Hastelloy C-276 alloy belongs to nickel - mo - Cr - iron - tungsten nickel-based alloy. It is one of the most corrosion-resistant modern metal materials. Mainly resistant to wet chlorine, all kinds of oxidizing chloride, chloride salt solution, sulfuric acid and oxidizing salt, in low temperature and medium temperature 1 have good corrosion resistance. Therefore, in the past 30 years, in harsh corrosive environment, such as chemical, petrochemical, flue gas desulfurization, pulp and paper, environmental protection and other industrial fields have a quite wide range of applications. The corrosion data of Hastelloy C-276 alloy are typical, but cannot be used as a standard, especially in unknown environment, the selection of materials must be tested. There is not enough Cr in Hastelloy C-276 alloy to resist corrosion in strong oxidizing environments such as hot 1. The alloy is mainly produced for chemical process environment, especially in the presence of mixed acid, such as flue gas desulfurization system discharge pipe.

Hastelloy C-22 alloy has excellent resistance to pitting, crevice corrosion and stress corrosion cracking. It has excellent resistance to oxidizing water media, including wet chlorine, nitric acid or a mixture of oxidizing acids containing chloride ions. Hastelloy C-22 alloy also has the ideal resistance to the reducing and oxidizing environments encountered during the process. Depending on the performance of this WAN energy, it can be used in some troublesome environments, or in a variety of production purpose plant applications. Hastelloy C-22 alloy has exceptional resistance to a variety of chemical environments, including strong oxidizing substances such as ferric chloride, copper chloride, chlorine, thermal contaminated solutions (organic and inorganic), formic acid, acetic acid, acetic anhydride, sea water and salt solutions. Hastelloy C-22 alloy has the ability to resist grain boundary precipitation formation in the weld heat affected zone, which makes it suitable for a variety of chemical process applications in the welding state.

Hastelloy B-2 alloy is a ni-MO138-2118-5638 cycle alloy with very low carbon and silicon content. It reduces the precipitation of carbides and other phases in the weld and heat affected zone, thus ensuring good corrosion resistance even in the welded state. As is known to all, Hastelloy B-2 alloy has excellent corrosion resistance in various reducing media, and can withstand the corrosion of hydrochloric acid at any temperature and concentration under atmospheric pressure. It has excellent corrosion resistance in non-aerated medium concentration of non-oxidizing sulfuric acid, various concentrations of phosphoric acid, high temperature acetic acid, formic acid and other organic acids, bromic acid and hydrogen chloride gas. At the same time, it is also resistant to halogen catalyst corrosion. Therefore, Hastelloy B-2 alloy is usually used in a variety of harsh petroleum and chemical processes, such as the distillation of hydrochloric acid, concentration, alkylation of ethylbenzene and low pressure carbonyl synthesis of acetic acid.
The medium temperature thermal stability of Hastelloy B-2 alloy is poor. When the iron content in Hastelloy B-2 alloy drops below 2%, the alloy is sensitive to the transformation of phase 3 (i.e. Ni4Mo phase, an ordered intermetallic compound). When the alloy stays in the temperature range of 650~750℃ for a long time, the phase 3 is generated instantly. The presence of phase 3 reduces the toughness of Hastelloy B-2 alloy, makes it sensitive to stress corrosion, and even causes the cracking of Hastelloy B-2 alloy in raw material production (such as hot rolling process), equipment manufacturing process (such as integral heat treatment after welding of Hastelloy B-2 alloy equipment) and service environment. At present, the standard test method for intergranular corrosion resistance of Hastelloy B-2 alloy is normal pressure boiling hydrochloric acid method and weight loss method. As hastelloy B-2 alloy is resistant to hydrochloric acid corrosion, it is not sensitive to test the intergranular corrosion tendency of hastelloy B-2 alloy by boiling hydrochloric acid at atmospheric pressure. It is found that the corrosion resistance of Hastelloy B-2 alloy depends not only on its chemical composition, but also on the control process of hot working. When the hot working process is not controlled properly, not only the grains of Hastelloy B-2 alloy grow up, but also the high Mo σ phase appears in the intergranular phase. Under this condition, the intergranular corrosion resistance of Hastelloy B-2 alloy decreases obviously. In the HCL test, the grain boundary erosion depth of coarse-grained plate and normal plate differs about twice.

Hastelloy B3 (N10675) is a nickel-based superalloy composed of nickel, molybdenum, cobalt and other elements, with a nickel content of about 65%. Hastelloy B3 (N10675) nickel-based alloy is a new material improved on the basis of Hastelloy B2, which improves the thermal stability of the material, thus improving the corrosion resistance, and at the same time, improves the hot forming and cold forming properties. In recent years, it has been more and more used in the production and manufacture of chemical equipment.
B-3 alloy is a new member of the nickel-molybdenum alloy family and has excellent corrosion resistance to hydrochloric acid at all temperatures and concentrations. It also has good corrosion resistance to sulfuric acid, acetic acid, formic acid, phosphoric acid and other non-oxidizing media.
Due to the adjustment of its chemical composition, its thermal stability is greatly improved compared with the original B-2 alloy. B-3 alloy has high resistance to pitting corrosion, stress corrosion, knife-edge corrosion and corrosion in the heat affected zone of welding. Excellent plastic properties can be maintained when exposed to medium temperature. Excellent pitting and stress corrosion cracking resistance; Excellent resistance to knife-edge corrosion and heat-affected zone corrosion; Excellent resistance to acetic acid, acetic acid, phosphoric acid and other non-oxidizing acids; Excellent resistance to hydrochloric acid corrosion at various concentrations and temperatures

Hastelloy C2000 The alloy is designed to resist a wide range of corrosive chemicals, including sulfuric, hydrochloric and hydrofluoric acids. Unlike the previously optimized Ni-Cr-Mo alloy, which can resist only oxidizing or reducing acids, C-2000 alloy has corrosion resistance in both environments. The combined action of molybdenum and copper (at 16% and 1.6% levels, respectively) gives the alloy excellent resistance to the corrosion of reducing media, while the high chromium content (23%wt) guarantees resistance to the corrosion of oxidizing media.