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. |
