|Designation GOST Cyrillic||12Х2НМФА|
|Designation GOST Latin||12X2HMFA|
|By chemical elements||12Cr2НMoV|
12KH2NMFA steel is used: for the manufacture of welded assemblies and structures, not subjected to heat treatment after welding (including off), which requires increased strength, but also for the manufacture of loaded welded parts. Steel can be used for carburized parts operating at temperatures of 230−250 °C, and welded and nesvorny parts operating at temperatures up to 500 °C.
Alloy structural steel high quality with low carbon content. Steel 12KH2NMFA strengthen by heat treatment (quenching in oil with subsequent tempering or normalizing with tempering).
|Sheets and strips||В33||GOST 11268-76, GOST 11269-76|
|Sheets and strips||В23||GOST 82-70|
|Bars and shapes||В32||TU 14-1-1885-85, TU 14-1-950-74|
According to TU 14-1-1885-85 the chemical composition is given for 12Х2НМФА-ВД steel. The presence of tungsten to 0.20%, titanium to 0.030% is not a rejection sign. In the steel, partial replacement of molybdenum with tungsten is allowed. The total content of molybdenum and tungsten converted to molybdenum from the calculation: three parts by weight of tungsten replace one part by weight of molybdenum, should correspond to the content of molybdenum indicated in the table. In this case, the content of tungsten in steel should not exceed 0.30%. The allowable variation in manganese content in steel is ± 0.010%.
|Section, mm||sT|s0,2, MPa||σU, MPa||d5, %||d10||y, %||KCU, kJ/m2||HB, MPa|
|Steel hot-rolled sheet (4-60 mm) 4-th and 5-th categories. Quenching in oil with 910±15 °C, leave at 490-550 °C, air cooling|
|Flats on the other 14-1-4118-2004|
|Bars and strip hot rolled and forged. Quenching in oil with 995-925 °C + vacation at 500-550 °C, air cooling|
|Rods made of steel 12KH2NMFA on the other 14-1-1885-85. Quenching in oil with 895-925 °C + Vacation at 480-510 °C, air cooling. In the graph KCU KCU values are shown along the fiber/KCU across the grain|
Description mechanical marks
|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|
|d10||Elongation after rupture|
|y||The relative narrowing|
|HB||Brinell hardness number|
|Macrostructure and pollution||Macrostructure of steel when testing for the breaks in the longitudinal direction and transverse templeto selected from rolled, should not have shrinkage, porosity, bubbles, cracks, delamination, inclusions and placenow and defects of fracture, listed in Annex 3 GOST 10243. The Central porosity, point heterogeneity and phase separation in the square should not exceed 1 points; layer-by-layer crystallization and the bright loop - 3 points reference scales GOST 10243. All other defects under GOST 10243, are not allowed. Pollution steel non-metallic inclusions should be according to the average score is not higher (in points): oxides of point 1,5, 2,0 stroke oxides, silicates fragile 1,0, 1,0 silicates plastic, silicates, non-deformed 2,5, 2,5 sulfides, nitrides stroke and point 1,0.|