Research On Lubrication Technology Of SUH409L Ferrite Stainless Strip Steel In Cold Rolling

Most domestic production of stainless steel uses multi-roll mill, and still now key technology of6roll cold tandem mill to produce stainless steel has not been mastered. In this paper, based on the background of cooperation project between Bao steel and Northeastern University "ferritic stainless steel cold rolling key technology research", we apply single stand4-high reversing cold mill and direct-pulling2/4-high mill to carry out SUH409L ferritic stainless steel rolling lubrication test. The experimental data is applied to debugging process parameters, then to optimizing the rolling process parameters to develop the key technology of the production of SUH409L ferrite stainless steel cold rolling mill for Bao steel.The main works and results were as following:(1) During single strip rolling, under different reduction ratio cases, trends of strip roughness, film thickness, surface gloss and the defect ratio were researched. It was found that with the increase of pressure ratio, the strip film thickness, roughness and defects ratio reduced and surface glossness improved.(2) The influence of roll roughness, emulsion concentration and temperature on the strip surface roughness, film thickness and the defect ratio was studied. During the experiments it was found that roll with high roughness plays an important role in decreasing film thickness rapidly.(3) The relationship among surface quality, roll material, rolling process parameters during SUH409L cold rolling process was studied. It was found that chromium-plated roll surface roughness declined more slowly than the common roll, roll wear resistance and service life were significantly improved, and strip surface quality was more stable and brighter after rolling.(4) During experiment of cold rolling process of tandem mill, the influence factors on slip cold tandem mill, trip break and uneven distribution of residual emulsion were analyzed, and the relevant prevention measures were brought forward.(5) After adjustment and optimization, when total rolling reduction is65%to75%, and outlet thickness is less than2.0mm, and emulsion concentration of tank S2is4.0-4.5%, and temperature is61～65℃, and concentration of S4boxes is1.5to1.7%, and temperature is54～58℃, roll roughness of stand1-4#constant, roll roughness of stand5#is0.3±0.1μm, the strips have good surface quality.