Billet cutting is an important part of the production process. The quality of billet length and weight directly affects the yield rate and length ratio of the rolling process. For a long time, the billet in the steelmaking process has been controlled by length, but the control accuracy is not high, resulting in large fluctuations in the weight of the billet (the specific deviation can be consulted in the steelmaking process, our factory does not have weight weighing). This is reflected in the rolling process, that is, the final cut of the steel bar is of different lengths, resulting in a large number of short-length materials.
For the processing of short-length materials, according to the requirements of the company’s quality assurance department, the cut ends less than 4m are directly put into scrap steel, the proportion is close to 1% of the total weight of the steel billet; those greater than 4m and less than the fixed length (usually 9m or 12m) are put into full-length materials, the proportion accounts for about 2% of the total steel amount.
In terms of benefits, in accordance with the principle of maximizing benefits, the company plans to assess the bar mill’s sizing ratio in 2011, requiring it to reach a high level of 99%. If the billet cannot achieve the fixed weight, it will be very difficult to achieve this target. If the billet can achieve the fixed weight, the sizing ratio can be increased by 1%, which will bring considerable economic benefits.
In terms of sales, although through-length materials are cheaper than fixed-length materials, due to the uneven lengths, secondary processing is required before users use them. Therefore, the sales of through-length materials are not ideal and often form backlogs. Long-term backlogs can easily lead to rust, which seriously affects the surface quality of the steel. The company has no choice but to reduce prices again. Such a vicious cycle is also a great loss to the company’s benefits.
In terms of technology, the steelmaking continuous casting machine currently has an online billet length measurement device. If you want to achieve billet weight determination, you can add a weight acquisition device based on the existing image processing system, and use PLC to process the weight parameters and perform logical reasoning. The camera-based sizing system can achieve weight determination cutting based on the processed data. This technology can be tested on a continuous casting machine in a targeted manner. If successful, it can be promoted throughout Laigang. This will be a huge innovation in the measurement system and automatic control, and the process level will have a qualitative leap.
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