阅读说明：本技术 一种冷轧钢筋生产方法 (Production method of cold-rolled steel bar ) 是由 陈伟 翟文 于 2020-12-04 设计创作，主要内容包括：一种冷轧钢筋生产方法,包括减径轧制、成型轧制,在减径轧制前对钢筋进行加热,加热温度为200℃至500℃,在成型轧制后具有热处理工序,热处理工序的钢筋加热温度范围为500℃-700℃。采用本工艺生产的冷轧钢筋,在强度指标取得一定改善的情况下,其塑性、韧性指标得到了较为明显的提升,相比较于现有的冷轧工艺,降低了轧制时钢筋的变形抗力,可降低轧制能耗约5-8%,各规格吨钢平均电耗降低2-4度。(A cold-rolled reinforcing bar production method comprises reducing rolling and forming rolling, wherein the reinforcing bar is heated before reducing rolling, the heating temperature is 200-500 ℃, a heat treatment procedure is carried out after forming rolling, and the heating temperature range of the reinforcing bar in the heat treatment procedure is 500-700 ℃. The cold-rolled steel bar produced by the process has obviously improved plasticity and toughness indexes under the condition of improving the strength index to a certain extent, and compared with the existing cold-rolling process, the cold-rolled steel bar has the advantages that the deformation resistance of the steel bar during rolling is reduced, the rolling energy consumption is reduced by about 5-8%, and the average power consumption of each specification per ton of steel is reduced by 2-4 degrees.)

1. A cold-rolled steel bar production method comprises reducing rolling and forming rolling, and is characterized in that: the steel bar is heated before reducing rolling, the heating temperature is 200 ℃ to 500 ℃, the heat treatment procedure is carried out after forming rolling, and the heating temperature range of the steel bar in the heat treatment procedure is 500 ℃ to 700 ℃.

2. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the heating temperature is 260-450 ℃.

3. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the heating temperature is 300 ℃ to 450 ℃.

4. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the reducing ratio of the reducing rolling is as follows: 0.79-0.87, adopting one or more rolling processes, and if the rolling processes are adopted, finishing the target reduction by 0.3 in the last rolling process; the remaining rolling passes completed 0.7 of the target reduction.

5. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the forming rolling reduction ratio is as follows: 0.6-0.9.

6. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the diameter range of the steel bar is phi 5 mm-phi 16 mm.

7. The method for producing cold-rolled steel bars according to claim 1, characterized in that: the reinforcing steel bar Rp produced by the method_0.2≥550MPa、R_m≥620MPa、A_5.65≥16%、A_gt≥6.0％、R_m/ Rp_0.2≥1.1。

Technical Field

The invention relates to a production technology of cold-rolled ribbed steel bars, in particular to a production method of cold-rolled steel bars, and belongs to the technical field of steel bar rolling.

Background

The prior 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. Trace elements such as titanium, niobium, vanadium and the like do not need to be added, and the dosage of rare metals is reduced. The high-ductility cold-rolled ribbed steel bar produced by adopting the technical scheme has the typical product of CRB600H and the mechanical propertyComprises the following steps: 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 obvious in excellence, 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 can be realized by more than or equal to 5.0 percent, 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 although a small part of products have better toughness and plasticity in the existing production method, the products with the performance can not be distinguished from all products in large-scale production, the whole CRB600H steel bar can not be developed and applied to occasions (such as anti-seismic steel bars) with higher requirements on toughness and plasticity, therefore, the distribution of the toughness and plasticity indexes at present limits the application occasions of the CRB600H steel bar, in addition, the steel bar is rolled and deformed under the normal temperature condition, the deformation resistance of the steel bar is larger, the energy consumption of the rolling process is higher, the average rolling power consumption (electric consumption) of each ton of steel bar is about 35 degrees, and the diameter of the existing cold-rolled ribbed steel bar is maximum 12mm, and then large-sized products cannot be produced. Although some technical schemes adopted in some documents can improve the strength and the elongation, the distribution of various performance indexes of the product after the product performance test spans a large interval, even if some products in the product can really reach some higher indexes, because the product with very low performance indexes in the product 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, and the development can overcome the defect of the productThe production process of the short plate is an effective way to solve the problem.

Disclosure of Invention

The invention aims to overcome the problems in the prior cold-rolled steel bar production and provides a cold-rolled steel bar production method.

In order to realize the purpose of the invention, the following technical scheme is adopted: a cold-rolled reinforcing bar production method comprises reducing rolling and forming rolling, wherein the reinforcing bar is heated before reducing rolling, the heating temperature is 200-500 ℃, a heat treatment procedure is carried out after forming rolling, and the heating temperature range of the reinforcing bar in the heat treatment procedure is 500-700 ℃.

Further, the method comprises the following steps of; the heating temperature is 260-450 ℃.

Further, the method comprises the following steps of; the heating temperature is 300 ℃ to 450 ℃.

Further, the method comprises the following steps of; the reducing ratio of the reducing rolling is as follows: 0.79-0.87, adopting one or more rolling processes, and if the rolling processes are adopted, finishing the target reduction by 0.3 in the last rolling process; the remaining rolling passes completed 0.7 of the target reduction.

Further, the method comprises the following steps of; the forming rolling reduction 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 reinforcing steel bar Rp produced by the method_0.2≥550MPa、R_m≥620MPa、A_5.65≥16%、A_gt≥6.0％、R_m/ Rp_0.2≥1.1。

The invention has the positive and beneficial technical effects that: the cold rolled steel bar produced by the process has the advantages that A of all products produced by the method is A under the condition that the strength index is improved to a certain extent_5.65≥16%、A_gtNot less than 6.0 percent, thereby the plasticity and toughness indexes are obviously improved, the steel bar can be integrally applied and developed to the direction of anti-seismic steel bars in large batch, the steel bar is preheated before reducing rolling, the steel bar is rolled under the condition of higher temperature, compared with the prior cold rolling process, the deformation resistance of the steel bar during rolling is reduced, the rolling energy consumption is reduced by about 5 to 8 percent, and each gauge is designedThe average power consumption of the graticule ton steel is reduced by 2-4 degrees.

Detailed Description

In order to more fully explain the implementation of the present invention, the implementation examples of the present invention are provided, which are merely illustrative of the present invention and do not limit the scope of the present invention.

Example 1:

the method is characterized in that a hot-rolled plain carbon steel disc strip with the specific mark of Q235 is taken as a raw material, the diameter phi of the hot-rolled plain carbon steel disc strip is 8mm, the hot-rolled plain carbon steel disc strip is subjected to head-to-tail welding connection and descaling treatment, then the hot-rolled plain carbon steel disc strip enters a heating furnace, the heating temperature is controlled at 280 ℃, and then reducing rolling and forming rolling are sequentially performed after heating. Wherein the reducing ratio of reducing rolling is 0.85, and a rolling process is adopted. The forming rolling reduction ratio is as follows: 0.6, one-pass rolling. And (3) the steel bar after rolling forming enters a final heat treatment process, and the heating temperature is 550 ℃. The heating time was 1.3S. Then air cooling and natural cooling are carried out 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 and selecting the diameter phi of 8mm, the disk strip is subjected to butt welding and descaling treatment from head to tail, then enters a heating furnace, the heating temperature is controlled at 300 ℃, and then is subjected to reducing rolling and forming rolling in sequence after being heated. Wherein the reducing ratio of reducing rolling is 0.87, and a rolling process is adopted. The forming rolling reduction ratio is as follows: 0.65, one-pass rolling. And (4) the steel bar after rolling forming enters a final heat treatment process, and the heating temperature is 580 ℃. The heating time was 1.3S. Then air cooling and natural cooling are carried out 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 taken as a raw material, the diameter phi of the disc strip is 10mm, the disc strip is connected in an end-to-end welding mode and subjected to descaling treatment, then the disc strip enters a heating furnace, the heating temperature is controlled at 310 ℃, and after heating, reducing rolling and forming rolling are sequentially carried out. Wherein the reducing ratio of reducing rolling is 0.8, and a rolling process is adopted. The forming rolling reduction ratio is as follows: 0.62, is a one-pass rolling. And (3) the steel bar after rolling forming enters a final heat treatment process, and the heating temperature is 600 ℃. The heating time was 1.5S. Then air cooling and natural cooling are carried out to obtain the high-performance steel bar product.

Example 4:

the hot-rolled smooth disk strip is produced by using hot-rolled plain carbon steel hot-rolled disk strips with specific mark of HPB300 as a raw material, selecting the diameter phi of 10mm, respectively, carrying out butt welding connection and descaling treatment on the disk strips end to end, then feeding the disk strips into a heating furnace, controlling the heating temperature at 330 ℃, and carrying out reducing rolling and forming rolling in sequence after heating. Wherein the reducing ratio of reducing rolling is 0.83, and a rolling process is adopted. The forming rolling reduction ratio is as follows: 0.62, is a one-pass rolling. And (4) the steel bar after rolling forming enters a final heat treatment process, and the heating temperature is 620 ℃. The heating time was 1.5S. Then air cooling and natural cooling are carried out to obtain the high-performance steel bar product.

Example 5:

the method is characterized in that a hot-rolled plain carbon steel disc strip with the specific mark of Q235 is taken as a raw material, the diameter phi of the disc strip is 10mm, the disc strip is connected in an end-to-end welding mode and subjected to descaling treatment, then the disc strip enters a heating furnace, the heating temperature is controlled at 300 ℃, and after heating, reducing rolling and forming rolling are sequentially carried out. The reducing ratio of reducing rolling is 0.87, two reducing rolling processes are adopted, the first reducing amount is 70%, the second reducing amount is 30%, and the forming rolling reducing ratio is as follows: 0.62, is a one-pass rolling. And (3) the steel bar after rolling forming enters a final heat treatment process, and the heating temperature is 590 ℃. The heating time was 1.3S. Then air cooling and natural cooling are carried out to obtain the high-performance steel bar product.

The heating temperature before rolling is adjusted to 230 ℃ and 450 ℃, and a cold rolling process is adopted, so that a cold-rolled steel bar product can be obtained.

After the products of the above examples are mixed, 100 samples are selected for testing, and all samples achieve Rp_0.2≥550MPa、R_m≥620MPa、A_5.65≥16%、A_gt≥6.0％、R_m/ Rp_0.2Not less than 1.1, wherein Rp_0.2Average value 563 MPa, R_mAverage value is 629 MPa; 100% of sample A_5.65≥16%、A_gtNot less than 6.0%, of which 83% measured sample A_5.65The value is between 16% and 17%, the rest is greater than 17%; 65% measurement sample A_gtThe value is more than 6.5 percent, which shows that the reinforcing steel bar produced by the method meets the CRB600H standard requirement,the toughness and plasticity indexes of the alloy are greatly improved.

Compared with the traditional production method of the cold-rolled steel bar, the method adds a heating procedure before reducing rolling, integrally improves the toughness and plasticity indexes of a rolled product after heating, effectively improves the consistency of the product, and achieves the unexpected technical effect.

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.