双金属复合管影响品质的因素 |
添加时间:2018/6/15 16:06:26 浏览次数: |
双金属复合管影响品质的因素: The factors affecting the quality of the bimetallic composite pipe: ① 由于外基管内表面形状不规则,不平高度影响了模具轮廓最大外圆尺寸全行程的通过。 (1) because of the irregular shape of the inner surface of the outer tube, the uneven height affects the total travel of the largest outer diameter of the die contour. 拉拔模具最大轮廓是机械加工的整圆,必须沿轴心线平行前行。模具与内衬管的材质为硬钢于软钢,在拉拔扩张过程中,模具嵌入在内衬管内表面中。当外基管不规则的内表面影响拉拔模具通过时,会造成拉拔模具轴线与内衬管轴线形成夹角,扩大了模具最大轮廓直径。当出现对称的不平高度时,由于作用在拉拔模具上的力,在3600方向上是对称的,这样就会造成拉拔模具无法避让。两种现象都会使内衬管受挤压处弯曲变形加大,造成拉拔模具最大轮廓处,切削内衬管表面,引起表面光洁度的破坏,甚至无法通过。这种状况在复合较大直径的双金属复合管时更为明显。 The largest contour of the drawing die is the machined circle, which must be parallel to the axis line. The material of the die and inner liner is hard steel in soft steel, and the die is embedded in the inner surface of the inner liner during the drawing and expanding process. When the irregular inner surface of the outer base tube affects the passing of the drawing die, the angle between the axis of the drawing die and the axis of the inner liner will be formed, and the maximum outline diameter of the die is enlarged. When there is a symmetrical uneven height, the force acting on the drawing die is symmetrical in the 3600 direction, so that the drawing die can not be avoided. The two phenomena will increase the bending and deformation of the inner liner, which causes the maximum outline of the drawing die, the surface of the inner lining of the cutting, the damage of the surface smoothness and even the failure to pass through. This situation is more obvious when combined with larger diameter bimetal composite pipes. 为了保证表面品质和功效,通常采用减小拉拔模具最大轮廓尺寸,因此复合后的双金属复合管结合力小。通常仅为0.2~0.3MPa之间。 In order to ensure the surface quality and efficiency, the maximum profile size of the drawing die is usually reduced, so the bimetal composite pipe after the composite has small adhesion force. It is usually only between 0.2~0.3MPa. ② 由于结合力低使得内外管环状结合面间隙大,内衬管在管端焊接处将反复承受介质输送过程中,压力交变的扭动、折弯,致使连接处出现材料疲劳、开裂,导致耐腐蚀性能下降—(折翘现象)。 Because of the low binding force, the inner lining of the inner and outer ring is large, and the inner liner will be repeatedly subjected to the transmission of the medium at the end of the pipe, and the pressure alternating twists and turns, resulting in the fatigue and cracking of the material at the junction, which leads to the decline of corrosion resistance - (the phenomenon of bending and warping). ③ 由于内衬管没有达到充分的塑性变形,内衬管内表面由作用力与反作用力产生的表面压应力,达不到充分的体现,表面压应力几乎没有反映。此时,内衬管中直缝焊接处仍处于拉应力状态,因此内衬管表面整体,尤其是直缝焊接处,抗热应力腐蚀能力下降。另外,采用拉拔工艺,拉拔模具呈直线运动,内衬管表面始终处于拉应力状态。 (3) because the inner lining pipe does not reach the full plastic deformation, the surface pressure stress produced by the force and reaction force on the inner surface of the inner liner can not be fully reflected, and the surface pressure stress is almost no reflection. At this time, the direct seam welding of the inner lining is still in the tension state, so the overall surface of the inner lining tube, especially the straight seam welding place, decreases the resistance to thermal stress. In addition, the drawing process is linear and the surface of the inner liner is always in tension state. |
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