A kind of method that improves control precision of coiling temperature
Technical field
The invention belongs to TEMPERATURE FOR HOT STRIP LAMINAR cooling technology field, a kind of method that improves control precision of coiling temperature is provided especially.
Background technology
In the hot-strip production process, need to be after rolling, use cooling facility for laminar flow that the band steel is cooled off before batching, obtain desirable metallographic structure and mechanical performance by control with coiling temperature and the cooldown rate of steel.
Conventional TEMPERATURE FOR HOT STRIP LAMINAR cooled region has 22 groups of collectors, is divided into thick cold-zone and cold sperm district, and 1~20 group is thick cold-zone, and every group comprises 4 upper headers and 4 lower collector pipe; 21,22 groups is the cold sperm district, and every group comprises 8 upper headers and 8 lower collector pipe, and every collector is by independent close/open valve gate control, and thick cold-zone is identical with the setting of cold sperm district discharge collector discharge, all sets larger.Every group of collector is equipped with 1 flowmeter, can only be by the discharge of flowmeter when the collector unlatching is intermittently adjusted in production.
For thicker steel grade, when the band steel after the hot rolling need to be lowered the temperature as early as possible from the condition of high temperature, collector will be opened since the 1st group successively along rolling direction, and this moment, the setting of collector discharge can accelerate more greatly to be with the steel cooling velocity; But, steel grade cooling heat transferring coefficient thinner when belt steel thickness is large, when control precision of coiling temperature is had relatively high expectations, the setting of collector discharge is unfavorable, in the production control process, the water yield required with each segmentation on the steel total length is different, for obtaining identical coiling temperature, collector is opened quantity along with the continuous adjustment of being traveling in of steel, opens and closes all to increase the coiling temperature fluctuating range, and then causes the fluctuation with steel total length mechanical performance.
As mentioned above, the best collector discharge that adapts to dissimilar products is different, each organizes the high request that collector discharge equalization can't satisfy different product control precision of coiling temperature and stable mechanical performance simultaneously, simultaneously in actual industrial production, the product type change is frequent, consider adaptability and the stability of control system and model, can not frequently adjust according to product type the discharge of collector.
Summary of the invention
The object of the present invention is to provide a kind of method that improves control precision of coiling temperature, solved and respectively organized the high request that collector discharge equalization can't satisfy different product control precision of coiling temperature and stable mechanical performance simultaneously, it is frequent also to have solved simultaneously the product type change, the problem of the discharge of collector be can not frequently adjust according to product type, control system and model stablized.Improve control precision of coiling temperature, stablized product quality.
Technique of the present invention comprises:
(1) collector discharge is respectively organized in optimization, adopts the principle of successively decreasing along rolling direction, arranges and respectively organizes collector discharge, and is as follows:
Table 1 collector discharge allocation list
For ensureing lower collector pipe water spray height, it is identical respectively to organize collector lower collector pipe discharge in thick cold-zone, the cold sperm district.Compare with the configuration of the collector discharge of routine, the discharge of upper header is than front 10 groups little in the 11st group to the 20th group.
Selection is since the 11st group of minimizing, is to consider that front 10 groups of collectors open the requirement that can satisfy the rolling rear quick cooling products of all needs.
(2) select cooling strategy.
Cooling strategy is stored in the server online database CSPP table, is automatically selected according to steel grade, specification by control system;
Online database CSPP table defines respectively the order of valve opening according to steel grade, thickness, comprising: from which group Open valve, leading portion cooling (10 groups of collectors of the 1st group of collector to the) or back segment cooling (10 groups of collectors of the 1st group of collector to the), the pattern of valve opening.
For steel grades such as pipe line steel, high-strength steel, need to adopt the strategy of " the leading portion master is cold ", namely open successively along rolling direction since the 1st group of collector;
For kinds such as the cold rolling base below the product thickness specification 3mm, silicon steel, employing is since the 11st group of cooling strategy that collector is sprayed water, because the water spray collector water yield is lower than front 10 groups, the temperature fluctuation that the opening and closing of collector cause reduces, and has improved control precision of coiling temperature.
(3) proportioning heat transfer coefficient
The water yield for the different layer cold water of 1-22 group, the different heat transfer coefficient of lower collector pipe difference proportioning on the 1-22 group, heat transfer coefficient is configured in respectively within the 0.85-1.25 scope, open the water yield of not counting on the same group in the model computational process relatively with the cooling effectiveness of steel to improve, improve the computational accuracy of coiling temperature control model.The proportioning of its heat transfer coefficient is as shown below:
The proportion relation of table 2 heat transfer coefficient and discharge
The invention has the advantages that: can satisfy simultaneously the high request of different product control precision of coiling temperature and stable mechanical performance, the product type change is frequent, need not frequently adjust according to product type the discharge of collector, has stablized control system and model.
Description of drawings
Fig. 1 TEMPERATURE FOR HOT STRIP LAMINAR cooled region schematic diagram.
Fig. 2 is that the collector group adopts impartial discharge configuration, adopts the coiling temperature control curve of the present invention's same steel grade specifications in front and back (the silicon steel BWG of thickness 2.5mm) and opens the collector number.
Fig. 3 is that the collector group adopts the discharge configuration of successively decreasing, and adopts the coiling temperature control curve of the present invention's same steel grade specifications in front and back (the silicon steel BWG of thickness 2.5mm) and opens the collector number.
The specific embodiment
Take the silicon steel BWG of thickness 2.5mm as example, the laminar flow cooling control system will be with the steel total length to be divided into about 200 sections, adopt this method before, begin water spray from the 11st group of collector, the water yield of lower collector pipe is 90m on the FEEDFORWARD CONTROL 11-16 group
3/ h, the water yield of lower collector pipe is 47m on the FEEDBACK CONTROL 21,22
3There is the phenomenon that causes certain section coiling temperature fast-descending along with opening increasing of collector number in/h, and as shown in Figure 2, band steel total length coiling temperature standard deviation equals 8.4.
After respectively organizing the collector water yield and use the strategy of spraying water since 11 groups of collectors according to table 1 configuration, the water yield of FEEDFORWARD CONTROL 11-16 group upper header is 80m
3/ h, the water yield of FEEDBACK CONTROL 21,22 upper headers is 35m
3/ h, the water yield 90m of FEEDFORWARD CONTROL 11-16 group lower collector pipe
3/ h, the flow of FEEDBACK CONTROL 21,22 groups of lower collector pipe is 47m
3/ h, coiling temperature control situation as shown in Figure 3.As seen from the figure, because the downward modulation of the single collector water yield increases to some extent with the corresponding collector sum of opening of each section of steel, but coiling temperature fluctuation phenomenon is eliminated, and uniformity also increases, and band steel total length coiling temperature standard deviation equals 7.3.
Satisfied simultaneously the high request of different product control precision of coiling temperature and stable mechanical performance after the invention process, improve the Strip Steel Coiling Temperature control accuracy, the product type change is frequent, need not frequently adjust according to product type the discharge of collector, stablize control system and model, improved product quality.