2013年7月28日,衡阳华菱钢管有限公司(简称华菱衡钢)Φ720 mm周期轧管机组利用新开发的735 mm孔型,首次成功生产出Φ720 mm×26 mm高压气瓶用管。鉴于周期轧管机容易发生断辊的情况,在设计735 mm孔型时,技术人员调整轧辊孔型的辊缝,增大轧辊工作段半径,以此降低轧辊断裂的概率。生产轧制前,通过预热芯棒、加强芯棒润滑以及精心准备各种工模具等,确保轧制钢管脱棒顺利,轧制电流波动正常。生产后经过检验,该批钢管的壁厚波动在2.5 mm内,属于较 July 28, 2013, Hengyang Valin Steel Pipe Co., Ltd. (referred to as Valin Heng Steel) Φ720 mm periodic tube rolling unit using the newly developed 735 mm hole, the first successful production of Φ720 mm × 26 mm high-pressure gas cylinder tube. In view of the periodic tube rolling machine prone to broken roller case, in the design of 735 mm hole, the technician to adjust the roller pass roll gap, increasing the radius of the roll work section, thereby reducing the probability of roll break. Before the production of the rolling, the preheating mandrel, strengthen the mandrel lubrication and careful preparation of various molds, etc., to ensure that the rolling steel bar off smooth, rolling current fluctuations normal. After production after testing, the batch of steel pipe wall thickness fluctuations in 2.5 mm, are more