General description
BPS-SB-1100SMA is an austenitic stainless, general purpose steel with good spring properties that in most cases fulfill demands regarding corrosion resistance, mechanical strength, fatigue and relaxation properties.
Service temperature ...............................up to 250°C
Chemical composition (nominal) %
|
C |
Si |
Mn |
P max |
S max |
Cr |
Ni |
Mo |
Others |
|
0.10 |
1.2 |
1.3 |
0.030 |
0.010 |
16.5 |
7 |
- |
- | Standards: EN: 1.4310
Forms of supply
The belt can be supplied either in coils . The coil weight is max 5 kg/mm (280lbs/inch) of belt width.
Hardening and tempering of the steel belt is needed to achieve the correct finish and to meet the properties required by the end user.
Dimensions
The following range of thicknesses and widths can be supplied as standard.
|
Thickness, mm |
Width, mm |
Thickness, inch |
Width, inch |
|
0.015 - 3.00* |
2 - 2400 |
.0006 - .118 |
.079 - 100 | Tolerances: See the tolerance tables
Mechanical properties
Static strength
Nominal values at 20°C (68°F)
|
Condition |
Tensile strength, Rm |
Proof strength, Rp0,2a) |
Elongation, A11,3 |
|
MPa |
ksi |
MPa |
ksi |
% |
|
A |
850 |
116 |
300 |
44 |
50 |
|
C |
1300 |
189 |
1150 |
167 |
15 |
|
CT |
1350 |
196 |
|
|
| a) Rp0.2 corresponds to 0.2% offset yield strength.
1 MPa = 1 N/mm2
A = Annealed
C = Cold rolled
CT = Cold rolled and tempered, 350°C (662°F)/3 h
Fatigue strength
Nominal values at 20°C (68°F) in a normal dry atmosphere. The fatigue limit is defined as the stress at which 50% of the specimens withstand a minimum of 2 million load cycles.
Reversed bending stress
Average stress = 0
Bending transversal to rolling direction.
Comparision made for different thicknesses and tensile strength levels.
|
Tensile strength,
Rm |
Fatigue limit, MPa |
|
Tensile strength,
Rm |
Fatigue limit, ksi |
|
|
Thickness, mm |
|
|
Thickness, inch |
|
MPa |
0,50 |
0,75 |
|
ksi |
0.020 |
0.030 |
|
1500 |
± 555 |
± 525 |
|
218 |
± 80.5 |
± 76.2 |
|
1700 |
± 560 |
± 545 |
|
247 |
± 81.3 |
± 79.1 | Fluctuating tensile stress
Minimum stress = 0
Specimens parallel to rolling direction.
Comparision made for different thicknesses and tensile strength levels.
|
Tensile strength,
Rm |
Fatigue limit, MPa |
|
Tensile strength,
Rm |
Fatigue limit, ksi |
|
|
Thickness, mm |
|
|
Thickness, inch |
|
MPa |
0,25 |
0,50 |
|
ksi |
0.010 |
0.020 |
|
1500 |
420 ± 420 |
405 ± 405 |
|
218 |
60.9 ± 60.9 |
58.8 ± 58.8 |
|
1700 |
460 ± 460 |
425 ± 425 |
|
247 |
66.8 ± 66.8 |
61.7 ± 61.7 |
Physical properties
The physical properties of a steel relate to a number of factors, including alloying elements, heat treatment and manufacturing route, but the following data can generally be used for rough calculations. These values refer to cold rolled material, at a temperature of 20oC(68oF) unless otherwise stated.
Density 7.9 g/cm3 (0.29 lb/in3)
Resistivity 0.8 mWm (31.5 mWinch)
Modulus of elasticity
'as delivered' ........................................approx 185 000 MPa (26 825 ksi)
tempered ...............................................approx 190 000 MPa (27 550 ksi)
Shear modulus
'as delivered' ...............
.........................approx 70 000 MPa (10 150 ksi)
Specific heat capacity 500 J/kg°C (in the temperature range 50-100°C)
Thermal expansion mean values in temperature ranges (x10-6)
|
Temperature, °C |
per °C |
Temperature, °F |
per °F |
|
20 - 100 °C |
15.5 |
68 - 200 |
8.5 |
|
20 - 200 °C |
16 |
68 - 400 |
9 |
|
20 - 300 °C |
16.5 |
68 - 550 |
9 |
Thermal conductivity
|
Temperature, °C |
W/m °C |
Temperature, °F |
Btu/ft h °F |
|
20 |
15 |
68 |
8.5 |
|
100 |
16 |
200 |
9 |
|
300 |
19 |
600 |
11 |
Corrosion resistance
It is very important to avoid corrosion in spring applications so as not to impair spring properties. BPS-SB-1100SMA is an austenitic stainless steel and has sufficient corrosion resistance in most applications. The corrosion resistance is almost the same as ASTM 304 and, compared to other low alloyed steels
Heat treatment
The strength of cold rolled BPS-SB-1100SMA can be increased by a tempering operation at 350°C (662°F) for 3 hours. An increase in tensile strength up to approx. 150 MPa (22 ksi) can be expected, depending on the initial cold rolled tensile strength. Further information on the nominal tempering effect can be seen under the "Mechanical properties" section. This heat treatment is also beneficial for relaxation and fatigue resistance.
Tempering is normally carried out by the customer after forming. To avoid discolouration, parts should be carefully cleaned before heat treatment. Tempering in open air furnaces gives a harmless brownish oxide on the surface.
Welding
BPS-SB-1100SMA like most austenitic stainless steels, has a good weldability. Welding, however, introduces excess heat into the material closest to the weld that breaks down the structure formed by cold working. As a consequence, this will decrease the mechanical properties of the welded area. The lowest practical heat input, <1.0 kJ/mm, and interpass temperature for multipass welding, <100°C, is recommended.
In most cases, the TIG (GTAW) method is preferable. It can be used either autogenously (without filler metal) or with filler metal. In both cases, pure argon (99.99%) should be used as the shielding gas.
When filler metal is used, 9.9.L or 19.9.LSi is recommended.
Disclaimer
Recommendations are for guidance only, and the suitability of a material for a specific application can be confirmed only when we know the actual service conditions. Continuous development may necessitate changes in technical data without notice.
|
