The edge plan view control method of the high-strength level pipeline pipeline steel of large broadening ratio
Technical field
The invention belongs to Medium and Heavy Plate Rolling technical field, in particular, provide the edge plan view control method of the high-strength level pipeline pipeline steel of a kind of large broadening ratio.
Background technology
In Heavy Plate Production, the flat shape after steel plate rolls is how not rectangular, must carry out crop end and trimming process, directly caused the loss of lumber recovery before delivery.At present, steel plain shape control method many employings MAS rolling, dogbone rolling method (DBR method) etc. of domestic and international heavy and medium plate mill, its essence is all the rolling with varying section by pony-roughing pass, realizes the squaring of finished steel plate.But for the high-strength level pipeline pipeline steel of large broadening ratio, the plan view control effect of its edge is unsatisfactory, and after steel plate rolling, head and tail width is narrower than middle part width, and namely edge " jujube core " shape is serious, directly cause the reduction of this specification kind lumber recovery, production cost increases.
Summary of the invention
The object of the present invention is to provide the edge plan view control method of the high-strength level pipeline pipeline steel of a kind of large broadening ratio, improve lumber recovery, reduce production cost.
The present invention at the three phases (i.e. shaping, broadening and axial rolling) of heavy and medium plate mill roughing, technique in control following technical parameter:
First, in roughing first stage shaping passage, carry out the rolling of variable cross-section thickness, form " digging pit " effect in the centre position of length direction after making steel plate rolling, steel plate centre position is thinner than steel plate thickness end to end, and thickness difference is that Δ h(" digs pit " degree of depth).Slab is turned round 90 ° afterwards and carry out broadening, now steel plate length becomes the width of actual rolling, due to wide different to thickness, also different to the reduction ratio at plate center from edges of boards, thus edge flat shape is improved.
" digging pit " degree of depth of steel plate forming passage sets in milling train second-level model, and milling train one-level executing agency is according to secondary setting value afterwards, by HGC hydraulic cylinder dynamic adjustments roll gap, finally makes steel plate reach the thickness difference of regulation along its length.
It is high-strength level pipeline pipeline steel that the present invention is suitable for steel grade, comprises X65, X70, X80 kind, and suitable thicknesses is (15-25) mm.
Roughing mill maximum rolling force 8500 tons, rolling torsion 3200KNm, the diameter × stroke of maximum reduction 40mm, HGC hydraulic roll gap control piston is φ 1500/1350 × 80mm, the maximum 29MPa of hydraulic pressure.In above capacity of equipment and optimum configurations conditioned basic, roughing important technological parameters is as follows:
The shaping reduction in pass of roughing is set as (14-26) mm, in variable cross-section THICKNESS CONTROL process, the depth delta h that " digs pit " sets according to broadening ratio size: as broadening ratio 1.5≤A < 2.2, need increase " digging pit " depth delta h of steel plate middle part, " digging pit " depth delta h is set to (4.1-6.1) mm; As broadening ratio 1.3 < A < 1.5, " digging pit " depth delta h is set to (3.0-4.0) mm.
Simultaneously, shaping passes speed must meet the adjustment requirement to roll gap in Varying-thickness control procedure of HGC hydraulic cylinder, and adopt and sting at a slow speed steel, rolling strategy, concrete controling parameters is set as: biting speed (1.0-1.2) m/s, mill speed (1.2-1.5) m/s, acceleration 0.5m/s
2.
Roughing broadening rolling (3-6) passage, draught per pass (15-30) mm.
By above measure, " digging pit " shape of shaping passage is symmetric, finally realizes steel plate edge shape and well control, thus control shear amount, improve lumber recovery.
Accompanying drawing explanation
The shaping passage of Fig. 1 roughing " is digged pit " figure.
Fig. 2 " digs pit " depth delta h3mm.
Fig. 3 " digs pit " depth delta h5mm.
Fig. 4 " digs pit " depth delta h8mm.
Fig. 2 ~ Fig. 4 is " digging pit " depth delta h effect of optimization comparison diagram.
Detailed description of the invention
Embodiment 1,17.5mmX80-1 pipe line steel
Billet bloom size: 302*1990*2985mm
Contract size: 17.5*3827*11800 mm
Broadening ratio: 1.92
Conclusion: to 17.5mmX80-1 pipe line steel, broadening ratio 1.92,25mm established by shaping reduction in pass.The shaping passage of the conventional model depth delta h that " digs pit " is 2.6mm, is 48.7mm through measuring in the middle part of steel plate with head and tail width difference; The shaping passage of the inventive method depth delta h that " digs pit " adopts 6mm, width differential 22.8mm, more conventionally arranges minimizing 53.2%.
Embodiment 2,19.2mm X70-W pipe line steel
Billet bloom size: 248*1802*2920mm
Contract size: 19.2*2552*12000 mm
Broadening ratio: 1.42
Conclusion: to 19.2mmX70-W pipe line steel, broadening ratio 1.42,20mm established by shaping reduction in pass.The shaping passage of the conventional model depth delta h that " digs pit " is 2.2mm, through measure in the middle part of steel plate with head and tail width difference 21.7mm; The shaping passage of the inventive method depth delta h that " digs pit " adopts 3.5mm, steel plate edge " jujube core " 4.6mm, more conventionally arranges minimizing 77.4%.
Embodiment 3,22mmX80-1 pipe line steel
Billet bloom size: 301*2375*3145mm
Contract size: 22*3812*12100 mm
Broadening ratio: 1.61
Conclusion: to 22mmX80-1 pipe line steel, broadening ratio 1.61,15mm established by shaping reduction in pass.The shaping passage of the conventional model depth delta h that " digs pit " is 3mm, through measure in the middle part of steel plate with head and tail width difference 25.6mm; The shaping passage of the inventive method depth delta h that " digs pit " adopts 5mm, steel plate edge " jujube core "-0.25mm, more conventionally arranges minimizing 99.0%, improves successful.