Material shape control
1）Material shape process parameters:
Rolling Mill | roughing mills | intermediate rolling | pre-finishing mill | finishing mill | |||||
Material type of the last flight of the unit（mm） | 77.0±0.5 | 35.5±0.3 | Φ6.5 | Φ8 | Φ10 | Φ12 | Φ14 | Φ16 | Control according to technical conditions of finished products |
20.2 | 19.6 | 19.6 | 19.0 | 22.0 | 20.2 | ||||
±0.2 | |||||||||
2）Material shape control principles and precautions:
The material type is strictly prohibited from exceeding the tolerance range. The tolerance control of the material type of adjacent flights should be uniform. The rough rolling and pre-finishing rolling should be pressed according to the rolling time as much as possible. The one-time adjustment range of the material type should not be too large, and the rough rolling should not exceed 0.5mm. The intermediate rolling does not exceed 0.3mm, and the pre-finishing rolling does not exceed 0.2mm. When adjusting the finished product size, only the first frame and the finished product frame of the finishing mill can be adjusted.
Finished product allowable maximum speed (m/s)
Specification | Φ6.5 | Φ8 | Φ10 | Φ12 | Φ14 | Φ16 |
Speed（m/s） | 86.0 | 76.0 | 50.0 | 35.0 | 29.0 | 21.0 |
The principle of speed-up when changing product specifications: under the condition that there is no equipment problem, the production will be carried out at the speed shown in the table after changing the specifications.
Tension and looper control requirements
1）Requirements for tension control between units and between units:
The roughing and intermediate rolling mills are rolled according to the micro-tension, and the tension value is minimized. It is advisable that the rolling piece fluctuates slightly after the bite. The pre-finishing looper is set strictly according to the specified set height value, and the adjustment amount of the looper is less than 3%. .
2）Quantity, location and parameters of the looper:
loop | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 9 |
Height of loop（mm） | — | — | 75 | 170 | 70 | 85 | 110 | 185 |
Controlled rolling and controlled cooling system:
temperature control point
|
| water tank | Tank control parameters or principles | length of the cold section of the head(m) | Length of tail lukewarm section(m) |
Into the finishing mill temperature
| 930±20 | 1#water tank | The 1# water tank is adjusted according to the temperature of the finishing mill. After rolling, the 2# and 3# water tanks are preferably used in the case of ensuring the spinning temperature to ensure fast cooling after rolling. | 0 | 0 |
Incoming module mill temperature
| — | 2-4#water tank | 0 | 0 | |
Spinning temperature
| 930±20 | 5#water tank | 0 | 0 | |
Cooling between finishing mills | On/off | — |
|
|
|
Auxiliary equipment control parameters:
1# Flying shear head lead coefficient | 45% | 2# Flying shear head lead coefficient | 10% |
1#Flying shear head cutting length | 160mm | 2# Flying shear head cutting length | 300mm |
1# Flying shear tail lead coefficient | 0 | 2# Flying shear tail lag coefficient | 17% |
1#Flying shear tail cutting length | 0 | 2# Flying shear tail cutting length | 450mm |
3# Flying shear head lead coefficient | 1.1% | Pinch roller speed lead factor
| 4% |
3#Flying shear head cutting length | 600~700mm | Pinch Roller Current Limit | 0 |
Breaking shear lead coefficient | 0 | Pinch roller holding pressure | 1.4MPa |
Spinning head speed lead coefficient | 2.0%~3.0% | pinch roll gap(off/on) | 3.5/5.5 |
Cloth Roller (RPM) | — | Pinch Roller Pinch Mode | clip tail |
Finished technical conditions:
Specification
| allowable deviation
| Out of roundness
| Surface Quality Requirements | tensile strength
| rate of reduction in area | Decarburized layer |
Φ6.5 | ±0.25 | ≤0.4 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
Φ8 | ±0.25 | ≤0.4 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
Φ10 | ±0.25 | ≤0.4 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
Φ12 | ±0.3 | ≤0.48 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
Φ14 | ±0.3 | ≤0.48 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
Φ16 | ±0.3 | ≤0.48 | No folds, creasing, stuttering | ≤400 | ≥28 | ≤1.5%D |
The key points of roller change, hole and guide control:
1）Replace the rolling groove in strict accordance with the specified rolling tonnage. In principle, the amount of steel passing through the rolling groove shall not be greater than the specified amount of steel passing through. If there are obvious cracks on the surface of the rolling groove, it can be replaced in advance when the block is dropped.
Rough rolling, intermediate rolling, pre-finishing rolling
1# | 2# | 3# | 4# | 5# | 6# | 7# | 8# | 9# |
16000 | 15000 | 16000 | 15000 | 14000 | 15000 | 4000 | 5000 | 2500 |
10# | 11# | 12# | 13# | 14# | 15# | 16# | 17# | 18# |
4500 | 2000 | 3500 | 2000 | 3000 | 4500 | 5000 | 4500 | 5000 |
2） When replacing rolls and grooves, carefully check the shape of the pass, and find that the phenomenon of wrong rolls must be adjusted.
3） When replacing rolls and grooves, carefully check whether the cooling water pipes of the rolling mill are unobstructed.
4）When replacing the guide, it is necessary to reasonably adjust the opening of the guide, the distance between the guide and the roll, and the alignment with the pass.
Inspection and control points of semi-finished products and finished products:
1）The dimensions of semi-finished products are measured online with calipers, and the material height of each flight is controlled so that it is within the specified range.
2）The surface quality of the intermediate material should be observed frequently, and if there are scars, ears, etc. on the surface, it should be stopped for inspection and treatment in time.
3） Take the tails of 1# shears, 2# shears and 3# shears every 1 hour for measurement, and accurately control the material size of key sorties.
4） The finished product sampler must check and measure the surface quality and external dimensions one by one, and notify the main console to stop rolling if there is any problem.
Key contents and requirements of daily inspection of rolling area:
1） Check the surface of the rolling groove of each pass, if there is serious cracking or falling blocks, stop and replace it in time.
2）Check the cooling water pipes of each roll to ensure that the cooling water pressure and flow can be correctly sprayed on the rolling groove.
3） Check the running stability of the rolling stock, and notify the main console to adjust the speed in time when the rolling stock fluctuates too much and has a tendency to stack steel.
4） Check the running condition of the rolling guide guard, and notify the main console to stop rolling in time when the guide wheel is stuck, steel falling and other phenomena are found.
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