Raw Materials

A good product needs targeted research.

A good product needs targeted research. Research into rigidity, for example, may lead us to propose a different material to the one you usually use. There is a long list of options. The materials we use most often are listed below. And here’s why

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General Points

Rapic Matieres premières pour ressorts 350pix

Industrial production of a spring calls for the material used to be compatible with the radii required, to be defect-free, inexpensive and readily available. In addition, it must have all the following properties:

  • High yield strength
  • Good fatigue resistance
  • Good corrosion resistance
  • Fitness for purpose (food-industry, medicine)

he purpose of a spring is to store and subsequently to release energy.

The more stress a material can bear before becoming distorted, the better suited it is for use in manufacturing springs.

In industrial spring production, the material used should preferably be:

  • Easy to coil
  • Defect-free
  • Inexpensive
  • Readily available

For this reason, most of our springs are made of steel (stainless or not)

Here are our three, most commonly used types of steel:

  • Unalloyed steel, cold drawn, patented (EN10270-1)
  • Unalloyed steel, oil-hardened and tempered (EN10270-2)
  • Stainless steel (EN10270-3)
  • European standards sort unalloyed drawn steels into five classes (SL [barely used], SM, SH, DM, DH) and alloyed drawn steels into nine classes (1.4310 (AISI302) is the most commun)

Drawn steels, often used in spring production, have good fatigue resistance and their yield strength increases when spring coiling is followed by heat treatment (tempering or aging)

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Treatments

These (unalloyed) steels have poor corrosion resistance but may easily be coated (white zinc, chromium, paint…) in accordance with the environment of your product.

They work at very low temperatures and are subject to stress relaxation at high temperatures.

Their application field is between -80°C and +150°C.

Hardened steels have good fatigue resistance and are less subject to stress relaxation than drawn steels.

Depending on the extent of relaxation permitted, their application field is between -20°C and +170°C

These steels have poor corrosion resistance and are more “brittle” and highly expensive.

To avoid corrosion problems, we suggest using stainless steel.

We mainly use 1.4310 grade stainless steel, also known as AISI 302. It contains 18% chromium and 8% nickel.

It has a fairly extensive application field of between -200°C and 300°C. Beware, however, that it is nonmagnetic only in the annealed condition. We offer matte, glossy and (high-resistance) 302.

Other grades we use on a regular basis are AISI 304, 316 and 17/7PH. Less commun, but even better material is the springflex SH (1.4462-S3).

Other materials may be used in special applications, such as phosphorus copper alloys for high electrical conductivity.

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Types of Steel

Some Properties of Frequently-Used Steels.
MatérialSH Steel302 stainless steel
Wire Diameter(mm) de 0.3 à 12 de 0.15 à 15
r(Kg/dm3) 7.85 7.90
G (N/mm²) 82000 73000
E (N/mm²) 206000 190000
Rm0 2300 2000
Rm = f(d) (N/mm²) 2300 - 850 log (d) 2000 - 680 log (d)
Maximum torsion stress t zul 0.56 Rm 0.56 Rm
Maximum tensile stress s zul 0.70 Rm 0.70 Rm
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Steel references

SM/SH Steel (Medium tensile static /High tensile static)

Galvanized SM/SH Steel

DM/DH (Medium tensile dynamic/High tensile dynamic)

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Stainless steel references

302

  • Matte
  • Glossy
  • HR (High resistance)

Main grades (spring and mold): 302, 304, 304L, 316, 316L, 316Ti, 631.

Springflex SH (Sandvik very high resistance stainless steel)

Etc.

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