The 00Cr33Ni55Mo8 (G-35) alloy was developed on the basis of Hastelloy G-30. Since the alloy increases the chromium to 33% and increases the molybdenum in the alloy to 8%, in order to make the alloy a single austenite structure, It is bound to increase the nickel content of the alloy, so the nickel content of the alloy exceeds 50% and enters the category of nickel-based corrosion-resistant alloys, leaving the ranks of iron-nickel-based corrosion-resistant alloys. G-35 alloy is the alloy with the highest chromium content of Ni-Cr-Mo corrosion-resistant alloy. The main purpose of this alloy is to provide more satisfactory corrosion-resistant structural materials for concentrated evaporator in wet-process phosphoric acid production. The alloy is the best corrosion resistance material under the condition of concentrated evaporation of wet phosphoric acid. In addition, its resistance to stress corrosion and pitting corrosion and crevice corrosion is much better than that of super austenitic stainless steel and iron nickel applied under this condition. Base corrosion resistant alloys Sanicro-28, G-30 and Alloy 31.Chemical composition and organizational structure
The chemical composition of G-35 alloy is shown in Table 8-7. Since this alloy is a U.S. Patent No. 6,740.29 grade, the upper and lower limits are not given for its main alloy composition. According to the given alloy composition, the alloy should be austenitic. The high temperature and low temperature should be composed of austenite structure, no phase change, so it can not be strengthened by heat treatment, and can only be strengthened by cold deformation.Mechanical properties
The room temperature transient mechanical properties of G-35 alloy are shown in Table 8-94, and the high temperature transient mechanical properties are shown in Table 8-95. The relationship between impact toughness and aging time of this alloy is shown in Table 8-96. These data show that the alloy not only has high room temperature and high temperature mechanical properties, but also has high impact properties at medium temperature and long time aging, indicating that the alloy has good moderate temperature microstructure thermal stability.
The chemical composition of G-35 alloy is shown in Table 8-7. Since this alloy is a U.S. Patent No. 6,740.29 grade, the upper and lower limits are not given for its main alloy composition. According to the given alloy composition, the alloy should be austenitic. The high temperature and low temperature should be composed of austenite structure, no phase change, so it can not be strengthened by heat treatment, and can only be strengthened by cold deformation.Mechanical properties
The room temperature transient mechanical properties of G-35 alloy are shown in Table 8-94, and the high temperature transient mechanical properties are shown in Table 8-95. The relationship between impact toughness and aging time of this alloy is shown in Table 8-96. These data show that the alloy not only has high room temperature and high temperature mechanical properties, but also has high impact properties at medium temperature and long time aging, indicating that the alloy has good moderate temperature microstructure thermal stability.
Table 8-94 Mechanical properties at room temperature of 00Cr33Ni55Mo8(G-35) alloy
| Solution treatment temperature/T |
test size |
Rm/MPa
|
Rp0.2/MPa
|
A/% |
|
1135 |
3. 2mm |
745 |
348 |
59 |
|
1121 |
6. 4mm |
703 |
344 |
66 |
|
1121 |
12. 7 mm |
689 |
318 |
72 |
|
1121 |
>1.0mm |
710 |
319 |
66 |
|
1121 |
<2. 5 mm |
689 |
338 |
68 |
Table 8-95 High-temperature transient mechanical properties of 00Cr33Ni55Mo8(G-35) alloy (average of plate and bar)
|
test temperature/t |
Rm/MPa
|
Rp0.2/MPa |
A/% |
|
93 |
692 |
313 |
69.3 |
|
149 |
656 |
278 |
68.2 |
|
204 |
623 |
248 |
69.5 |
|
260 |
600 |
232 |
67.9 |
|
316 |
583 |
219 |
68.8 |
|
371 |
570 |
217 |
72.3 |
|
427 |
561 |
215 |
72.8 |
|
482 |
543 |
204 |
71.0 |
|
538 |
521 |
194 |
72.7 |
|
593 |
501 |
185 |
72.0 |
|
649 |
483 |
184 |
70.0 |
Table 8-96 Impact properties of 00Cr33Ni55Mo8(G-35) alloy
|
Heat treatment state |
Impact absorption work/J |
Heat treatment state |
Impact absorption work/J |
|
Solid solution state |
>358 |
Solid solution +538 ° C x 2000 h aging |
>358 |
| Solid solution X2000H aging |
>358 |
Solid solution +593°C x2000h aging |
>358 |
| Solid solution +4821 x2000h aging |
>358 |
Solid solution + 649 ° C x 2000 h aging |
104 |
Corrosion resistance
A general corrosion
The corrosion resistance in various acids is summarized in Table 8-97. The G-35 alloy has better uniform corrosion resistance than the In¬conel 625 alloy. It has good resistance to uniform corrosion in both oxidizing and reducing acids. Figure 8-87 to Figure 8-91 show the isocorrosion of G-35 alloy in various acids. From these data, it can be seen that the corrosion rate of 0. lmm/a is used as a criterion. The boiling temperature can be used in the mass fraction <65% nitric acid; the boiling temperature can be used in the mass fraction less than 6% phosphoric acid, in the high quality fraction. 110 ° C can be used in phosphoric acid; in reducing acids, it is safe to use at room temperature under severe corrosion mass fraction. The test results of the evaporation conditions of wet-process phosphoric acid show that (Fig. 2-13), the corrosion resistance of G-35 alloy is much better than Sanicro-28, alloy 31, G-30 and Hastelloy C- which have been widely used in this condition 2000.
The corrosion resistance in various acids is summarized in Table 8-97. The G-35 alloy has better uniform corrosion resistance than the In¬conel 625 alloy. It has good resistance to uniform corrosion in both oxidizing and reducing acids. Figure 8-87 to Figure 8-91 show the isocorrosion of G-35 alloy in various acids. From these data, it can be seen that the corrosion rate of 0. lmm/a is used as a criterion. The boiling temperature can be used in the mass fraction <65% nitric acid; the boiling temperature can be used in the mass fraction less than 6% phosphoric acid, in the high quality fraction. 110 ° C can be used in phosphoric acid; in reducing acids, it is safe to use at room temperature under severe corrosion mass fraction. The test results of the evaporation conditions of wet-process phosphoric acid show that (Fig. 2-13), the corrosion resistance of G-35 alloy is much better than Sanicro-28, alloy 31, G-30 and Hastelloy C- which have been widely used in this condition 2000.
Table 8-97 General Corrosion Resistance of 00Cr33Ni55Mo8 (G-35)
|
test medium |
Quality score/% |
temperature/℃ |
corrosion rate/ mm • a-1
|
|
|
G-35合金 |
625合金 |
|||
|
hydrochloric acid HCl |
1 |
boiling |
0. 05 |
0.23 |
|
5 |
79 |
1.23 |
4.65 |
|
|
10 |
38 |
0. 17 |
0.30 |
|
|
20 |
38 |
0.42 |
0. 36 |
|
|
Hydrobromic acid HBr |
2.5 |
boiling |
<0.01 |
<0.01 |
|
5 |
93 |
<0.01 |
0. 60 |
|
|
7.5 |
93 |
<0.01 |
0.93 |
|
|
10 |
79 |
<0.01 |
0. 82 |
|
|
20 |
66 |
0.44 |
0.65 |
|
|
Hydrofluoric acid HF |
1 |
79 |
0. 15 |
0.31 |
|
5 |
52 |
0. 1 |
0. 70 |
|
|
10 |
52 |
0. 24 |
2.23 |
|
|
20 |
52 |
3.49 |
4.33 |
|
|
sulfuric acidh2so4 |
10 |
93 |
<0.01 |
0.24 |
|
20 |
93 |
0.01 |
0.58 |
|
|
30 |
93 |
2. 62 |
0.68 |
|
|
40 |
79 |
<0.01 |
0. 58 |
|
|
50 |
79 |
2. 30 |
0. 89 |
|
|
Nitric acidhno3 |
20 |
boiling |
<0.01 |
0.01 |
|
40 |
boiling |
0.01 |
0. 14 |
|
|
60 |
boiling |
0. 06 |
0.46 |
|
|
70 |
boiling |
0. 10 |
0.58 |
|
B pitting and crevice corrosion
00Cr33Ni55Mo8 (G-35) alloy, due to high Cr and Mo content, its pitting resistance equivalent value (PRE value) is above 59, thus giving the alloy good pitting and crevice corrosion resistance, using ASTM G- The results of CPT and CCT measurement of C method and D method of 48 are shown in Table 8-98. The pitting resistance of this alloy is close to that of Inconel 625 alloy, which is significantly better than G-30, alloys 31, 28 and 254SMO. Its crevice corrosion resistance is better than G-30, alloys 31 and 28 are better than Inconel 625 alloy.
00Cr33Ni55Mo8 (G-35) alloy, due to high Cr and Mo content, its pitting resistance equivalent value (PRE value) is above 59, thus giving the alloy good pitting and crevice corrosion resistance, using ASTM G- The results of CPT and CCT measurement of C method and D method of 48 are shown in Table 8-98. The pitting resistance of this alloy is close to that of Inconel 625 alloy, which is significantly better than G-30, alloys 31, 28 and 254SMO. Its crevice corrosion resistance is better than G-30, alloys 31 and 28 are better than Inconel 625 alloy.
Table 8-98 Pitting corrosion and crevice corrosion resistance of 00Cr33Ni55Mo8 (G-35) alloy
| alloy name |
CFT/°C (ASTM G-48C ） |
CCT/°C (ASTM G-48D） |
alloy name |
CPT/t (ASTM G-48C ） |
CCT/°C (ASTM G-48D） |
|
316L |
15 |
0 |
G-30 |
67.5 |
37.5 |
| 254SM0 |
60 |
30 |
G-35 |
90 |
45 |
|
28 |
45 |
17.5 |
625 |
100 |
40 |
|
31 |
72.5 |
42.5 |
C-2000 |
>120 |
80 |
C stress corrosion
OOCr33Ni55Mo8 (G-35) alloy, due to its high nickel content, has high stress resistance (boiling 45% MgCl2) stress corrosion resistance comparable to Inconel 625 and C-2_ alloy, significantly better than iron-nickel Etched alloy and super austenitic stainless steel (Table 8-99).
OOCr33Ni55Mo8 (G-35) alloy, due to its high nickel content, has high stress resistance (boiling 45% MgCl2) stress corrosion resistance comparable to Inconel 625 and C-2_ alloy, significantly better than iron-nickel Etched alloy and super austenitic stainless steel (Table 8-99).
Table 8-99 SCC resistance of 00Cr33Ni55Mo8 alloy (boiling 45% MgCl2 ASTM G-36)
|
alloy name |
SCC crack time/h |
alloy name |
SCC crack time/h |
|
3I6L |
2 |
G-30 |
168 |
|
254SMO |
24 |
G-35 |
1008h no SCC |
|
28 |
36 |
625 |
1008h no SCC |
|
31 |
36 |
C-2000 |
1008 h no SCC |
Thermal processing, cold working, heat treatment and welding performance
A hot processing and cold forming
G-35 is superior to G-3 and G-30 due to its copper-free and high nickel content, and is roughly equivalent to 625 alloy. Due to the good plasticity of the alloy, easy cold working and cold forming, the high strength and work hardening characteristics of the alloy require greater forming force during cold forming, and stress treatment should be eliminated in time after cold forming. Cold forming is often the preferred forming process in the manufacturing process.
B heat treatment
00Cr33Ni55Mo8 (G-35) corrosion resistant alloy, except for special requirements, is usually used in solid solution state, and its solution treatment process is 11211 heat preservation and rapid cooling or water quenching. The thermoformed parts must be solution treated prior to final fabrication or assembly to ensure optimum corrosion resistance of the alloy.
C welding
The weldability of G-35 alloy is similar to that of C-276 alloy. Three welding methods are usually used depending on the cross-sectional dimensions and construction characteristics of the material. GTAW should be used for thin-plate welding and thick-plate root welds; GMAW should be used for medium-thickness welding; SMAW should be used for on-site welding, and coated strips should be used. It is not recommended to use the submerged arc welding to weld the G-35 alloy. Because the input heat is too high and the cooling rate is slow, it will greatly harm the turbidity resistance of the alloy. In order to reduce the precipitation of the second phase in the heat affected zone, the interlayer temperature should be controlled below 93T. For cold-worked alloys, direct soldering is not recommended, which causes a lot of trouble. Therefore, the cold-worked alloy must be solution treated before soldering.
G-35 welding wire is recommended for GTAW and GMAW welding, and G-35 welding electrode is recommended for SMAW welding.
The mechanical properties of the weldment are shown in Table 8-100~Table 8-102.
A hot processing and cold forming
G-35 is superior to G-3 and G-30 due to its copper-free and high nickel content, and is roughly equivalent to 625 alloy. Due to the good plasticity of the alloy, easy cold working and cold forming, the high strength and work hardening characteristics of the alloy require greater forming force during cold forming, and stress treatment should be eliminated in time after cold forming. Cold forming is often the preferred forming process in the manufacturing process.
B heat treatment
00Cr33Ni55Mo8 (G-35) corrosion resistant alloy, except for special requirements, is usually used in solid solution state, and its solution treatment process is 11211 heat preservation and rapid cooling or water quenching. The thermoformed parts must be solution treated prior to final fabrication or assembly to ensure optimum corrosion resistance of the alloy.
C welding
The weldability of G-35 alloy is similar to that of C-276 alloy. Three welding methods are usually used depending on the cross-sectional dimensions and construction characteristics of the material. GTAW should be used for thin-plate welding and thick-plate root welds; GMAW should be used for medium-thickness welding; SMAW should be used for on-site welding, and coated strips should be used. It is not recommended to use the submerged arc welding to weld the G-35 alloy. Because the input heat is too high and the cooling rate is slow, it will greatly harm the turbidity resistance of the alloy. In order to reduce the precipitation of the second phase in the heat affected zone, the interlayer temperature should be controlled below 93T. For cold-worked alloys, direct soldering is not recommended, which causes a lot of trouble. Therefore, the cold-worked alloy must be solution treated before soldering.
G-35 welding wire is recommended for GTAW and GMAW welding, and G-35 welding electrode is recommended for SMAW welding.
The mechanical properties of the weldment are shown in Table 8-100~Table 8-102.
Table 8-100 Mechanical properties of G-35 weldments
|
Welding process |
Sampling position |
temperature/V |
Rm/MPa
|
Rp0.2/MPa
|
A/% |
|
GTAW |
12. 7mm Transverse sample |
room temperature |
696 |
438 |
44.0 |
|
260 |
545 |
310 |
40.0 |
||
|
538 |
448 |
249 |
37.0 |
Table 8-101 V-notch M ratio impact performance of 00Cr33Ni55Mo8 (G-35) alloy weldment
|
welding |
sample location |
Opening |
temperature/℃ |
Impact absorption work/J |
|
GMAW |
12. 7 mm Transverse sample |
Middle weld |
room temperature |
273 |
|
-196 |
207 |
|||
| Heat affected zone（HAZ) |
room temperature |
>358 |
||
|
-196 |
>358 |
Table 8-102 Effect of aging on weldment (12. 7mm sheet, GMAW) lateral impact performance
|
Opening |
Aging time/h |
Aging temperature/℃ |
Impact absorption work/ Akv/ J |
|
Middle weld |
2000 |
427 |
302 |
|
Middle weld |
2000 |
482 |
297 |
|
Middle weld |
2000 |
538 |
304 |
|
Middle weld |
2000 |
593 |
169 |
|
Middle weld |
2000 |
649 |
107 |
Physical properties
The room temperature density of the alloy: 8.72 g/cm3; the melting point range of the alloy: 1332~1361 °C.
The thermal conductivity, specific heat capacity, thermal diffusivity and electrical resistivity of the alloy are shown in Table 8-103. The linear expansion coefficient and dynamic elastic modulus (Young’s modulus) are shown in Table 8-104 and Table 8405, respective.
The room temperature density of the alloy: 8.72 g/cm3; the melting point range of the alloy: 1332~1361 °C.
The thermal conductivity, specific heat capacity, thermal diffusivity and electrical resistivity of the alloy are shown in Table 8-103. The linear expansion coefficient and dynamic elastic modulus (Young’s modulus) are shown in Table 8-104 and Table 8405, respective.
Table 8-103 Thermal conductivity, specific heat capacity, thermal diffusivity and resistivity of 00Cr33Ni55Mo8 (G-35)
|
temperature/℃ |
Thermal conductivity /W • (m •℃)-1 |
Specific heat capacity /J• (kg•℃)-1 |
Thermal diffusivity /cm2 • s-1 |
Resistivity / uΩ• m
|
|
room temperature |
10 |
450 |
0.028 |
1. 18 |
|
100 |
12 |
470 |
0.031 |
1. 19 |
|
200 |
14 |
490 |
0. 034 |
1.20 |
Table 8-104 Linear Expansion Coefficient of 00Cr33Ni55Mo8(G-35) Alloy
|
temperature/t |
Average coefficient of linear expansion/x 10 ―6•℃-1
|
temperature range |
Average coefficient of linear expansion/x10-6•℃-1 |
|
21 -100 |
12.3 |
21 -400 |
13.4 |
|
21 -200 |
12.6 |
21 -500 |
13.6 |
|
21 -300 |
13.2 |
21 -600 |
14. 1 |
Table 8-105 Dynamic elastic modulus of 00Cr33Ni55Mo8(G-35) alloy (Young’s modulus)
|
temperature/°c |
Dynamic elastic mode M (Young’s modulus M) / GPa |
temperature/°c |
Dynamic elastic mold (Young’s mode S) / GPa |
|
room |
204 |
538 |
177 |
|
316 |
189 |
649 |
170 |
|
427 |
183 |
Application
00Cr33Ni55Mo8 (G-35) alloy is mainly used in wet carbonic acid concentrated evaporator, equipment and components for strong oxidizing acid solution. It has excellent corrosion resistance in HF-containing nitric acid solution, and can be used for nitric acid and hydrofluoric acid. Acid pickling equipment and devices and components in strong oxidizing acidic medium containing F_ and cr should have broad application prospects under the conditions of nuclear fuel chemical reprocessing equipment.
00Cr33Ni55Mo8 (G-35) alloy is mainly used in wet carbonic acid concentrated evaporator, equipment and components for strong oxidizing acid solution. It has excellent corrosion resistance in HF-containing nitric acid solution, and can be used for nitric acid and hydrofluoric acid. Acid pickling equipment and devices and components in strong oxidizing acidic medium containing F_ and cr should have broad application prospects under the conditions of nuclear fuel chemical reprocessing equipment.
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Post time: Jun-25-2019