Steel 70
Description
Steel 70
Steel 70: 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 Steel 70 grade.
General steel 70
| Substitute brand |
| steel 65G. |
| Delivery type |
| Circle 70, rolled sections, including shaped: GOST 14959−79, GOST 2590−71, GOST 2591−71, GOST 2879−69, GOST 7419.0−78, GOST 7419.1−78, GOST 7419.3−78, GOST 7419.5−78 — 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 7419.1−78, GOST 7419.3−78, GOST 7419.5−78 — GOST 7419.8−78. Tape GOST 1530−78, GOST 2284−79, GOST 219969−76, GOST 21997−76. Strip GOST 4405−75, GOST 82−70, GOST 7419.2−78, GOST 7419.4−78. Forgings and forged billets GOST 1133−71. Wire GOST 9389−75. Thick sheet GOST 1577−81, GOST 19903−74. |
| Application |
| springs, springs and other parts that require increased strength and elastic properties, as well as wear resistance. |
Chemical composition of steel 70
| Chemical element |
% |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
0.50−0.80 |
| Copper (Cu), no more |
0.20 |
| Nickel (Ni), no more |
0.25 |
| Sulfur (S), no more |
0.035 |
| Carbon (C) |
0.67−0.75 |
| Phosphorus (P), no more |
0.035 |
| Chromium (Cr), no more |
0.25 |
Mechanical properties of 70 steel
Mechanical properties
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
HB |
| Steel categories: 3.3A, 3B, 3V, 3G, 4.4A, 4B. Hardening 830 ° С, oil, tempering 470 ° С. |
Samples |
835 |
1030 |
nine |
thirty |
|
| Normalization |
|
510 |
910 |
17 |
29 |
252 |
| Wire. Hardening 920 ° С, cooling in oil at 40 ° С, holding for 1 min. Vacation 500 ° С, exposure 15 min. |
6.5 |
|
1240 |
7 |
47 |
315 |
Technological properties of steel 70
| Forging temperature |
| The beginning is 1200, the end is 850. |
| Weldability |
| not applicable for welded structures. KTS with subsequent heat treatment. |
| Machinability by cutting |
| at HB 183−241, K υ tv.spl. = 0.7, K υ b.st. = 0.6. |
| Tendency to release ability |
| not inclined |
| Flock sensitivity |
| insensitive |
Temperature of critical points of steel 70
| Critical point |
° C |
| Ac1 |
730 |
| Ac3 |
743 |
| Ar3 |
727 |
| Ar1 |
693 |
Physical properties of steel 70
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
206 |
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| Torsional shear elastic modulus G, GPa |
78 |
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| Density of steel, pn, kg / m 3 |
7810 |
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| Thermal conductivity coefficient W / (m ° С) |
|
68 |
52 |
37 |
29 |
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| 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 |
12.3 |
13.0 |
13.8 |
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| Specific heat (C, J / (kg ° C)) |
483 |
487 |
|
521 |
|
567 |
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