08ХМФЧА steel is used: for the manufacture of seamless hot-deformed pipes with improved corrosion and cold-resistance (article 08ХМФЧА), with an outer diameter from 60 to 325 mm, strength class not less than K52, infield pipelines, transporting products of oil wells (discharge lines of production wells and the oil-gathering system at pressures up to 6.5 MPa).

Note

Structural alloy steel of high corrosion resistance and cold-resistance.

Standards

Name	Code	Standards
Steel pipes and fittings to them	В62	TU 1317-006.1-593377520-2003, TU 14-3Р-124-2012, TU 1319-369-00186619-2012

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu	N	Al	V	Mo
TU 1317-006.1-593377520-2003	0.08-0.13	≤0.015	≤0.015	0.45-0.65	0.5-0.7	0.2-0.4	≤0.25	Rest	≤0.25	≤0.008	0.03-0.05	0.04-0.1	0.1-0.2
TU 1319-369-00186619-2012	0.07-0.14	≤0.005	≤0.015	0.47-0.63	0.52-0.68	0.19-0.38	≤0.25	Rest	≤0.3	≤0.01	0.02-0.05	0.04-0.08	0.12-0.18

Fe is the basis.
According to TU 1317-006.1-593377520-2003 the chemical composition is given for steel grade 08ХМФЧА. The mass fraction of hydrogen in the steel in the metal of the pipe should not exceed 1.0 ppm (2.0 ppm in the ladle sample, niobium and titanium can be added from the calculation of the mass fraction to 0.030% and 0.010%, respectively.) In the deoxidized steel for the globularization of sulfide inclusions Silicocalcium and ferrocerium are introduced from the calculation of a mass fraction of calcium and cerium of 0.050%.
According to TU 1319-369-00186619-2012 the chemical composition is given for steel grade 08HMFCHA for a ladle sample. The steel must be subjected to modifying treatment with calcium alloys and rare earth elements (cerium, etc.). In the case of using a modifying element only calcium, the ratio of the mass fraction of calcium to the mass fraction of sulfur in the steel should be at least 1.0. The total mass fraction of calcium is not more than 0.0060%. The hydrogen content in the liquid steel should not be more than 2.5 ppm. It is permissible to introduce titanium, niobium and other carbonitride-forming elements into the steel. The total mass fraction of titanium, niobium and vanadium should not be more than 0.15%. The carbon equivalent value should not be more than 0.40% for pipes with a wall thickness of less than 14 mm, and not more than 0.43% for pipes with a wall thickness of 14 mm or more.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	KCU, kJ/m²	HRB
Pipe the seamless hot-deformed heat-treated in the delivery condition on the other 1319-369-00186619-2012. In the graph indicated KCU KCV-50°C/KCU-60°C)
	372-491	≥510	≥23	≥981/588	≤92
Seamless tubes gas & oil heat-treated in the delivery condition on the other 1317-006.1-593377520-2003 (samples in the delivery condition specified strength class, in the column the value is KCU KCV-50 °C)
168-325	372-491	≥510	≥23	≥980	≤92

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
d₅	Elongation after rupture
KCU	Toughness
HRB	Rockwell hardness (indenter steel, spherical)

Technological properties

Name	The value
Macrostructure and pollution	Contamination of the steel pipes on the other 1319-369-00186619-2012 non-metallic inclusions shall not exceed the average score (not to exceed): sulphide (S) and 1.5 for pipes production path, the 2.5 pipe from other manufacturers; oxides (FROM, OS) - 2,5; silicates (CX, SP, SN) of 2.5; nitrides - 1,0.
Microstructure	In the microstructure of tubes subjected to the heat treatment in the mode "full annealing + vacation" should be no more than two continuous strips of ferrite; it allowed a few torn strips of ferrite. Banding of the microstructure of steel pipe subjected to the heat treatment in the mode "full hardening + tempering from MKI + vacation" or "normalization + tempering from MKI + holiday" should not exceed 2 points of the scale 3 the GOST 5640.
Corrosion resistance	In the medium H2S: speed General corrosion ≤ 0.3 mm/year; resistance to hydrogen cracking, CLR = 0 % CTR = 0 %; resistant to sulfide corrosion stress cracking ≥ 80 % of σ0,2.
The corrosion rate	The rate of General corrosion should not exceed 0.5 mm/year.

Steel 08ХМФЧА (08ХМФЧ)

Designation

Description