某5 000 mm宽厚板生产线轧制厚板时头部0.2～1.0 m范围内厚度超差较严重，极大地影响了产品尺寸精度与成材率。究其原因为轧制力预报偏差较大及头部辊缝补偿过度使得实际辊缝偏小，造成头部厚度偏薄，且随着钢板厚度越厚，该现象越明显。通过对L2轧制力设定模型及L1头部厚度控制系统的相关参数进行优化，经多次工业试验及应用，取得了显著效果，头部厚度合格率由原来的50%提高到90%以上。

The out-of-tolerance of head thickness ranging from 0.2 m to 1.0 m was serious while rolling heavy plate in an 5 000 mm heavy plate production line，which greatly affected the dimensional precision and the yield rate of the plate product. The reasons for that were：the deviation of rolling force prediction was too large，and the excessive roll gap compensation at head of plate causing actual rolling gap is too small，which result in thinner head thickness，and it become more obvious with the increasing of plate aim thickness. According to the parameter optimization of the head thickness control system in L1 and the rolling force setting model in L2，after repeated experiments and industrial applications，apparent effect was obtained，the head thickness qualified rate was improved from 50% to above 90%.