Although the slitting and rolling process has effectively improved production efficiency and greatly increased output, the size of each rolled piece after slitting may not be exactly the same due to factors such as steel temperature fluctuation, groove wear, hole system design, guide installation, groove processing accuracy, etc., that is, there is a line difference.
If you want to achieve higher economic benefits, you need to ensure the quality of steel, and you need to reduce the line difference through various means.
The main reasons for the line difference are as follows:
1. The pre-slitting frame or the slitting frame import guide is not aligned with the groove, and the guide is biased to one side. At this time, the material that deviates from the hole shape has a larger cross-sectional area, and the size of the finished product will become larger after rolling.
2. Inconsistent hole wear. Due to factors such as inconsistent cooling of the groove, irregular materials in the previous pass, or hole design, the hole wear will be inconsistent. The cross-sectional area of the hole with severe wear will increase, resulting in the size of the finished product to increase.
3. The roll gap on both sides of the roller is inconsistent. After changing the rolls, if the roll gap control on both sides of the K4-K3-K2-K1 rolls is inconsistent, the hole area on the side with the larger roll gap will be larger, resulting in a larger finished product size on that side.
4. The processing accuracy of the groove is not high. This is mainly related to the wear and repair accuracy of the forming tools in the roll hole processing workshop and the processing method.
5. There are problems with the material shape control of the finishing mill. Cutting production pays great attention to the matching of the material shape of the finishing mill. Poor matching will cause line difference.
6. The main reasons for line difference are generally concentrated in the aging of the K4 groove, the misalignment of the K3K4 guide guard, and the deformation of the K6 material.
Solution to line difference:
1. Accurately install the guide guard. Pre-adjust the guide guard before changing the roll to ensure that all parties are aligned and fixed.
2. Improve the cooling water pipes of the K4 and K3 batches, enhance the cooling effect, and do a good job of spot inspection during the production process.
3. When changing the rollers of the finishing mill, the mill is operated in a jog mode, and the roll gaps on both sides of the rolls are measured with the same welding rod, and the deviation is controlled within 0.1mm.
4. Improve the roll material. It is recommended to use high-speed steel rolls for K3 split rolls, and pay attention to improving the processing accuracy of the hole type.
5. Strictly control the material shape of each pass according to the process requirements, and adjust the guide gap with the sample rod as required.