Inconel 686, NS 3309

Inconel 686, NS 3309 (00Cr21Ni58Mol6W4) is a modified Ni-Cr-Mo corrosion-resistant alloy that increases the Cr content in the 00Crl6Ni60Mol6W4 alloy to 21% and the Fe content to less than 1.0%. This improvement makes the alloy have both the corrosion resistance of the 00CH6Ni60Mo16W4 alloy and the corrosion resistance of the 00Cr22Ni60Mol3W3 alloy. In addition, the low carbon, low silicon and low iron content make the alloy have extremely high heat of organization. The stability, which reduces or inhibits the precipitation of harmful phases, gives the Inconel 686, NS 3309 (00Cr21Ni58M016W4) alloy excellent sensitization resistance and greatly improves the intergranular corrosion resistance of the alloy.
8.3.5. 1 Chemical composition and organizational structure
The chemical composition of 00Cr21Ni58Mol6W4 alloy is shown in Table 8-7. The alloy is a 7-phase structure with a face-centered cubic structure in the solution treatment state, and a very small amount of precipitated phase precipitates in the sensitized state, and the properties of the alloy are exhibited.
Does not have a significant impact.
8. 3.5.2 Mechanical properties
The room temperature tensile properties of 00Cr21Ni58Mol6W4 alloy in solid solution state and the effect of cold working on mechanical properties at room temperature.

Table 8-5 Room Temperature Mechanical Properties of Inconel 686 Alloy in Solid Solution State

High-cycle fatigue of 00Cr21 Ni58Mol6W4 alloy rod (038. 1mm rod) with a yield strength of 789 MPa. Inconel 686, NS 3309 alloy fracture toughness data and aging effect on its impact properties are shown in Table 8-57 and Table 8-58. As can be seen from Table 8-58, 760 to 980 ° C is the precipitation sensitive temperature.

Table 8-57 Inconel 686, NS 3309, 00Cr21Ni58Mo16W4

Table 8-58 Aging 100h for Inconel 686, NS 3309, 00Cr21Ni58Mo16W4

The high temperature transient tensile properties of the alloy are summarized in Table 8-59.

Table 8-59 High-temperature transient tensile properties of Inconel 686, NS 3309 alloy

8.3.5.3 Corrosion resistance A general corrosion
The corrosion resistance of Inconel 686, NS 3309 alloy in various acidic media is shown in Table 8-60 and Table 8-61 .The alloy’s resistance to uniform corrosion is superior to all commercial Ni-Cr-Mo corrosion resistant alloys in the media tested.

Table 8-60 Inconel 686, NS 3309, Alloy Corrosion Resistance in Various Acids (168h Test)

Table 8-61 Corrosion of Inconel 686, NS 3309 Alloy in Hydrochloric Acid and Phosphoric Acid (192h Test)

B intergranular corrosion
The intergranular corrosion resistance of this alloy is better than that of Inconel 686 alloy but less than that of alloy 59. The sensitization test results of 871 °C are shown in Table 8-62.
C pitting and crevice corrosion
Inconel 686 alloy has good pitting and crevice corrosion resistance. The test data of pitting and crevice corrosion resistance in some media are shown in Table 8-63 and Figure 8-49. It is known from the data that the pitting and crevice corrosion resistance of this alloy is superior to other Ni-Cr-Mo corrosion resistant alloys.

Table 8-62 Intergranular Corrosion of Sensitized Inconel 686 Alloy (871 °C Sensitization)

Table 8-63 Pitting corrosion and crevice corrosion resistance ofInconel 686 Alloy

1 PRE = %Cr + 3.3%Mo.
2 The temperature was at 851 ° C and the chemical properties of the solution were destroyed.
3 The composition of the Green Death solution is 11. 5% H2S04 + 1.2% HC1 acid + 1% FeCl3 + 1% CuCl2, and the chemical properties of the solution at 120 °C are destroyed.

8.3.5.4 Thermal processing, cold working, heat treatment and welding performance
A hot processing
The alloy has high thermal deformation resistance, and its hot working heating temperature can be performed with reference to C-276 alloy. The most suitable hot working temperature is 1150 ~ 1200 °C.
B Cold working
686 alloy is easy to be cold-formed and cold-worked. Due to its high strength level and easy work hardening, it needs to apply a large deformation force. After cold working, the strength of the alloy increases and the plasticity decreases, but the cold deformation reaches 30. At room temperature, the elongation at room temperature of the alloy is still above 10%, as shown in Figure 8-50.

C heat treatment
A suitable solution treatment temperature is 1121 ° C heating and quenching.

D welding
Alloy 686 can be welded by conventional welding methods. The metal can be alloyed with the same composition. The surfacing metal has the best pitting resistance (Table 8-64).

8. 3.5.5 Physical properties
The elastic modulus and Poisson’s ratio of Inconel 686, NS 3309 alloy are shown in Table 8_65, and other physical properties are shown in Table 8-66. The density of the alloy was 8.73 g/cm3, the melting point ranged from 1338 to 1380 °C, and the relative magnetic permeability of the alloy was 1.0001 (15.9 kA/m).

Table 8-64 in a harsh oxidizing chloride solution (1.3% HCU1% CUC12 + 1% FeCl3)
Critical pitting point (CPT/mV) of 686 and other nickel-chromium-molybdenum (tungsten) alloy surfacing layer

Table 8-65 Inconel 686, NS 3309, modulus of elasticity and Poisson’s ratio of alloy

Table 8-66 Physical properties of Inconel 686, NS 3309, alloy

8.3.5.6 Application
This alloy is mainly used in chemical processing, pollution control, pulp production and paper industry, waste incineration equipment and marine environment. It is used for equipment and components that are not suitable for other materials. The use of seawater resistant fasteners in ships has been obtained. Satisfying result.