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Hastelloy C-2000 alloy is a new type of Ni-Cr-Mo corrosion-resistant alloy introduced at the end of the 20th century. The difference from 00Cr23Ni59Mol6 alloy is the addition of Cu. The addition of Cu improves the ability of the alloy to resist the reduction of acidic media, especially the ability to withstand sulfuric acid corrosion. Since Cu has a function of promoting the precipitation of the phase, the intergranular corrosion resistance of the alloy is not as good as that of the Hastelloy C-2000 alloy.

Chemical composition and organizational structure
The chemical composition of Hastelloy C-2000 alloy is shown in Table 8-7. In the solid solution state, the alloy is a face-centered cubic 7-phase structure. There is a precipitated phase under sensitization conditions, and the interphase phase P phase is slightly more than that of the Hastelloy C-2000 alloy.

Table 8-77 Mechanical properties at room temperature (solid solution state) of hastelloy C-2000 alloy

plate/ mm	Rp1.0/MPa	Rp0.2/MPa	Ductility (50mm)/%
1.6	752	358	64.0
3.2	765	393	63.0
6.4	779	379	62.0
13	758	345	68.0
25	752	372	63.0

Corrosion resistance

A general corrosion
In the reducing medium such as H2SO4, HCl acid and HF acid, the uniform corrosion resistance of this alloy is similar to that of other Ni-Cr-Mo alloys. The composite action of Mo and Cu makes it more resistant to corrosion by reducing medium (Fig. 8-55). The Cr content of this alloy w (Cr) = 23% ensures its corrosion resistance in oxidizing medium. It has a unique corrosion resistance in a reducing medium containing iron ions, copper ions or dissolved oxygen.

B intergranular corrosion
The intergranular corrosion resistance of this alloy is equivalent to Hastelloy C-276 alloy, but not to alloy59, see Table 8-71 and Table 8-72. The short-time sensitization data is shown in Figure 8-67. Under the sensitization conditions of more than lh, under the test conditions of ASTM G-28A, C-2000 has better intergranular corrosion resistance than C-276, C-22 and 686 alloys, and less than alloy 59. Under the ASTM G-28B test conditions, its resistance to intergranular corrosion is only equivalent to C-276 alloy, lower than C-22, 686 and Alloy 59.

Under short-time sensitization conditions, C-2000′s resistance to intergranular corrosion is significantly better than C-276, C-22 and 686 alloys, but not as good as Alloy 59.

C stress corrosion

Pitting corrosion and crevice corrosion stress corrosion test results in boiling 45% MgCl2 indicate that C-2000 and C-22, C-276 alloys have excellent stress corrosion resistance, and stress corrosion does not occur in 1000h test (Table 8-78). See pitting corrosion and crevice corrosion performance in Figure 8-68 and Figure 8-69 and Table 8-78. In Green Death solution, the critical pitting temperature of C-2000 alloy is slightly lower than C-22 alloy and slightly higher than C-276 and C-4 alloy. In 6% FeCl3 solution, C-2000 has the best resistance. Crevice corrosion performance. The 10% FeCl3+ (ASTM G48) C-2000 has the same CPT as C-22, C-276, 686 and Alloy 59. CCT is superior to C-22 alloy in the same way as C-276, 686 and Alloy 59.8. 3.7.4 Hot working, cold working, heat treatment and welding performanceSince the alloy contains Cu, thermal processing becomes difficult, but the hot working of the alloy can be carried out by the process of 00Cr23Ni59Mol6 alloy. The cold working and heat treatment characteristics are the same as those of the 59 alloy. This alloy is easy to weld, except for the filling metal containing Cu, the other welding processes and characteristics are the same as the 59 gold. It is recommended to use manual arc welding (SMAW), tungsten argon arc welding (CTAW) and gas protection f (GMAW). It is not advisable to use acetylene welding and submerged arc welding. When multi-layer welding, the temperature between the layers should be controlled by gas shielded welding. When the oxygen content of the protective gas exceeds 1%, the surface of the weld must be sanded after each pass.

Table 8-78 Stress corrosion resistance of hastelloy C-2000 alloy in boiling 45% MgCl2 solution (U-shaped specimen)

TEST Material	Stress corrosion time/h	test material	Outside of the time when stress corrosion occurs
316L stainless steel	2	Hastelloy C-22	1000HStress free corrosion
254SMo super stainless	24	Haslelloy C-276	1000hStress free corrosion
20Cb-3 alloy	24	Hastelloy C-2000	1000hStress free corrosion

Physical properties
Density: 8.50 g/cm3; linear expansion coefficient thermal conductivity (room temperature): 9.1 W/(m • K); resistivity (room temperature): 1.28 uΩ• m.

Application
Primarily used in chemical processing equipment and components where both oxidized and reductive corrosive media exist, such as reactors, heat exchangers, valves, pumps, and fasteners. It has excellent corrosion resistance in HF acid, so it is more suitable for the environment of HF acid production and use of fluoride-containing catalysts.

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Post time: Jun-24-2019