Centering calibration method for rolling center line

Abstract

The invention provides a centering calibration method for a rolling center line. Centering of the rolling center line is measured, the relative levelness degrees of guide rails and positioning plates are measured through a leveling ruler and a frame leveler, and the guide rails and the positioning plates are leveled; the positions of sliding rails, positioning blocks and press-down plates of a machine frame relative to a central boring hole are measured through a three-dimensional coordinatograph and adjusted to meet the standards; the position degree of the machine frame in a housing through a centering instrument and adjusted to be qualified. The zero position of a rolling mill housing servo hydraulic cylinder is calibrated, and the position degree of the central boring hole of the machine frame is measured through the centering instrument. The servo hydraulic cylinder is started, the change of the position degree of the machine frame central boring hole is detected through the centering instrument, if the position degree of the central boring hole is qualified, the rolling mill housing has the resetting calibration conditions, new basic data are input in a servo press-down program, and calibration of the rolling mill housing servo hydraulic cylinder is completed. According to the centering calibration method for the rolling center line, measurement and calibration data are accurate and reliable, the accuracy of the rolling line of a PQF continuous mill is greatly improved, rejected products which is uneven in wall thickness or broken during rolling can be reduced, and the product quality and yield of steel pipes are improved.

Description

technical field [0001] The invention belongs to the field of mechanical equipment, in particular to a method for centering and marking the rolling center line of a PQF seamless steel pipe continuous rolling mill. Background technique [0002] PQF six-stand 3-roller hot continuous seamless steel pipe continuous rolling mill is an important equipment on the φ177mm hot-rolled seamless steel pipe production line in the seamless factory. Its function is to reduce the capillary diameter and wall thickness through rolling deformation, so that The internal metallographic structure of the material extends linearly; at the same time, the surface finish of the inner and outer surfaces of the waste tube is improved, and the uniformity of the wall thickness is improved. The rolling process requires that the error of the rolling center line of the PQF continuous rolling mill is δ≤±0.1mm. If it is out of tolerance, the steel pipe rolled by the continuous rolling mill will have defects suc...

AI Technical Summary

Problems solved by technology

[0003] 1. The centering measurement data is inaccurate, resulting in a large error in the rolling center line adjusted according to the data

Due to the space limitation of the archway of the continuous rolling mill, after the zero frame is installed in the archway, the two slide rails of the vertical positioning datum on the zero rack and the guide rails in the archway and four horizontal positioning datums on the zero rack The contact gap between the positioning block and the positioning plate in the archway cannot be measured, and can only be felt by the slight movement when it is installed in the zero rack and when the rack is locked.

The inaccurate measurement data leads to low position accuracy of the positioning reference parts (guide rails, positioning plates) in the archway adjusted according to the data, which in turn causes the rolling center line of the continuous rolling mill to shift

[0004] 2. The zero calibration method of the servo hydraulic cylinder is incorrect, resulting in large zero calibration errors

Therefore, the zero position of the servo hydraulic cylinder calibrated according to its state is inaccurate, which leads to the out-of-tolerance position accuracy of the roll stand in the archway, that is, the out-of-tolerance precision of the rolling center line of the continuous rolling mill

[0005] 3. The accuracy of the rolling center line of the continuous rolling mill is out of tolerance due to the neglect of some details in the calibration process, such as: the defects such as unevenness and scratches caused by the bumping of the guide rails and positioning plates in the archway are not thoroughly introduced. Measurement errors; or measurement errors caused by unclean cleaning of the guide rails and positioning plates in the archway; or measurement errors caused by the flatness of 2 guide rails or 4 positioning plates in the archway during the initial installation, etc.

[0006] 4. When the simulated steel rolling is not carried out after the calibration of the rolling center line, the state experiment of the roll reduction is used to finally confirm whether there is a gap in the 18 servo indenter systems? Are the connecting bolts of the position encoders of the 18 servo hydraulic cylinders loose? These problems will cause the theoretical value of the 18 roll reductions input according to the rolling table to be inconsistent with the actual reduction during rolling.

In turn, the rolled steel pipes have defects such as uneven wall thickness and rolling folds.

[0007] Due to the above reasons, the accuracy of the rolling center line of the continuous rolling mill after calibration is low, and more waste products are produced during production, resulting in a decline in the yield of the production line

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