Analysis In Seamless Pipe Reducing-sizing Process By Fem

The main task of reducing-sizing in the seamless pipe production process is to control the dimensional accuracy and residual stress of products, to meet certain quality requirements. A lot of factors affect the quality of seamless pipe, under the parameters of reducing-sizing unit has been given, the materials and temperature in reducing-sizing process affect the product quality greatly. To improving product quality, it is necessary to research the factors which affecting product quality.Based on the thermal elastic-plastic analysis principle, the heat transfer analysis principle, the contact analysis principle and finite element theory, Used the nonlinear finite element software ABAQUS to establish the finite element analysis model in seamless pipe reducing-sizing process. Applying this model, firstly, analyzed the equivalent stress field, equivalent strain field and variation of displacement of special node of N80 grade steel pipe at temperature of 900. Followed by comparison of the equivalent force field, equivalent strain field, temperature field and displacement changes of special node of N80 and BT100H grade steel through the typical post-roll at temperature of 900 for reducing-sizing. Finally, simulated N80 and BT100H grade seamless pipe in reducing-sizing process at different temperatures to compare the pipe diameter, wall thickness and ellipticity under various programs, to select the suitable temperature in reducing-sizing process under the existing conditions.It can be obtained through numerical simulation: the metal from contact with the roller at the top of the region to roll joints mobile in the seamless pipe reducing-sizing process, so that the steel diameter which contacting the top of roll decreased, the steel diameter which contacting the roll joints increased, but the increased less than increased. The top of roll and roll joints interchangeable in odd and even frame, so the pipe overall diameter decreased and wall thickness increased through many frames repeatedly. The final frame is pivotal process to control ellipticity and size steel diameter. Two kinds of steel pipe set at the same temperature for reducing its variation of equivalent stress field etc was consistent, the existing N80 grade steel production can provide a reference for BT100H grade steel. The maximum equivalent residual stress was reduced with the temperature being increased in two kinds of steel reducing-sizing process. The diameter deviation of seamless pipe was gradually decreased with the temperature being increased in reducing-sizing process. The change wall thickness was not clear with the same kind of seamless pipe reducing-sizing process at different temperature. The two kind seamless pipes reducing-sizing process at temperature of 900 can be obtain better ellipticity Deviation, according to the reality of N80 grade steel, it is proposed that the BT100H grade steel producing at temperature of 900 will be achieved better effect under the current process.The results of this research provide the theoretical basis and reference for studying the BT100H grade seamless pipe reducing-sizing process.