Nitralloy 135 Alloy Steel

General Characteristics of Nitralloy Steel

This is a low alloy nitriding steel with moderate hardenability. It shows high case hardness and maintains its core strength during nitriding. Vacuum arc remelting provides superior micro-cleanliness.

Chemical analysis-typical

C% Mn% Si% Cr% Mo% Al%
0.40 0.60 0.30 1.60 0.35 1.20


Aircraft gears, forged shafts, pinions, crankshafts, cams, camshafts and bolts


Heat uniformly to 2000-2025ºF (1090-1105ºC) and do not forge below 1700ºF (925ºC.) Air cool after forging.

Heat Treatment


Heat to 1700ºF (925ºC) and slow cool or sub-critical anneal at 1250-1300ºF (675-705.)


at 1800ºF (980ºC) for 1-4 hours and air cool.


Austenitize at 1700-1750ºF (925-955ºC) for ½ hr per inch of cross section and water or oil quench. Water quench is preferred when cross section exceeds 1 inch in thickness.


The tempering temperature is between 1000-1300ºF (540-705ºC) depending upon required properties, and basically 1 hour at temperature per inch of thickness.


the nitriding time, temperature and method will depend upon the final product application. The nitriding temperature is normally 900-1100ºF (480-595ºC.)


Machinability is satisfactory in the annealed or normalized conditions.


This alloy may be welded by normal fusion methods, with preferable preheat and postheat. Welding will only be carried out prior to surface hardening.