The invention discloses a method for preventing thin strip steel from being fractured at the start moment. The method is applied to a cold continuous rolling unit. The method comprises the steps thatrolling force, formed at the stop moment, of the cold continuous rolling unit is acquired as memory rolling force; then, when roller replacement of the cold continuous rolling unit is completed and each roller gap is in the opened state, current winding tension corresponding to the start moment is determined, wherein the current winding tension is 1.5-3 times set winding tension, and furthermore,the covering phenomenon of a rolling mill section can be eliminated; and in addition, corresponding current actual rolling force, formed at the start moment, of each rack of the cold continuous rolling unit is determined based on the memory rolling force, and each rack of the cold continuous rolling unit is controlled to conduct downwards-pressing according to the corresponding current actual rolling force, formed at the start moment, of each rack, wherein the current actual rolling force of the first rack, the current actual rolling force of the second rack, the current actual rolling force of the third rack and the current actual rolling force of the fourth rack of the cold continuous rolling unit each accounts for 90-95% of the memory rolling force. By means of the method, the strip steel can be prevented from being fractured due to the excessively-large rolling force, thus strip fracturing of a rolling mill is avoided, and the cold continuous rolling unit is controlled to be started.

Method for preventing thin strip steel from being fractured at start moment

The embodiment of the invention discloses a starting method of a cold tandem rolling mill for high-strength steel. The starting method comprises the steps that a tension value is preset at an outlet of the cold tandem rolling mill; roll forces of a first rack, a second rack, a third rack, a fourth rack and a fifth rack are respectively adjusted to respective preset values; a tension value is preset at an inlet of the cold tandem rolling mill, and the cold tandem rolling mill is started; inclined values of hydraulic cylinders between the racks are adjusted; when tension values of each of the racks are stabilized, whether the difference value between the thickness of high-strength steel of an outlet of the fifth rack and the target thickness is greater than a preset difference value or not is judged; the roll forces from the first rack to the fourth rack are adjusted if the difference value between the thickness of high-strength steel and the target thickness is greater than the preset difference value, so that the difference value is less than the preset difference value; and the cold tandem rolling mill is operated to produce the high-strength steel based on a preset speed. The starting method of the cold tandem rolling mill for high-strength steel solves the problem that starting failure exists due to the difficult control over the roll force in the prior art.

Starting method of cold tandem rolling mill for high-strength steel

The invention provides a method and system for starting a five-stand tandem cold mill through material strips. The method comprises steps as follows: rolling stands are controlled to press down simultaneously to reach original rolling force in a material strip pattern; the mill is controlled to start in a threading speed, the first rolling stand, the second rolling stand, the third rolling stand,the fourth rolling stand and the fifth rolling stand sequentially convert from the original rolling force in the material strip pattern to rolling force set in a regulation, the speeds of adjacent rolling stands are allocated in a preset proportion, the tension-speed ratios of the rolling stands are corrected in a preset time period, and the running rolling stand runs in an automatic closed-loop control manner after the transition length. According to the method and system, the speed and tension of the mill and the control modes of press-down systems during mill starting in the material strippattern are comprehensively considered, and the material strip pattern transition processes of the press-down systems of the rolling stands are controlled precisely according to different set target values of products in different specifications. The strip head thickness control precision can be significantly improved and the production efficiency is enhanced through high-precision control of themill starting process achieved through the material strips.

Method and system for starting five-stand tandem cold mill through material strips

A method for preventing belt breakage of a finished gate of a UCM rolling mill during starting is suitable for the starting process. The method comprises the steps that S1, the starting rolling force of the finished gate is reduced by 1000-1500 KN on the basis of a standard value; S2, the roller bending force of a starting roller of the finished gate is reduced by 20-30 KN on the basis of a standard value; S3, the forward pull force of the finished gate is reduced to 90-95% of a program set value; and S4, the starting rolling speed of the finished gate is increased by 30 m/min on the basis of a standard value. By the adoption of the method, a safe and efficient processing mode is established for starting and conventional rolling of a reversible cold rolling mill unit, accidents are prevented, and the working efficiency is improved.

Method for preventing belt breakage of finished gate of UCM rolling mill during starting

An embodiment of the invention provides a high-strength steel rolling method and device. The method comprises the steps of controlling the reduction ratio of a first rack to be 15% to 25%, the rollingforce to be 23929 kn to 26448 kn and the speed to be 79 mpm to 81 mpm; controlling the reduction ratio of a second rack to be 15% to 25%, the rolling force to be 24752 kn to 27356 kn, the speed to be104 mpm to 106 mpm and the forward slip to be -0.955 to 3.045; controlling the reduction ratio of a third rack to be 15% to 25%, the rolling force to be 23465 kn to 25935 kn, the speed to be 154 mpmto 156 mpm and the forward slip to be -0.954 to 3.046; controlling the reduction ratio of a fourth rack to be 12%-20%, the rolling force to be 23144 kn to 25580 kn, the speed to be 199 mpm to 201 mpmand the forward slip to be -0.957 to 3.043; and controlling the reduction ratio of a fifth rack to be 5% to 15%.

High-strength steel rolling method and device

The invention discloses a raw material plate starting method of a cold rolling mill. When a first starting signal related to starting in a raw material plate starting mode is received, the roll bending force of each rack in a rack group is loaded to a roll bending force set value, and the compacting and rolling force of the cold rolling mill is loaded to a rolling force set value; when a second starting signal is received after the first starting signal, the real time rolling mill speed of the cold rolling mill is increased at a constant speed to a first set speed value; when that the real time rolling mill speed reaches a preset critical speed value is detected, whether tensions between the racks are stable or not is judged, and whether strip steel thickness deviations are stable or not is judged; and when the tensions between the racks and the strip steel thickness deviations are all stable, the rolling mill speed of the cold rolling mill is increased to a second set speed value from the first set speed value. The raw material plate starting method provided by the invention solves the problem of starting difficulty caused when all racks are started at the same time, further the loss due to waste products is reduced, and the yield is effectively improved.

Zhao Xinhua

Papers

Raw material plate starting method for cold rolling mill