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  • 锻件与铸件的区别
  • 本站编辑:杭州崇贤重型机械有限公司发布日期:2018-01-22 10:46 浏览次数:
铸件法兰盘的特点是容易获得其他方法不易获得的形状复杂的工件;铸件法兰盘成本低;可以采用特殊工艺获得精密铸件,其表面不经加工即有理想的光洁度;铸件成形简单,比锻造法兰盘价格便宜;但铸件法兰盘内容易出现缺陷及非致密区,在强腐蚀及高压场合国内的技术一般不能保证锻件的质量.
The characteristics of the casting flange is easy to obtain the workpiece other methods is not easy to obtain the shape of complex casting flange; low cost; precision castings can be obtained using a special process, the surface without processing has ideal finish; casting forging flange than simple, low price; but prone to defects and flange plate castings non dense area, ensure the quality of forgings in strong corrosion and high pressure situations of domestic technology cannot in general.
 
锻件法兰盘是使用锻打设备对棒料进行锻打成型,一般无法锻打出比较复杂的工件,需要较大的加工量,但锻件法兰盘组织结构比较致密,不容易出现内部缺陷,因此广泛用于要求高的部件加工,如阀座、阀芯、阀杆等,在高压及强腐蚀合金阀门中,锻件阀体也被大量采用。
Forging flange is used for forging equipment for bar forging, forging workpiece to play more complex, need a large amount of processing, but the structure of forging flange is compact, not prone to internal defects, so it is widely used in machining high requirements, such as valve seat, valve, valve stem, in high pressure and strong corrosion of alloy valve, forging valve also widely used.
 
尽管铸造技术已经有了巨大的发展,并利用计算机技术辅助优化结构设计和浇铸过程的流体几何设计,但是要达到1类或2类接受标准的X射线/MT或PT质量要求仍然是极端困难的,而这些都是核电站、热电站或石化工业内的苛刻环境所要求的标准。因此就需要进行焊接改进。但是,在焊补后,铸件阀门的整体质量和可靠性就变得难于保证。有时所有这些问题都遗留在铸件焊接金属框架里。测试杆通常针对每个温度,但是它们的分析可能是不确定的。即使圆形测试杆表明化学特性和物理特性是可接受的,逐渐本身仍然可能存在难于察觉的有损强度或防腐能力的内部缺陷。
Although the casting technology has made tremendous development, and the use of computer aided geometric design of fluid structure optimization design and casting process, but to achieve the 1 class or 2 class X ray /MT or PT quality acceptance standard is still extremely difficult, which are nuclear power plants, thermal power stations or in petrochemical industries the harsh environment of the required standard. Therefore, it is necessary to improve the welding. However, after welding, the overall quality and reliability of the casting valve becomes difficult to guarantee. Sometimes all of these problems are left in the metal frame of the castings. The test rod is usually directed at each temperature, but their analysis may be uncertain. Even if the circular bar indicates that the chemical and physical properties are acceptable, it may still be difficult to detect internal defects that are detrimental to strength or corrosion resistance.
 
铸件阀门或法兰内部的其它一些缺点是,凝固过程中,在不均匀收缩造成的应力集中和接近熔点温度下金属的低强度的综合作用下,出现的清晰裂缝和热撕裂。较低的铸造温度会形成冷疤,熔化金属出现的沙粒或炉渣的累积会导致污点。低级的铸造作业也可能造成其它缺陷。
Some other defects in the valve or flange of castings are clear cracks and thermal tears during the solidification process under the combined action of the stress concentration caused by uneven shrinkage and the low strength of metals near melting point temperature. Low casting temperatures can cause cold scars, and the accumulation of sand grains or slag from molten metals will lead to stains. Low grade casting may also cause other defects.
 
铸件的改进要满足X射线质量的要求就要靠缺陷部位的磨削,焊补,热处理和重复测试和检验。即使在这种情况下,阀门的阀座和垫圈面或碰焊端可能会显示需要通过重焊和机加工的细线裂缝。
The improvement of castings to meet the requirements of X - ray quality depends on the grinding, repair, heat treatment and repeated testing and testing of the defective parts. Even in this case, the valve seat and washer face or bump welding end may display fine line cracks that require heavy welding and machining.
 
铸件过程建造了精致的颗粒结构,并改进了金属的物理属性。在零部件的现实使用中,一个正确的设计能使颗粒流在主压力的方向。
The casting process built a fine particle structure and improved the physical properties of the metal. In the practical use of parts, a correct design can make the particle flow in the direction of the main pressure.
 
锻件需要每片都是一致的,没有任何多孔性、多余空间、内含物或其他的瑕疵。这种方法生产的元件,强度与重量比有一个高的比率。这些元件通常被用在飞机结构中。
Forgings require that each piece is consistent, without any porosity, excess space, inclusions, or other defects. The component produced by this method has a higher ratio of strength to weight than that of weight. These elements are usually used in aircraft structure.
 
锻件的优点:锻件的优点有可伸展的长度、可收缩的横截面;可收缩的长度、可伸展的横截面;可改变的长度、可改变的横截面。锻件的种类有:自由锻造/手锻、热模锻/精密锻造、顶锻、滚锻和模锻。
The advantages of forging are: the advantages of forgings include stretchable length, shrinkable cross section, shrinkable length, extensible cross section, variable length and variable cross section. The types of forgings include free forging / hand forging, hot die forging / precision forging, top forging, roll forging, and die forging.
 
为什么选择锻件?与铸件比较,锻件阀门的阀体具有更加均匀结构,更好的密度,更好的强度完整性,更好的尺寸特性,和更小的尺寸误差。定向构造(管线)在整个强度和应力方面都比铸件具有更高的性能。
Why do you choose the forgings? Compared with castings, the valve body of forging valve has more uniform structure, better density, better strength integrity, better dimensional characteristics and smaller size error. The directional structure (pipeline) has a higher performance than the casting in the whole strength and stress.
 
(1) 高强度
(1) high strength
热锻造促进在结晶和晶粒细化,使得材料能够达到比较大可能的强度和一致性,并且件与件之间的变异比较小。颗粒流精密地沿着阀体轮廓流动,这些连续的流线有利于减少疲劳或常见故障的发生率。
Hot forging promotes crystallization and grain refinement, allowing the material to achieve maximum possible strength and consistency, and the minimum variation between parts and parts. The flow of the particle flow is precisely along the body profile, and these continuous streamlines help to reduce the incidence of fatigue or common failures.
 
(2) 可靠性
(2) reliability
能够满足设计结构要求的锻件性一直是锻件比较重要的优点之一,在某种程度上位于上述特性之首
Forgings, which meet the requirements of the design structure, have always been one of the most important advantages of the forgings, to some extent at the top of the above characteristics.
 
(3) 结构完整性
(3) structural integrity
锻造消除了内部缺陷,产生了连贯一致的金相组织,保证了优异的性能。在应力和晶体内腐蚀问题严重的地方,锻件都能够保证较长的使用寿命和无故障服务。
Forging eliminates internal defects and produces a coherent and consistent metallographic organization that ensures excellent performance. In places where stress and internal corrosion are serious, forgings can guarantee long service life and failure free service.
 
(4) 一致性
(4) consistency
闭模锻造的尺寸一致性造成关键壁厚的完全控制,避免了铸造工艺中铁心移位造成的缺陷,通过优质,无分离钢锭和1万至3万吨压力机的冲击力保证了没有内部缺陷的、一致的金相结构。
The dimensional consistency of closed die forging results in the complete control of the key wall thickness, avoiding the defects caused by the shifting of the core in the casting process. Through the impact of high quality, no separation steel ingot and 10 thousand to 30 thousand ton presses, it ensures the consistent metallographic structure without internal defects.
 
锻件的质量保证,通过锻件的使用,以及其一致性和高质量,对于1类铸造部件的X射线需求就消失了。美国海军在核潜艇和航空母舰上使用锻件作为部件时也持同样的态度。对于锻件成品,ASME法典的全部要求就是超声检验(U.T.),磁粉(M.T.)或液体渗透试验(P.T.)。通过U.T., M.T.,或P.T.方法发现的报废锻件,是非常罕见的。部件的采购,其交货期是可以控制的,因此阀门的交货也就更可靠。.铸件和锻件阀体的定向构造比较锻件在温度变化很大的环境下,其蠕变的抗疲劳强度比铸件高出3倍多。
The quality assurance of the forgings, through the use of forgings, as well as its consistency and high quality, disappears the X - ray demand for the 1 types of casting parts. The United States Navy also holds the same attitude when it uses forgings as parts on nuclear submarines and aircraft carriers. For the finished product, the full requirements of the ASME code are ultrasonic inspection (U.T.), magnetic powder (M.T.) or liquid penetration test (P.T.). Discarded forgings found by U.T., M.T., or P.T. methods are very rare.  The delivery of the components can be controlled, so the delivery of the valves is more reliable. The directional structure of the valve body of the castings and forgings compares the creep fatigue strength of the forgings more than 3 times higher than that of the casting under the condition that the forging has a very high temperature change.