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对某厂Q345特厚板粗轧过程中缺陷的压合条件,以二维刚-粘塑性有限元法进行了数值模拟。结果表明:在足够的压下率下,特厚板中矩形缺陷能够被压合,缺陷的尺寸及在厚度方向的位置对缺陷压合有很大影响;板坯表面的缺陷压合所需的临界压下率最大,t/8(t代表厚度)处所需的临界压下率最小,即表面处的缺陷最难压合,缺陷压合由难到易按所处位置依次为表面、t/2、t/4和t/8,将该厂特厚板轧制道次压下率提高到18%以上,将可有效避免成品中缺陷的出现;矩形缺陷的长高比λ越大,临界压下率越小,越易压合;当λ从小于1增大到大于1的过程中,临界压下率急剧减小,但当λ继续增大,临界压下率减小的趋势变得比较平缓;当λ<1时,呈双“Y”型闭合;当λ≥1时,呈“Z”型闭合。
The lamination condition of the defect during the rough rolling process of the Q345 heavy plate in a factory was numerically simulated by two-dimensional rigid-viscoplastic finite element method. The results show that the rectangular defects can be press-fitted under a sufficient reduction rate, the size of the defects and the position in the thickness direction greatly affect the press-fit. The defects on the surface of the slab need not The critical reduction ratio is the largest, t / 8 (t represents the thickness) at the critical reduction required at the minimum, that is, the surface of the most difficult to lap the defects, the lamination from easy to easy to press the location of the surface, t / 2, t / 4 and t / 8, the plant extra heavy plate rolling pass reduction rate increased to 18% or more, will be able to effectively avoid the appearance of defects in the finished product; rectangular defect height ratio λ greater, The critical reduction rate is smaller and the easier it is to be compressed. When λ increases from less than 1 to more than 1, the critical reduction rate decreases sharply. However, as λ continues to increase, the critical reduction rate decreases When λ <1, it is double “Y” type closed; when λ≥1, it is “Z” type closed.