Steel 12X8 (1X8)

Designation

Name The value
Designation GOST Cyrillic 12Х8
Designation GOST Latin 12X8
Transliteration 12H8
By chemical elements 12Cr8
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
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
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 sT|s0,2, MPa σU, 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
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

Technological properties

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.