Cast iron hxt (CHNHT)
Designation
| Name |
The value |
| Designation GOST Cyrillic |
НХТ |
| Designation GOST Latin |
HXT |
| Transliteration |
NHT |
| The chemical elements |
НCrTi |
| Name |
The value |
| Designation GOST Cyrillic |
ЧНХТ |
| Designation GOST Latin |
ChHXT |
| Transliteration |
ChNHT |
| The chemical elements |
ZrНCrTi |
Description
Cast iron NHT is used: for the manufacture of parts with high mechanical properties, wear resistance and corrosion in slightly alkaline, gaseous media (internal combustion engines and technical oxygen) and water solutions (of piston ring blanks piston compression and oil control rings, valve seats and valve guides of diesel engines and engine compressors, parts smoothing presses and grinding mills, paper machines).
Note
Nickel corrosion resistant, low alloy, modified, heat-resistant grey iron.
Standards
| Name |
Code |
Standards |
| Castings with special properties (cast iron and steel) |
В83 |
GOST 7769-82, OST 1 90077-72 |
Chemical composition
| Standard |
C |
S |
P |
Mn |
Cr |
Si |
Ni |
Fe |
Ti |
| OST 1 90077-72 |
2.9-3.3 |
≤0.1 |
≤0.3 |
0.6-0.9 |
0.25-0.55 |
1.7-2.3 |
1.5-2 |
The rest |
0.05-0.12 |
| GOST 7769-82 |
2.7-3.4 |
≤0.15 |
0.3-0.6 |
0.8-1.6 |
0.2-0.6 |
1.4-2 |
0.3-0.7 |
The rest |
0.05-0.12 |
Fe is the basis.
According to OST 1 90077-72, with the following mechanical properties and microstructure satisfactory, the following deviations in chemical composition are acceptable: for carbon ± 0.10%, for chromium, silicon, molybdenum, nickel and copper + 0.2% for each.
Mechanical characteristics
| σB, MPa |
Brinell hardness number, MPa |
| Castings on OST 1 90077-72 |
| ≥275 |
217-302 |
Description mechanical marks
| Name |
Description |
| σB |
Limit short-term strength |
Technological properties
| Name |
The value |
| Macrostructure and contamination |
The appearance of the fracture of castings on OST 1 90077-72 should be dense, fine-grained, light-gray, with no signs of chill. Surface of castings shall be cleaned of sand and metal penetration. Sprues, heaving, bays, growths and veining must be cut or polished by abrasive material in the tolerances on the drawing. Nikitina, crack and end-to-end sinks are not allowed. |
| Microstructure |
According to OST 1 90077-72 microstructure of castings after aging should consist of pearlite and acicular sorbitol, graphite, small plate and scatter and separate inclusions of complex phosphide-carbide eutectic. The casting is allowed pearlitic-ferritic microstructure. |
| Features of heat treatment |
According to OST 1 90077-72 castings of modified cast iron are subjected to natural or artificial aging consisting of heat treatment at a temperature of 550-600°C for 3,0-4,0 hours (depending on wall thickness of casting). |
