DIN / EN · Europe · 1 designation

71Si7

71Si7 is a material in the category Spring steels, held under material number 1.5029. Its recorded composition includes C 0.68–0.75%, Si 1.5–1.8%, P 0.035%, S 0.035% and Mn 0.6–0.8%. No cross-standard equivalents are recorded for this grade yet. Its recorded density is 7.85 g/cm³.

Material no. 1.5029
Category Spring steels · 52 grades
Designations 1

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About Spring steels

Spring steels are alloy steels designed to store and release elastic energy repeatedly without permanent deformation. They are characterised by a combination of strength, hardness and resilience, making them suitable for springs, clips, washers and other components subjected to repeated flexing or shock.

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

Chemical composition

5 elements on file · weight %

What this alloy is

Iron — the balance, never listed by a standard — 96.9 %Si — 1.7 %C — 0.7 %Mn — 0.7 %Traces & impurities · 0.1 %

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

Element	% by weight
	0.68–0.75
	1.5–1.8
	0.6–0.8
	0.035
	0.035

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	0,68-0,75	0.680	0.750	Range
Si	1,50-1,80	1.500	1.800	Range
P	0,035	0.035	0.035	Exact
S	0,035	0.035	0.035	Exact
Mn	0,60-0,80	0.600	0.800	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

Not enough recorded composition to predict a transformation temperature for this grade — missing: Ni, Cr, Mo.

Physical & mechanical properties

Density7,85g/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 1.5, a shared category, and a published range for Si / Mn 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.

38Si71.5023

Si 1,50-1,80 · Mn 0,50-0,80