Steel 55
Description
Steel 55
Steel 55: 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 55 grade.
General steel 55
| Substitute brand |
| steel: 50, 60, 50G. |
| Delivery type |
| Long products, including shaped: GOST 1050−74, GOST 2590−71, GOST 2591−71, GOST 2879−69, GOST 8509−86, GOST 8510−86, GOST 8239−72, GOST 8240−72. Calibrated bar GOST 7414−75, GOST 8559−75, GOST 8560−78. Polished bar and silver bar GOST 14955−77. Thick sheet GOST 1577−81, GOST 19903−74. Tape GOST 1530−78, GOST 2284−79. Strip GOST 1577−81, GOST 103−76, GOST 82−70. Forgings and forged billets GOST 8479−70, GOST 1131−71. Rolls OST 24.013.21−85, GOST 5399−69, OST 24.013.04−83. |
| Application |
| after normalization with tempering and quenching with tempering — gear wheels, rolling rolls, rods, heavily loaded shafts, axles, tires, lightly loaded springs and springs, plowshares, track pins, gearbox clutches, nozzle bodies and other parts operating on friction. |
Chemical composition of steel 55
| Chemical element |
% |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
0.50−0.80 |
| Copper (Cu), no more |
0.25 |
| Arsenic (As), no more |
0.08 |
| Nickel (Ni), no more |
0.25 |
| Sulfur (S), no more |
0.040 |
| Carbon (C) |
0.52−0.60 |
| Phosphorus (P), no more |
0.035 |
| Chromium (Cr), no more |
0.25 |
Mechanical properties of steel 55
Mechanical properties of forgings
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
| Normalization |
| KP 315 |
100−300 |
315 |
570 |
fourteen |
35 |
34 |
167−207 |
| Hardening. Vacation. |
| KP 490. |
<100 |
490 |
655 |
sixteen |
45 |
59 |
212−248 |
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 |
| Hardening 840 ° С, oil. |
| 200 |
1620−2210 |
1720−2280 |
2−3 |
7−12 |
5−10 |
64 |
| 300 |
1350−1790 |
1500−1940 |
3−4 |
20−25 |
5−10 |
56 |
| 400 |
1100−1380 |
1260−1590 |
4−5 |
31−36 |
19−49 |
47 |
| 500 |
820−1000 |
970−1120 |
7 |
41−45 |
39−78 |
40 |
| 600 |
600−700 |
800−890 |
10−11 |
51−54 |
69−108 |
thirty |
Mechanical properties depending on the section
| Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
| Hardening 840 ° C, water. Vacation 400 ° C, air. |
| 20 |
870−990 |
1060−1210 |
7−8 |
43−52 |
54−67 |
341 |
| 40 |
640−740 |
900−1000 |
10−11 |
43−47 |
39−53 |
290 |
| 60 |
590−650 |
820−930 |
10−12 |
42−46 |
32−49 |
266 |
| Hardening 840 ° C, water. Vacation 500 ° C, air. |
| 20 |
710−800 |
900−1000 |
10−12 |
53−59 |
59−98 |
285 |
| 40 |
550−610 |
820−900 |
12−14 |
45−52 |
49−69 |
264 |
| 60 |
510−570 |
750−850 |
13−14 |
43−52 |
39−59 |
239 |
| Normalization 830−860 ° C, air. Vacation 650−800 ° С, oven. |
| <100 |
325 |
650 |
12 |
35 |
29 |
|
| 101−300 |
315 |
630 |
eleven |
28 |
25 |
170−229 |
| 301−500 |
305 |
610 |
ten |
25 |
25 |
|
| Normalization 830−860 ° C, air. Vacation 550−600 ° C, oven or air. |
| <1200 |
|
|
|
|
|
215−255 |
Technological properties of steel 55
| Forging temperature |
| Beginning 1240, end 800. Sections up to 400 mm are cooled in air. |
| Weldability |
| Not applicable for welded structures. KTS with subsequent heat treatment. |
| Machinability by cutting |
| In the normalized state at HB 212−225 K υ tv.spl. = 1, K υ b.st. = 0.65. |
| Tendency to release ability |
| Not inclined. |
| Flock sensitivity |
| Insensitive. |
Temperature of critical points of steel 55
| Critical point |
° C |
| Ac1 |
725 |
| Ac3 |
755 |
| Ar3 |
750 |
| Ar1 |
690 |
| Mn |
320 |
Impact strength of steel 55
Impact strength, KCU, J / cm 2
| Delivery status, heat treatment |
+20 |
-20 |
-50 |
| Hot rolled |
26 |
eighteen |
thirteen |
Endurance limit steel 55
| σ -1, MPa |
τ -1, MPa |
n |
Heat treatment, steel condition |
| 377 |
219 |
1E + 6 |
Tempering 790 C, water. Vacation 650 С, air. |
Hardenability of steel 55
Hardening 850 C. Hardness for hardenability strips HRCe.
| Distance from the end, mm / HRC e |
| 1.5 |
3 |
4.5 |
6 |
7.5 |
nine |
12 |
fifteen |
eighteen |
24 |
| 54−63 |
41.5−59.5 |
35−53 |
32−46.5 |
30−41 |
28.5−38.5 |
27−35.5 |
26−34 |
25−33 |
22.5−32 |
| Amount of martensite,% |
Crit. Diam. in water, mm |
Crit. Diam. in oil, mm |
| 50 |
16−28 |
9−16 |
Physical properties of steel 55
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
210 |
|
|
|
|
|
|
|
|
|
| Density of steel, pn, kg / m 3 |
7280 |
|
|
|
|
|
|
|
|
|
| Thermal conductivity coefficient W / (m ° С) |
|
68 |
55 |
|
36 |
32 |
|
|
|
|
| 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) |
11.0 |
11.9 |
12.7 |
13.4 |
14.0 |
14.5 |
14.8 |
12.5 |
13.5 |
14.4 |
| Specific heat (C, J / (kg ° C)) |
479 |
487 |
|
525 |
571 |
|
|
|
|
|
