Steel 70S3A
Description
Steel 70S3A
Steel 70S3A: 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 70S3A.
General information about steel 70S3A
| Delivery type |
| Long products, including shaped: GOST 14959−79, GOST 2590−71, GOST 2591−71, GOST 2879−69, GOST 7419.0−78 — GOST 7419.8−78. Calibrated bar GOST 7417−75, GOST 8559−75, GOST 8560−78. Polished bar and silver bar GOST 14955−77, GOST 7419.0−78 — GOST 7419.8−78. Strip GOST 103−76, GOST 4405−75. Wire GOST 14963−78. Forgings and forged billets GOST 1133−71. |
| Application |
| heavy-duty springs for critical purposes. |
Chemical composition of 70S3A steel
| Chemical element |
% |
| Silicon (Si) |
2.4−2.8 |
| Manganese (Mn) |
0.60−0.90 |
| Copper (Cu), no more |
0.20 |
| Nickel (Ni), no more |
0.25 |
| Sulfur (S), no more |
0.025 |
| Carbon (C) |
0.66−0.74 |
| Phosphorus (P), no more |
0.025 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of steel 70S3A
Mechanical properties
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
HRC e |
| Steel categories: 3.3A, 3B, 3V, 3G, 4.4A, 4B. Hardening 850 ° С, oil, tempering 470 ° С. |
Samples |
1470 |
1670 |
6 |
25 |
|
| Forged bar. Annealing. Isothermal quenching 900 ° С with holding at 320 ° С |
15−16 |
|
1060 |
2 |
thirteen |
60 |
| Forged bar. Annealing. Isothermal quenching 900 ° С with holding at 340 ° С |
15−16 |
|
1270 |
4 |
fifteen |
49 |
| Springs. Annealing 840−850 ° C. Winding 850−880 ° C. Hardening 850−880 ° С, oil. Vacation 460−470 ° C. |
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|
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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 |
| Forgings with a cross section of 16−25 mm. Annealing. Hardening 900 ° C. |
| 250 |
1520 |
1740 |
|
ten |
|
60 |
| 350 |
1520 |
1740 |
7 |
17 |
27 |
56 |
| 450 |
1220 |
1690 |
6 |
|
37 |
49 |
Mechanical properties versus test temperature
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hardening 830 ° С, oil. Vacation 450 ° C. |
| 20 |
1540 |
1780 |
ten |
|
24 |
| 200 |
1440 |
1710 |
12 |
32 |
29 |
| 300 |
1270 |
1620 |
sixteen |
32 |
|
| 400 |
1220 |
1400 |
20 |
65 |
|
Technological properties of steel 70S3A
| Forging temperature |
| Beginning 1100, end 800. |
| Tendency to release ability |
| inclined |
Temperature of critical points of steel 70S3A
| Critical point |
° C |
| Ac1 |
865 |
| Ac3 |
780 |
| Mn |
270 |
Physical properties of steel 70S3A
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
214 |
208 |
198 |
192 |
185 |
180 |
152 |
139 |
132 |
|
| Torsional shear elastic modulus G, GPa |
83 |
81 |
76 |
79 |
69 |
67 |
57 |
52 |
49 |
|
| Thermal conductivity coefficient W / (m ° С) |
25 |
26 |
27 |
28 |
29 |
29 |
29 |
28 |
27 |
|
| 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) |
11.4 |
12.3 |
12.8 |
13.3 |
13.7 |
14.1 |
14.3 |
12.8 |
|
|
| Specific heat (C, J / (kg ° C)) |
480 |
510 |
520 |
535 |
565 |
585 |
620 |
700 |
|
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