Steel 30G
Description
Steel 30G
Steel 30G: 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 grade — Steel 30G.
General steel 30G
Substitute brand |
steel: 35, 40G |
Delivery type |
long products, including shaped: GOST 4543−71, GOST 2590−71, GOST 2591−71, GOST 2879−69. Calibrated bar GOST 4543−71, GOST 8559−75, GOST 8560−78, GOST 7417−75, GOST 1051−73. Polished bar and silver bar GOST 4543−71, GOST 14955−77. Thick sheet GOST 1577−81, GOST 19903−74. Strip GOST 103−76, GOST 82−70. Forgings and forged billets GOST 1133−71, GOST 4543−71. |
Application |
improved parts, which are subject to low strength requirements: rods, axles, cylinders, discs, bolts, nuts, screws and others. |
Chemical composition of steel 30G
Chemical element |
% |
Silicon (Si) |
0.17−0.37 |
Manganese (Mn) |
0.70−1.0 |
Copper (Cu), no more |
0.30 |
Nickel (Ni), no more |
0.30 |
Sulfur (S), no more |
0.035 |
Carbon (C) |
0.27−0.35 |
Phosphorus (P), no more |
0.035 |
Chromium (Cr), no more |
0.30 |
Mechanical properties of steel 30G
Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
Bar. Hardening 860 ° C, water. Vacation 600 ° С, air |
25 |
315 |
540 |
20 |
45 |
78 |
Tape. Hardening 810−820 ° C. Vacation 400 ° C, air. |
3 |
|
1130 |
6−7 |
|
|
Mechanical properties depending on the tempering temperature
vacation t, ° С |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
A bar with a cross section of 70 mm. Hardening 850 ° С, oil. |
300 |
540 |
780 |
20 |
45 |
39 |
400 |
540 |
760 |
20 |
52 |
29 |
500 |
490 |
700 |
21 |
59 |
49 |
600 |
440 |
640 |
25 |
69 |
117 |
Mechanical properties depending on the section
Heat treatment, delivery condition |
Section, mm |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
Hardening 840 ° C, water. Vacation 550 ° C. |
Sample cutting location — center |
40 |
540 |
710 |
25 |
|
137 |
Sample cutting location — edge |
40 |
590 |
740 |
22 |
65 |
157 |
Sample cutting location — center |
80 |
490 |
650 |
24 |
|
108 |
Sample cutting location — edge |
80 |
560 |
730 |
21 |
64 |
157 |
Sample cutting location — center |
120 |
490 |
600 |
22 |
|
98 |
Sample cutting location — edge |
120 |
540 |
710 |
21 |
63 |
147 |
Sample cutting location — center |
160 |
490 |
590 |
23 |
|
88 |
Sample cutting location — edge |
160 |
530 |
700 |
22 |
63 |
137 |
Sample cutting location — center |
200 |
450 |
600 |
27 |
63 |
98 |
Mechanical properties versus test temperature
test t, ° C |
σ 0.2, MPa |
σ B, MPa |
δ 5 ,% |
ψ,% |
KCU, J / m 2 |
Normalization 900 ° C, air. Vacation 680−710 ° C. |
-20 |
370 |
710 |
20 |
32 |
136 |
20 |
330 |
630 |
29 |
46 |
145 |
100 |
305 |
590 |
21 |
41 |
200 |
Technological properties of steel 30G
Forging temperature |
Beginning 1250, end 800. Billets with a cross section up to 400 mm are cooled in air. |
Weldability |
restrictedly weldable. Welding methods: RDS, ADS submerged arc. Heating and subsequent heat treatment is recommended. KTS without restrictions. |
Machinability by cutting |
In the normalized state at HB 149−197 K υ tv.spl. = 1.0, K υ b.st. = 0.80. |
Tendency to release ability |
inclined at 1.0% Mn |
Flock sensitivity |
not sensitive |
Temperature of critical points of steel 30G
Critical point |
° C |
Ac1 |
723 |
Ac3 |
810 |
Ar3 |
785 |
Ar1 |
680 |
Mn |
870 |
Impact strength of steel 30G
Impact strength, KCU, J / cm 2
Delivery status, heat treatment |
+20 |
-20 |
-70 |
Normalization 870 С, air |
98 |
34 |
sixteen |
Endurance limit of steel 30G
σ -1, MPa |
τ -1, MPa |
n |
σ B, MPa |
σ 0.2, MPa |
Heat treatment, steel condition |
353 |
216 |
|
|
|
Quenching 840 C, water. Vacation 500−550 C. |
265 |
|
5E + 6 |
490 |
|
|
235 |
|
5E + 6 |
580 |
|
|
412 |
|
|
820 |
650 |
Tempering 790 C, water. Vacation 600 C. |
Hardenability of steel 30G
Hardening 810 C. Hardness for strips of hardenability HRCe.
Distance from the end, mm / HRC e |
1.5 |
3 |
4.5 |
6 |
nine |
12 |
fifteen |
21 |
thirty |
36 |
54 |
48.5 |
40.5 |
35.5 |
32 |
thirty |
28 |
25 |
22 |
20.5 |
Physical properties of steel 30G
Test temperature, ° С |
20 |
100 |
200 |
300 |
400 |
500 |
600 |
700 |
800 |
900 |
Normal elastic modulus, E, GPa |
204 |
|
|
|
|
|
|
|
|
|
Density of steel, pn, kg / m 3 |
7810 |
|
|
|
|
|
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|
Thermal conductivity coefficient W / (m ° С) |
|
76 |
65 |
53 |
44 |
38 |
|
|
|
|
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) |
12.6 |
13.9 |
14.6 |
15.0 |
15.5 |
15.6 |
14.8 |
|
|
|
Specific heat (C, J / (kg ° C)) |
470 |
483 |
546 |
601 |
864 |
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