers of the unit are put into use.