Cast iron hxt (CHNHT)

Designation

Name The value
Designation GOST Cyrillic НХТ
Designation GOST Latin HXT
Transliteration NHT
By chemical elements НCrTi
Name The value
Designation GOST Cyrillic ЧНХТ
Designation GOST Latin ChHXT
Transliteration ChNHT
By 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 (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 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 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 properties

σU, MPa HB, MPa
Castings on OST 1 90077-72
≥275 217-302

Description mechanical marks

Name Description
σU Limit short-term strength
HB Brinell hardness number

Technological properties

Name The value
Macrostructure and pollution 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).