german car stainless steel manifold bmw,german car stainless steel manifold blocks,german car stainless steel manifold adapter kit Ningbo Lingmai Machinery Manufacturing Co., Ltd. , https://www.lingmaimfg.com
ç²— casting a large anisotropic structure of titanium-aluminum-based alloy;
ä¸¥æ ¼ Strict control of the adverse effects of interstitial elemental nitrogen and its compounds on material properties;
 Under vacuum smelting conditions, fluctuations in alloy composition due to volatilization of alloying elements (especially aluminum, chromium ) have an adverse effect on performance.
The investment casting technology of titanium and its alloys has been developed along with the development of the aerospace industry. And it has been widely used in the manufacture of various types of titanium alloy structural parts. From the current domestic and international development trends, titanium and its alloy investment casting technology has become the fastest growing and most applicable one of several near-net forming processes. However, with the continuous expansion of the application range of titanium and its alloy castings, cost control is also an important indicator to limit its wide application under the premise of ensuring quality.
Although the graphite type has low cost, the surface quality of the parts is poor, and it is easy to form carburizing pollution on the surface of the net shape and the near net shape casting, and it is also difficult to manufacture thin-walled and complicated-shaped parts. The refractory metal surface ceramic shell has high strength and high chemical stability to titanium liquid, and can manufacture high quality and large complex castings. However, due to its high thermal conductivity and heat capacity, it is difficult to manufacture ultra-thin wall castings (δ ≤ 1.5 mm), and its product competitiveness is degraded due to its complicated process and high raw material cost. PCC U.S. company with the highest chemical stability of thorium oxide (ThO 2) facing shell technology, has produced a variety of large, complex castings, but can not solve the problem of radioactive shell. Germany's HITAL Company uses fused yttrium oxide yttria (Y 2 O 3 ) to produce titanium precision castings, which have been cast thin-walled titanium-aluminum castings, but it is difficult to promote due to the high cost of yttrium oxide. Japan's three construction vessels (Co., Ltd.) developed a calcium oxide (CaO) shell process to produce small titanium castings, but the shell manufacturing and storage process is quite complicated.
Using the new precision casting mold shell, ISM melting and centrifugal casting process, the research group completed the blank manufacturing of the main swirler parts. The composition meets the design requirements, the nitrogen content is ≤0.5×10 -5 , and the oxygen content is ≤0.35×10 -3 . The surface of the casting is silvery white with a clear outline, traces of the flow and cold separation. The castings were observed by metallography and found to have casting cracks between the dendrites. After 12800C, 3 hours, 200MP hot isostatic pressing, most of the micropores and crack defects can be eliminated.
Titanium aluminum intermetallic compound investment shell casting process
Titanium-aluminum-based alloy is an ideal high temperature lightweight structural materials, expected to be widely applied to the hot end member aerospace and automotive. However, due to the complicated structure of the parts themselves, the strength and hardness of the titanium-aluminum-based alloy are high at room temperature, so the use of traditional machining technology is bound to increase the cost. In recent years, the vacuum low pressure suction casting (CLV) method and permanent die casting method have been used abroad to solve the problem of filling and feeding of titanium-aluminum alloy castings . The high-temperature structural parts such as the impeller and the compressor valve are cast, and the test shows that the casting has good performance and the cost is much lower than that of the deformed alloy. After solving the following key process technologies, it is possible to manufacture high-performance, low-cost titanium-aluminum-based high-temperature structural parts using investment casting precision casting technology: