21 NiCrMo 2 2
21 NiCrMo 2 2 is a material in the category Case hardening steels, held under material number 1.6543. We list 17 designations recorded for this grade, in the standards UNS, AISI / SAE and PN. Its recorded composition includes C 0.18–0.23%, Si 0.2–0.35%, Cr 0.4–0.6%, Mn 0.7–0.9% and Ni 0.4–0.7%. Its recorded density is 7.85 g/cm³.
If you came for one of these
The most-used names for this grade.About Case hardening steels
Case hardening steels are steels designed to develop a hard, wear-resistant surface while retaining a tough and ductile core. They are used for components such as gears, shafts and other machine parts exposed to contact wear and cyclic loading.
This describes the material class as a whole. Always confirm the individual grade against the standard before ordering.
Also known as
18 designations · 4 standards · nothing hidden- 21 NiCrMo 2 2This grade’s own nameWithdrawn
Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here.
Chemical composition
8 elements on file · weight %What this alloy is
Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade.
| Element | % by weight |
|---|---|
0.18–0.23 | |
0.2–0.35 | |
0.7–0.9 | |
0.035 | |
0.035 | |
0.4–0.6 | |
0.2–0.3 | |
0.4–0.7 |
The scale is logarithmic, not the element’s raw share of the alloy — the only honest way to fit 0.01 % and 100 % in one picture, and it means every value here can be compared with every other.
| Element | As publishedsource text, verbatim | Min% by weight | Max% by weight | Bound |
|---|---|---|---|---|
| C | 0,18-0,23 | 0.180 | 0.230 | Range |
| Si | 0,20-0,35 | 0.200 | 0.350 | Range |
| P | 0,035 | 0.035 | 0.035 | Exact |
| S | 0,035 | 0.035 | 0.035 | Exact |
| Cr | 0,40-0,60 | 0.400 | 0.600 | Range |
| Mn | 0,70-0,90 | 0.700 | 0.900 | Range |
| Ni | 0,40-0,70 | 0.400 | 0.700 | Range |
| Mo | 0,20-0,30 | 0.200 | 0.300 | Range |
The published column is the source string byte-for-byte, decimal comma and all; Min and Max are the parsed bounds. Elements not listed have no value on file — they are omitted, never inferred.
Predicted transformation temperatures
computed from composition · °CThese four temperatures are a CALCULATION from this grade's own composition, using the published Li, Niebuhr, Meekisho & Atteridge (1998) model — never a measurement, and computed from the UPPER BOUND of each element's specified range, not a mid-range figure. Where this grade also has a measured transformation point (Ac1, Ac3, Ar1, Ar3) on file, it is shown separately, in Physical & mechanical properties, and is never replaced by the predicted figures here — Ae (predicted, equilibrium) and Ac/Ar (measured, on heating or cooling) are different physical quantities and can differ by tens of degrees; a mismatch between the two is not an error in either.
Physical & mechanical properties
An absent property means we hold no value for it — it is left out rather than estimated, interpolated from a neighbouring grade, or filled from a handbook. It does not mean the property is undefined for the material.
Similar grades — and why
Selection rule, stated so you can disagree with it: same number class 1.6, a shared category, and a published range for Mn / Ni that overlaps this grade’s. These are neighbours in composition space — they are not equivalents, and none is claimed to be interchangeable with this grade.
Looking for this grade under another name?
Search the catalogue by designation, material number or composition — every name on this page is itself a way in.