Compact type fine-grain high-strength plate strip steel production line flexible manufacturing method

Abstract

The invention discloses a compact type fine-grain high-strength plate strip steel production line flexible manufacturing method. The method comprises an uncoiling pretreatment zone, a cleaning zone, adirect fire heating zone, a longitudinal-transverse magnetic compound induction heating zone, a rapid soaking zone, a rapid cooling zone, a tension straightening leveling zone and an aftertreatment coiling zone. In the direct fire heating zone, an operation plate strip is heated in the section from the initial temperature to the largest 600-700 DEG C. In the longitudinal-transverse magnetic compound induction heating zone, a longitudinal and transverse magnetic compound induction heating furnace composed of longitudinal magnetic flux induction heating and transverse magnetic flux induction heating forms a high-temperature rapid heating zone, wherein longitudinal magnetic heating is responsible for heating in the temperature section of 600-700 DEG C, and transverse magnetic heating is responsible for heating in the temperature section of 600-1200 DEG C; and two kinds of initial temperature for starting the two kinds of heating are flexibly combined according to the steel kind and the production heating capability, rapid heating in the recrystallization high-temperature zone interval of plate strips is achieved, the heating speed is 50-1000 DEG C / s; and soaking time of the rapid soaking zone is 0-40 s, the rapid cooling zone rapidly cools the plate strips, and the average cooling speed is 50-1000 DEG C / s.

Description

technical field [0001] The invention relates to the field of steel plate production, in particular to a flexible manufacturing method for a compact fine-grained high-strength plate and strip steel production line. Background technique [0002] At present, there are a variety of plate and strip steel products in the steel industry, which can be roughly divided into structural steel, deep-drawing steel, and panel steel according to their uses. Plate and strip structural steel products are mostly used in many industries such as construction machinery, containers, and automobiles. This type of steel has high requirements on the yield and tensile strength of the material. Develop in the direction of ultra-high strength, while maintaining high plasticity, that is, to obtain high-strength plastic product, typical steel types include DP steel, TRIP steel, complex phase CP steel, TWIP steel, Q&P steel, boron steel, etc.; Punching steel is mostly used in household appliances, automob...

AI Technical Summary

Problems solved by technology

However, the modern continuous annealing process also has major deficiencies: (1) The modern continuous annealing process is based on traditional heating methods, such as direct gas heating, gas radiant tube heating, resistance wire radiant tube heating, etc.

These heating methods have relatively high heating efficiency in the low temperature section (<500°C), and the fastest heating rate can reach 30-50°C / s, while heating in the high temperature section, especially in the material recrystallization temperature range (600-850°C About), the heating rate is generally below 10°C / s, which makes the modern continuous annealing unit very long, ranging from a few PASS to dozens of PASS to meet the requirements of the heating process

The longer the continuous annealing unit, the more complicated it is. The strip steel is prone to buckling, deviation, or even strip breakage when it runs at high speed for a long time in the furnace, which causes great difficulties in production, operation and maintenance. Large, many contacts in the strip steel furnace are likely to cause many problems such as scratches on the surface quality. For steel plates with high surface quality, such as O plates, the yield is low; (2) The heating furnace of the modern continuous annealing process has a large thermal inertia, and the temperature control Poor precision, difficult production of products with high process requirements (such as Q&P steel, etc.), difficult transition of specifications and varieties, and large furnace volume, large heat dissipation, high energy consumption, and high emissions, all of which limit the improvement of the economic and social benefits of the enterprise; At the same time, modern continuous annealing furnaces are generally suitable for mass production conditions, and with the development of social needs, the requirements for small batch flexible production are also getting higher and higher. Large-scale continuous annealing furnaces have large thermal inertia and high maintenance costs. , There are big deficiencies in the adaptability of the production organization of the product

[0006] 3. In the existing strip steel heat treatment process, whether it is bell annealing or continuous annealing, the heating process is the traditional direct fire heating or radiation heating method, which greatly limits the improvement of the material heating rate, and also limits the Changes in new products, processes and equipment technologies

However, the existing iron and steel production process has many procedures and huge equipment, especially those involving heat treatment processes, such as the low efficiency and poor surface quality of the bell annealing furnace, while the mainstream continuous annealing process is efficient and has good surface quality, but it is also There are a series of problems such as the unit leader, the operation pass of the strip (the pass is composed of a complete uplink section and the downlink section), and the thermal inertia of the heating furnace. The degree of mutual correlation is high, and each production process and link may have a major impact on the quality of the produced product and the cost of production and operation, and the flexibility of the unit is poor

For example, poor control of the steel composition window will cause the quality of subsequent heat treatment products to be substandard; (2) In the existing heat treatment process, the heating furnace for strip steel products is very long, and the strip steel runs in the furnace for a long time, resulting in a series of Production problems and quality defects such as curved broken belts, scratches in the furnace, etc. At the same time, the furnace is long and the heating rate is slow, and the recrystallized grains of the product are easy to grow, which cannot further improve the microstructure and mechanical properties of the product.

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