ASTM · United States · 18 designations

B 755

B 755 is a designation in ASTM for the material held under material number 2.4858, also listed as NiCr21Mo. It is a material in the category Nickel and cobalt alloys. We list 18 designations recorded for this grade, in the standards DIN / EN, UNS, ASTM, BS and AFNOR.

Material no. 2.4858
Category Nickel and cobalt alloys · 87 grades
Designations 18

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If you came for one of these

The most-used names for this grade.

About Nickel and cobalt alloys

Nickel and cobalt alloys are metallic materials whose properties are developed through nickel-, cobalt-, or combined alloying systems. They are characterised by strong resistance to corrosion, oxidation, wear, and loss of strength at elevated temperatures, making them suitable for turbine components, chemical-processing equipment, and other demanding high-temperature applications.

This describes the material class as a whole. Always confirm the individual grade against the standard before ordering.

Also known as

18 designations · 5 standards · nothing hidden

This grade’s own namerecorded in our sources as this grade’s own designation under that standard.

Indicativetaken from a published cross-reference table; a close match, not a guarantee of interchangeability. Verify against the mill certificate before ordering.

Withdrawndesignation no longer current — a separate column from the two above, so a name can be same grade and withdrawn at once.

DIN / ENEurope · 1

NiCr21MoThis grade’s own name

UNSUnited States · 2

ASTMUnited States · 13

BSUnited Kingdom · 1

3072-76Indicative

AFNORFrance · 1

NC 21 FeDUIndicative

Every designation on file is listed — no truncation, no “+ n more”. Each one is itself a route that leads back here.

Chemical composition

13 elements on file · weight %

What this alloy is

Iron — the balance, never listed by a standard — 27.6 %Ni — 42 %Cr — 21.5 %Mo — 3 %Traces & impurities · 5.9 %

Logarithmic scale, 0.01 % to 100 % — every value here compares directly, decade by decade.

Element	% by weight
	≤ 0.025
	≤ 0.5
	≤ 1
	0.02
	0.015
	19.5–23.5
	2.5–3.5
	38–46
	≤ 1
	1.5–3
	≤ 0.2
	0.6–1.2
	Balance

0.01 %0.1 %1 %10 %100 %

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	≤0,025	—	0.025	Max
Al	≤0,20	—	0.200	Max
Si	≤0,50	—	0.500	Max
P	0,02	0.020	0.020	Exact
S	0,015	0.015	0.015	Exact
Ti	0,60-1,20	0.600	1.200	Range
Cr	19,5-23,5	19.500	23.500	Range
Mn	≤1,00	—	1.000	Max
Fe	Rest/Bal.	20.040	37.865	Balance
Co	≤1,00	—	1.000	Max
Ni	38,0-46,0	38.000	46.000	Range
Cu	1,50-3,00	1.500	3.000	Range
Mo	2,50-3,50	2.500	3.500	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

This grade's composition falls outside the published model's validated range (a low-alloy composition window), so no transformation temperature is predicted here.

Physical & mechanical properties

Density8,14g/cm³Exact

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 2.4, a shared category, and a published range for Ni / Fe 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.

NiCr13Mo6Ti32.4662

Ni 40,0-45,0 · Fe Rest/Bal.