Research On Buckling Control Of Cold Rolled Strips

In the application of continuous annealing furnace, vertical annealing application isthe most, because of the use of vertical annealing furnace has the advantages of less landoccupation, many product performance is good, it is also an important technical means ofcold rolled strip steel production, demand of today’s technological progress on "soft, thinstrip width," of the very strong, double standards and requirements of surface quality well,the strip of high strength, so the vertical type continuous annealing furnace has madeirreplaceable status. However, with the continuous improvement of product quality andmanufacturing quantity requirements of the promotion of the production, the product doesnot allow for surface quality issue and serious buckling, buckling once generated will bescrapped for tens of meters or even hundreds of meters, buckling phenomenon in verticalcontinuous annealing furnace has occurred from time to time, which not only makes therapidly rising cost of production, will disrupt the production rhythm, increase the waste ofresources, such as iron and steel, coal, waste water,electricity and the others. Manyexperts study and reflection direction is how to speed up the strip production rhythm,reduce strip in the furnace hot buckling.Strip buckling is the main factor affecting the continuous annealing furnaceof highspeed, stable production. In the production of thin plate or sheetdeep drawing highperformance requirements, control the buckling occursvery difficult.In this paper, using the finite element method for nonlinear analysis,simulation andanalyses the principle of buckling, illustrates the relationship between the furnace rollertension and transverse compressive stress, the interaction between the thermal crown ofbucklingas well as the role of the three main influencing factors.The paper also describes the common complex contour and shape of the furnace, andhow it will affect the buckling occurs, the initial shape andfurnace roller matching degreeshould be used as the cold rollingmanufacturers develop stable production parameters,suppressed thecritical buckling problem. In this paper, the focus of many scholars at homeand abroad, explore the buckling phenomenon is caused by thethermodynamics, thisviewpoint is very one-sided. Although the influenceof uneven temperature furnace on thinsheets of Poisson ratio, modulus of elasticity and other mechanical parameters, also cancause the change of the critical point buckling, but the simulation experimentproves,buckling "force" is mainly composed of a transverse compressive stressand tension generation, the common force is greater than the uneven distribution of the valueof thermal stress, temperature caused by unevenlocal elastic modulus, Poisson’s ratiochange, not enough to affect thebuckling deformation under tension. The buckling isusually in the center line of the guide roller symmetrical, more shows that thermal stressinbuckling does not play a major role.