SteelKey facts
- Hard drawn spring wire is strengthened by cold drawing, which is done at room temperature.
- Oil tempered spring wire is hardened by quenching and then tempered, which trades some hardness for toughness.
- EN 10270-2 is the standard for oil hardened and tempered spring steel wire, and EN 10270-1 covers patented cold drawn wire.
- The spring drawing decides the type, so the wire type, standard and tensile band belong in the order.
- Reinwent’s spring wire is high carbon wire from 1.3 to 4 mm, with standards on request.
The short answer
A spring has to be stiff and elastic at once. Steel gets there by two common routes. In the first the wire is pulled through dies until the drawing itself has made it strong. In the second the wire is hardened by quenching in oil and then tempered, so the strength comes from heat treatment of the wire. The first is called hard drawn, the second oil tempered, and both end up as coil springs.
This page helps a buyer choose between the names and write the order. It does not rank them. For the spring itself, start with what spring wire is, and for the standards read spring wire standards.
How hard drawn spring wire gets its strength
Hard drawn means the wire is left in its drawn state. Wikipedia says wire drawing is usually done at room temperature and that the strengthening effect can be substantial. IspatGuru describes drawn steel as stronger than the rod it started from. The wire gets harder and stronger and loses ductility, which is the general rule of cold work.
Our guide to hard drawn vs annealed wire explains that rule against soft wire, and the wire drawing process shows the steps. For spring work the point is simple: the strength is built in by the pull through the dies,.
The European standard in this family is EN 10270-1. BSI lists it as covering patented cold drawn unalloyed spring steel wire. Patented is in the title, but none of the pages we read explains the step, so we do not explain it either.
How oil tempered spring wire gets its strength
Oil tempered wire follows a different order of work. Wikipedia defines quenching as rapid cooling of steel, with oil among the liquids used, and says it leaves steel very hard and sometimes too brittle. Tempering is then done after quenching. Wikipedia says it gives greater toughness by decreasing hardness, and that ductility usually rises as brittleness falls.
So the name tells you two things: the wire was hardened in oil, and it was tempered afterwards to take the brittleness out. We give no tempering figures. None of the sources we read ties a figure to spring wire, and the right values belong to the mill and the standard.
The European standard for this wire is EN 10270-2. BSI says it applies to oil hardened and tempered spring steel wire made from unalloyed or alloyed steels, and that the wire is mainly loaded in torsion, as in coil springs for compression and extension.
The two routes side by side
| Feature | Hard drawn | Oil tempered |
|---|---|---|
| Where the strength comes from | Cold drawing through dies | Quenching in oil, then tempering |
| Standard family | EN 10270-1 (patented cold drawn) | EN 10270-2 (oil hardened and tempered) |
| Steel named in the standard scope | Unalloyed | Unalloyed or alloyed |
| Main loading in the scope | Static and dynamic duty | Torsion, as in coil springs |
| What a buyer writes | Diameter, standard, class, tensile band | Diameter, standard, grade, tensile band |
Read the table as scope wording, not as a quality ranking. The two standards were written for different wires, and the grade or class inside each one sets the numbers.
Where each type is used
The same duty can be met either way, so use depends on the spring. Wikipedia says many grades of steel can be hardened and tempered to raise elasticity and resist deformation, which is the case for the oil tempered route. Hard drawn wire is the usual choice where the spring drawing names a cold drawn standard.
Both wires go into coil springs, the compression, extension and torsion kinds described in our spring wire guide. Our own product page adds vehicle springs such as suspension springs and formed parts that must return to shape after bending. It does not say which route those parts follow, and we do not assign one. The material behind both types is covered in high carbon steel wire, and the whole map of wire is in types of steel wire.
What a buyer should specify
- Diameter in millimetres. Our spring wire is offered from 1.3 to 4 mm. Convert any gauge number with the wire gauge chart.
- Wire type. Say hard drawn (patented cold drawn) or oil hardened and tempered, in the words of your drawing.
- Standard and class or grade. EN 10270-1 for the first and EN 10270-2 for the second, or the one your customer names.
- Tensile band. Write a minimum and maximum in N/mm² where strength matters. See what high tensile wire means.
- Surface. Bare or coated, as your coiling line and the spring’s environment require.
- Coil weight. Give the weight your winding machine takes. How coils travel is in the container loading guide.
- Duty, quantity and port. State whether the spring is under static or dynamic load.
If you only know the spring maker’s old name for the wire, send it as it is written. We will put it to manufacturers and ask for the standard behind it.
What Reinwent offers
Reinwent is a trading and sourcing company, not a manufacturer. We do not draw, quench or temper wire. Our spring steel wire is high carbon spring wire from 1.3 to 4 mm, with standards on request. We do not state on the page which of the two routes a given coil follows. The wire type, the standard and the tensile band are agreed per order and confirmed in the quotation.
We source from manufacturers in Türkiye, collect their offers and set them on one basis. The supply route is described in spring steel wire from Türkiye. A quotation reaches you within 12 hours at the latest. When your diameter, type, standard, tensile band and coil weight are settled, request a quote.
