Steel 20KHMFL

Designation

Name	The value
Designation GOST Cyrillic	20ХМФЛ
Designation GOST Latin	20XMFL
Transliteration	20HMFL
By chemical elements	20CrMoV

Description

20KHMFL steel is used: for the manufacture of parts of valves, body parts, cylinders, casting parts, steam, gas, hydraulic turbines and axial compressors operating at temperatures to +540 °C; casting equipment parts (valves) for nuclear power stations, heat supply stations, heat and power plants, experimental and research nuclear reactors and installations.

Note

Steel pearlitic class.

Standards

Name	Code	Standards
Steel castings	В82	GOST 977-88, OST 108.961.04-80, TU 108.02.123-87, TU 5.961-11151-92
Castings with special properties (iron and steel)	В83	OST 108.961.02-79, OST 108.961.03-79
Welding and cutting metals. Soldering, riveting	В05	RTM 108.020.122-78

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	V	Mo
OST 108.961.02-79	0.18-0.25	≤0.025	≤0.025	0.6-0.9	0.9-1.2	0.2-0.4	≤0.3	Rest	≤0.3	0.2-0.3	0.5-0.7
GOST 977-88	0.18-0.25	≤0.025	≤0.025	0.6-0.9	0.9-1.2	0.2-0.4	-	Rest	-	0.2-0.3	0.5-0.7

Fe is the basis.
According to OST 108.961.04-80, the total sulfur and phosphorus content should be ≤ 0.050% for all possible tolerances.
According to TU 5.961-11151-92 for castings of grades 1 and 2 the mass fraction of cobalt in steel should not exceed 0.20%, and for castings in the direct irradiation zone - 0.15%.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d	y, %	KCU, kJ/m²	HB, MPa
Normalization at 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C, air cooling
100	≥275	≥491	≥16	≥35	≥294	-
Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Homogenization at 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
-	≥275	≥490	≥16	≥35	≥490	159-223
Casting parts of gas turbines. Homogenization at 970-1000 °C, air cooling + Normalization at 960-980 °C, air cooling + Vacation at 710-740 °C, air cooling
-	≥314	≥490	≥15	≥30	≥290	159-223
Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Homogenization at 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
-	≥260	≥480	-	≥32	-	-
Casting parts stationary steam turbines. Homogenization (normalization) when 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C, air cooling
150х170	280-550	≥500	≥16	≥35	≥294	156-223
Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Homogenization at 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
-	≥250	≥470	-	≥34	-	-
Casting parts stationary steam turbines. Homogenization (normalization) when 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C, air cooling
100х150	300-550	≥500	≥16	≥35	≥294	159-223
Castings with wall thickness up to 100 mm in the delivery state on the other 5.961-11151-92. Homogenization at 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C. the Critical temperature of brittleness of TKO ≤ 55 °C.
-	≥250	≥460	-	≥35	-	-
Casting parts stationary steam turbines. Homogenization (normalization) when 970-1000 °C + Normalization at 960-980 °C + Vacation at 710-740 °C, air cooling
60х150	320-550	≥500	≥16	≥35	≥294	159-223

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
d	Elongation after rupture
y	The relative narrowing
KCU	Toughness
HB	Brinell hardness number

Technological properties

Name	The value
Weldability	Limited weldability. The welding process - SMAW. When welding requires preheating. After welding and repair of defects by welding is used vacation at 690-710 °C.
Welding defects	Welding defects of castings after cutting is carried out with preliminary and attendant heating up to 350-400 °C. for semi-automatic welding in carbon dioxide environment used wire SV-08ХГСМФА with a diameter of 2 mm at a current of 300-350 A. Welding defects by manual welding is done with electrodes type e-09Х1МФ (GOST 9467) brand ЦЛ20. When heat treated after welding defects to cool in the oven to 100-150 °C at a rate of 30-50 °C/h and further in the air.