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.
| 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 |
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 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.
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 |
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.