Steel 55S2
Description
Steel 55S2
Steel 55S2: 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 55S2.
General information of steel 55S2
| Substitute brand |
| sali: 50S2, 60S2, 35X2AF. |
| Delivery type |
| Pipe 55с2, 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 14959−79, 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. Forgings and forged billets GOST 14959−79, GOST 1133−71. |
| Application |
| springs and springs used in the automotive industry, tractor construction, railway transport and other branches of machine building. |
Chemical composition of steel 55S2
| Chemical element |
% |
| Silicon (Si) |
1.5−2.0 |
| Manganese (Mn) |
0.60−0.90 |
| Copper (Cu), no more |
0.20 |
| Nickel (Ni), no more |
0.25 |
| Sulfur (S), no more |
0.035 |
| Carbon (C) |
0.52−0.60 |
| Phosphorus (P), no more |
0.035 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of steel 55S2
Mechanical properties
| Heat treatment, delivery condition |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
HRC e |
| Steel categories: 3.3A, 3B, 3V, 3G, 4.4A, 4B. Hardening 870 ° C, oil or water, tempering 470 ° C. |
1175 |
1270 |
6 |
thirty |
|
|
|
| Annealing 750−780 ° С, cooling with a furnace |
440 |
760 |
21 |
42 |
sixteen |
222 |
|
| Normalization 840 ° C |
370 |
690 |
|
35 |
|
197 |
|
| Isothermal quenching 870 ° С, cooling in molten salt at a temperature of 300 ° С |
1220 |
1640 |
8 |
|
|
|
47 |
| Isothermal quenching 870 ° С, cooling in molten salt at 360 ° С |
1110 |
1350 |
|
|
85 |
|
42 |
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 |
| 350 |
1860 |
2030 |
7 |
31 |
23 |
50 |
| 400 |
1830 |
1910 |
nine |
36 |
27 |
48 |
| 450 |
1470 |
1530 |
eleven |
46 |
41 |
44 |
| 500 |
1130 |
1220 |
12 |
47 |
48 |
41 |
| 550 |
1060 |
1180 |
thirteen |
50 |
56 |
34 |
| Samples with a diameter of 17−22 mm. Annealing at 900 ° C, 2 h. Hardening at 850 ° C, oil, cooling after tempering in a furnace with 2-hour exposure |
| 300 |
1960 |
2250 |
five |
20 |
|
|
| 400 |
1670 |
1830 |
8 |
39 |
|
|
| 500 |
1270 |
1350 |
12 |
39 |
|
|
| 600 |
830 |
1080 |
fifteen |
42 |
|
|
Technological properties of steel 55S2
| Forging temperature |
| Beginning 1200, end 800. Cooling of workpieces with a section up to 250 mm in air, 251−300 mm — in a pit. |
| Weldability |
| not applicable for welded structures. |
| Machinability by cutting |
| In hot-rolled condition at HB 255−269 K υ tv.spl. = 0.65, K υ b.st. = 0.33. |
| Tendency to release ability |
| not inclined |
| Flock sensitivity |
| not sensitive |
Temperature of critical points of steel 55C2
| Critical point |
° C |
| Ac1 |
755 |
| Ac3 |
810 |
| Ar3 |
870 |
| Ar1 |
690 |
| Mn |
272 |
Endurance limit of steel 55S2
| σ -1, MPa |
τ -1, MPa |
σ B, MPa |
σ 0.2, MPa |
Heat treatment, steel condition |
| 421 |
294 |
1270 |
|
Tempering 880 C, oil. Vacation 400−460 C. |
| 598 |
|
1200 |
1050 |
|
| 720 |
|
1400 |
1300 |
|
| 769 |
|
1710 |
1690 |
|
Hardenability of steel 55S2
Hardening 850 ° C.
| Distance from the end, mm / HRC e |
| 1.5 |
3 |
4.5 |
6 |
nine |
12 |
fifteen |
eighteen |
27 |
39 |
| 58−66 |
56−64 |
51.5−62 |
47.5−59 |
38.5−55 |
35−49.5 |
33−44.5 |
31−41.5 |
28−37.5 |
27−35.5 |
| Amount of martensite,% |
Crit. Diam. in water, mm |
Crit. Diam. in oil, mm |
Crete. hardness, HRCэ |
| 50 |
57−98 |
31−57 |
49−52 |
| 90 |
71 |
40 |
55−58 |
Physical properties of steel 55S2
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
196 |
|
|
|
|
|
|
|
|
|
| Torsional shear elastic modulus G, GPa |
78 |
|
|
|
|
|
|
|
|
|
