Steel Х56

Designation

Name The value
Designation GOST Cyrillic Х56
Designation GOST Latin X56
Transliteration H56
By chemical elements Cr56

Description

Х56 steel is used: for the manufacture of electric-welded longitudinal pipes ekspandirovannogo increased corrosion resistance and cold-resistance, used for pipelines, process and field pipelines for operating pressure up to 7.4 MPa to transport crude oil and petroleum products, pipelines of formation pressure maintenance in any climatic zones.

Standards

Name Code Standards
Steel pipes and fittings to them В62 TU 1381-116-00186654-2013

Chemical composition

Standard C S P Mn Cr Si Ni Fe Cu N Al V Nb
TU 1381-116-00186654-2013 ≤0.12 ≤0.005 ≤0.015 ≤0.7 0.5-0.7 0.17-0.5 0.3-0.4 Rest 0.2-0.3 ≤0.01 0.02-0.05 0.04-0.09 0.04-0.06
Fe is the basis.
According to TU 1381-116-00186654-2013 the chemical composition is given for steel grade X56. The mass fraction of calcium in the steel should not be more than 0.0050% (50ppm) (optional). For globularization of inclusions, steel is treated with calcium-containing materials. The alloying of REM steel is allowed. The ratio of Ca / S is not less than 1. It is possible to add titanium from the calculation of the mass fraction in steel no more than 0.030%. Steel should be subjected to vacuum degassing: the mass fraction of hydrogen in the liquid steel after degassing should be no more than 2ppm. The mass fraction of hydrogen is taken from the document on the quality of rolled sheets. If the hydrogen content is more than 2ppm, the slabs should be subjected to anti-flock treatment (PFD) in heated or unheated rings. The mass fraction of Nb + V is not more than 0.15%. In the steel, the carbon content is allowed up to 0.14% in an amount not exceeding 15% of the order quantity. Permissible deviations in chemical composition: carbon + 0.010%, manganese + 0.020%, silicon ± 0.050%, sulfur + 0.0010%, phosphorus + 0.0030%, aluminum + 0.010%, copper +0.050 % by nickel +0,050, by chromium ± 0,050%, by vanadium + 0,020%, by nitrogen + 0,0010%. The carbon equivalent value should not exceed 0.43, and the resistance parameter against cracking P cm should not exceed 0.25.

Mechanical properties

Section, mm sT|s0,2, MPa σU, MPa d5, % d KCU, kJ/m2 HRC HRB HV, MPa
Plates for pipes according to TU 1381-116-00186654-2013 (samples transverse, in the column δ indicates the value of δ2, KCU-60°C/KCV-20°C)
≥415 490-610 - ≥30 ≥700/700 - ≤86 -
Pipe on the other 1381-116-00186654-2013 (samples transverse, are indicated in the graph KCU KCU-60°C/KCV-20°C)
≥390 490-610 ≥20 - ≥392/392 ≤22 - ≤250

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
d Elongation after rupture
KCU Toughness
HRC Rockwell hardness (indenter diamond spheroconical)
HRB Rockwell hardness (indenter steel, spherical)
HV The Vickers hardness

Technological properties

Name The value
Corrosion resistance On the other 1381-116-00186654-2013: Speed General corrosion ≤0.5 mm/year; Resistance to hydrogen cracking in the CLR≤6%, CTR≤3%; Resistance to stress corrosion cracking under tension σth ≥72% of σT.