Small diameter and thin wall tube is a trend of development for air-conditioner pipe now, the outside crack, inside wrinkle and orifice flat easily appear during a small elbow pipes preparation. The causing reason of copper tube defects was analyzed and the position and size of core was optimized. These results show that the cracks easily occur at outside and expand towards inner when the bend angle is 180°, the wrinkles appear at the inner of tube during the angle of 0~90°. The optimal parameter is 5.80 mm core diameter and 2 mm ahead for Φ7×0.41mm copper tube. According to these parameters during bending tube experiments, the defects of outside crack, inside wrinkle and flatness were basically eliminated and the excellent tubes were obtained.%当今空调铜管的发展趋势表现为小口径、薄壁,小弯头管在弯制过程中易出现管口扁平、外侧管壁开裂和内侧起皱等缺陷.采用DEFORM有限元软件分析了铜管弯制过程中缺陷产生原因,并对芯杆位置和尺寸进行了优化.研究结果表明:当弯曲角度为180°时,铜管易产生外侧裂纹,并由外侧向内侧扩展;在弯曲角度为0~90°范围内铜管内侧易出现起皱现象;Φ7×0.41mm铜管弯曲时较优的芯杆直径为5.80mm,提前量为2mm.根据以上参数,对铜管进行了弯曲试验,并没有出现外裂、内皱和扁平等缺陷,获得了优良的小弯头管.
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