Steel 20KHN4FA
Description
Steel 20KHN4FA
Steel 20KHN4FA: brand of steels and alloys. Below is the systematized information on the purpose, chemical composition, types of supplies, substitutes, temperature of critical points, physical, mechanical, technological and casting properties for the grade — Steel 20XN4FA.
General information about steel 20XN4FA
| Substitute brand |
| steel 18Х2Н4МА. |
| Delivery type |
| Cellular products, including shaped: GOST 4543−71, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated bar GOST 4543−71, GOST 7417−75, GOST 8559−75, GOST 8560−78, GOST 1051−73. Polished bar and silver bar GOST 4543−71, GOST 14955−77. Strip GOST 103−76. Forgings and forged billets GOST 1133−71. Pipes OST 14−21−77. |
| Application |
| Intake valves, bolts, studs and other critical parts operating in a corrosive environment at elevated temperatures (300−400 ° C). |
Chemical composition of steel 20KhN4FA
| Chemical element |
% |
| Vanadium (V) |
0.10−0.18 |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
0.25−0.55 |
| Copper (Cu), no more |
0.30 |
| Nickel (Ni) |
3.75−4.15 |
| Sulfur (S), no more |
0.025 |
| Carbon (C) |
0.17−0.24 |
| Phosphorus (P), no more |
0.025 |
| Chromium (Cr) |
0.70−1.10 |
Mechanical properties of steel 20XN4FA
Mechanical properties at elevated temperatures
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 10 ,% |
ψ,% |
KCU, J / m 2 |
| Samples with a cross section of 10 mm. Hardening 850 ° С, oil. Vacation 580 ° C. |
| 20 |
740 |
890 |
fifteen |
64 |
53 |
| 100 |
710 |
830 |
thirteen |
64 |
63 |
| 200 |
|
830 |
12 |
63 |
56 |
| 300 |
670 |
820 |
12 |
61 |
99 |
| 400 |
590 |
700 |
12 |
70 |
92 |
| 500 |
445 |
580 |
eleven |
57 |
82 |
| 600 |
205 |
360 |
thirteen |
50 |
104 |
Mechanical properties depending on the tempering temperature
| vacation t, ° С |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hardening 870 ° C, water. Cooling after tempering in oil. |
| 200 |
1200 |
1500 |
12 |
58 |
90 |
| 400 |
1150 |
1300 |
thirteen |
62 |
90 |
| 600 |
990 |
1040 |
sixteen |
65 |
120 |
Mechanical properties of the bar
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hardening 850 ° С, oil. Vacation 630 ° С, water. |
25 |
685 |
880 |
12 |
50 |
98 |
Technological properties of steel 20XN4FA
| Forging temperature |
| Beginning 1200, end 800. Sections larger than 40 mm are cooled slowly. |
| Weldability |
| not applicable for welded structures. |
| Tendency to release ability |
| inclined |
| Flock sensitivity |
| sensitive |
Temperature of critical points of steel 20KhN4FA
| Critical point |
° C |
| Ac1 |
710 |
| Ac3 |
750 |
| Mn |
310 |
Impact toughness of steel 20XN4FA
Impact strength, KCU, J / cm 2
| Delivery status, heat treatment |
+20 |
-20 |
-50 |
-80 |
| Quenching 870 C, water. Vacation 200 С, oil. |
100 |
60 |
80 |
71 |
| Quenching 870 C, water. Vacation 400 С, oil. |
110 |
79 |
72 |
63 |
| Quenching 870 C, water. Vacation 600 С, oil. |
116 |
82 |
70 |
60 |
Endurance limit of steel 20XN4FA
| σ -1, MPa |
n |
σ B, MPa |
σ 0.2, MPa |
| 480 |
1E + 6 |
1020 |
980 |
| 500 |
1E + 6 |
1070 |
1030 |
Physical properties of steel 20XN4FA
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Thermal conductivity coefficient W / (m ° С) |
|
38 |
38 |
37 |
35 |
34 |
31 |
29 |
28 |
27 |
| Ud. electrical resistance (p, Nom. m) |
360 |
470 |
480 |
560 |
640 |
720 |
|
1020 |
1120 |
1180 |
| Test temperature, ° С |
20−100 |
20−200 |
20−300 |
20−400 |
20−500 |
20−600 |
20−700 |
20−800 |
20−900 |
20−1000 |
| Linear expansion coefficient (a, 10−6 1 / ° С) |
11.7 |
12.7 |
13.7 |
|
|
15.4 |
|
|
|
|
Sensitivity to embrittlement of steel 20XN4FA
| Temperature, ° С |
Time, h |
KCU, J / cm 2 |
| 325 |
1000 |
61 |
| 475 |
1000 |
22 |
