Steel 45G
Description
Steel 45G
Steel 45G: 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 45G.
General information of steel 45G
| Substitute brand |
| steel: 40G, 50G |
| Delivery type |
| long products, including shaped: GOST 4543−71, GOST 2590−71, GOST 2591−71, GOST 2879−69, GOST 10702−78. Calibrated bar GOST 4543−71, GOST 7417−75, GOST 8559−75, GOST 8560−78, GOST 10702−78, GOST 1051−73. Polished bar and silver bar GOST 4543−71, GOST 14955−77, GOST 10702−78. Strip GOST 4543−71, GOST 103−76. Forgings and forged billets GOST 1133−71, GOST 4543−71. |
| Application |
| crankshafts, connecting rods, axles, propeller shafts, brake levers, friction discs, gear wheels, splined and gear shafts, anchor bolts. |
The chemical composition of steel 45G
| Chemical element |
% |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
0.70−1.00 |
| Copper (Cu), no more |
0.30 |
| Nickel (Ni), no more |
0.30 |
| Sulfur (S), no more |
0.035 |
| Carbon (C) |
0.42−0.50 |
| Phosphorus (P), no more |
0.035 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of 45G steel
Mechanical properties
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
HB |
| Bar. Hardening 850 ° С, oil. Vacation 600 ° C, air. |
25 |
370 |
620 |
fifteen |
40 |
49 |
|
| Annealing: heating up to 780 ° С at a speed of 340 deg / h, holding, cooling with a furnace at a speed of 40 deg / h. |
|
390 |
650 |
23 |
50 |
43 |
179 |
| Normalization 810 ° C, air. |
|
460 |
730 |
21 |
57 |
55 |
228 |
Mechanical properties at elevated temperatures
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 10 ,% |
ψ,% |
| Normalization 830 ° C (coarse-grained structure) |
| 200 |
370 |
760 |
ten |
22 |
| 300 |
285 |
740 |
20 |
35 |
| 400 |
265 |
590 |
20 |
47 |
| 500 |
220 |
520 |
37 |
52 |
| Annealing (fine grain structure) |
| 200 |
570 |
810 |
fifteen |
40 |
| 300 |
460 |
780 |
25 |
52 |
| 400 |
375 |
640 |
25 |
55 |
| 500 |
255 |
450 |
45 |
60 |
Mechanical properties depending on the tempering temperature
| vacation t, ° С |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
δ 4 ,% |
ψ,% |
KCU, J / m 2 |
HB |
| A bar with a section of 25 mm. Hardening 790 ° C, water |
| 375 |
1230 |
1310 |
|
nine |
42 |
fourteen |
418 |
| 450 |
1120 |
1210 |
|
eleven |
48 |
39 |
340 |
| 525 |
900 |
1000 |
|
thirteen |
51 |
59 |
302 |
| A bar with a section of 25 mm. Hardening 810 ° C, oil |
| 375 |
|
1280 |
|
8 |
40 |
17 |
351 |
| 525 |
810 |
950 |
|
fourteen |
52 |
68 |
269 |
| A bar with a section of 25 mm. Hardening 850 ° C, oil |
| 300 |
600 |
880 |
sixteen |
|
50 |
39 |
|
| 400 |
580 |
880 |
sixteen |
|
50 |
49 |
|
| 500 |
580 |
870 |
eighteen |
|
51 |
49 |
|
| 600 |
500 |
780 |
22 |
|
57 |
68 |
|
Mechanical properties depending on the section
| Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
| Hardening 840 ° C, water. Vacation 570 ° С, air. |
| thirty |
550 |
800 |
eighteen |
55 |
78 |
| 50 |
490 |
760 |
eighteen |
55 |
68 |
| 120 |
450 |
740 |
sixteen |
50 |
59 |
| 200 |
430 |
740 |
sixteen |
45 |
59 |
| 240 |
430 |
740 |
sixteen |
45 |
59 |
Technological properties of steel 45G
| Forging temperature |
| Beginning 1190, end 820. |
| Weldability |
| difficult to weld. ADS welding method. Preheating and subsequent heat treatment are recommended. |
| Tendency to release ability |
| not inclined |
Temperature of critical points of steel 45G
| Critical point |
° C |
| Ac1 |
715 |
| Ac3 |
735 |
| Ar3 |
710 |
| Ar1 |
635 |
Endurance limit of 45G steel
| σ -1, MPa |
σ B, MPa |
σ 0.2, MPa |
| 418 |
670 |
375 |
| 409 |
770 |
690 |
Hardenability of steel 45G
| Distance from the end, mm / HRC e |
| |
| |
| Heat treatment |
Amount of martensite,% |
Crit. Diam. in water, mm |
Crit. Diam. in oil, mm |
Crete. hardness, HRCэ |
| Hardening |
50 |
30−50 |
10−25 |
45−49 |
| |
90 |
25−42 |
8−20 |
52−55 |
