Bar full-flow control rolling and control cooling production line

Abstract

The invention relates to a bar full-flow controlled rolling and controlled cooling production line. The production line comprises a heating furnace, a high-pressure water dephosphorization nozzle, a rough rolling unit, a first flying shear, an intermediate rolling unit, a control rolling device, a second flying shear, a finish rolling unit, a transition guide groove, a control cooling device, a closing guide groove, a third flying shear, an auxiliary cooling bed, a cooling bed, an 850-t cold shear and a finishing three-section chain, wherein a first cooling device is arranged below a straightening plate of the cooling bed; second cooling devices are arranged below a cooling bed body of the cooling bed and below an outlet chain of the finishing three-section chain; the structures of the transition guide groove and the control cooling device are improved; and temperature testers are arranged at the inlet of the rough rolling unit, the inlet of the finish rolling unit, the outlet of the finish rolling unit, the outlet of the transition guide groove structure, the outlet of the auxiliary cooling bed, the inlet of the cooling bed, the outlet of the cooling bed, the inlet of a middle chain of the finishing three-section chain, the inlet of the outlet chain of the finishing three-section chain and the position of a collecting frame of the finishing three-section chain respectively. The production line can achieve high-precision flexible control in the whole product production process and reduce alloy production cost.

Description

technical field [0001] The invention relates to a full-process controlled rolling and controlled cooling production line for bars. Background technique [0002] The existing bar workshop mainly produces three representative products: HRB500(E) series products, which contain high V alloys, and the process adopts high temperature rolling on the cooling bed; ordinary HRB400(E) series products, the process adopts low temperature rolling + Continuous controlled cooling; export materials (representative British standard material) series products, the process adopts low temperature rolling + continuous controlled cooling, and the surface forms complete tempered martensite. The three products have different requirements on the process. At present, the process flow of the bar production line is simple: heating furnace→high-pressure water descaling→rough rolling unit→1# flying shear→middle rolling unit→2# flying shear→finishing rolling unit→controlling Cold device→3# flying shear→coo...

AI Technical Summary

Problems solved by technology

[0003] (1) The temperature monitoring on the production line cannot effectively supervise the temperature of the whole process of the rolled piece; (2) There is an unreasonable problem in the design structure of the original transition guide groove between the finishing rolling unit and the cooling device: the base of the guide groove adopts a fixed type , the guide groove is composed of four sections of about 55cm long seamless pipes placed on a bracket. The guide groove branch pipe is made of seamless pipes welded on the guide entrance, fixed on the bracket with a pressure plate and an inclined iron, and the bracket is directly placed onto the fixed base

When a steel pile accident occurs in the production of bars with this structure, the running bars are easy to pile up and damage the equipment, resulting in serious deformation of the guide groove branch pipe, and the continued use increases the probability of steel pile accidents

In addition, the installation accuracy of the guide groove branch pipe and the guide groove bracket is poor, and when it is used on the line, the front and rear centering of the outlet guide of the front finishing rolling unit and the inlet of the rear control cooling device are adjusted by adjusting the left and right positions of the guide groove bracket

Since the transition guide trough, the exit guide of the finishing rolling mill, and the cooling device assembled on the traversing trolley are all moving, there is no fixed rolling center line reference point for comparison. This is a key point affecting production stability and a failure point for long-term stacking of steel

(3) The cooling device currently adopts a box-type water tank with a total length of 8.4m, which is installed on two traversing trolleys, which are connected by bolts, and the two trolleys are driven by separate hydraulic cylinders; After the water pipe is passed through, the closing guide groove is also placed on the independent traversing trolley, which is driven by a separate hydraulic cylinder, the trolley synchronization is poor, and the neutrality before and after passing through the water tank is poor

The water pipe inside the water tank relies on circular pipe clamps to fix and align the water pipes. The circular pipe clamps are easy to wear and tear, resulting in loose compression and seriously affecting the alignment.

There is no blowback air (or blowback water) device in the water-piercing device, and the water is seriously carried behind the steel bar, resulting in uneven cooling on the surface of the steel bar, which is prone to wavy bays and seriously affects the quality of the finished product

The biggest problem is that the water-piercing device cannot realize single-line, single-group or intermittent water transfer, and the single boiling water mode cannot meet the requirements for specifications and process changes

(4) The steel is placed on the cooling bed at 850-950°C, and no effective cooling measures are taken in the follow-up. The large-scale steel only relies on natural cooling to cool down, and the speed is slow. The subsequent tempering temperature is high, and the grains of the structure will temper and grow. , the grain size of the steel becomes coarser, resulting in a decrease in performance

In addition, the straightening plate and the rack are easily deformed in the state of high temperature and thermal expansion for a long time, resulting in bending deformation of the steel, and the cooling speed of large specifications is too slow, resulting in bends or burrs during cold shearing, resulting in quality complaints

(5) When the steel is subjected to large cold shearing, the temperature is between 200°C and 450°C. Due to the high temperature, the head of the steel is prone to shear bends or burrs, which are caused by downstream customers during welding or mechanical connection. Many problems, quality complaints also occur from time to time

(6) When the steel reaches the three-segment chain, the temperature is 200-400°C. This temperature range is just in the blue brittle range. The head of the steel turns blue, and the counter cannot work normally, which greatly increases the labor intensity of the workers.

(7) The temperature of the steel is around 200°C when it is collected and bundled. At this time, the steel is bundled and stored in a stack. The temperature of the stacked steel is high, the heat dissipation speed is slow, and it is in an aging state for a long time, resulting in a significant decline in the performance of the steel. To avoid qualified steel bars after aging, more alloys must be added, which increases production costs

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