GARBA 178Mo

Stainless spring wire. Similar to EN 1.4310 with increased tensile strength

GARBA 178Mo is a general-purpose austenitic stainless steel that is used for springs and other components requiring good fatigue resistance and good resistance against atmospheric corrosion. Addition of molybdenum increases the tensile strength as compared to GARBA 188 and also increases the resistance against localised and general corrosion.

Chemical composition

C (%) Si (%) Mn (%) P max. (%) S max. (%) Cr (%) Ni (%) Mo (%)
0.05 - 0.15 2.00 2.00 0.045 0.015 16.00 - 19.00 6.00 - 9.50 0.80

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 - 0.40 2250 - 2590
0.41 - 0.50 2200 - 2530
0.51 - 0.65 2150 - 2470
0.66 - 0.80 2100 - 2420
0.81 - 1.00 2050 - 2360
1.01 - 1.25 2000 - 2300
1.26 - 1.50 1950 - 2240
1.51 - 1.75 1900 - 2190
1.76 - 2.00 1850 - 2130
2.01 - 2.50 1750 - 2010
2.51 - 3.00 1700 - 1960
3.01 - 3.50 1650 - 1900
3.51 - 4.25 1600 - 1840
4.26 - 5.00 1550 - 1780
5.01 - 6.00 1500 - 1730
6.01 - 7.00 1450 - 1670
7.01 - 8.00 1400 - 1610

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.

Heat conductivity

Temperature °C 20 100 200 400
W/(m* °C) 15.0 16.0 18.0 20.0

Resistivity

Temperature oC 20 100 200 300
nΩm 700 750 800 950

Linear expansion

Pro °C 30–100 30–200 30–400
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. 420 ºC for 0.5 - 4 hours.