Chinese name: nickel-based corrosion resistant alloy mbth: corrosion resistant nickel-based alloy matrix: nickel content: more than 50% is called: introduction, development process, category, production technology and heat treatment technology of nickel-based corrosion resistant alloy. Corrosion-resistant Nickel-based alloy is based on nickel and can resist corrosion in some media, which is called nickel-based corrosion-resistant alloy. In addition, corrosion-resistant alloys containing more than 30% nickel and more than 50% nickel plus iron are usually called iron-nickel-based corrosion-resistant alloys (see stainless acid-resistant steel). 1905 nickel-copper alloy (monel alloy Ni 70 Cu30) produced in America is the earliest nickel-based corrosion-resistant alloy. 19 14 years, the United States began to produce illium R. 1920 years, Germany began to produce illium R.. In 1970s, nearly 50 kinds of corrosion-resistant alloys were produced in various countries. Among them, Ni-Cu, Ni-Cr, Ni-Mo, Ni-Cr-Mo(W), Ni-Cr-Mo-Cu, Ni-Fe-Cr and Ni-Fe-Cr-Mo are widely used, with more than ten brands. China began to develop nickel-based and iron-nickel-based corrosion-resistant alloys in the 1950s, and by the end of 1970s, there were more than ten brands. Nickel-based corrosion resistant alloys Most nickel-based corrosion resistant alloys have austenite structure. In the state of solution and aging treatment, there are intermetallic phases and metal carbonitrides on the austenite matrix and grain boundary of the alloy. Various corrosion-resistant alloys are classified according to their compositions, and their characteristics are as follows: the corrosion resistance of cast nickel-copper alloy is better than that of nickel in reducing medium and better than that of copper in oxidizing medium, and it is the best material for resisting high-temperature fluorine gas, hydrogen fluoride and hydrofluoric acid without oxygen and oxidant (see metal corrosion). Nickel-chromium alloy is mainly used for oxidizing medium. It is resistant to high temperature oxidation and corrosion of sulfur and vanadium gases, and its corrosion resistance increases with the increase of chromium content. This alloy also has good resistance to hydroxide (such as NaOH and KOH) corrosion and stress corrosion. Nickel-molybdenum alloy is mainly used under the condition of reducing medium corrosion. It is the alloy with the best corrosion resistance to hydrochloric acid, but in the presence of oxygen and oxidant, the corrosion resistance will obviously decrease. Nickel-chromium-molybdenum (tungsten) alloy has the properties of the above nickel-chromium alloy and nickel-molybdenum alloy. It is mainly used under the condition of redox mixed medium. This alloy has good corrosion resistance in high temperature hydrogen fluoride gas, hydrochloric acid and hydrofluoric acid solution containing oxygen and oxidant and wet chlorine at room temperature. Nickel-chromium-molybdenum-copper alloy has both nitric acid corrosion resistance and sulfuric acid corrosion resistance, and also has good corrosion resistance in some redox mixed acids. According to the chemical composition of the alloy, especially the contents of C, S, P and Si, and the requirements for purity, the production process can adopt electric arc furnace, vacuum induction furnace melting or secondary refining process. In order to make the corrosion-resistant alloy have good thermoplasticity, the deoxidation process should be strictly controlled during smelting. Some alloys need to add proper amount of Al or Ca, Mg and rare earth as the final deoxidizer. Electroslag remelting process can significantly improve the thermoplasticity of some alloys. The deformed nickel-based corrosion-resistant alloy is easy to combine with sulfur in furnace gas during heating to form nickel sulfide with low melting point, and cracks occur during processing. Therefore, electric furnace, shielding gas heating furnace or low sulfur fuel heating furnace should be used for heating. See table 1 for the hot working temperature range. These alloys usually have good cold working properties. After each solution or annealing treatment, the allowable cold working deformation is generally between 20-80%. Heat treatment process The heat treatment process of corrosion-resistant alloys (Table 2) adopts solid solution heat treatment, so as to maximize the solid solution of various precipitated phases in the alloy, thus obtaining good corrosion resistance and mechanical properties. However, because the grain size has a great influence on the intergranular corrosion resistance and stress corrosion resistance of alloys, some alloys often adopt relatively low solution treatment temperature in order to refine the grains. In addition, precipitation hardening corrosion-resistant alloys require both corrosion resistance and high hardness, so the process of one or two aging treatments after solid solution is often adopted. A typical nickel-based corrosion-resistant alloy