Steel 74 (M74)

Designation

Name The value
Designation GOST Cyrillic 74
Designation GOST Latin 74
Transliteration 74
By chemical elements 74
Name The value
Designation GOST Cyrillic М74
Designation GOST Latin M74
Transliteration M74
By chemical elements Mo74

Description

74 steel is used: for the manufacture of railway rails P50.

Note

M74 — steel open-hearth rail.
Allowed production of rails P50 of the oxygen-Converter steel when you stop the purge of iron in the carbon content not less than 0.60%. Thus in the designation of steel grades the letter «M» is replaced by letter «K» — К74.

Standards

Name Code Standards
Rails. Lining. Lining. Crutches В42 GOST 7174-75, GOST 18267-82, GOST 24182-80

Chemical composition

Standard C S P Mn Si Fe
GOST 24182-80 0.69-0.8 ≤0.045 ≤0.035 0.75-1.05 0.18-0.4 Rest
Fe is the basis.
In rails made of Kerch ores, the content of phosphorus is not more than 0.040%, sulfur is not more than 0.050%, arsenic is not more than 0.15%.
The rails of Group II must be made of calm open-hearth steel, deoxidized with aluminum or manganese-aluminum alloy.

Mechanical properties

Section, mm sT|s0,2, MPa σU, MPa d5, % y, % KCU, kJ/m2 HB, MPa
The mechanical properties of rails type R50 GOST 18267-82. Bulk quenching in oil + Furnace vacation
≥794 ≥1176 ≥6 ≥25 ≥245 341-388
Mechanical properties of steel for rails type R50 GOST 24182-80 on delivery
- ≥860 ≥5 - - -

Description mechanical marks

Name Description
sT|s0,2 Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σU Limit short-term strength
d5 Elongation after rupture
y The relative narrowing
KCU Toughness
HB Brinell hardness number