2010-03-05 13:14:20 阅读1 评论0 字号:大中小
译文:
采油井口装置(采油树)用闸阀是油田用量{zd0}的专用闸阀,在闸阀制造过程中,阀体静水压强度试验和密封性能试验合格率太低(30%~70%),并长期困扰生产厂。本文结合我厂的生产实际,就上述问题的症结进行了分析,提出解决办法。 1、毛坯铸造工艺的改进 我厂井口闸阀采用砂模铸钢毛坯,阀体加工过程中,在与阀座配合的内螺纹处经常出现气孔、缩松等铸造缺陷,经对阀体剖面的宏观分析发现,在图1所示的热节区,有程度不同的缩松现象,为解决上述问题,我们对铸造工艺进行多次改进试验。 1)改进浇冒口系统。将设置在阀体两侧圆柱面的浇冒口系统改为在阀体底部设置的横直浇口系统; 2)改砂模铸造为熔模铸造; 3)改侧浇法为顶浇法,且使中法兰向下。由于熔模铸造比砂模铸造具有更好的透气性、更快、更均匀的冷却条件,所以组织更为致密。由于钢液从顶部浇入,又是从冒口直接浇入,浇冒口的位置靠近热节区。为铸件创造了极为有利的顺序凝固条件,热节区得到及时的补缩,所以经工艺改进后生产的铸件组织致密,xx了缩松、缩孔等铸造缺陷,产品合格率达到99%以上。 2、提高机加制造精度的措施 密封效果是阀门制造的关键要素。密封问题历来是机械加工行业很难解决的问题,为提高阀门的制造精度,保证阀门密封效果,经过理论研究和生产实践,归纳出以下几点改进措施。 阀体是闸阀生产中最关键的加工件,由于结构的要求,其阀座密封面与中心对称面倾斜3o~6o.对于中小型闸阀的阀体,我们采用卧式车床加辅助弯板工装来完成阀座倾斜面的加工。但必须保证让弯板倾斜角度(3o~6o)与阀体的工艺要求一致。同时,更应严格地保证机床中心高与弯板工装中心高重合。允许误差控制在0.02mm~0.04mm之间。此外,阀体在加工过程中需考虑一次压紧、定位的准确性和可靠性。如图2所示,应将靠车床主轴线的重直面视为参照基准,利用弯板垂直面上的楔式槽与楔形块的滑动将阀体一端法兰面找正压紧,分别进行两面加工。此外,阀体在加工过程中,需在车床工装上靠回转盘旋转180o完成两端阀体内腔的加工。回转精度是靠分布在回转法兰两个对称分布的锥形定位销孔的重复定位来保证的。转位误差为0.01mm~0.02mm。 另外,要选择合适的配重与弯板配用。众所周知,车床上弯板工装的静平衡直接影响车床的加工精度和生产效率,所以我们在弯板的配重形状和布局上下了很大功夫,一是尽可能减少配重的回转半径,二是在布局上采用外圆内方的结构、改善圆周方向的动平衡性能,使得机床转速及工件的加工精度尽可能提高。 {zh1},要保证密封副内各部件的协调加工: 即:阀体与闸板斜度的一致性;阀体与加工阀体弯板斜度的一致性;闸板与车削用斜度盘的一致性;闸板与磨削斜度台的斜度的一致性。 四种一致性之间相互联系、相互制约、相互依靠。四种一致性,我们是以车床弯板的斜度为依据,经多次筛选、磨削出标准斜度板,反过来再用标准斜度板修磨闸板车床用斜度工装,控制好四种一致性,生产率提高了,组装精度得以保证。 除此之外,还应有效地控制阀座的研磨工序,保证阀座表面平面度不低于100:0.01,保证表面粗糙度表面不受划伤、磕碰、研磨砂粒度不均等因素的影响,以达到研磨后的{zj0}效果,保证阀座的精度。 通过以上一系列有效措施和质量控制,目前我厂生产的井口阀产品合格率达98%以上。
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原文:
Oil wellhead (Christmas Tree) with valve in the oilfields, the largest amount of special valve, the valve manufacturing process, the valve hydrostatic strength test and sealing performance test pass rate is too low (30% ~ 70%), and long-term troubled manufacturing facility. In this paper, our factory actual production on the crux of the problem are analyzed and put forward solutions. 1, Blank Casting Process Improvement Our factory wellhead valve used rough sand cast mold, body process, in cooperation with the valve seat at the inner often thread pores, shrinkage and other casting defects, based on a body section of the macro-analysis found that, in Figure 1 The hot spot area as shown, there are varying degrees of shrinkage phenomenon, in order to solve these problems, we conducted a number of improvements to the casting process test. 1) improving the pouring riser systems. Will be set up on both sides of the valve body cylindrical surface of the pouring riser system to the set in the valve at the bottom of horizontal straight gate system; 2) The change for the sand casting investment casting; 3) Change the top side of pouring pouring Law Act, and so that the flange down. As the Investment Casting Sand casting is better than the air permeability, faster, more uniform cooling conditions, so the organization is more dense. As the molten steel poured from the top income, but also from the riser directly poured into the pouring riser located close to the hot spot area. For the casting to create a very favorable condition of the order of solidification, hot spot areas to receive timely feeding, therefore, the process improved the organization of production casting dense, eliminating the Shrinkage and other casting defects, product qualification rate reached 99%. 2, to improve manufacturing precision machining of measures Sealing effect is a key element of the valve manufacturer. Sealing problem has always been difficult to solve mechanical problems processing industry, in order to improve manufacturing precision valves to ensure that the valve sealing effect, through theoretical research and production practice, sum up the following improvements. Valve is the valve production process the most critical parts, because of structural requirements, the valve seat sealing surface with the center symmetry plane tilt 3o ~ 6o. For the small gate of the valve body, we have adopted a horizontal lathe adjuvant bending tooling to complete the seat tilted surface processing. However, we must ensure that for bending angle (3o ~ 6o) in line with the valve body of the process requirements. At the same time, it should strictly ensure that machine center height with a high coincidence of bending tooling center. Allowable error between the control 0.02mm ~ 0.04mm. In addition, the valve during processing to be considered on