Steel 12X8 (1X8)

Designation

Name	The value
Name	The value
Designation GOST Cyrillic	12Х8
Designation GOST Latin	12X8
Transliteration	12H8
By chemical elements	12Cr8

Name	The value
Name	The value
Designation GOST Cyrillic	1Х8
Designation GOST Latin	1X8
Transliteration	1H8
By chemical elements	1Cr8

Description

12X8 steel is used: for the manufacture of seamless pipes for petroleum refining and petrochemical industries operating at temperatures to +450 °C; the furnace and the communication pipes used in power and heat networks; of billets intended for production of tubes of the cracking units of oil refining.

Note

Steel martensitic class.

Standards

Name	Code	Standards
Name	Code	Standards
Steel pipes and fittings to them	В62	GOST 550-75, TU 14-3-457-76, TU 14-3-463-2005
Blanks. Of the workpiece. Slabs	В31	TU 14-1-583-73

Chemical composition

Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu
Standard	C	S	P	Mn	Cr	Si	Ni	Fe	Cu
TU 14-3-457-76	≤0.12	≤0.03	≤0.035	0.3-0.6	7.5-9	0.17-0.37	≤0.4	Rest	≤0.25

Fe is the basis.
According to TU 14-1-583-73, GOST 550-75, TU 14-3-457-76 the chemical composition is given for steel grade 12X8. In the finished rolled products, deviations in chemical composition are allowed in accordance with GOST 20072.

Mechanical properties

Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²	HB, MPa
Section, mm	s_T\|s_0,2, MPa	σ_U, MPa	d₅, %	y, %	KCU, kJ/m²	HB, MPa
Tubular billet on the other 14-1-583-73 after annealing
	≥215	≥390	≥24	≥50	≥1177	≤170
Tubes seamless cold - and warm, heat-treated in the delivery condition according to GOST 550-75
	≥216	≥392	≥22	-	-	≤170
Pipe kiln and communication in the delivery condition on the other 14-3-457-76 (impact strength is specified for tubes with wall thickness ≥ 12 mm and is determined for longitudinal samples)
	≥196	≥392	≥22	≥50	≥780	≤170

Description mechanical marks

Name	Description
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
y	The relative narrowing
KCU	Toughness
HB	Brinell hardness number

Technological properties

Name	The value
Name	The value
Macrostructure and pollution	The macrostructure of billets, check for the etched cross templeto should not have shrinkage looseness, bubbles, delaminations, voids, cracks, inclusions and placenow visible without using the magnifying devices. The defects allowed on a point inhomogeneity, the Central porosity and segregation must not exceed 2 points (for each species), subcortical bubbles at 1 point at a depth of less than 2 mm.