Steel 20ХН3А
Description
Steel 20ХН3А
Steel 20ХН3А: a brand of steels and alloys. Below is a 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 20XN3A.
General information about steel 20ХН3А
Substitute brand |
steel: 20HGNR, 20HNG, 38XA, 15H2GN2TA, 20HGR. |
Delivery type |
Circle 20хн3а, 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, GOST 8479−70. Pipes OST 14−21−77. |
Application |
Gears, shafts, bushings, power pins, bolts, worms, couplings and other case-hardened parts that require high strength, ductility and toughness of the core and high surface hardness, operating under shock loads and at negative temperatures. |
Chemical composition of steel 20ХН3А
Chemical element |
% |
Silicon (Si) |
0.17−0.37 |
Manganese (Mn) |
0.30−0.60 |
Copper (Cu), no more |
0.30 |
Nickel (Ni) |
2.75−3.15 |
Sulfur (S), no more |
0.025 |
Carbon (C) |
0.17−0.24 |
Phosphorus (P), no more |
0.025 |
Chromium (Cr) |
0.60−0.90 |
Mechanical properties of steel 20ХН3А
Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
Bar. Hardening 820 ° С, oil. Vacation 500 ° C. water or oil. |
|
fifteen |
735 |
930 |
12 |
55 |
108 |
|
Forgings. Hardening. Vacation |
KP 590 |
<100 |
590 |
735 |
fourteen |
45 |
59 |
235−277 |
KP 685 |
<100 |
685 |
835 |
thirteen |
42 |
59 |
262−311 |
Cementation 920−950 ° C. Normalization 870−890 ° C, air. Vacation 630−660 ° С, air. Hardening 790−810 ° С, oil. Vacation 180−200 ° C, air. |
|
100 |
690 |
830 |
eleven |
50 |
69 |
240 |
Mechanical properties depending on the tempering temperature
vacation t, ° С |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HRC e |
Normalization 860 ° C, air. Hardening 810 ° С, oil. |
200 |
1270 |
1510 |
fifteen |
60 |
73 |
43 |
300 |
1260 |
1370 |
12 |
62 |
54 |
42 |
400 |
1180 |
1260 |
thirteen |
64 |
59 |
39 |
500 |
960 |
1000 |
19 |
66 |
83 |
32 |
600 |
720 |
780 |
24 |
73 |
162 |
22 |
Mechanical properties depending on the section
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HRC e |
Hardening 850 ° С, oil. Vacation 200 ° C, air. |
five |
1220 |
1420 |
12 |
55 |
86 |
44 |
fifteen |
1180 |
1370 |
thirteen |
65 |
76 |
44 |
20 |
1080 |
1270 |
thirteen |
65 |
89 |
44 |
Hardening 880 ° С, oil. Vacation 600 ° C, air. |
thirty |
700 |
800 |
20 |
70 |
167 |
|
50 |
610 |
730 |
19 |
71 |
167 |
|
80 |
580 |
700 |
23 |
68 |
167 |
|
220 |
510 |
660 |
fourteen |
51 |
167 |
|
220 |
570 |
690 |
23 |
67 |
157 |
|
Technological properties of steel 20ХН3А
Forging temperature |
Beginning 1220, end 800. Sections up to 100 mm are cooled in air, 101−300 mm — in a pit. |
Weldability |
restrictedly weldable. RDS, ADS under flux. |
Machinability by cutting |
In the hot-rolled state at HB 177, σ B = 610 MPa K υ b.st. = 0.95. |
Tendency to release ability |
inclined |
Flock sensitivity |
sensitive |
Temperature of critical points of steel 20ХН3А
Critical point |
° C |
Ac1 |
730 |
Ac3 |
810 |
Ar3 |
700 |
Ar1 |
615 |
Mn |
340 |
Impact strength of steel 20ХН3А
Impact strength, KCU, J / cm 2
Delivery status, heat treatment |
+20 |
-20 |
-40 |
-50 |
-60 |
Blank with a section of 10 mm. Hardening 850 С, oil. Vacation 200 C. |
86 |
|
85 |
|
|
Blank with a cross section of 30 mm. Tempering 880 C, oil. Vacation 560 С. |
167 |
|
69 |
64 |
|
Workpiece with a cross section of 50 mm. Tempering 880 C, oil. Vacation 560 С. |
167 |
|
83 |
73 |
|
Workpiece with a section of 80 mm. Tempering 880 C, oil. Vacation 560 С. |
167 |
|
69 |
|
|
Normalization 860 C, air. Guenching 810 С, oil. Vacation 600 C. |
196 |
122 |
100 |
|
86 |
Billet with a section of 220 mm. Tempering 880 C, oil. Vacation 630 C. |
167 |
|
118 |
78 |
|
Endurance limit of steel 20ХН3А
σ -1, MPa |
τ -1, MPa |
n |
σ B, MPa |
Heat treatment, steel condition |
382 |
|
1E + 6 |
960 |
Tempering 820 С, oil. Vacation 200 C. |
338 |
225 |
1E + 6 |
730 |
Tempering 820 С, oil. Vacation 500 S. |
421 |
|
1E + 6 |
940 |
Hardening 800 C, oil. Vacation 500 S. |
Hardenability of steel 20ХН3А
Tempering 830 C.
Distance from the end, mm / HRC e |
1.5 |
3 |
4.5 |
6 |
7.5 |
nine |
12 |
fifteen |
21 |
39 |
43−51 |
42−50.5 |
41−50 |
39−49 |
37−5-46 |
35.5−46 |
33−43 |
31−40.5 |
27.5−35.5 |
22−31 |
Amount of martensite,% |
Crit. Diam. in water, mm |
Crit. Diam. in oil, mm |
Crete. hardness, HRCэ |
50 |
70−96 |
44−62 |
32−37 |
90 |
42−64 |
20−38 |
39−44 |
Physical properties of steel 20ХН3А
Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
Normal elastic modulus, E, GPa |
212 |
204 |
194 |
188 |
169 |
169 |
153 |
138 |
132 |
|
Torsional shear elastic modulus G, GPa |
83 |
80 |
76 |
70 |
68 |
66 |
59 |
53 |
51 |
|
Density of steel, pn, kg / m 3 |
7850 |
7830 |
|
7760 |
|
|
7660 |
|
|
|
Thermal conductivity coefficient W / (m ° С) |
36 |
35 |
34 |
33 |
33 |
31 |
31 |
thirty |
28 |
|
Ud. electrical resistance (p, Nom. m) |
270 |
300 |
350 |
450 |
550 |
650 |
|
|
|
|
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) |
11.5 |
11.7 |
12.0 |
12.6 |
12.8 |
13.2 |
13.6 |
11.2 |
|
|
Specific heat (C, J / (kg ° C)) |
494 |
507 |
523 |
536 |
565 |
586 |
624 |
703 |
|
|