Material selection for springs

Selection Of Material

Springs

Preeti S Joddabge

TE Mechanical (75)

A Spring is a mechanical device that

returns to its original shape, size and

position after it is stretched , squeezed

or twisted.

Types of springsCompressible Springs

Tension Springs

Cantilever/ Beam Spring

Torsion Springs

Properties of alloying elementsManganese (0.25-13%): Increases strength at high temperatures by

eliminating the formation of iron sulfides. Manganese also improves

hardenability, ductility and wear resistance.

Nickel (2-20%): . Nickel increases strength, impact strength and toughness,

while also improving resistance to oxidization and corrosion. It also increases

toughness at low temperatures when added in small amounts.

Chromium (0.5-18%): At over 12 percent content, chromium significantly

improves corrosion resistance. The metal also improves hardenability,

strength, response to heat treatment and wear resistance.

Silicon (0.2-2.0%): This metalloid improves strength, elasticity, acid

resistance and results in larger grain sizes, thereby, leading to greater

magnetic permeability.

Vanadium : Stabilizes ferrite and tin

Purpose of Heat Treatment

Cold DrawnHard

DrawnOil

Tempered

Oil tempering is done to

reduce brittleness

Cold drawing

process

Hard drawing process

Best Material – Carbon Steel

Music Wire (ASTM A228)Highest quality cold drawn, high carbon wire. Good surface finish.

Maximum Operating Temperature : 250 °F

Modulus of Elasticity (E) (psi x 106) : 30.0

Minimum Tensile Strength (psi x 106) : 230 – 399

Density (lb/in3): 0.284

Nominal Chemistry : C 0.70 - 1.00% , Mn 0.20 - 0.60%

Stainless Steel 302/304 (ASTM A313)

Cold drawn general purpose corrosion and heat resistant.



Minimum Tensile Strength (psi x 106) : 125 - 325


Nominal Chemistry : Cr 17.0 - 19.0% , Ni 8.0 - 10.0%

Music wire Stainless Steel

304/302

Medium Quality Material

Hard Drawn MB (ASTM A227)Cold drawn. Average stress applications. Can be readily electroplated.



Minimum Tensile Strength (psi x 106) : Class I: 147 – 283 ,Class II: 171 - 324


Nominal Chemistry : C 0.45 - 0.85% ,Mn 0.60 - 1.30%

Oil Tempered MB (ASTM A229)Cold drawn and heat treated before fabrication. Slight scale on surface.

General purpose spring wire.



Minimum Tensile Strength (psi x 106) : Class I: 165 – 293 , Class II: 191 - 324


Nominal Chemistry : C 0.55 - 0.85% , Mn 0.60 - 1.20%

Hard Drawn MB Oil Tempered MB

Other Material – Ferrous

Oil tempered silicon Chrome (ASTM A401)Cold drawn and heat treated before fabrication. Used for shock loads and moderately

elevated temperatures.





Nominal Chemistry : C 0.51 - 0.59% , Cr 0.60 - 0.80% ,Si 1.20 - 1.60%

Oil Tempered Chrome Vanadium (ASTM A231)Cold drawn and heat treated before fabrication. Used for shock loads and

moderately elevated temperatures.





Nominal Chemistry : C 0.48 - 0.53% ,Mn 0.70 - 0.90% ,Cr 0.80 - 1.10% , V 0.15 Min %

Oil tempered silicon

Chrome

Oil Tempered Chrome

Vanadium

Other Material – Non Ferrous Phosphor Bronze (ASTM B159)Cold drawn. Good corrosion resistance and electrical conductivity.





Nominal Chemistry : Cu 94.0 - 96.0%, Sn 4.0 - 6.0%

Beryllium Copper (ASTM B197)

Cold drawn. Good corrosion resistance and electrical conductivity. Good physical strength.





Nominal Chemistry : Cu 98.0%, Sn 2.0%

CNC Multi-Axes Wire Bender

Machine

•Computer guided forming

machine provides feed.

•Sensor records angle of each

spring

•Can produce 2000 springs per

hour depending on side

•Can produce all kinds of springs

but on different forming machines

• The diameter ranges from as

thin as hair to as thin as a broom

stick.

Natural Springs

Thank You

Reference : Wikipedia

Introduction To Machine Design – VB Bhandari

http://springipedia.com/material-spring-materials.asp

http://www.bettersprings.com/

http://springipedia.com/material-spring-materials.asp

Material selection for springs

Engineering

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