Steel 40G2
Description
Steel 40G2
Steel 40G2: a brand of steels and alloys. Below is the systematized information on the purpose, chemical composition, types of supplies, substitutes, temperature of critical points, physical, mechanical, technological and casting properties for the brand — Steel 40G2.
General information about steel 40G2
| Substitute brand |
| steel: 45G2, 60G. |
| 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 Polished bar and silver bar GOST 4543−71, GOST 14955−77. Strip GOST 103−76. Forgings and forged billets GOST 1133−71, GOST 4543−71 |
| Application |
| axles, crankshafts, piston drains, levers, camshafts, cardan shafts, axle shafts and other parts. |
Chemical composition of steel 40G2
| Chemical element |
% |
| Silicon (Si) |
0.17−0.37 |
| Manganese (Mn) |
1.40−1.80 |
| Copper (Cu), no more |
0.30 |
| Nickel (Ni), no more |
0.30 |
| Sulfur (S), no more |
0.035 |
| Carbon (C) |
0.36−0.44 |
| Phosphorus (P), no more |
0.035 |
| Chromium (Cr), no more |
0.30 |
Mechanical properties of 40G2 steel
Mechanical properties
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
HB |
| Bar. Hardening 860 ° C, oil. Vacation 650 ° С, air |
25 |
380 |
660 |
12 |
40 |
|
| Annealing: heating up to 775 ° С at a rate of 250 deg / h, holding, cooling at a rate of 40 deg / h |
|
380 |
660 |
23 |
57 |
179 |
| Normalization 870−925 ° C, air. Hardening 800−830 ° С, oil. Vacation 425 ° C. |
38 |
930 |
1100 |
ten |
40 |
331 |
Mechanical properties depending on the tempering temperature
| vacation t, ° С |
σ 0.2, MPa |
σ B, MPa |
δ,% |
δ 10 ,% |
ψ,% |
KCU, J / m 2 |
HB |
| A bar with a section of 28 mm. Tempering 820 ° С, oil |
| 250 |
1490 |
1760 |
|
4 |
19 |
ten |
500 |
| 300 |
1470 |
1620 |
|
6 |
thirty |
ten |
460 |
| 400 |
1270 |
1330 |
|
ten |
50 |
59 |
400 |
| 500 |
980 |
1080 |
|
fifteen |
60 |
127 |
340 |
| 600 |
780 |
850 |
|
19 |
62 |
176 |
250 |
| A bar with a section of 25 mm. Hardening 830 ° С, oil. Cooling after tempering in oil |
| 375 |
|
1390 |
8 |
|
44 |
ten |
402 |
| 450 |
950 |
1040 |
12 |
|
55 |
29 |
321 |
| 525 |
880 |
980 |
fourteen |
|
55 |
35 |
286 |
| 600 |
680 |
800 |
eighteen |
|
65 |
90 |
241 |
Mechanical properties depending on the section
| Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ,% |
ψ,% |
KCU, J / m 2 |
HB |
| Sealing 820 ° C, water. Vacation 600 ° C, water. |
| Sample cutting location — center |
50 |
590 |
770 |
eighteen |
57 |
68 |
220 |
| Sample cutting location — center |
75 |
540 |
730 |
eighteen |
54 |
59 |
210 |
| Sample cutting location — edge |
75 |
|
820 |
sixteen |
60 |
68 |
242 |
| Sample cutting location — center |
100 |
490 |
720 |
eighteen |
56 |
29 |
210 |
| Sample cutting location — edge |
100 |
660 |
800 |
sixteen |
60 |
41 |
241 |
Mechanical properties versus test temperature
| test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 10 ,% |
ψ,% |
| Annealing 900 ° С, air, then heating to 650 ° С, cooling with an oven |
| -20 |
450 |
800 |
eighteen |
40 |
| 100 |
410 |
740 |
17 |
40 |
Technological properties of steel 40G2
| Forging temperature |
| The beginning is 1180−1200, the end is 800−850. Slow cooling of sections larger than 60 mm. |
| Weldability |
| difficult to weld. RDS, heating and subsequent heat treatment is required. |
| Machinability by cutting |
| at HB 201 K υ tv.spl. = 0.8, K υ b.st. = 0.7. |
| Tendency to release ability |
| inclined |
| Flock sensitivity |
| sensitive |
Temperature of critical points of steel 40G2
| Critical point |
° C |
| Ac1 |
713 |
| Ac3 |
780 |
| Ar3 |
710 |
| Ar1 |
627 |
| Mn |
340 |
Endurance limit of steel 40G2
| σ -1, MPa |
σ B, MPa |
Heat treatment, steel condition |
| 196 |
720 |
Quenching 850 С, water. Vacation 620 C. |
Hardenability of steel 40G2
Hardness for strips HRCe.
| Distance from the end, mm / HRC e |
| 2 |
five |
ten |
fifteen |
20 |
25 |
thirty |
35 |
40 |
45 |
| 55−62 |
52−61.5 |
39.5−57.5 |
32−53.5 |
27.5−48.5 |
25.5−43.5 |
24−40.5 |
23.5−37.5 |
22.5−36.5 |
22−35.5 |
| Heat treatment |
Amount of martensite,% |
Crit. Diam. in water, mm |
Crit. Diam. in oil, mm |
Crete. hardness, HRCэ |
| Hardening |
50 |
48−93 |
24−61 |
43−46 |
| |
90 |
38−71 |
16−44 |
48−53 |
Physical properties of steel 40G2
| Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
| Normal elastic modulus, E, GPa |
212 |
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| Density of steel, pn, kg / m 3 |
7800 |
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