GARBA 188

Stainless spring wire

GARBA 188 is a general-purpose austenitic stainless steel, which is used for springs and other components requiring good fatigue resistance. The formability is excellent and the corrosion resistance is good against atmospheric corrosion

Chemical composition

C (%) Si (%) Mn (%) P max. (%) S max. (%) Cr (%) Ni (%)
0.05 - 0.15 2.00 2.00 0.045 0.015 16.00 - 19.00 6.00 - 9.50

Mechanical properties

For round wire

Diameter (mm) Tolerance (± mm) Tensile Strength (N/mm²)
0.30 - 0.65 0.008 -
0.66 - 1.01 0.010 -
1.02 - 2.26 0.015 -
2.27 - 4.01 0.020 -
4.02 - 6.26 0.025 -
6.27 - 8.00 0.030 -
0.30 - 0.30 2150 - 2470
0.31 - 0.40 2100 - 2420
0.41 - 0.50 2050 - 2360
0.51 - 0.65 2000 - 2300
0.66 - 0.80 1950 - 2240
0.81 - 1.00 1900 - 2190
1.01 - 1.25 1850 - 2130
1.26 - 1.50 1800 - 2070
1.51 - 1.75 1750 - 2010
1.76 - 2.00 1700 - 1960
2.01 - 2.50 1650 - 1900
2.51 - 3.00 1600 - 1840
3.01 - 3.50 1550 - 1780
3.51 - 4.25 1500 - 1730
4.26 - 5.00 1450 - 1670
5.01 - 6.00 1400 - 1610
6.01 - 7.00 1350 - 1550
7.01 - 8.00 1300 - 1500

Surface conditions

Surface performance
AC-surface 0.30–8.00 mm Ø. The AC-coating can be removed before heat treatment by using a 10-20% nitric acid pickle at room temperature.

Physical properties

E and G modulus of elasticity

Abt. 180 kN/mm2 in drawn condition.
Abt. 185 kN/mm2 after heat treatment.

E and G modulus of shear

Abt. 70 kN/mm2 in drawn condition.
Abt. 73 kN/mm2 after heat treatment.
Density: 7.90 kg/dm3.

Heat conductivity

Temperature oC 20 100 200 400
W/(m* oC) 15.0 15.5 17.5 20.0

Resistivity

Temperature oC 20 100 200 300
nΩm 700 750 800 950

Linear expansion

Pro oC 30-100 30-200 30-300
x10-6 17.0 17.5 18.5

Specific heat capactity

Temperature oC 20 100 200 400
J/(kg* oC) 440 480 520 560

Recommendations

Heat treatment

As soon as possible after coiling, the springs should be stress relieved.
Recommended temperature for compression springs or tension springs without initial tension is approx. 350ºC for 0.5 - 3 hours.