NS 3301 alloy

NS 3301 alloy is the lowest content of molybdenum in nickel-chromium-molybdenum corrosion-resistant alloy. It is mainly used for the above-mentioned simple nickel-chromium corrosion-resistant alloy 0Crl5Ni75Fe under the condition of low corrosion resistance and high temperature strength. 00Crl6Ni76Mo2Ti alloy is characterized by high temperature resistant HF gas, easy to process, easy to form and weld, and high cost. The molybdenum alloy is inexpensive.

Chemical composition and organizational structure
The chemical composition of NS 3301 alloy is shown in Table 8-7. The alloy is a pure austenite structure in a solid solution state, and a small amount of carbide precipitates in an aged or sensitized state.

The transient mechanical properties of NS 3301 alloy at room temperature and high temperature are shown in Table 8-91. High temperature fatigue and permanent strength are shown in Figure 8-78 and Figure 8-79.

Table 8-91 Mechanical properties of 00Crl6Ni76Mo2Ti (NS 3100) alloy

Corrosion resistance
The corrosion resistance of NS 3301 alloy in oxidizing medium is slightly lower than that of 0Cr15Ni75Fe alloy, and the corrosion resistance in acid, alkali, salt and high temperature HF gas is better than 0Crl5Ni75Fe alloy.
The corrosion resistance of NS 3301 alloy in high temperature gases of fluorine gas, hydrogen fluoride and hydrogen chloride is summarized in Table 8-92. The alloy exhibits good corrosion resistance, especially in high temperature gases. The presence of oxygen (air) in the medium is not as sensitive as high molybdenum alloys. In air containing gases, the alloy is not The corrosion rate is significantly increased. Figure 8-80 shows the corrosion resistance of NS 3301 alloy in hydrogen fluoride gas. Since the 55th generation, the I® temperature has increased and the corrosion of the alloy has accelerated significantly. In the booked gas = the corrosion resistance of this alloy is acidified with temperature as shown in Figure 8_81. For comparison, the data of 0Cr15Ni75Fe is introduced. Obviously, the corrosion resistance of NS 3301 alloy in the same temperature and concentration of HF gas. Better than 0Crl5Ni75Fe alloy.

Table 8-92 Corrosion resistance of NS 3301 alloy in several local temperature gases

Corrosion tests in 5% HF acid show that the corrosion resistance of this alloy is better than Ni68Cu28 (Monel 400) alloy and 0Crl5Ni75Fe (Inconel 600) allo

Thermal processing, cold working, heat treatment and welding performance
A hot processing
NS 3301 alloy is the best Ni-Cr-Mo corrosion resistant alloy with hot workability. Some thermoplastic evaluation results are shown in Figure 8-83 to Figure 8-85. According to the plastic evaluation test results and practice, the hot working temperature range of this alloy is 950 – 1200^, and the most ideal hot working temperature is 1160 -1180deg.
B Cold working
The cold workability of this alloy is the same as that of the general Cr-Ni austenitic stainless steel, and no difficulty is encountered. Cold work can harden the alloy, and the hardened or semi-hardened alloy is suitable for the manufacture of elastic parts. The cold work hardening characteristics are shown in Figure 8-86.
C heat treatment _ _
In order to obtain the best performance of corrosion resistance, mechanical properties, etc., the alloy should be treated with t solution. The recommended solution temperature is 1100~1150 °C, which can improve the anti-sensitization performance by using titanium as a fixed carbon. Stabilization treatment can also be carried out, and the stabilization temperature is the same as that of the titanium-stabilized Cr-Ni austenitic stainless steel.

D welding
This alloy has good weldability and can be used with TIG, MIG and manual arc welding. The welding electrode is a No. 1 electrode of Dongjian, and the filling wire is a nickel-based No. 1 welding wire. The mechanical properties and corrosion resistance of welded joints are comparable to those of the parent metal.

application
This alloy is a corrosion-resistant alloy developed in China to solve the corrosion problems caused by F-, Cl-wet medium corrosion and high-temperature HF gas encountered in nuclear fuel production, and can also be used in similar service environments in the chemical industry. . Practice has shown that equipment and components made with this alloy have achieved satisfactory results in a high temperature HF environment of 550 °C.

Table 8-93 Physical properties of 00Crl6Ni76Mo2Ti alloy