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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                  
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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