| Seamless steel pipe has a wide range of applications and large demand,and their specifications and production capacity are also expanding.However,for the current market supply and demand situation,there is a phenomenon that the output of ordinary steel pipes are too large and the production capacity of high-quality products are insufficient.Many steel tube mills have not fully utilized their technical features and advantages.Therefore,how to improve the quality of products by using the capacity of existing continuous rolling mills is a problem that all steel pipe practitioners must concerned.This paper takes Baosteel 0140 full-floating mandrel mill as the research object,and uses the secondary development function of ABAQUS finite element software to design the plug-in program of MM rolling process.By simulating the rolling process of ?21 8×18.5mm steel pipe,the stress,strain and motion of metal under different hole conditions were summarized,and the influence of capillary eccentricity and diameter-to-wall ratio on the size of the export pipe was investigated.The design of the continuous rolling process is optimized for the purpose of uniform wall thickness and elimination of "bamboo joints".The major results include:(1)The Python language was used to design the plug-in of multi-format and material steel tube automatic modeling and post-processing result output for the MM steel tube continuous rolling process.Including hole design,material library data,and various stress and strain and cross-sectional output outputs for subsequent automated modeling calculations and data processing.(2)The deformation of the steel pipe is mainly concentrated in the first four frames.The entrance first contacted a certain point on the side wall,and shrinks radially from the contact point to the roll gap,and the wall thickness near the top of the hole increases slightly;The second pass is first contacted with the flange and the radial strain gradually decreases along the top of the hole to the nip.(3)Designed a eccentric and unbiased capillary tube and a different eccentricity capillary contrast model.It was found that the eccentricity of the capillary tube had a certain corrective effect on the waste tube.The thinner the steel pipe,the more likely it is to deform,and the thick-walled steel pipe is significantly stronger than the thin-walled steel pipe in terms of wall thickness uniformity and rolling force stability control.(4)The tension-free simulation method is used to determine the roll diameter,and the new continuous rolling speed system is designed by combining the tension and the elongation coefficient.By comparing the longitudinal and transverse dimensions of the waste pipe,it is found that the outer diameter of each longitudinal angle is smaller than before,but the"bamboo",phenomenon has been significantly improved,and the outer diameter deviation rate has been reduced.After improved speed system,the extreme values of the head,middle and tail wall thickness are more concentrated than before,the difference in thickness between adjacent angles is reduced and become more uniform.(5)The optimization of the continuous rolling process eliminates the problem that the second frame is underfilled,the fourth frame is overfilled,and the rear frame is not wellrounded under the original process system.The wall thickness deviation rate of the horizontal pipe was reduced from 10,7%to 6.9%;the central wall thickness deviation rate was reduced from 11.5%to 4.0%;the tail wall thickness deviation rate was reduced from 8.1%to 7.7%.The longitudinal outer diameter"bamboo" phenomenon is reduced,there is no obvious phenomenon of pile steel and steel pulling,and the whole rolling process is relatively stable. |
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