Steel 12МХЛ (12ХМЛ)

Designation

Name The value
Designation GOST Cyrillic 12МХЛ
Designation GOST Latin 12MXL
Transliteration 12MHL
By chemical elements 12MoCr
Name The value
Designation GOST Cyrillic 12ХМЛ
Designation GOST Latin 12XML
Transliteration 12HML
By chemical elements 12CrMo

Description

12МХЛ steel is used: for the manufacture of castings parts, steam, gas, hydraulic turbines and axial compressors operating at temperatures up to +510 °C.

Note

Steel pearlitic class.

Standards

Name Code Standards
Castings with special properties (iron and steel) В83 OST 108.961.02-79
Steel castings В82 OST 108.961.04-80
Welding and cutting metals. Soldering, riveting В05 RTM 108.020.122-78

Chemical composition

Standard C S P Mn Cr Si Ni Fe Cu Mo
OST 108.961.04-80 ≤0.13 ≤0.03 ≤0.03 0.5-0.8 0.5-0.8 0.25-0.5 ≤0.3 Rest ≤0.3 0.4-0.6
OST 108.961.02-79 ≤0.13 ≤0.025 ≤0.025 0.5-0.8 0.5-0.8 0.25-0.5 ≤0.3 Rest ≤0.3 0.4-0.6
Fe is the basis.
According to OST 108.961.02-79 and OST 108.961.04-80 the chemical composition is given for steel grade 12MHL.

Mechanical properties

sT|s0,2, MPa σU, MPa d y, % KCU, kJ/m2
Casting parts of gas turbines. Normalization at 880-920 °C, air cooling + vacation at 620-650 °C, cooling with the furnace to 300 °C, air cooling
≥196 ≥392 ≥20 ≥40 ≥490
Casting of body parts stationary steam turbines. Normalization at 880-920 °C + vacation at 620-650 °C, air cooling
≥200 ≥400 ≥20 ≥40 ≥490

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
d Elongation after rupture
y The relative narrowing
KCU Toughness

Technological properties

Name The value
Welding defects Welding defects of castings after cutting is carried out with preliminary and attendant heating up to 200-250 °C. With semi-automatic welding in carbon dioxide environment used wire SV-08ХГСМА with a diameter of 2 mm at a current of 300-350 A. Welding defects by manual welding is done with electrodes type e-09Х1М (GOST 9467) brand SSSI-13/HMM. Welding of samples with a volume of 5000 cm3 is necessary to produce a cascade fashion without interruption. In case of interruption of the portion of the defect must be preheated to 200-250 °C.