Production practice of hot delivery and hot chargi

Production practice of hot delivery and hot charging of continuous casting billets at Yonggang

introduces the development of hot delivery and hot charging work at Yonggang since 2012 and the experience of doing a good job in hot charging production. The effect of energy saving and consumption reduction is very significant, and makes a preliminary analysis of the adverse factors restricting hot charging production and the growth potential of future hot charging benefits

hot delivery and hot charging of continuous casting billets is one of the energy-saving technologies mainly promoted in the iron and steel industry. It has the advantages of saving energy, improving the production capacity of heating furnace, reducing the burning loss of continuous casting billets and the temperature difference between the inside and outside of billets, improving the yield of products, accelerating the logistics flow and reducing the repeated reshipment of billets. Steel rolling heating furnace is an important equipment in steel production, and it is also one of the main equipment to check whether each function of the experimental machine can operate normally. It accounts for about 65% - 70% of the consumption in the steel rolling process. Therefore, implementing the technology of hot delivery and hot charging of continuous casting slabs and reducing the energy consumption of rolling reheating furnace are important factors to improve the competitiveness of steel products. In particular, in 2012, Yonggang began to upgrade its products and develop industrial materials such as cold heading and medium carbon steel. Wire rod products are mainly made of special steel, and the product structure is more complex, which gradually reduces the hot charging rate of continuous casting billets. In recent years, the hot delivery and hot charging of continuous casting billets are mainly concentrated in the 3# continuous caster of steelmaking plant 1 with relatively few varieties and relatively large production batches and the corresponding wire rod 2. 4. Slowly press the handles on both sides of the sample down the plant. At the same time, the distance between the discharging roller table of 3# continuous caster and the heating furnace workshop of the second wire rod plant is less than 50 meters, which provides favorable conditions for hot delivery and hot charging of continuous casting slabs

main problems and reasons

(1) the second wire rod plant and the first steelmaking plant are located closest, but the continuous casting billet still adopts the traditional logistics transportation mode

(2) in the original hot charging and hot delivery device from 3# continuous caster in steelmaking plant 1 to wire rod plant 2, the elevator has high requirements for the straightness of continuous casting slabs. When the continuous casting slabs are slightly bent, the elevator cannot lift the continuous casting slabs to the upper roller table, and is forced to interrupt the hot charging and hot delivery of continuous casting slabs

(3) due to the relatively short direct feeding roller table, the original hot charging and hot feeding device cannot place excess continuous casting billets, and there is no continuous casting billet buffer bench in the middle. Therefore, it is difficult to meet the quality requirements of continuous casting billet feeding by furnace in case of sudden failure and shutdown of steel rolling

(4) the continuous casting slab quality of 3# continuous casting machine in steelmaking plant 1 fluctuates greatly, and the continuous casting slab that is changed and pending approval affects the hot charging and hot delivery of continuous casting slab; The frequent change of varieties and specifications in the second wire rod plant has affected the hot charging and hot delivery of continuous casting billets; All kinds of faults still occur frequently in the first steelmaking plant and the second wire rod plant, and the planned maintenance arrangements are not synchronized, which affect the hot charging and hot delivery of continuous casting billets

(5) with the traditional automobile hot charging and hot delivery mode, there is a lack of effective communication and coordination between the 3# continuous caster of the first steelmaking plant and the second wire rod plant, and mutual production information cannot be shared; The hot charging temperature and hot charging rate of hot charging and hot delivery in the second wire rod plant are still collected and recorded manually, with a low degree of automation, resulting in large workload and statistical deviation

(6) in 2012, the hot charging rate of billets in the second wire rod plant was only about 40%, and the average hot charging temperature of billets was below 400 ℃

technical measures for improvement

in order to realize the hot delivery and hot charging of continuous casting slabs, give full play to the geographical layout advantages and capacity matching advantages between the 3# continuous casting machine of the first steelmaking plant and the second wire rod plant, a set of hot delivery and hot charging device is designed between the two plants, which has the following characteristics:

(1) the steel transfer machine is reformed to realize two-way movement. When the continuous casting slabs need hot delivery, the steel transfer machine can send the continuous casting slabs to the steering roller table; When the continuous casting billet does not need hot delivery, the steel transfer machine can send the continuous casting billet to the walking beam cooling bed

(2) an infrared thermal detector is added to the direct feed roller table. When the thermal detector detects that there is hot billet on the roller table, the front roller is started. E. according to the scientific understanding of the theoretical principle and practical experience of the method, the roller motor transports hot billet; When the hot billet passes, the thermal detector detects that the hot billet conveying on the roller table is completed, and the motor of the rear roller table immediately stops running, and the whole direct feeding roller table achieves the goal of power saving

(3) add a new insulation cover above the direct feeding roller table to reduce the heat dissipation speed of the continuous casting slab on the one hand, and prevent the bending of the continuous casting slab caused by uneven heat dissipation on the other hand; The bearing seat of the hot delivery roller table adopts water cooling to protect the long-term operation of the roller table equipment

(4) the weighing device of continuous casting billet solves the difference between the theoretical weight and the actual weight of billet, and ensures the accuracy of steel-making and rolling yield, metal yield and other indicators

(5) the continuous casting billet is sent to the workshop of the second wire rod plant, and the high-temperature billet is lifted from the direct feeding roller table to the charging roller table of the heating furnace by the mechanical fixture of the crane, which completes the hot delivery and hot charging of the continuous casting billet

(6) the statistical software of billet hot delivery temperature measurement and hot charge rate is designed and developed, which solves the problems of inaccurate manual temperature measurement data and large statistical workload. At the same time, it provides convenience for the stoker of the heating furnace to adjust the blast furnace gas consumption in real time according to the hot charge temperature of continuous casting billet

(7) the production information exchange mechanism of hot charging and hot delivery of continuous casting billets, such as weighing device, hot delivery signal of continuous casting billets, steering roller table monitoring, etc., is set between the first steelmaking plant and the second wire rod plant. There is a clear contact method and monitoring at key positions. Both parties strengthen communication and timely provide information feedback according to the production situation to ensure the normal production of hot charging and hot delivery

(8) the continuous casting billet is sent to the workshop of the second wire rod plant through the roller table. The surface temperature of the billet reaches 696 ℃, and the core temperature is higher, 390 ℃ higher than the surface temperature of the billet transported by automobile. The energy-saving advantage is very obvious

management measures

4.1 reasonably arrange the production plan and scheduling

(1) the sales office and the general dispatching office improve the hot charging and hot delivery rate of continuous casting billets from the perspective of production scheduling, and prepare the production plan of 3 # continuous caster in the first steelmaking plant based on the finished product market demand plan of the second wire rod plant, so as to ensure the synchronization of both parties

(2) redistribute the rolling specification series in the steel rolling branch, and reduce the replacement frequency of rolling specifications through specialized and batch rolling to ensure the matching of steel-making and steel rolling capacity

(3) the monthly planned maintenance and annual planned maintenance of 3# continuous caster in steelmaking plant 1 and wire rod plant 2 are linked to ensure synchronization. Through the exchange of production information, the daily maintenance of both parties can achieve synchronization

4.2 standardization management

(1) it stipulates the time for the shift of steelmaking plant 1 to check the batch number and billet count, and strive to complete these works within 30 minutes for each shift, so as to improve the proportion of billet hot charging and hot delivery

(2) it is stipulated that the billet composition of the 3# continuous caster in steelmaking plant 1 can be transmitted to wire rod plant 2 in real time before the continuous casting billet is put into the furnace. In order to facilitate the heating system of the heating furnace, the temperature difference range of cold and hot billets corresponds to different heating methods to ensure the heating quality of billets and gas consumption

(3) the assessment system for the post personnel of billet hot charging and hot delivery has been formulated, which has improved the hearts and minds of the relevant post personnel

(4) it is stipulated that steel making and rolling regularly carry out statistical analysis and reporting of the data of hot delivery and hot charging of billets, and continuously improve the level of hot delivery and hot charging

implementation effect

5.1 reduce the unit consumption and oxidation burning loss of blast furnace gas per ton of material

the cumulative unit consumption and oxidation burning loss of blast furnace gas in the same period of 2013 and 2012 decreased by 73.03m/t and 3.12kg/t respectively compared with the same period last year

5.2 the hot charging temperature and hot charging rate have increased significantly

2013 monthly cumulative average hot charging temperature is 540 ℃, the average hot charging rate is 69.77%, which is 220 ℃ higher than the same period last year, and the hot charging rate is 18.53%

5.3 benefit calculation

based on the annual Rolling volume of 900000 tons in the second wire rod plant and the hot charging and hot delivery rate of continuous casting billets of 69.77% (calculated according to the average in 2013), compared with the same period in 2012, the blast furnace gas efficiency was saved by 6.5727 million yuan, the oxidation burning loss efficiency was reduced by 10000 yuan, and the automobile transportation cost was saved by 596500 yuan

in addition, after the hot delivery of continuous casting billet, the transportation volume of roller table is increased, but the operation volume of steel-making walking cooling bed and traveling crane is reduced, and the power consumption of roller table transportation is far less than that of the above two equipment. The above three items can increase the company's efficiency by 12.7852 million yuan in the whole year

in recent years, the temperature of hot delivery and hot assembly machine barrel has also been set at 200 ° C; The company has made fruitful progress. The implementation of hot charging production has alleviated the contradiction that the capacity of heating furnace can not meet the capacity of rolling mill. The machine hour output of hot charging production units has increased, the technical and economic indicators have been improved, and various energy consumption has also decreased, achieving better economic benefits. As the main contradictions restricting the current hot charging production are solved one by one, the total hot charging amount and hot charging temperature of the whole company will be further improved in the future, and the energy-saving effect will be more remarkable