A rolling process method for B500B British standard steel material after rolling and centralized cooling

Abstract

The present application belongs to the technical field of steel rolling, and relates to a rolling process method for concentrated cooling of B500B British standard steel after rolling. The B500B British standard steel is rolled by using HRB400E-3D steel, the composition of the billet, the temperature of the heating furnace and the rolling temperature are controlled, a new water penetrating device is used, high rigidity short stress line bar rolling mill arranged in a flat-stand alternation mode is used, and concentrated rapid water cooling process is used after finish rolling. Through a water tank temperature automatic control system, the temperature difference is automatically adjusted and kept within 5 degrees. A finished product rack load signal control program is added, the load signal after the finished product rolling mill bites into the steel is used to control the action of the flying shear and the apron, and accurate cutting of the double length and segmented unloading of the apron are realized. Compared with HRB400E and 500E steel, the profit of the B500B British standard steel is increased by about 80 yuan, and according to the production of 20,000 tons per year, the profit is increased by 1.6 million yuan. By using the finished product "concentrated cooling" rolling process, the mechanical properties of the British standard steel meet the requirements of the BS4449:2005 standard.

Description

Technical Field

[0001] This invention belongs to the field of steel rolling technology, specifically relating to a rolling process method for centralized cooling of B500B British standard steel after rolling. Background Technology

[0002] British Standard B500B steel bars are one of the high-strength hot-rolled ribbed steel bar grades with a characteristic yield strength of 500 MPa in the BS4449:2005 standard. The BS4449:2005 standard has a clear upper limit on the carbon equivalent of B500B steel bars, which is stricter than the requirements of the Chinese standard for the same grade, with a carbon equivalent 0.05% lower than the Chinese standard. British Standard B500B steel bars have excellent strength, with a tensile strength exceeding 500 MPa, which can meet the strength requirements of building structures. They also have good toughness, capable of withstanding large deformation and impact loads; the surface undergoes special treatment, providing good corrosion resistance, allowing them to be used in harsh environments such as humid, acidic, and alkaline conditions.

[0003] Currently, Yongfeng Lingang Company mainly produces national standard HRB400E and HRB500E hot-rolled ribbed steel bars. However, its B500B British standard export steel requires billets with different compositions than HRB400E and HRB500E. Each production run of B500B British standard export steel requires the separate smelting of billets different from those used for rolling national standard steel, resulting in higher energy consumption and longer delivery times compared to national standard steel. Summary of the Invention

[0004] To address the problems in the prior art, the present invention aims to provide a rolling process method for centralized cooling of B500B British standard steel after rolling.

[0005] The technical solution adopted by this invention to solve its technical problem is: a rolling process method for centralized cooling of B500B British standard steel after rolling, comprising the following steps:

[0006] 1) Use HRB400E-3D steel to roll B500B British standard steel, and control the billet composition, heating furnace temperature and rolling temperature;

[0007] 2) A new type of water cooling device is adopted, and high-rigidity short-stress bar mills with alternating horizontal and vertical arrangement are used for rolling. After finishing rolling, a centralized rapid water cooling process is adopted. Through the automatic temperature control system of the water tank, the temperature difference is automatically adjusted and maintained within ±5 degrees.

[0008] 3) Add a load signal control program for finished product stands. Use the load signal after the finished steel is bitten into the mill to control the flying shear and skirt plate actions, so as to achieve precise shearing of multiple lengths and segmented unloading of steel by the skirt plate.

[0009] Furthermore, the main components of the steel billet in step 1) are as follows: Specifications: C: 0.20-0.22wt%, Si: 0.40-0.60wt%, Mn: 1.45-1.60wt%, V: 0.035-0.045wt%, S: ≤0.045wt%, P: ≤0.045wt%.

[0010] Furthermore, the furnace temperature control in step 1) is as follows: Specifications: Triple heating temperature 890±30℃, Double heating temperature 950±20℃, Single heating temperature 1125±20℃, Irradiation temperature 1115±20℃.

[0011] Furthermore, the rolling temperature control in step 1) is as follows: Specifications: rolling temperature 1010±10℃, cooling bed temperature 640-650℃.

[0012] Furthermore, in step 2), the novel water permeator is a turbulent cooling water permeator.

[0013] Furthermore, the multiple-length shearing employs dual-signal precision shearing based on pre-shear heat inspection and finished mill load.

[0014] The present invention has the following beneficial effects:

[0015] This invention employs a novel turbulent cooling water purifier, combined with a controlled rolling and cooling process layout. It utilizes a high-rigidity short-stress bar mill with alternating horizontal and vertical arrangement for rolling, followed by a centralized rapid water cooling process after finishing rolling. It also adds a load signal control program for finished product stands to achieve precise shearing at multiple lengths and segmented unloading of steel skirts. Furthermore, it adopts an automatic water tank temperature control system to automatically adjust the water tank frequency after setting the temperature, thereby automatically maintaining a temperature difference within ±5 degrees Celsius.

[0016] Compared to HRB400E and 500E steel grades, B500B British standard steel has a profit margin of about 80 yuan higher. Based on an annual production of 20,000 tons, this could increase profits by 1.6 million yuan.

[0017] By adopting a post-finished "centralized cooling" rolling process, the mechanical properties of British standard steel meet the requirements of BS4449:2005. Compared with the "controlled cooling and controlled rolling" process, the temperature entering the finishing mill is increased by 45 degrees Celsius, the current of the finishing mill is reduced by 50A, and the electricity saved per ton of steel is approximately 7.47 kWh. Based on a production of 20,000 tons and an electricity price of 0.66 yuan per kWh, the electricity cost savings are 20,000 * 7.47 * 0.66 = 98,600 yuan. Detailed Implementation

[0018] The following are specific embodiments of the present invention, which further describe the technical solution of the present invention. However, the scope of protection of the present invention is not limited to these embodiments. All changes or equivalent substitutions that do not depart from the concept of the present invention are included within the scope of protection of the present invention.

[0019] A rolling process for B500B British standard steel with centralized cooling after rolling includes the following steps:

[0020] 1) B500B British standard steel is rolled using HRB400E-3D steel grade. The composition of the billet, the temperature of the heating furnace and the rolling temperature are controlled as shown in Tables 1, 2 and 3 below.

[0021] Table 1. Steel Billet Composition Table

[0022]

[0023] Table 2 Heating Furnace Temperature Control Table

[0024]

[0025] Table 3 Rolling Temperature Control Table

[0026]

[0027]

[0028] 2) A new type of turbulent flow cooling water purifier is adopted to achieve rapid cooling of steel and improve cooling efficiency. Without affecting surface quality, it enables the final rolling process with four water tanks for forced water purging, ensuring the steel meets performance standards. Without increasing the number of purging units, the reverse resistance nozzles are closed to replace the purging units, reducing the purchase cost of the water purifier.

[0029] Combining the controlled rolling and cooling process layout, a high-rigidity short-stress bar mill with alternating horizontal and vertical arrangement is used for rolling. After finishing rolling, a centralized rapid water cooling process is adopted. Through the automatic water tank temperature control system, the water tank frequency is automatically adjusted after the set temperature is reached, so as to automatically adjust and maintain the temperature difference within ±5 degrees.

[0030] 3) The study investigates the contribution of each water tank to performance and the internal density and grain size level of the "centralized cooling" strong quenching process after rolling; it also studies the multiple-length segmentation and skirt unloading procedures for low-temperature steel. A load signal control program for finished product stands is added, using the load signal after the finished mill steel is bitten in to control the flying shear and skirt actions, achieving precise multiple-length shearing and skirt segmentation unloading.

[0031] To ensure the precise shearing and segmented unloading of low-temperature steel, the shearing and skirting processes employ dual signals: pre-shearing heat inspection and finished mill load.

[0032] By adopting the "centralized cooling" rolling process after the finished product is produced, compared with the "controlled cooling and controlled rolling" process, the temperature entering the finishing mill is increased by 45 degrees Celsius, the current of the finishing mill is reduced by 50A, and the electricity saved per ton of steel is approximately 7.47 kWh. Based on a production of 20,000 tons and an electricity cost of 0.66 yuan per kWh, the electricity cost saved is 20,000 * 7.47 * 0.66 = 98,600 yuan.

[0033] This invention is not limited to the above-described embodiments. Anyone should know that any structural changes made under the guidance of this invention, and any technical solutions that are the same as or similar to this invention, fall within the protection scope of this invention.

[0034] The technologies, shapes, and structures not described in detail in this invention are all known technologies.

Claims

1. A rolling process for B500B British standard steel with centralized cooling after rolling, characterized in that, Includes the following steps: 1) B500B British standard steel is rolled using HRB400E-3D steel grade, and the composition of the billet, the temperature of the heating furnace and the rolling temperature are controlled; 2) A new type of water cooling device is adopted, and high-rigidity short-stress bar mills with alternating horizontal and vertical arrangement are used for rolling. After finishing rolling, a centralized rapid water cooling process is adopted. Through the automatic temperature control system of the water tank, the temperature difference is automatically adjusted and maintained within ±5 degrees. 3) Add a load signal control program for finished product stands. Use the load signal after the finished steel is bitten into the mill to control the flying shear and skirt plate actions, so as to achieve precise shearing of multiple lengths and segmented unloading of steel by the skirt plate. The main components of the steel billet in step 1) are as follows: φ32 specification, C: 0.20-0.22wt%, Si: 0.40-0.60wt%, Mn: 1.45-1.60wt%, V: 0.035-0.045wt%, S: ≤0.045wt%, P: ≤0.045wt%; The temperature control of the heating furnace in step 1) is as follows: φ32 specification, three heating temperature 890±30℃, two heating temperature 950±20℃, one heating temperature 1125±20℃, and heat soaking temperature 1115±20℃. The rolling temperature control in step 1) is as follows: for φ32 specification, the initial rolling temperature is 1010±10℃, and the cooling bed temperature is 640-650℃. The novel water permeator in step 2) is a turbulent cooling water permeator.

2. The rolling process method for centralized cooling of B500B British standard steel after rolling as described in claim 1, characterized in that, The multiple-length shearing employs dual signals of pre-shear heat inspection and finished mill load for precise shearing.

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