Open AccessMETAL FORMING DURING PIPES REDUCTION ON A THREE-HIGH ROLLING MILL
Author(s) -
А. С. Алещенко,
А. С. Будников,
Eugene Kharitonov
Publication year - 2019
Publication title -
izvestiâ vysših učebnyh zavedenij. černaâ metallurgiâ
Language(s) - Uncategorized
Resource type - Journals
SCImago Journal Rank - 0.3
H-Index - 7
eISSN - 2410-2091
pISSN - 0368-0797
DOI - 10.17073/0368-0797-2019-10-756-762
Subject(s) - ovality , blank , deformation (meteorology) , reduction (mathematics) , rolling mill , radius , materials science , mill , process (computing) , engineering , metallurgy , composite material , structural engineering , mechanical engineering , geometry , mathematics , computer science , computer security , operating system
Pipe rolling plants (PRP) with three-high screw rolling mills are used to produce hot-rolled seamless pipes. In Russia, two such rolling units are used: PRP 160 at Pervouralsk Novotrubny Plant and PRP 200 at Volzhsky Pipe Plant. Recently, the most acute issue is increasing their technological capabilities. There is a need of expanding size and grade mix, as well as non-traditional use of gauge and rolling mill for screw rolling. The paper presents results of experimental study of the process of reduction or un-adjusting rolling of pipes on three-high screw rolling mills with an increase in reduction of diameter up to 25 %. The results of computer finite element modeling in QFORM program are provided. The aim of this work was to study effect of rolling process with increased reduction in diameter on change of metal form in deformation zone and changes in geometrical dimensions at reduction of cups with different wall thickness on the pilot mill. Important role in process of metal forming during screw rolling (especially when rolling hollow products and pipes) plays cupped blank ovality that is equal to the ratio of the roll radius when the metal comes in contact with the roller to the radius under the roller in the cross section of deformation zone. Ovality characterizes stability of change in geometric dimensions of pipes and their resistance to deformation in inter-roll space. The reduction of thin-wall cupped blank is accompanied by large va lues of ovality, deformation process is less stable, and as a result, form defects (faceting) and end defects occur during plug rolling. Ovality at plug rolling increases more intensely in comparison with plugless rolling. Presence of plug limits displacement of metal in axial direction and contributes to displacement of metal in gaps between rollers. At plugged rolling, it is necessary to use rolls with collars allowing main reduction along the wall, thereby localizing reduction zone on the plug, and reducing ovality of cupped blanks.