Steel 03Н18К9М5Т (ЭП637; МС200)

Designation

Name	The value
Designation GOST Cyrillic	03Н18К9М5Т
Designation GOST Latin	03H18K9M5T
Transliteration	03N18K9M5T
By chemical elements	03Н18Co9Mo5Ti

Name	The value
Designation GOST Cyrillic	ЭП637
Designation GOST Latin	EP637
Transliteration	EhP637
By chemical elements	-

Name	The value
Designation GOST Cyrillic	МС200
Designation GOST Latin	MC200
Transliteration	MS200
By chemical elements	MoС200

Description

03Н18К9М5Т steel is used: for the production of bodies of rocket motors, the shafts of helicopters, welded hulls, engines, pressure vessels of large dimensions, details of artillery and small guns, hulls of submarines, submersibles, high-load disc turbines, gears and parts gears, spindles, worms, etc.; heavily loaded machine parts and mechanisms operating in conditions of far North.

Note

Maraging high-alloy, corrosion-resistant, heat-resistant and heat-resistant steel with higher structural stability in the temperature range from cryogenic to +500 °C.

Standards

Name	Code	Standards
Processing of metals by pressure. Forgings	В03	TU 14-1-1530-75, TU 14-1-1531-75
Bars and shapes	В32	TU 14-1-3039-80, TU 14-1-1898-76

Chemical composition

Standard	C	S	P	Mn	Si	Ni	Fe	Cu	Al	B	Ti	Mo	Co
TU 14-1-3039-80	≤0.03	≤0.01	≤0.01	≤0.1	≤0.1	17.7-19	Rest	-	≤0.15	-	0.5-0.8	4.6-5.5	8.5-9.5
TU 14-1-1898-76	≤0.03	≤0.01	≤0.01	≤0.1	≤0.1	17.7-19	64.797-68.7	Rest	≤0.15	≤0.003	0.5-0.8	4.6-5.5	8.5-9.5

Fe is the basis.
According to TU 14-1-1898-76 and TU 14-1-3039-80 the chemical composition is given for steel grade 03N18K9M5T (EP637).
According to TU 14-1-3039-80, if steel is smelted by open smelting with subsequent electron-beam remelting, then the carbon content is not more than 0.020% and in this case the steel is marked 02N18K9M5T-EL (EP637A-EL). The calculated content of modifiers and deoxidizers: magnesium, hafnium, cerium, germanium and boron is established by the supplier's technological instructions and their residual content in the metal is not determined by chemical analysis. In the finished product, deviations in the sweat of the norms of chemical composition are permissible: nickel -0.20%, silicon and manganese - not regulated, but the sum of their content should not exceed 0.20% and in this case the steel is marked 02N18K9M5T-EL (EP637A-EL ), sulfur and phosphorus are not regulated, but the sum of their content should not exceed 0.020%. The residual chromium content should not exceed 0.30%.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	y, %	KCU, kJ/m²
Bars hot rolled and pressed extra virgin in the state of delivery on the other 14-1-1898-76. Quenching + Aging (longitudinal samples)
	≥1850	≥1950	≥40	≥350
Bars and rods, hot-rolled 03Н18К9М5Т-VD (ЭП637-VD, ВКС210-VD) TU 14-1-3039-80. Hardening in air, 810-830 °C + Aging at 500-520 °C (extract 3 hours), air cooling
	-	≥1913	≥45	≥290

Description mechanical marks

Name	Description
s_T\|s_0,2	Yield strength or limit of proportionality with a tolerance for residual deformation of 0.2%
σ_U	Limit short-term strength
y	The relative narrowing
KCU	Toughness

Technological properties

Name	The value
Weldability	Well welded in thin and massive loft.
Microstructure	The macrostructure of the steel on the other 14-1-3039-80 should not have shrinkage and looseness, bubbles, cracks, inclusions, crusts, delamination and placenow visible without using the magnifying devices.