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In the process of steel tube production, continuous tube rolling is the foremost forming procedure and the critical step that decides the dimension precision and the surface quality. In the actual production of the 140 mm full floating mandrel mill in Steel Tube Branch in Baosteel, steel T91 was chosen to be the typical sample, self made rolling force transducer and mandrel velocity testing equipment were used, and a series of comprehensive tests on rolling parameters including the rolling force and mandrel velocity were carried out. After the experiment, the friction state between rolling tube and mandrel was analyzed. The friction coefficient was calculated and the values of 0033-0074 in each mill were obtained. The friction coefficient increases obviously along the rolling direction. 相似文献
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针对340MPM机组(Multi-Stand Pipe Mill限动芯棒连轧管机组)芯棒服役过程建立三维有限元模型,研究芯棒在服役过程中温度场变化规律.同时,通过对热应力的研究,分析了芯棒热疲劳裂纹萌生机理及裂纹在芯棒内部的扩展规律.对比实测数据与模拟结果,认为所建立的有限元模型能够反映芯棒温度变化趋势.芯棒首次脱管后表面最高温度为630℃,此后经历三次反复的水冷降温和空冷返温过程,冷却结束后表面最高温度为98℃.脱管后,芯棒表面轴向和环向压缩热应力均达到900 MPa,第三次水冷结束时刻,轴向拉伸热应力达到186 MPa,环向拉伸热应力达到221 MPa.芯棒的拉压交变热应力使其表面出现热疲劳裂纹并逐渐扩展,环向裂纹扩展至距表面17.5mm深、轴向裂纹扩展至距表面20mm深时会显著受阻,热应力对轴向裂纹的促进作用强于环向裂纹. 相似文献
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摘要:针对自动轧管机轧制薄壁不锈钢管中出现的严重横向壁厚不均问题,借助于三维有限元分析软件Simufact,对X10CrNiTi18不锈钢管典型规格112mm×4.5mm自动轧管过程进行数值模拟。研究了不同轧辊孔型结构参数、芯棒润滑状态、轧辊孔型磨损及穿孔毛管偏心对自动轧管横向壁厚精度的影响。结果表明:随着芯棒摩擦因数的增大,所轧荒管横向壁厚精度明显恶化;偏心毛管轧制所轧荒管依旧偏心,延伸轧制对穿孔毛管偏心壁厚纠偏能力有限;磨损的孔型修模后,采用负芯补轧制较增大芯棒直径轧制所轧荒管横向壁厚不均度增大;采用三段式圆弧孔型,所轧荒管横向平均壁厚更接近目标壁厚,横向壁厚不均度由原孔型的13.55%下降到9.94%,横向壁厚精度明显改善。 相似文献
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In view of serious uneven transverse wall thickness of thin walled stainless steel tube rolled by automatic plug mill,the automatic tube rolling process of X10CrNiTi18 stainless steel tubes with typical specification of 112mm×4.5mm was numerically simulated by using 3D finite element analysis software Simufact. The influence of different roll pass structure parameters, different mandrel lubrication state, roll pass wear and eccentricity of pierced shell on transverse wall thickness accuracy of automatic rolling tube was analyzed. The results show that as the friction coefficient of the mandrel increases, the accuracy of transverse wall thickness of the rolled tube deteriorates obviously. The hollow tube rolled by eccentric pierced shell is still eccentric, and it shows that the elongation rolling has a limited ability to correct the eccentric wall thickness of the pierced shell. With repaired the worn pass, the unevenness of the transverse wall thickness of the rolled tube increases using the negative mandrel compensation rolling compared with the increase of mandrel diameter. The average transverse wall thickness of the rolled tube is closer to the target wall thickness by using three section arc groove, and the transverse wall thickness unevenness decreases from 13.55% of the original groove to 9.94%, and the transverse wall thickness accuracy is obviously improved. 相似文献
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三辊轧制荒管壁厚偏心控制是无缝钢管壁厚精度控制的重要环节。基于生产试验分析了荒管壁厚偏心的特征,运用解析方法建立了三辊轧制荒管壁厚偏心的理论计算模型,针对实际生产条件进行了预报计算与比较,分析了三辊轧管工艺因素对荒管壁厚偏心的影响特点,并进一步讨论了改善荒管壁厚偏心的方法。研究结果表明,荒管壁厚偏心的基本特征表现为“偏心螺旋型”,在荒管壁厚不均中的占比达80%以上;毛管壁厚偏心和温度偏心是影响三辊轧制荒管壁厚偏心的最重要因素;增大三辊轧制减壁量、降低毛管温度、提高轧辊台肩高度、增大轧辊转速有利于减小荒管壁厚偏心。 相似文献
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为减少连铸与热轧工序之间坯料再加热的能源消耗,连铸直轧技术蓬勃发展,其关键技术之一在于连铸与轧制工序之间的补热工艺。针对板坯连铸直轧实际生产中对补热工艺的要求,建立了纵向磁通和横向磁通感应补热有限元模型,分析了板坯的补热过程。结果表明,纵向磁通对板坯表面整体补热效果好,但无法解决板坯边角温度偏低的问题;横向磁通可有效地对板坯边角进行局部补热;选择合适的电流大小和板坯移动速度,可使板坯温度分布更均匀。同时,使用自制的感应补热样机做补热试验,对补热效果进行检验,所得的试验结果与模拟结果一致。分析结果对板坯连铸直轧在实际生产中的感应补热工艺具有指导意义。 相似文献
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涟钢冷轧产品初检合格率与同类产品相比偏低,主要是屈强比偏高、伸长率低、冲压性能差等。针对这一问题,对热轧、冷轧以及退火平整等工艺参数对冷轧冲压板产品合格率的影响进行了分析,结果表明通过优化热轧卷取温度、冷轧压下率、退火制度以及平整伸长率,可以将退火板卷的初检合格率提高到99.48%,满足冷轧冲压板批量生产的要求。 相似文献
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为了简化钢轨万能轧制过程的三维几何模型,首先把带箱形孔型立辊简化为等效的平辊,然后分别给出轨腰、轨头及轨基的运动学许可速度场,求出在此速度场下相应变形区的塑性变形功率以及速度间断面上消耗的功率,计算中考虑了由于前滑和后滑而产生的摩擦功率.根据刚塑性体的变分原理求解水平辊和两个立辊轧制力和轧制力矩的近似解.通过比较理论值和实验值可知,利用变分原理求出的力能参数近似解稍大于实验值但最大误差不超过20%,因此根据变分原理进行力能参数计算和轧制工艺参数设定及优化是比较可靠的. 相似文献
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