Steel 20KH2N4A
Description
Steel 20KH2N4A
Steel 20Kh2N4A: 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 20X2H4A.
General information about steel 20X2H4A
Substitute brand |
steel: 20ХГНР, 15ХГН2ТА, 20ХГНТР. |
Delivery type |
Circle 20x2n4a, long products, including shaped: GOST 4543−71, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78, GOST 1051−73. Polished bar and silver bar GOST 14955−77. Strip GOST 103−76. Forgings and forged billets GOST 1133−71. Pipes OST 14−21−77. |
Application |
Gears, pinion shafts, pins and other case-hardened, especially critical, highly loaded parts, which are subject to requirements for high strength, ductility and toughness of the core and high surface hardness, operating under shock loads and at negative temperatures. |
Chemical composition of steel 20X2H4A
Chemical element |
% |
Silicon (Si) |
0.17−0.37 |
Manganese (Mn) |
0.30−0.60 |
Copper (Cu), no more |
0.30 |
Nickel (Ni) |
3.25−3.65 |
Sulfur (S), no more |
0.025 |
Carbon (C) |
0.16−0.22 |
Phosphorus (P), no more |
0.025 |
Chromium (Cr) |
1.25−1.65 |
Mechanical properties of steel 20X2H4A
Fur. properties at elevated temperatures |
Fur. properties depending on tempering temperature |
Fur. properties depending on the section |
Fur. bar properties |
Mechanical properties at elevated temperatures
test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
Sample 10 mm in diameter, 50 mm long, forged and annealed. Deformation rate 5 mm / min. Strain rate 0.002 1 / s. |
700 |
63 |
120 |
56 |
78 |
800 |
45 |
56 |
64 |
95 |
900 |
36 |
56 |
58 |
100 |
1000 |
22 |
37 |
63 |
100 |
1100 |
20 |
27 |
59 |
100 |
1150 |
sixteen |
26 |
65 |
100 |
1220 |
sixteen |
22 |
71 |
100 |
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 840 ° С, oil. |
200 |
1360 |
1500 |
7 |
56 |
120 |
300 |
1280 |
1400 |
7 |
60 |
100 |
400 |
1140 |
1300 |
7 |
63 |
120 |
500 |
970 |
1170 |
ten |
67 |
220 |
600 |
790 |
1000 |
eleven |
72 |
235 |
Mechanical properties depending on the section
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
Quenching, tempering |
thirty |
820 |
940 |
12 |
50 |
80 |
277 |
50 |
820 |
940 |
12 |
50 |
70 |
277 |
80 |
820 |
940 |
12 |
50 |
70 |
269 |
120 |
780 |
900 |
12 |
50 |
60 |
262 |
160 |
760 |
880 |
12 |
50 |
60 |
262 |
200 |
740 |
860 |
12 |
50 |
60 |
262 |
240 |
720 |
860 |
12 |
50 |
60 |
255 |
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 |
HB |
HRC e |
Hardening 860 ° C, oil. Hardening 780 ° С, oil. Vacation 180 ° C, air or oil. |
fifteen |
1080 |
1270 |
nine |
45 |
78 |
|
|
Cementation 900−920 ° C, air. Hardening 780−810 ° С, oil. Vacation 180−200 ° C, air. |
50 |
1050 |
1220 |
12 |
45 |
118 |
360 |
57−64 |
Cementation 920−950 ° C. Normalization 900−920 ° C, air or quenching 880−920 ° C, oil. Vacation 630−660 ° С, air. Hardening 780−820 ° С, oil. Vacation 150−200 ° C, air. |
150 |
830 |
1080 |
nine |
35 |
78 |
321−420 |
57−64 |
Technological properties of steel 20X2H4A
Forging temperature |
Beginning 1200, end 800. Sections up to 100 mm are cooled in air, 101−350 mm — in a pit. |
Weldability |
difficult to weld. Welding methods: RDS, ADS submerged arc, EShS. Heating and subsequent heat treatment are required. |
Machinability by cutting |
After normalization and tempering at HB 259 σ B = 880 MPa K υ tv.spl. = 0.72, K υ b.st. = 0.63. |
Tendency to release ability |
not inclined |
Flock sensitivity |
sensitive |
Temperature of critical points of steel 20X2H4A
Critical point |
° C |
Ac1 |
710 |
Ac3 |
800 |
Ar1 |
640 |
Impact toughness of steel 20X2H4A
Impact strength, KCU, J / cm 2
Delivery status, heat treatment |
+20 |
-20 |
-40 |
-70 |
Tempering 820 С, oil. Vacation 500 S. |
147 |
147 |
157 |
|
Longitudinal specimens from forging (Quenching 880 C, oil. Quenching 780 C, oil. Tempering 200 C) |
65 |
61 |
63 |
62 |
Cross specimens from forging (hardening 880 C, oil. Quenching 780 C, oil. Tempering 200 C) |
32 |
33 |
35 |
thirty |
Endurance limit of steel 20X2H4A
σ -1, MPa |
τ -1, MPa |
σ B, MPa |
σ 0.2, MPa |
Heat treatment, steel condition |
617 |
372 |
1220 |
1050 |
HB 360 |
333 |
230 |
730 |
610 |
HB 238 |
382 |
|
960 |
680 |
HB 322 |
421 |
|
940 |
850 |
|
Hardenability of steel 20X2H4A
Normalization 850 C. Hardening 840 C. Hardness for hardenability strips HRCe.
Distance from the end, mm / HRC e |
3 |
five |
ten |
fifteen |
20 |
thirty |
40 |
50 |
60 |
41.5−49.5 |
40.5−48.5 |
35.5−45.5 |
31−40 |
28−36.5 |
25−33 |
23.5−31 |
23−30.5 |
22.5−30.5 |
Physical properties of steel 20X2H4A
Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
Normal elastic modulus, E, GPa |
203 |
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Density of steel, pn, kg / m 3 |
7850 |
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Thermal conductivity coefficient W / (m ° С) |
|
24 |
|
|
eighteen |
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