论文部分内容阅读
在大量测温及对螺旋桨铸件本体解剖的基础上，发现黄铜大型螺旋桨铸件的内 部，常有铁元素偏析、桨叶晶粒组织不良以及缩松等缺陷。为了提高大桨铸造质量， 建议使用冷铁或激冷材料，控制铸件的凝固过程。为此，专门浇注了一个试验桨，在 桨叶上不加冷铁、单面加冷铁和两面加冷铁。对桨叶断面上成分偏析和晶粒组织的各 种情况进行了研究。并且，通过数字模拟铸件凝固过程的电子计算机方法、合理的配 置冷铁，控制螺旋桨的凝固方向。 研究表明： １．采用冷铁可以有效的控制黄铜大型螺旋桨的晶粒组织及部分铁元素形成的宏 观偏析。 ２．现行大桨的铸造工艺常常难以消除热节处的缩松、缩孔，因而，应当采取措 施如使用冷铁或其他激冷材料，控制大型螺旋桨铸件的凝固顺序。 ３．大型螺旋桨可通过数字模拟铸件凝固过程的电子计算机方法，合理地设计冷 铁的数量和位置，以控制其凝固过程．
Based on a large number of temperature measurements and the anatomy of propeller castings, it has been found that there are often defects such as segregation of iron elements, poor grain structure of the blades and shrinkage in the interior of the brass large propeller castings. In order to improve the quality of the large paddle casting, it is recommended to use chilled iron or chilled materials to control the solidification process of the castings. To that end, a test paddle was specially cast with no chilled iron on the paddles, plus chilled iron on one side and chilled iron on both sides. Various conditions of segregation and grain structure on the blade section were studied. And, by numerical simulation of the solidification process of castings computer method, a reasonable allocation of chill iron, control the direction of the solidification of the propeller. Research shows that: 1. The use of chill iron can effectively control the macro-segregation of the grain structure of the large brass propeller and the formation of some iron elements. 2. The current large paddle casting process is often difficult to eliminate shrinkage, shrinkage at the hot section, therefore, measures should be taken such as the use of chilled iron or other chilled materials, control of large propeller casting solidification sequence. 3. Large propellers can be controlled by the computerized method of digitally simulating the solidification of castings by properly designing the number and location of chilled iron.