不锈钢弯管的皱波问题及其预防措施(下)

The Wrinkle Problem of Stainless Steel Elbow Pipe and Its Preventive Measures(Ⅱ)

为了预防不锈钢管冷弯时出现皱波的问题,首先从管件制造标准化角度考察和评估了冷弯方法的优点及其合理应用范围,然后通过两个典型案例分析了冷弯时发生皱波的"薄"壁条件和影响因素。分析指出,皱波的实质是拱腹压缩塑性变形区的"压杆"失稳屈折现象。依据钢管to/do和Ro/do决定的弯管"薄"壁度,合理设置芯棒型式模具加工精度和安装"间隙",从力学上增强"压杆"抗压稳定度,是预防皱波的必要保障。不锈钢管制造标准允许的to和do公差带往往大于"薄"壁弯管所必须的模具间隙,有时会在小批量多品种规格不锈钢弯管时产生皱波,但只要把握"薄"壁度,重视芯棒结构、模具间隙及弯管参数的合理调整,不锈钢冷弯管时的皱波问题是可以解决的。

In order to prevent wrinkling problem during stainless steel pipe cold bending, first of all, from the perspeetive of pipe fittings manufacturing standardization, it inspected and evaluated the advantages of cold bending method and its reasonable application scope, then analyzed the ＂thin＂ wall condition and influence iactors when stainless steel cold bending through two typical cases. The analysis indicated that the essence of the wrinkling is pressure rod unstability and buckling phenomenon in intrados eonlpressive plastic deformation area. According to the steel pipe ＂＇thin＂ wall degree decided by t,/d,, and R,/d,. set up reasonably mandrel type, and the clearance determined by other mold processing and installation pmsicion, to strengthen the stability against crushing of compression bat＂ i^om mechanics, this is a necessary safeguard against wrinkling. The tolerance zone of to anti do specified in stainless steel pipe manufacturing standard is often than the （tie clearance of ＂thin＂ wall thickness bends, sometimes lira wrinkling appear in small batch muhivarietal specifications stainless steel elbow pipe. However, as long as grasp the ＂thin＂ wall thickness degree, pay attention to the （：ore rod structure, reasonably adjust die clearance and bending pipe parameters, tile wrinkling problem of＂ stainless steel cold bend can be solved.