CN116254535A - Continuous pickling control method for high-strength steel of middle plate - Google Patents

Abstract

The invention discloses a continuous pickling control method for medium plate high-strength steel, which belongs to the field of pickling steel production, wherein the medium plate high-strength steel has a thickness specification of 4.0-6.0mm and a yield strength of 500-650MPa; the specific procedures and the control method are as follows: (1) feeding operation: the feeding operation unit comprises an uncoiler inlet shear welding machine and an inlet loop; welding by using filler wire; the inlet loopers are controlled according to the looper amount less than or equal to 50 percent; (2) phosphorus breaking operation: the elongation of the phosphorus breaker is 0.2-0.3%; (3) pickling operation: the pickling speed is 30-50m/min; (4) withdrawal and straightening operation: the elongation of the withdrawal and straightening is 0.2%; (5) coiling operation: comprises the steps of building Zhang Jiaozhi, shearing and coiling to obtain a finished product. Realizing continuous acid washing and stable batch production of high-strength steel with the thickness of 4.0-6.0mm and the yield strength of 500-650 MPa.

Description

Continuous pickling control method for high-strength steel of middle plate

Technical Field

The invention relates to a steel production method, in particular to a method for producing high-strength steel with the yield strength of 500-650MPa and the width of less than or equal to 1300mm by a continuous pickling line.

Background

Because of the requirement of the industries such as automobiles, household appliances, buildings and the like for reducing the cost of steel, the pickling products of the hot-replacement cold-replacement type in each large steel factory gradually replace the traditional steel.

And the high-strength automobile steel QSTE500 TM-QSTE 550TM series and S500MC-SM550MC series have the thickness of more than or equal to 4.0mm, and have huge competitive power in marketing and profit. At present, the type of steel with the thickness of 4.0-6.0mm cannot be rolled by using a traditional cold continuous rolling mill, and most of the type of steel is produced by pickling hot rolled plates. For the middle plate high-strength steel with the thickness more than or equal to 4.0mm and the yield strength more than or equal to 500MPA, the continuous pickling line in each country is basically not produced at present due to the thick and high strength of strip steel, the middle plate high-strength steel is produced by adopting a push-pull type pickling line, the push-pull type pickling line also comprises a phosphorus breaker and a pickling tank, two strip steels do not need to be welded, a traction roller and a drive roller system are adopted for threading and coiling, and the pull roller is adopted for pushing the threading and coiling, so that the production speed is low, the strip steel shape is poor, and the push-pull type pickling line is more suitable for producing middle plate pickling products.

Based on the method, all iron and steel enterprises actively seek the existing continuous pickling line to carry out production breakthrough, but the existing continuous pickling line is designed to produce the continuous pickling hot rolled low-carbon steel with the specification thickness of 0.8-6.0mm, the width of 900-1500mm and the strength level: the yield strength is less than or equal to 500MPa, and the tensile strength is less than or equal to 600MPa. The production line design technical accessories require that the production thickness of the pickling product is 4.0-6.0mm, the pickling product is required to be low-carbon steel, the yield strength is less than or equal to 400MPa, and the width is less than or equal to 1300mm. The technology of the process method for producing the hot base plate with flower galvanized product with thick specification and the equipment thereof, CN 110359001A) can be used for realizing continuous pickling production with the yield strength of between 290 and 320MPa and 0.8 and 4.0mm, but has the following technical defects when the production with the thickness of between 4.0 and 6.0mm and the yield strength exceeding 400MPa is carried out: (1) because the high-strength steel adopts low-carbon feeding, the alloy components such as Mn, si and the like have high content and high strength, the thickness of strip steel is thick, and welding defects such as weld failure and air holes easily occur in the welding process of a welding machine; (2) the middle plate high-strength strip steel is wound by a tension roller system, and in the straightening and bending process of the phosphorus breaker and the tension leveler, larger tension is needed, and the welded joint of the two strip steels is repeatedly bent, so that the strip steel is easily broken under the action of huge tension to generate a strip breakage accident; (3) the middle plate high-strength steel has high strength and thick strip steel, and in the process of straightening the plate shape and damaging the iron scale on the surface of the strip steel, the tension roller in front of the phosphorus breaker has overlarge load and gives an alarm to stop; (4) because the strip steel is thick and the length of the steel coil is short, the strip steel is easy to have over-acid cleaning defects in the acid cleaning process, and meanwhile, the strip steel is easy to have yellow spot defects in the rinsing tank; (5) after the flying shears at the outlet of the production line are sheared, the belt heads are tilted upwards, the upper shearing edge of the flying shears is frequently blocked to stop, and the shearing edge is easy to damage due to impact on the shearing edge; (6) the loose ring of the outer ring and the opening degree of the belt head of the strip steel after coiling and tail throwing are large, and the strip steel cannot be packaged.

Therefore, how to overcome the design capacity level of the production line, and realize continuous acid washing and batch production of high-strength steel with the thickness of 4.0-6.0mm and the yield strength of 500-650MPa is a technical problem which needs to be solved in the field.

Disclosure of Invention

Aiming at the defects of the prior art, the invention provides a control method for continuous pickling of medium-plate high-strength automobile steel, which realizes continuous pickling with the thickness of 4.0-6.0mm and the yield strength of 500-650MPa and stable batch production.

The technical scheme for solving the technical problems is as follows: a continuous pickling control method for high-strength steel of a middle plate is characterized by comprising the following steps of: the high-strength steel of the middle plate has a thickness specification of 4.0-6.0mm and a yield strength of 500-650MPa; comprises uncoiling, welding, phosphorus breaking, acid washing, rinsing, withdrawal and straightening, shearing, coiling and finished product preparation; the specific procedures and the control method are as follows:

(1) Feeding operation: the feeding operation unit comprises an uncoiler, an inlet shear, a welding machine and an inlet loop; welding by using filler wire; the inlet loopers are controlled according to the looper amount less than or equal to 50 percent;

(2) And (3) phosphorus breaking operation: the elongation of the phosphorus breaker is 0.2-0.3%;

(3) Acid washing operation: the pickling speed is 30-50m/min;

(4) And (3) pulling and straightening: the elongation of the withdrawal and straightening is 0.2%;

(5) Coiling operation: comprises the steps of shearing and coiling to obtain a finished product.

Further, a tension leveler Zhang Jiaozhi is also included between the tension leveler and the shear leveler.

Further, the filler wire selected is a low C low Mn wire.

Further, the welding wire composition includes C:0.06-0.09%; si:0.6-0.95%, mn:1.50-2.1%, S:0.10-0.16%, P:0.11-0.16%.

Further, the outlet looper is controlled in 12-20% looper.

Further, in the pickling operation, the temperature of the No. 1 groove is 75-78 ℃, and the temperatures of the No. 2 groove, the No. 3 groove, the No. 4 groove and the No. 5 groove are 73-75 ℃; the water temperature of the rinsing tank is 45-50 ℃.

Furthermore, when the welding line passes through the phosphorus breaking machine and the tension leveler, the phosphorus breaking machine and the tension leveler adopt an opening mode.

Further, in the winding operation, the winding weight is required to: the raw material roll weight is less than or equal to 8t and less than or equal to 16t, and the finished product outlet is not separated; the raw material roll weight is more than or equal to 21t, and the finished product roll weight is more than or equal to 10.5t; the raw material roll weight is more than or equal to 26t, and the finished product roll weight is more than or equal to 12.5t.

Further, in the above-mentioned positioning procedure of the tail in the winding operation, the length of the tail was 5cm.

Further, after the coiling operation, the position of the band head after coil unloading is pressed onto the saddle of the transportation trolley, and the opening degree of the band head is reduced through the dead weight of the band steel.

Compared with the prior art, the invention has the following outstanding beneficial effects:

1. the invention overcomes the design capacity level of the production line, and realizes continuous acid washing operation of high-strength steel with the thickness of 4.0-6.0mm and the yield strength of 500-650MPa;

2. the quality of welding seams at the welding positions of the medium plate high-strength steel is guaranteed, the welding seams are not broken in the production process, and the production stability is realized;

3. the technical defect that the surface of the strip steel in the rinsing section is easily oxidized to generate yellow spots due to the fact that the production speed is low in the conventional medium plate pickling technology is overcome;

4. the problem that the strip steel is warped after being sheared by the flying shears is solved, the condition that the shearing strip steel is blocked by the strip steel and is stopped is avoided, and the defect that the strip steel is stopped in a pickling section and a rinsing section is reduced;

5. the straightening extension is redistributed, and before the outlet section is cut and sheared, the extension rate of the stage of phosphorus breaking and straightening is reduced by re-straightening the head and the tail of the strip steel, so that the early warning strip breakage and stopping signals caused by the overrun of equipment load are avoided;

6. the problem that the strip steel cannot be packaged due to overlarge opening degree and loose ring of the outer ring in the coiling process is solved, and the packaging requirement of subsequent products is met.

Drawings

Fig. 1 is a schematic diagram of the macro arrangement of the present invention.

FIG. 2 is a schematic view of the structure of the tension leveler roller set of the present invention.

Fig. 3 is a schematic view of the structure of the steering roller set of the present invention.

Fig. 4 is a schematic view of the structure of the pinch roll unit of the present invention.

FIG. 5 is a schematic diagram of the puck mechanism of the present invention.

Detailed Description

The invention is further described below in connection with the following detailed description.

For the purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. Furthermore, all numbers expressing, for example, quantities of ingredients used in the specification and claims, other than in any operating example or where otherwise indicated, are to be understood as being modified in all instances by the term "about". At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques.

Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.

It should also be understood that any numerical range recited herein is intended to include all sub-ranges subsumed therein. For example, a range of "1 to 10" is intended to include all subranges between (and including) the stated minimum value of 1 and the stated maximum value of 10, that is, having a minimum value equal to or greater than 1 and a maximum value equal to or less than 10.

In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, unless explicitly stated otherwise, the use of "or" means "and/or", even though "and/or" may be explicitly used in certain instances. Further, in this application, the use of "a" or "an" means "at least one" unless specifically stated otherwise. For example, "a" first material, "a" coating composition, etc., refer to one or more of any of these items.

The invention adopts a hot substrate pickling process: hot rolling raw materials, uncoiling, welding, phosphorus breaking, pickling, rinsing, pulling and straightening, building Zhang Jiaozhi, shearing, coiling and obtaining a finished product. The thickness specification of the product is 4.0-6.0mm.

The specific procedures and the control method are as follows:

1. feeding operation

The feeding operation unit comprises an uncoiler, an inlet shear, a welding machine and an inlet loop.

Wherein:

(1) Welding process control of welding machine

The high-strength steel adopts low-carbon low-alloy high-strength steel, the alloy components of the hot rolling raw materials are high in Mn and Si content (C: 0.04-0.09%, si:0.15-0.45%, mn: 1.25-1.55%), the yield strength is more than or equal to 500MPa, welding defects of weld joint are easy to occur in welding operation in the prior art, and the quality qualification rate of the weld joint is less than 40%, so that the hot rolling raw materials are produced by adopting a push-pull type acid washing production line, and the continuous acid washing difficulty is high.

The invention performs the following control:

(1) selection of filler wire

The invention adopts filler wire for welding, and the diameter of the filler wire is 0.8mm: in the embodiment, the welding wire is low-C and low-Mn (C: 0.06-0.09%, si:0.6-0.95%, mn:1.50-2.1%, S:0.10-0.16%, P: 0.11-0.16%).

The welding is carried out through gas shielded welding, so that the grain size of the welding seam is thinned, the plastic toughness is effectively improved, the bending performance of the welding joint is further improved, and the problem of cracking of the welding seam is effectively solved.

(2) Welding process parameters

High-strength automobile steel welding parameters with thickness not less than 4.0 mm: the laser power of the welding machine is 11.76-12Kw, the welding speed is 4.2-6.0m/min, the pressure of a rolling wheel is 75-98bar, the preheating power is 18-22Kw, the annealing power is 22-28Kw, and the gap (transmission side/operation side) is 0.10/0.12mm; defocus 2.5mm.

The maximum thickness difference of the adjacent welded strip steel is 1mm, and the yield strength difference is less than or equal to 150MPa.

For example, the production specification is 4.0-6.0mm, the yield strength is less than 500MMPa, and the welding is not performed by filling wires.

For example, the production specification is 4.0-6.0mm, the yield strength is more than or equal to 500MMPa, the strength is high, the content of Si and Mn in alloy components is high, the alloy components are put into filler wire welding, and the wire feeding speed is 4.1-6.2m/min.

The specific welding parameters are as follows

(2) Loop quantity control

The main function of the inlet loop is to store strip steel, so that when a short fault occurs in the production line, the short adjustment time is ensured.

The production line is from the welding machine, the inlet loop, the acid washing section, the rinsing section, the withdrawal and straightening machine and the outlet loop to the production line outlet slitting shear and the coiling machine about 2000 meters. 6 layers of strip steel are sleeved at the inlet, and the whole length is 1050 meters; the loop quantity is controlled by pulling the loop trolley to move forwards and backwards through the hoisting equipment, and the strip steel is required to be pulled in the motion process of the loop trolley, so that the motion action of the loop trolley is aggravated in the strip steel charging process, the pulling force is suddenly increased, and meanwhile, the condition of welding seam re-welding possibly occurs in the middle plate high-strength steel welding.

The strip steel enters an outlet loop after coming out of the withdrawal and straightening machine, and the outlet loop is 540 m, and four layers of strip steel are used. The loop is oversized, the winch pulls the trolley to move and requires larger pulling force, so as to protect winch equipment, and meanwhile, the high-strength inlet loop and the high-strength outlet loop of the middle plate are limited in order to ensure the stability of the high-strength steel welding seam.

If the production specification is 4.0-6.0mm, the yield strength is less than 500MMPa, the inlet loop is less than or equal to 70%, and the outlet loop is less than or equal to 40%;

if the production specification is 4.0-6.0mm, the yield strength is more than or equal to 500MMPa, the inlet loopers are controlled according to the amount of less than or equal to 50 percent, and the number of medium plate high carbon steel welding seams in the inlet loopers is less than or equal to 2; the outlet looper is controlled according to 12-20% looper.

The control ensures the quality of the welding seam at the welding position of the medium plate high-strength steel, ensures that the welding seam is not broken in the production process, and realizes the production stability.

2. Phosphorus breaking operation:

the middle plate high-strength steel has high strength and thick strip steel, and the tension roller in front of the phosphorus breaker has overlarge load and gives an alarm to stop in the process of straightening the plate shape and damaging the iron scale on the surface of the strip steel.

And (3) weld joint protection: and the welding line passes through the phosphorus breaker and adopts an opening mode.

For example, the production specification is 4.0-6.0mm, the yield strength is less than 500MMPa, and the elongation of the phosphorus breaker is 0.6-0.8%;

if the production specification is 4.0-6.0mm and is more than or equal to 500MPa, the elongation of the medium-plate high-strength steel control phosphorus breaker is 0.2-0.3%, the post-pickling effect of broken iron scales can be achieved, and the strip steel shape is improved to a certain extent.

3. Acid washing operation:

because the strip steel is thick and the length of the steel coil is short, the strip steel is easy to have over-acid cleaning defects in the acid cleaning process, and meanwhile, the strip steel is easy to have yellow spot defects in the rinsing tank.

(1) Pickling speed

From the production line inlet welding machine to the production line outlet coiling machine, the total length of the whole pickling production line is about 2000 meters, and according to 18-28 tons of medium plate high-strength steel in each coil, the total length of each coil of steel is about 350-600 meters, about 3-5 coils of materials are arranged in the production line, and 3-5 medium plate high-strength steel welding seams are arranged in the whole production line. Meanwhile, the production time of the weld joint of the middle plate high-strength steel is influenced by repeated welding in the inlet welding process, so that the risk of shutdown of the middle plate high-strength steel and disconnection of the weld joint of the middle plate high-strength steel is avoided, and the production speed is reduced as a whole.

For example, the production specification is 4.0-6.0mm, the yield strength is less than 500MPa, the welding seam welded by a welding machine has good quality, the welding time is short, the stability of the welding seam is high, and the pickling process speed of the strip steel is 40-100m/min.

For example, the production specification is 4.0-6.0mm, the pressure is more than or equal to 500MPa, and the pickling speed is 30-50m/min to ensure the stability of the production process.

(2) Parameters of pickling

If the production specification is 4.0-6.0mm, the temperature is more than or equal to 500MPa, the low-temperature and low-concentration control is adopted, the temperature of a No. 1 groove is 75-78 ℃, and the temperatures of a No. 2 groove, a No. 3 groove, a No. 4 groove and a No. 5 groove are 73-75 ℃; the production speed of the strip steel is low, the temperature is too high, the surface of the strip steel is easy to be subjected to over-pickling, meanwhile, the high-strength steel of the middle plate contains Si and Mn alloy components, and the surface of the strip steel is easy to be blackened after pickling, so that the high-strength steel of the middle plate is controlled by adopting low temperature and low concentration, and the concentration of free acid in a No. 1 groove is 45-50g/l; because the production speed of the middle plate high-strength steel is low, a protective water film on the strip steel surface in the rinsing tank is easily evaporated, and the strip steel surface is oxidized to form yellow spot defect, so that the rinsing water temperature is controlled at a low temperature, the evaporation speed of the water film on the strip steel surface is reduced, the water temperature of the rinsing tank is controlled according to 45-50 ℃, and the rinsing tank is controlled by adopting a passivating agent of 1.0-1.5 per mill. In the production of the medium-plate high-strength steel, an operator automatically increases the concentration of the passivating agent added in the rinsing section 1 hour in advance, the surface of the strip steel is cleaner due to the action of the rinsing water passivating agent, and a protective film is formed on the metal surface to prevent the surface of the strip steel from being oxidized.

For example, the production specification is 4.0-6.0mm, the yield strength is less than 500MPa, the passivating agent is 0.8 per mill, and the rinsing water temperature is 45-60 ℃.

The technical defect that the surface of the strip steel in the rinsing section is easily oxidized to generate yellow spots due to the fact that the production speed is low in the conventional medium plate pickling technology is overcome.

4. Withdrawal and straightening work

And (3) weld joint protection: and the welding seam passes through the tension leveler, and an opening mode is adopted.

For example, the production specification is 4.0-6.0mm, the yield strength is less than 500MPa, and the tensile elongation is 0.4%;

if the production specification is 4.0-6.0mm, the yield strength is more than or equal to 500MPa, the tension leveled elongation is 0.2%, and the tension leveled elongation is too large, so that the tension is too large, and an alarm stop signal is easy to appear.

Normally producing low carbon steel by adopting 1 roller box, 1 bending roller and 1 straightening roller; in order to ensure the shape of the middle plate high-strength automobile steel, the double-roller box is used for simultaneous application, and the 1 bending roller and the 2 straightening rollers are used for simultaneous application.

5. Coiling operation

Comprises the steps of building Zhang Jiaozhi, shearing and coiling to obtain a finished product.

The building Zhang Jiaozhi can be realized by using a tension roller and a straightening roller before shearing equipment in coiling operation, the outlet building Zhang Jiaozhi redistributes straightening extension, and the elongation rate of the stage of phosphorus breaking and straightening is reduced by re-straightening the head and tail of the strip steel before slitting and shearing of the outlet section, so that early warning strip breakage and stopping signals caused by overrun of equipment load are avoided.

The rolling weight requirement is as follows:

1) The raw material roll weight is less than or equal to 8t and less than or equal to 16t, and the finished product outlet is not separated;

2) The raw material roll weight control is more than or equal to 21t (1250 mm), and the finished product roll weight control is more than or equal to 10.5t (1250 mm in width);

3) The raw material roll weight is more than or equal to 26t (1500 mm), the finished product roll weight is more than or equal to 12.5t (1500 mm in width),

the product outlet is divided into at most 2 sub-rolls. The weight of the raw materials is too small, the length of the strip steel is too short, if the strip steel is subjected to repeated welding conditions or other short equipment problems in the welding process of a welding machine, the strip steel is not adjusted in time, the strip steel is easy to stop, the defect of stopping spots is generated, meanwhile, the number of welding seams of the high-strength steel is increased in a production line, and the risk of strip breakage of the welding seams is increased.

The strapping requires:

and (3) punching three binding belts on the pickling middle plate with the thickness of more than or equal to 4.0 mm. The strip steel is too thick, the tail part of the strip steel of the outer ring of the strip steel after coiling has slight opening degree, and the opening degree is that the tail part of the strip steel of the outermost ring cannot be tightly attached to a steel coil, and the tail part is separated from the second ring of the strip steel.

The opening degree is to the risk that the tie exists to collapse, increases three tie one can tight the coil of strip, and two is from the safety aspect that prevents the tie and collapse.

Under the existing hardware condition of the pickling line, after the process is improved, the middle plate product with the thickness specification of 4.0-6.0mm, the yield strength of more than or equal to 500MPa and the width of less than or equal to 1300mm can be stably produced. And the high-strength steel 2100 tons with the quality-inspection qualification rate of 98.6% and no joint weld breakage accident is produced in 2022 by QSTE500 TM-QSTE 550TM series and S500MC-SM550MC series with the specification of 4.0-6.0mm.

In actual production, the defects of loose rings of the outer rings, large opening degree of the belt head, upward warping of the belt head and the like of the middle plate high-strength steel are easy to occur at the outlet, and the subsequent packaging treatment is affected: because the strip steel has thick thickness and high strength, after the flying shears at the outlet of the production line shear, the strip head is tilted upwards, and the guide plate table is frequently blocked to stop; in the prior art, rubber sleeves and belts are often adopted to coil middle plate automobile steel, the tension force of the belts is small, the outer ring and the inner ring of the steel plates are easy to loose, the middle plate high-strength steel outer ring is loose, and only quality degradation can be achieved after the middle plate high-strength steel outer ring cannot be packaged at all. In addition, because the middle plate high-strength steel has high strength, the strip steel is thick and is not easy to coil, the opening degree of the strip steel is overlarge after the strip steel is coiled and thrown, the standard requirement is less than or equal to 10cm, the strip steel can reach 20-40cm practically, and the strip steel cannot be packaged.

In order to better realize coiling operation, reduce the opening degree of the belt head and prevent steel from being blocked, and build Zhang Jiaozhi for the second time, the invention improves the outlet equipment of the pickling line.

The invention provides outlet equipment of an acid washing production line, which is macroscopically arranged as shown in figure 1 and comprises a tension straightening roller set 1, a slitting assembly 4, a steering roller set 6 and a scroll 7. In this embodiment, a pinch roll set 3 is further included between the tension straightening roll set 1 and the slitting assembly 4, and an oiling machine 2 is further included between the tension straightening roll set 1 and the pinch roll set 3. The steering roller group 6 and the scroll 7 are two groups.

The tension straightening roller set 1 establishes tension to ensure the running of strip steel; the oiling machine 2 is used for oiling the surface of the strip steel and preventing rust; the pinch roll set 3 ensures the strip steel stability in the strip steel slitting process and prevents the strip steel from slipping; the cutting assembly 4 is used for cutting the continuous strip steel in a rolling way; the steering roller set 6 comprises a steering roller and a compression roller, and when the strip steel passes through the winding shaft, the strip steel is ensured to enter the winding shaft for winding; the reel 7 winds the strip steel 5.

The tension straightening roller set 1 is used for forming tension with the winding shaft 7 of the winding unit, and as shown in fig. 2, the tension straightening roller set 1 comprises a No. I compression roller 16, a No. I tension roller 15, a No. II compression roller 12, a No. II tension roller 14, a straightening roller 13 and a hydraulic cylinder 17 which are arranged on a roller frame.

The I compression roller 16 is pressed to the I tension roller 15 under the action of the pressing device above the I tension roller 15, and the II compression roller 12 is pressed to the II tension roller 14 under the action of the pressing device below the II tension roller 14. In this embodiment, the diameters phi 1250, 16 and 270 of the tension rollers 15 and 14 and the tension rollers 16 and 12 are described. The specific construction and control of the press roller and the pressing device are prior art and will not be described in detail here.

The I-size press roll 16 is positioned in front of the II-size tension roll 14. The strip steel 5 walks in the tension straightening roller set 1 in an inverse S shape, and specifically enters the upper part of the straightening roller 13 from the position between the No. II compression roller 12 and the No. II tension roller 14 through the position between the No. I compression roller 16 and the No. I tension roller 15, and around the No. I tension roller 15 and the No. II tension roller 14.

In normal production, the I-type press roll 16 and the II-type press roll 12 are in a lifting state, the outlet strip steel 5 runs for 40min/m before the slitting assembly 4 is slit, and after a pressing device of the I-type press roll 16 and the II-type press roll 12 receives a pressing signal, the pressing device presses down for about 2 seconds; the purpose of the two pressing roller pressing operation is to prevent the strip steel 5 from being fixed after the strip steel is cut by the flying shears, and prevent the strip steel from sliding backwards.

The straightening roller 13 is positioned at the front lower part of the II-type tension roller 14. The hydraulic cylinder 17 is used for lifting the straightening roller 13, the hydraulic cylinder 17 can be directly connected with two ends of the straightening roller 13, or can be realized through the leverage of the connecting frame 11 in the embodiment, specifically, the middle section of the connecting frame 11 is hinged with the roller frame, the front end is used for jacking the straightening roller 13, and the rear end is connected with the lower end of the telescopic rod of the hydraulic cylinder 17.

The pressing device of the pressing roller I16, the pressing device of the pressing roller II 12 and the hydraulic cylinder 17 are controlled by an electric program in a linkage way. Namely, when the production thickness is more than or equal to 4.0mm, an operator selects a chain use state, at the moment, when the I-type press roll 16 and the II-type press roll 12 are pressed down, the hydraulic cylinder 17 drives the straightening roll 13 to jack up 15mm upwards and synchronously act with the II-type press roll 12, at the moment, a straightening relation is formed between the straightening roll 13 and the II-type press roll 12, and the former roll of tape head and the later roll of tape tail at the cutting position of the medium plate can have a straightening effect.

As shown in fig. 3, the steering roller group 6 includes a steering roller 64, a rear pressing roller 62, a front pressing roller 66, a rear pressing assembly, and a front pressing assembly, which are mounted on a steering roller frame. Between the turning roll 64 and the reel 7 is a guide table 68.

The rear press roller 62 is arranged above the turning roller 64, and the pressing contact between the rear press roller 62 and the turning roller 64 is realized by a rear pressing assembly. In this embodiment, the rear pressing assembly includes a rear hydraulic rod 63 and a rear pressing beam 61, the lower end of the rear hydraulic rod 63 and the front end of the rear pressing beam 61 are respectively hinged to the steering roller frame, and the upper end of the rear hydraulic rod 63 and the rear end of the rear pressing beam 61 are hinged. The rear pressing beam 61 is used to press the rear pressing roller 62 against the steering roller 64.

The front press roller 66 is arranged above the front of the turning roller 64, and the front press roller 66 is in pressing contact with the turning roller 64 through a front pressing assembly. In this embodiment, the front pressing assembly includes a front hydraulic rod 67 and a front pressing beam 65, the lower end of the front hydraulic rod 67 and the rear end of the front pressing beam 65 are respectively hinged with the steering roller frame, and the upper end of the front hydraulic rod 67 is hinged with the front end of the front pressing beam 65. The front pressing beam 65 is used to press the front pressing roller 66 against the steering roller 64.

When the slitting assembly 4 shears the slitting coil, the tail of the former coil is thrown under the action of no tension. The front press roller 66 is used when the strip steel 5 is worn, and is used for pulling the strip head to the reel 7 for coiling through the strip threading guide plate 68, and the tail is not thrown. When the production thickness is more than or equal to 4.0mm, an operator selects to throw the front press roller 66, the rear press roller 62 and the front press roller 66 are started to press down simultaneously when the strip steel of the coiling machine is thrown, and the tail strip steel 5 has a downward buckling trend when the strip steel is thrown, so that the tail strip steel can be attached to a steel coil after coiling. And the pressure of the back pressure roller 62 is optimized, the pressure is adjusted from 90MPa to 110MPa, and when the thickness of the strip steel is less than 4.0mm, the front pressure roller 66 is not used.

As shown in fig. 4, the pinch roll set 3 includes a carrier roller 34, an upper pinch roll 32, a lower pinch roll 33 and a pressing device 31, which function to keep the strip steel stable during the shearing process of the slitting assembly 4, and also prevent the strip steel from sliding backwards under the action of losing tension.

The carrier roller 34 is positioned behind the lower pinch roll 33, and the roller surface of the carrier roller 34 is higher than the roller surface of the lower pinch roll 33, so that the strip steel 5 obliquely enters between the upper pinch roll 32 and the lower pinch roll 33. The pressing device 31 is used for driving the upper pinch roll 32 to press the lower pinch roll 33. In this embodiment, the roller surface of the carrier roller 34 is 10mm higher than the roller surface of the lower pinch roller 33.

When the strip steel is reduced by 40m/min, the upper pinch roll 32 and the No. I press roll 16 and the No. II press roll 12 of the tension straightening roll set 1 are simultaneously pressed down before the strip steel 5 is sheared by the slitting assembly 4, and a simple bending effect is formed among the carrier roll 34, the upper pinch roll 32 and the lower pinch roll 33, so that the strip head of the strip steel is in a downward buckling trend after the shearing of the slitting assembly 4.

The slitting assembly 4 comprises an upper cutting edge 42, a lower cutting edge 43 and a pinch roller mechanism.

As shown in FIG. 5, the puck mechanism includes puck 41, link 45, and C-frame 46.

The C-shaped frame 46 is mounted to the upper cutting edge 42 in conjunction therewith.

The upper arm and the lower arm of the C-shaped frame 46 have a through hole, the connecting rod 45 passes through the through hole, the upper end is fixedly connected with the frame of the slitting assembly 4, and the lower end is connected with the wheel shaft of the pinch roller 41. The connecting rod 45 is connected with a screw thread 44 in a threaded manner at a position above the upper arm of the C-shaped frame 46, a clamping plate is fixedly arranged at a position above the lower arm of the C-shaped frame 46, and a compression spring 47 is sleeved between the clamping plate and the upper arm of the C-shaped frame 46. In this embodiment, the pressing wheel 41 is a 5-inch iron core rubber-lined polyurethane pressing wheel.

In the free state (A state), the bottom of the pinch roller 41 is about 50mm lower than the lowermost end of the upper blade 42. The C-shaped frame 46 moves downwards along with the upper cutting edge 42 (B state), when the upper cutting edge 42 is positioned at the lowest position, the pinch roller 41 presses on the plane of the strip steel, due to the existence of the compression spring 47, the pinch roller 41 keeps a certain pressure (< 15 bar), when the unit production thickness is more than or equal to 4.0mm, and the strength is more than or equal to 500MPa at the highest, the bottom of the pinch roller 41 is lower than the lowest end of the upper cutting edge 42 by about 30mm, so that the head of the strip steel is effectively prevented from warping, and the strip threading is ensured to be smoothly completed at the upper cutting edge 42.

In order to reduce the opening degree of the belt head, in the optimization scheme, the positioning program of the belt tail is revised, the length of the belt tail is adjusted to 5cm from 8cm, the position of the belt head after coil stripping is pressed onto the saddle of the transportation trolley, and the opening degree of the belt head is reduced through the dead weight of the strip steel.

The present embodiment is not described in detail, and is known in the art.

It is noted that while the present invention has been described in detail with respect to specific embodiments thereof, it will be apparent to those skilled in the art that various modifications can be made therein without departing from the spirit and scope thereof.

Claims (10)

1. A continuous pickling control method for high-strength steel of a middle plate is characterized by comprising the following steps of: the high-strength steel of the middle plate has a thickness specification of 4.0-6.0mm and a yield strength of 500-650MPa; comprises uncoiling, welding, phosphorus breaking, acid washing, rinsing, withdrawal and straightening, shearing, coiling and finished product preparation; the specific procedures and the control method are as follows:

(1) Feeding operation: the feeding operation unit comprises an uncoiler, an inlet shear, a welding machine and an inlet loop; welding by using filler wire; the inlet loopers are controlled according to the looper amount less than or equal to 50 percent;

(2) And (3) phosphorus breaking operation: the elongation of the phosphorus breaker is 0.2-0.3%;

(3) Acid washing operation: the pickling speed is 30-50m/min;

(4) And (3) pulling and straightening: the elongation of the withdrawal and straightening is 0.2%;

(5) Coiling operation: comprises the steps of shearing and coiling to obtain a finished product.

2. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: and a building Zhang Jiaozhi is also arranged between the tension leveler and the shearing.

3. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: the filler wire is selected to be a low-C low-Mn welding wire.

4. A method for controlling continuous pickling of high-strength steel for a middle plate according to claim 3, wherein the method comprises the following steps: the welding wire comprises the following components: 0.06-0.09%; si:0.6-0.95%, mn:1.50-2.1%, S:0.10-0.16%, P:0.11-0.16%.

5. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: the outlet looper is controlled according to 12-20% looper.

6. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: in the pickling operation, the temperature of a No. 1 groove is 75-78 ℃, and the temperature of a No. 2 groove, a No. 3 groove, a No. 4 groove and a No. 5 groove are 73-75 ℃; the water temperature of the rinsing tank is 45-50 ℃.

7. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: when the welding line passes through the phosphorus breaking machine and the tension leveler, the phosphorus breaking machine and the tension leveler adopt an opening mode.

8. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: in the coiling operation, the coiling weight requires: the raw material roll weight is less than or equal to 8t and less than or equal to 16t, and the finished product outlet is not separated; the raw material roll weight is more than or equal to 21t, and the finished product roll weight is more than or equal to 10.5t; the raw material roll weight is more than or equal to 26t, and the finished product roll weight is more than or equal to 12.5t.

9. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: in the positioning procedure of the tape tail in the coiling operation, the length of the tape tail is 5cm.

10. The method for controlling continuous pickling of medium-plate high-strength steel according to claim 1, wherein the method comprises the following steps: after the coiling operation, the position of the band head after coil unloading is pressed onto the saddle of the transportation trolley, and the opening degree of the band head is reduced through the dead weight of the band steel.

Images