METHOD AND APPARATUS FOR CONTINUOUSLY HOT ROLLING OF FERROUS LONG PRODUCTS

• Main Authors: SHORE, TERENCE, WOODROW, HAROLD E, PUCHOVSKY, MELICHER
• Format: Patent
• Language: English; Korean
• Published: 15.01.1999
• Edition: 6
• Subjects: MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVINGMATERIAL; PERFORMING OPERATIONS; PUNCHING METAL; ROLLING OF METAL; TRANSPORTING

본 발명은 길이가 긴 철 제품의 연속 열간 압연 방법에 있어서, 제품을 적어도 3개의 연속되는 압연 통로를 통과시키는 단계를 구비하고, 상기 압연 통로 중 적어도 제2 및 제3압연 통로가 그곳을 통과하는 제품에 원형 횡단면 형상을 주는 형태가 되도록 하고, 상기 압연 통로가 적어도 총 14%의 제품 횡단면적 감소를 단계적으로 작게 일어나게 하는 크기이고 총감소의 약 20%이하가 상기 압연 통로중 마지막 통로에서 일어나도록 하고, 상기 압연 통로의 처음 및 마지막 압연 사이의 시간 간격이 압연되는 제품의 횡단면에 걸친 결정립 크기가 2 ASTM 이상 변화되지 않도록 하는 것을 특징으로 하는 길이가 긴 철 제품의 연속 열간 압연 방법 및 장치에 관한 것이다. A method and apparatus for continuously hot rolling ferrous long products which employs a "post finishing" block of roll stands downstream from the finishing stands of the mill. Water boxes or other like cooling devices are preferably interposed between the last mill finishing stand and the postfinishing block. The post finishing block includes at least two reduction stands followed by at least two sizing stands. The reduction stands have an oval-round pass sequence, and the sizing stands have a round-round pass sequence. Clutches or other equivalent means are employed in the drive train to permit changes to be made between the interstand drive speed ratios of at least the reduction stands, and also between some or all of the remaining sizing stands. A fixed rolling schedule is provided for all roll stands in advance of the finishing stands. Thus, the finishing group is supplied with a first process section having a substantially constant cross sectional area and configuration. The first process section is passed through the finishing group and rolling occurs in either none, some, or all of the finishing roll stands, depending on the size of the desired end product. The product then continues through water cooling boxes to the post finishing block as a second process section. The interstand drive speed ratios of the roll stands in the post finishing block are appropriately adjusted to accommodate rolling of the second process section. The total reductions affected in the initial reduction stands of the post finishing block are well above 14%, thereby producing an increased energy level in the product sufficient to create a substantially uniform distribution of fine grains. Typically, such total initial reductions will be on the order of about 20-50%. Significantly lighter reductions on the order of 2-15% are taken in the final round-round pass sequences of the post finishing block to obtain the desired close sizing tolerances in the finished product. The time interval between the higher reduction affected in the oval-round pass sequence and the lighter reductions affected during sizing in the round-round pass sequence is such that the resulting grain size throughout the product cross section will not vary by more than 2, and in most cases by less than 1 ASTM grain size number.