电焊钢管高精度边部弯曲成型CRE法的开发

在生产壁厚从薄壁到厚壁很大范围的电焊钢管机组，以提高外径和壁厚变化轧辊共用性和提高边部成形性能及稳定质量为目的，新日本制铁公司则设计和开发出把上下轧辊以垂直轴为忠才交叉是到适合的所规定弯曲曲率和壁厚间隙形状的交叉轧辊边部弯曲ＣＲＥ成型法。已制成试验机进行了成形试验，并进行数值解析，根据所要求弯曲曲率轧辊共用性，以及有效利用弯曲力矩来提高边部成形性能和减少压痕的高精度成形，其优越性和可靠性已经得到了

Development of CRE (Cross Roll Edge-bend) Method for ERW Pipe Forming

Authors investigated a method for improving the commonality of rolls in ability against a variety of the outside diameter and wall thickness of ERW pipes, together with improving their edge formability and also stabilizing their quality in the ERW piping mill, where tubes having a wide wall thickness range from a thin-walled tube to a thick-walled are manufactured. And CRE (cross roll edge-bend) method has been thereby developed, which can regulate the gap profile, obtained by rotating and crossing on the vertical axis of upper and lower rolls, to accommodate to both a required bending curvature and a wall thickness. From the results of formability test using a testing stand made on an experimental basis together with the numerical analysis, it has been proved that the CRE method has a validity and is an advantageous processing method that improves in both the commonality of rolls in service ability to cope with any required bending curvatures and the high precision edge formability with less impression defects through an effective action of bending moment.