| 304 stainless steel has been widely used in production and life because of its good mechanical properties,processing formability,corrosion resistance and oxidation resistance.The production process is relatively mature.However,for some users who use 304 stainless steel ribbon,the traditional production process is adopted to meet the special requirements of ultra-low carbon and high precision.The output of 304 stainless steel strip can no longer meet user needs.Therefore,aiming at the special requirements of ultra-low carbon and high precision put forward by special users,the production process of 304 stainless steel strip was improved from two aspects of steelmaking and cold rollingImprovement of 304 stainless steel plate and strip production process,including:1.Steelmaking process control:(1)AOD furnace:the addition of ferrosilicon and fluorite spheres has the smallest impact on the carbon increase of molten steel during reduction period,that is,when the content of ferrosilicon carbon is not more than 0.16%,and the content of fluorite sphere carbon is not more than 0.90%,the amount of carbon increase in molten steel is not greater than 0.16%.More than 0.012%.Finally,it is determined that the inlet temperature of AOD molten steel is>1560 C,the carbon content of the first inversion is controlled to 0.02-0.03%.Lime is added in batches before the first inversion.The temperature of each batch is above 1600 C,the quantity of single batch is not more than 2.0t,the reduction temperature of AOD is above 1580 C,the chemical composition of tapping is less than 0.023%,and the tapping temperature is above 1580 C.(2)LF furnace:the maximum carbon increase is 0.018%.Finally,the LF slag content is 4.0?5.0t and the argon flow rate is less than 450L/min.(3)continuous casting:the casting temperature of the ladle is 1460?1545 C,the drawing speed is 1.0m/min,and the section is 180*1300mm.(4)Hot rolling:reheating furnace temperature 1250-1270 C,soaking section temperature 1240-1290 C,finishing rolling temperature 1050 C,laminar cooling using front section cooling,coiling temperature 720 20.(5)Annealing pickling:The speed of the annealing pickling line process section is controlled by TV<180,the maximum speed of the process is 80m/min,and the control temperature is 1180 C.2.Production process control of cold rolling:(1)Rolling force:first pass absolute reduction is less than 0.6 mm,front tension is set to 45 tons,rear tension is set to 38 tons,and neutral angle is reduced by reducing the tension difference between front and back.(2)Flatness:Scanning raw material flatness,optimizing target curve in advance.When thickness H is less than 1.0mm,the control range of DS and OS loose edge is within-10-2NIT;thickness H>1.0mm,DS and OS loose edge is within-6-8.5NIT.(3)High reduction rolling:increase the reduction rate of the first three passes,select the shape control mode of micro-edge wave for finishing passes,and control the oil temperature at 40-47 C.(4)Paperless rolling:finish rolling speed is less than 200 m/min,coiling unit tension is controlled below 26 Kg/mm2.After finishing rolling,after removing the work roll,on-line rewinding is done once,rewinding tension is set to 16-22 tons,speed is 125 m/min.The corrugated paper is added to the head to improve the crease defect of the strip head. |
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