
General Points
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)

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.

Types of Steel
Matérial | SH Steel | 302 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 |

Steel references
SM/SH Steel (Medium tensile static /High tensile static)
Galvanized SM/SH Steel
DM/DH (Medium tensile dynamic/High tensile dynamic)

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.