Harmful impurity elements have a negative impact on the mechanical properties and structure of high-temperature alloys, so their content must be strictly controlled. At the same time, the lower the content, the more beneficial it is to the mechanical properties and structure of high-temperature alloys, which also reflects the higher quality level of high-temperature alloys. So, how to control the content of harmful impurity elements?
According to the American aerospace material standard ASM 2280, the content of trace impurities bismuth (Bi), thallium (Tl), tellurium (Te), lead (Pb) and selenium (Se) in the production of nickel-based high-temperature alloys must be controlled below 0.5~5ppm. At the same time, antimony (Sb), arsenic (As), cadmium (Cd), gallium (Ga), germanium (Ge), gold (Au), indium (In), mercury (Hg), potassium (K), silver (Ag) ), sodium (Na), thorium (Th), tin (Sn), uranium (U) and zinc (Zn) are controlled. The content of each element must be controlled below 50 ppm, and the total of the 15 elements The content cannot exceed 400ppm. Some foreign factories have stricter control requirements for these elements. For example, GE Company not only controls the five elements Bi, Te, Se, Pb, and Tl according to ASM2280, but also controls 29 other trace elements. In this way, in addition to the five elements, 39 Each element is required to be controlled below 25ppm, and the total content of 39 elements must not exceed 400ppm. At present, the sum of the above 45 elements in high-quality high-temperature alloys produced by advanced foreign manufacturers is usually less than 100 ppm.
In contrast, the control of impurity elements in high-temperature alloys in my country is quite different from that in foreign countries. Generally, only five harmful elements are controlled, and some alloys also control the silver content. Therefore, in my country, the minimum controlled content of these six elements in high-quality high-temperature alloys has reached the ASM2280 standard, but the types of controlled impurity elements are still far behind. In order to produce high-temperature alloys at the internationally advanced level, we must strengthen the control of harmful impurity elements, control more trace elements in accordance with international standards, and at the same time gradually reduce the content of these elements.
In addition to harmful impurity elements, the content of trace impurity elements such as sulfur, phosphorus, silicon and manganese is also gradually reduced. According to the requirements of GE, the Si content should be controlled below 400ppm, and the sulfur, phosphorus and manganese contents should be below 20ppm. However, for some deformed alloys or individual casting alloys, phosphorus can be as high as 200ppm, which is beneficial to performance. The oxygen and nitrogen content should be controlled below 10ppm. The high-temperature alloys actually produced by foreign factories have lower controlled contents of these elements. For example, the IN-713C master alloy smelted in a vacuum induction furnace by the American company Canon Muskegen has a nitrogen content of 5 to 6 ppm, an oxygen content of 1 to 2 ppm, and a sulfur content of 7 to 13 ppm. The oxygen content in IN-718 alloy is below 5ppm, the sulfur content is below 20ppm, and the nitrogen content is below 20ppm. The second-generation single-crystal superalloy produced by the company has the content of O, N and S controlled at 1ppm when it is smelted with new charge. In the alloy smelted with 50% new charge, the content of these elements is also controlled below 5ppm.
Therefore, controlling the content of harmful impurity elements and other trace impurity elements, as well as reducing the content of elements such as sulfur, phosphorus, manganese, oxygen and nitrogen, is the key to producing high-quality high-temperature alloys. This requires starting from the selection of raw materials, optimization of production processes, and updating of equipment to gradually improve the production level of high-temperature alloys in my country to meet the needs of domestic and foreign markets.
Tianjin Anton Metal Manufacture Co., Ltd. is a company specializing in the production of various nickel-based alloys, Hastelloy alloys and high-temperature alloy materials. The company was established in 1989 with a registered capital of 10.0 million, specializing in the production and sales of alloy materials. Anton Metal’s products are widely used in aerospace, chemical industry, electric power, automobile, nuclear energy and other fields, and can also provide customized alloy material solutions according to customer needs. If you need to know the price consultation of alloy materials or provide customized alloy material solutions, please feel free to contact the sales staff.
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Post time: Nov-18-2023
