CN112658046A

CN112658046A - Energy-saving production method of high-ductility cold-rolled steel bar

Info

Publication number: CN112658046A
Application number: CN202011422050.0A
Authority: CN
Inventors: 陈伟; 翟文
Original assignee: Anyang Fuxing Heli New Material Co ltd
Current assignee: Anyang Fuxing Heli New Material Co ltd
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-04-16
Anticipated expiration: 2040-12-08
Also published as: CN112658046B

Abstract

The method for producing the high-ductility cold-rolled steel bar in an energy-saving way comprises rolling and heat treatment, wherein the rolling comprises reducing rolling and forming rolling which are arranged in tandem, and is characterized in that: the heat treatment adopts two heat treatments, the first heat treatment is positioned between the reducing rolling and the forming rolling, the temperature of the first heat treatment is 300-600 ℃, the second heat treatment is positioned after the forming rolling, the temperature of the second heat treatment is more than 530 ℃ and less than 680 ℃, and the temperature of the second heat treatment is higher than the temperature of the first heat treatment. The process reduces the power consumption to 5-8 degrees/ton as a whole, and greatly improves the mechanical performance index of the product produced by the production process while reducing the power consumption.

Description

Energy-saving production method of high-ductility cold-rolled steel bar

Technical Field

The invention relates to a production technology of high-ductility cold-rolled steel bars, in particular to a method for producing high-ductility cold-rolled steel bars in an energy-saving mode, and belongs to the technical field of steel bar production.

Background

The existing cold rolling production technology adopts the technical means disclosed in the patent CN 201110114872: reducing the diameter of the Q215 or Q235 disc by a rolling mill, wherein the reducing ratio is 0.79-0.87; reducing the diameter of the steel plate by a second rolling mill and simultaneously scoring, wherein the diameter reduction ratio is 0.59-0.88; meanwhile, the steel bar after being scored is subjected to heat treatment for 1-3s at the temperature of 550-670 ℃; the steel bars after heat treatment (soaking) are naturally cooled in the air, and after the ordinary I, II-grade steel bars are treated by the process, the internal structure and the grain size of the steel bars are changed, so that the strength and the elongation of the steel bars are improved and are close to IV-grade steel bars compared with III-grade steel. Without adding microelements such as titanium, niobium and vanadiumAnd the dosage of rare metals is reduced. The high-ductility cold-rolled ribbed steel bar produced by the technical scheme has the advantages that a typical product is a CRB600H high-strength steel bar, for the CRB600H high-strength steel bar, the national quality inspection and quarantine bureau publishes the national standard 'cold-rolled ribbed steel bar' GBT 13788-. The successful development of the CRB600H high-strength steel bar changes the history that micro-alloy must be added in the production of thin-diameter high-strength steel bars in China, provides excellent products for the transformation type upgrade and technical progress of the steel and building industry, provides reliable support for the application and elimination of medium-small-diameter high-strength steel bars in plate and wall members, and the applicant has realized the large-scale high-speed mass production of the CRB600H high-strength steel bar, and the mechanical properties of the CRB600H product are as follows: rp_0.2≥540MPa，Rm≥600MPa，A_5.65Not less than 14%, Agt not less than 5.0%, Rm/Rp0.2 not less than 1.05. The product is subjected to cold plastic deformation and heat treatment on the basis of common carbon steel, the comprehensive mechanical property is greatly improved, compared with a hot rolled product, the strength index of the steel bar is very obvious, but the toughness and plasticity indexes of the steel bar have certain limitations, and compared with the performance indexes of an alloyed steel bar and an anti-seismic steel bar in a common hot rolling process, the performance indexes of the alloyed steel bar and the anti-seismic steel bar have a large difference. For example: the product produced by the current production process requires A_5.65Not less than 14 percent, and the product A is counted by inspection tests in the production practice for many years_5.65Not less than 14%, A of 75% of the samples measured_5.65The value is between 14% and 15%, another 15% of the samples measured is between 15% and 16%, and 10% of the samples measured is A_5.65Value greater than 16%, A of the individual samples_5.65The value can also reach more than 18 percent, the Agt of all samples is more than or equal to 5.0 percent and can be realized, but the Agt value of 87 percent of measured products is between 5.0 percent and 6.0 percent, and only the Agt value of about 13 percent of measured products is more than 6.0 percent, so that the products with the performance can not be distinguished from all products in large-scale production although a small part of the products have better toughness and plasticity in the existing production method, and the whole steel bar of CRB600H can not be toughness and plasticityThe application of the CRB600H steel bars is limited by the current distribution of toughness and plasticity indexes, and the steel bars are rolled and deformed under normal temperature conditions, so that the deformation resistance of the steel bars is high, the energy consumption of rolling procedures is high, and the average rolling power consumption (power consumption) of each specification per ton of steel is about 35 degrees (under the condition of good production normal power consumption). Chinese patent application No. 2019101869290 discloses a system and a method for producing high-ductility ribbed steel bars, wherein a heat treatment process is provided between a reducing rolling mill (i.e. reducing rolling) and a rolling rib rolling mill (i.e. forming rolling), the heating temperature of the heat treatment process is limited below 200 ℃ for achieving technical purposes, and the heat treatment process is carried out below 700 ℃ after the rolling rib rolling mill for achieving certain strength and plasticity, although the technical scheme increases the strength and plasticity to a certain extent, the original starting point of the product is too low from the original production line index disclosed in the technical scheme, even if the product produced by the technical scheme is transformed by the equipment and process, the requirement of the CRB600H steel bar can not be met, for example, the a5.65 required by the CRB600H is not less than 14%, but the elongation disclosed in the technical scheme is between 13-18%, therefore, although some technical schemes adopted in the patent and other documents can improve the strength and the elongation, the distribution of various performance indexes after the product performance test spans a large interval, even if part of the products can reach some higher indexes, because the products have low performance indexes, the products can not be distinguished in the production process, is similar to the wooden barrel effect in management, the application occasion of the whole batch of products is determined by the product with the lowest performance index, the development of the production process method capable of overcoming the product short plate is an effective way for solving the problem, therefore, how to further develop the production process of the reinforcing steel bars deeply so that the overall performance index of the reinforcing steel bars can be improved, the production process is more environment-friendly, and the products have more market competitiveness, which is a problem in the next process development.

Disclosure of Invention

The invention aims to overcome the problems in the prior production of the high-ductility cold-rolled steel bar and provide a method for producing the high-ductility cold-rolled steel bar in an energy-saving manner.

In order to realize the purpose of the invention, the following technical scheme is adopted: the method for producing the high-ductility cold-rolled steel bar in an energy-saving way comprises rolling and heat treatment, wherein the rolling comprises reducing rolling and forming rolling which are arranged in tandem, and is characterized in that: the heat treatment adopts two heat treatments, the first heat treatment is positioned between the reducing rolling and the forming rolling, the temperature of the first heat treatment is 300-600 ℃, the second heat treatment is positioned after the forming rolling, the temperature of the second heat treatment is more than 530 ℃ and less than 680 ℃, and the temperature of the second heat treatment is higher than the temperature of the first heat treatment.

Further, the method comprises the following steps of; the reducing ratio of the reducing rolling is as follows: 0.79-0.87, the reducing rolling adopts one or more reducing rolling processes, and if the plurality of reducing rolling processes are adopted, the last reducing rolling process finishes 0.3 of the target reducing amount; the rest reducing rolling processes finish the target reducing amount by 0.7, and the forming reducing ratio is as follows: 0.6-0.9.

Further, the method comprises the following steps of; the diameter range of the steel bar is phi 5 mm-phi 16 mm.

Further, the method comprises the following steps of; the rear end of the production process is provided with a spiral collecting area or a straight bar collecting area, or is simultaneously provided with a spiral collecting area and a straight bar collecting area.

The invention has the positive and beneficial technical effects that: through trial production, the power consumption of the forming and rolling process of the process is reduced by about 37.4 percent, the overall power consumption is reduced by 4-6.5 percent, the overall power consumption is reduced by 5-8 degrees/ton, the mechanical performance index of the product produced by the production process is greatly improved while the power consumption is reduced, and all the products can meet the requirement of Rp_0.2Not less than 540MPa, Rm not less than 600MPa, A of all products_5.65Not less than 16.5 percent, Agt not less than 6.2 percent, wherein over 55 percent of the product A_5.65Not less than 17 percent (which lays a good foundation for better indexes in the follow-up process), the plasticity index of the product produced by the process is obviously improved as a whole, and the defect that the lower limit of the product index in the traditional production can meet the requirement but is integrally distributed to be required is overcomeThe problem near the upper part of the obtained index enables the product to be used in the occasions with higher requirements as a whole. The process of the invention can realize the effect of energy saving and the integral upward shift of the product plasticity index.

Detailed Description

Example 1:

the method comprises the steps of taking a Q235 plain carbon steel hot-rolled smooth disc strip as a raw material, selecting a diameter phi 8mm for production, carrying out end-to-end butt welding and descaling treatment on the disc strip, then carrying out reducing rolling on the disc strip, carrying out heating in a heating furnace in a heat treatment process after the reducing rolling is finished, controlling the heating temperature at 430 ℃, carrying out heating time at 1.5S, and carrying out forming rolling after the heat treatment process is finished. Wherein the reducing ratio of reducing rolling is 0.85, and a rolling process is adopted. The reduction ratio of the forming rolling is 0.61, and the rolling is one-pass rolling. Carrying out secondary heat treatment at 600 ℃ after forming and rolling, wherein the heat treatment time is 0.7S; and air cooling and naturally cooling the steel bars after the second heat treatment to obtain the high-performance steel bar product.

Example 2:

the hot-rolled smooth disk strip is produced by taking a hot-rolled plain carbon steel disk strip with the specific mark of HPB300 as a raw material, selecting the diameter phi of 10mm, carrying out end-to-end butt welding and descaling treatment on the disk strip, then carrying out reducing rolling on the disk strip, then carrying out heating treatment on the disk strip in a heating furnace in a heat treatment process, controlling the heating temperature at 480 ℃, heating the disk strip for 1.8S, and carrying out forming rolling on the disk strip after the heat. Wherein the reducing ratio of reducing rolling is 0.83, and a rolling process is adopted. The reduction ratio of the forming rolling is 0.62, and the rolling is one-pass rolling. Carrying out secondary heat treatment at 580 ℃ after forming and rolling, wherein the heat treatment time is 0.7S; and air cooling and naturally cooling the steel bars after the second heat treatment to obtain the high-performance steel bar product.

Example 3:

the method is characterized in that a hot-rolled plain carbon steel disc strip with the specific mark of Q235 is used as a raw material, the diameter phi of the hot-rolled plain carbon steel disc strip is 12mm, the hot-rolled plain carbon steel disc strip is produced, the disc strip is subjected to butt welding and descaling treatment from head to tail, then the disc strip enters a heating furnace of a heat treatment process, the heating temperature is controlled at 490 ℃, the heating time is 2.6 seconds, and after the heat treatment process is finished. Wherein the reducing ratio of reducing rolling is 0.85, and a rolling process is adopted. The reduction ratio of the forming rolling is 0.6, and the one-pass rolling is adopted. Carrying out secondary heat treatment at 550 ℃ after forming and rolling, wherein the heat treatment time is 1S; and air cooling and naturally cooling the steel bars after the second heat treatment to obtain the high-performance steel bar product. .

Example 4:

the method comprises the steps of taking a Q235 plain carbon steel hot-rolled smooth disc strip as a raw material, selecting a diameter phi 6mm for production, carrying out end-to-end butt welding and descaling treatment on the disc strip, then carrying out reducing rolling on the disc strip, carrying out heating in a heating furnace in a heat treatment process after the reducing rolling is finished, controlling the heating temperature at 420 ℃, carrying out heating time at 1.5S, and carrying out forming rolling after the heat treatment process is finished. Wherein the reducing ratio of reducing rolling is 0.85, two reducing rolling processes are adopted, the first reducing amount is 70%, and the second reducing amount is 30%. The reducing ratio of the forming rolling is 0.61, and the rolling is one-pass rolling. Carrying out secondary heat treatment at 600 ℃ after forming and rolling, wherein the heat treatment time is 0.6S; and air cooling and naturally cooling the steel bars after the second heat treatment to obtain the high-performance steel bar product.

The following table shows the process current comparison for forming and rolling when the process is used for production:

tests prove that the average power saving rate of the forming rolling mill in the process reaches 37.4 percent, the main energy consumption of the existing production process is a heating furnace and a rolling procedure, the total power consumption of the product per ton steel is about 125 ℃, the new production process is adopted, the rolling energy consumption is reduced by about 4-6.5 percent, and the average power consumption per ton steel is reduced by 5-8 percent.

Rp was achieved for all samples_0.2≥550MPa、R_m≥620MPa、A_5.65≥16%、A_gt≥6.0％、R_m/ Rp_0.2Sample A of not less than 1.1, 100%_5.65≥16.5%、A_gtNot less than 6.2%, of which 55% measured sample A_5.65Not less than 17%, 65% of the measurement sample A_gtThe value is more than 6.5%, which shows that the toughness and plasticity indexes of the steel bar produced by the method are greatly improved while the steel bar meets the CRB600H standard requirement.

Compared with the traditional cold-rolled steel bar production method, the method has the advantages that the first heat treatment process is arranged between the reducing rolling and the forming rolling, the forming rolling is carried out after heating, the plastic index of the product is integrally increased, the energy-saving effect is obvious, the method further advances towards the green production direction, the market competitiveness of the product is improved, and the unexpected technical effect is achieved.

After the embodiments of the present invention have been described in detail, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the invention, and it is intended that all simple modifications, equivalent changes and modifications made to the above embodiments based on the technical spirit of the present invention shall fall within the technical scope of the present invention, and the present invention shall not be limited to the embodiments illustrated in the description.

Claims

1. The method for producing the high-ductility cold-rolled steel bar in an energy-saving way comprises rolling and heat treatment, wherein the rolling comprises reducing rolling and forming rolling which are arranged in tandem, and is characterized in that: the heat treatment adopts two heat treatments, the first heat treatment is positioned between the reducing rolling and the forming rolling, the temperature of the first heat treatment is 300-600 ℃, the second heat treatment is positioned after the forming rolling, the temperature of the second heat treatment is more than 530 ℃ and less than 680 ℃, and the temperature of the second heat treatment is higher than the temperature of the first heat treatment.

2. The method for energy-saving production of a high-ductility cold-rolled reinforcing steel bar according to claim 1, wherein: the reducing ratio of the reducing rolling is as follows: 0.79-0.87, the reducing rolling adopts one or more reducing rolling processes, and if the plurality of reducing rolling processes are adopted, the last reducing rolling process finishes 0.3 of the target reducing amount; the rest reducing rolling processes finish the target reducing amount by 0.7, and the forming reducing ratio is as follows: 0.6-0.9.

3. The method for energy-saving production of a high-ductility cold-rolled reinforcing steel bar according to claim 1, wherein: the diameter range of the steel bar is phi 5 mm-phi 16 mm.

4. The method for energy-saving production of a high-ductility cold-rolled reinforcing steel bar according to claim 1, wherein: the rear end of the production process is provided with a spiral collecting area or a straight bar collecting area, or is simultaneously provided with a spiral collecting area and a straight bar collecting area.