Analysis of casting and rolling plate shape control

Release time：2014-11-06

　　In the production process of aluminum strip and foil, strip shape control is very important. Bad shape cause exceed the standard of flatness during rolling process, and even frequent breakage, leading to severe scrap. Not only directly affects the rate of finished products, but also increase the auxiliary production time, shortening the life cycle of the roll, affects the production efficiency, increase the cost of production. Shape control is a systematic project,should be the first source of cast rolling plate shaped grab, because the roll casting flatnessdirectly affects the subsequent rolling process of plate shape control.

　　Aluminium alloy casting rolling plate shape control

　?。?） roll casting flatness measuring method

　　Usually the main evaluation of slab thickness transverse and longitudinal distribution. Cast rolling plate transverse thickness tolerance is controlled in the range of 0.5%, and the shapemust have in some measure method is convex; in the section from the center to both sides is divided into several equal distance of measuring points of thickness. Cast rolling plate thickness longitudinal tolerance control is within 0.75%; the measuring method is in a period of such as 200 -- 300mm slice a production line of every serial sections, roll a circumferential length, each piece of measurement method as before and numbered to fill in a form, get longitudinal data distribution throughout the thickness.

　?。?） in continuous roll casting crown control

　　In certain pre pressure roller, roller shape convexity can influence factors offset the roll bending,flattening, the corresponding thermal expansion etc Convexity and pre pressure, length of the roller, the roller sleeve wall thickness, roll sleeve material hardness, aluminium and aluminium alloys and so on.

　?。?） pre pressure control

　　A pre shaped pressure has little direct influence on board, but in the production side of separateadjustable pre pressure, can change the thickness of the plate. Usually in the slab thin side,online reducing pre - pressure parameters can be incremental sheet thickness, reduced without affecting the casting and rolling slab transverse thickness tolerance. According to the empirical data, the pre pressure adjustment of parameters in the given value 10%, slab thickness can change about 1%.

　?。?） the cast rolling zone control

　　If the slab sides exist certain board, can be thin slab casting mouth platform side position fine-tuning recede, unilateral extended length of roll casting zone, i.e. length solid rolling areaincreased, change roll contact pressure distribution and slab rolling deformation rate, plate thickness can be incremental, narrowing cast rolling plate transverse thickness difference.According to the empirical data, the cast rolling zone extended control within the given value10%, slab thickness can change about 1.5%.

　?。?） roll suit with precision and grinding use system control

　　In general, the coaxial error the roller body and the roller core should be less than 0.02mm, the casting roll sleeve inside and outside cylindrical surface of the coaxial error should be less than0.02mm, the diameter of the roller and the roller surface of the assembled coaxial error should be less than 0.04mm, so that the strip in the roll circumference within the scope of the thickness difference can be less than 0.06mm.

　　Casting roll must strictly implement the regular car grinding system, strengthen the flatnessmeasuring and tracking, the shape control and roll sleeve surface cracking, corrosion,deformation condition into consideration together.

　　Grinding amount = roll maximum crack depth * 2+0.2 - 0.5mm.

　　Car after grinding roll parameters for coaxiality cylindricity: 0.02mm, 0.03mm, two roller diameteris less than 0.05mm, surface roughness R alpha 0.4, can ensure the flatness of longitudinalthickness deviation control precision to meet the requirements; the car after grinding, the needfor a period of time so that the internal residual stress recovery and put into use.

　?。?） the circulating cooling system

　　In order to guarantee the effect of cooling roll everywhere, we must ensure that the flow of cooling water and inlet and outlet temperature, import and export of the temperature difference is too large or less traffic, will cause the roller sleeve expansion uneven, affecting slabtransverse thickness difference. Generally, inlet pressure is 0.3 0.5MPa, the water inlettemperature of less than 30 DEG C, import and export of temperature 2 to 5 degrees celsius.

　　The sink is reasonable in structure, such as rectangular round bottom tank, sine

　　Curve flat water tank, the radial import and roll core hole in the same longitudinal section in cross arrangement, can enhance the uniform cooling effect, and reduce sink blocked. The roll core circulation channel blockage, water flow is not smooth, will cause the corresponding siteexpansion aggravated, serious wear and tear, material strength decreased, the thickness of plate super bad. In order to guarantee the normal use when the sink is unimpeded, conditionalunits can use soft water, no conditions can use detergent solvent cleaning regularly or rolldegloving cleaning roller core channel.

　　Zhang Yingli （7）

　　A certain Zhang Yingli （about 6 - 10N/mm）， can be tension leveling on the shape to a certain extent, reduce the phenomenon of roll bonded and change shape. The number of effectivecontrol, can be cast rolling plate shape control in an ideal state, to meet the requirements of the subsequent rolling on the original shape of the.