Sandvik Nanoflex® is a precipitation hardening stainless steel specifically designed for applications requiring high strength combined with good ductility in the final product. The grade is characterized by high formability in the as-delivered condition and its strength is increased after ageing of the final product.
The characteristics in general can be said to be a combination of properties of ordinary austenitic stainless and low alloyed ferritic steels. This means that properties such as elastic modulus, mechanical properties and thermal expansion are comparable to ferritic steels (such as low alloyed carbon steels or chromium steels) while properties such as corrosion resistance are more comparable to austenitic stainless steels.
- Excellent mechanical properties, very high tensile strength and hardness levels can be achieved
- Corrosion resistance comparable to ASTM 304L or ASTM 316L depending on condition
- Retained mechanical properties at temperatures up to at least 400oC (750oF)
- UNS: S46910
Chemical composition (nominal) %
Size range and tolerances
|Surface finish||Size range, mm (in.)|
|Coated||0.40 - 6.00 (0.016 - 0.24)|
|Diamond drawn (bright)||0.10 - 2.50 (0.004 - 0.098)|
|Dimension||Spool no||Wire weight|
|0.10 - 0.290||0.0039 - 0.0114||7||3|
|>0.161 - 1,60||0.0063 - 0.0630||23||max 16|
|1.60 - 1.80||max 20|
|>1.80 - 2.50||max 60|
|>2.50 - 6.00||max 100|
In exceptional cases, spools or coils of lower weight than given in the above tables can be included in a delivery.
The diameter tolerance is normally D2. The wire can also be supplied with tolerance grade D1 and D3.
|0.10 - 0.125||-||0.004|
|>0.125 - 0.25||0.003||0.005|
|>0.25 - 0.50||0.004||0.007|
|>0.50 - 1.00||0.005||0.009|
|>1.00 - 1.60||0.006||0.011|
|>1.60 - 2.50||0.008||0.014|
|>2.50 - 4.00||-||0.018|
|>4.00 - 6.00||-||0.022|
|0.004 - 0.005||-||0.00016|
|>0.005 - 0.010||0.00012||0.00020|
|>0.010 - 0.020||0.00016||0.00028|
|>0.020 - 0.039||0.00020||0.00035|
|>0.039 - 0.063||0.00024||0.00043|
|>0.063 - 0.098||0.00032||0.00070|
|>0.098 - 0.236||-||0.00087|
Forms of supply
The material is delivered in lots and forms adapted to the customer's requirements:
- in coils with weights up to 150 kg
- on various types of spools with wire weights up to 1 000 kg
- in straightened lengths up to 4 m
Density, g/cm3 (lb/in3): 7.9 (0.29)
|Temperature, oC||W/m oC||Temperature, oF||Btu/ft h oF|
1) For material in aged condition
|Temperature, oC||J/kg oC||Temperature, oF||Btu/ft h oF|
1) For material in aged condition
Mean values in temperature ranges (x10-6)
The material has a coefficient of thermal expansion close to that of carbon steel. This gives it definite design advantages over normal austenitic stainless steels. The values given in the table are average values in the temperature ranges.
|Temperature, oC||30 - 100||30 - 200||30 - 300||30 - 400|
|Carbon steel (0,2 %C)||12.5||13||13.5||14|
|Temperature, oF||86 - 200||86 - 400||86 - 600||86 - 700|
|Carbon steel (0,2 %C)||7||7||7.5||7.5|
Modulus of elasticity
The E-modulus is dependent on dimension, condition, direction and amount of cold reduction of the material. The data below have been achieved by tensile testing at 20oC (68oF) of cold rolled strips along the rolling direction and they are typical values only. At ageing an increase of the E-modulus with 15 - 20 x103 MPa can be expected.
|MPa||E(x103) MPa||ksi||E (x103) ksi|
The possible ranges for the mechanical properties both in cold rolled and aged condition are indicated below.
The strength level after ageing depends on the amount of cold deformation and therefore also on the dimension.
For more information regarding ageing, click here.
|Condition||Proof strength, Rp0.2a)||Tensile strength, Rm|
|Flat rolled wire|
|600 - 1800
1200 - 2400
|87 - 261
174 - 348
1 MPa = 1 N/mm2
a) Rp0.2 correspond to 0.2% offset yield strength.
At elevated temperatures
The values represents testing on material cold worked to 1650 MPa and subsequently aged at 475°C for 4 hours.
|Temperature||Tensile strength, Rm|
The material has a corrosion resistance comparable to ASTM 304L or ASTM 316L depending on condition and environment.
Pitting and crevice corrosion
The Critical Pitting corrosion Temperature, CPT, has been decided using Electrochemical CPT testing at 300 mV in NaCl solutions of different concentrations at pH = 6.0, ground test samples (600 mm). All results are average values from six measurements.
Figure 1: Critical pitting temperatures (CPT) for Sandvik Nanoflex®, ASTM 304 and ASTM 316 at varying concentrations of sodium chloride. Potentiostatic determinations at +300 mV (SCE), pH= 6.0
Figure 2: Isocorrosion diagram for Sandvik Nanoflex®, ASTM 304L and ASTM 316L in stagnant sulfuric acid. The curves for ASTM 304L and 316L and the dot for Sandvik Nanoflex® represents a corrosion rate of 0.1 mm/year.
The material was developed for applications requiring ultra-high strength in combination with good fracture toughness. The strength is increased remarkably at a heat treatment in the temperature range of 400 - 450oC (750- 840oF), whereby precipitation occurs in the martensitic matrix. This heat treatment is called ageing or tempering and it is preferably made on the final product, to first take advantage of the good formability in as delivered condition.
The optimum ageing is made at 475oC (885oF) for 4 hours. Some examples of the ageing effect on the tensile strength is given below.
|Tensile strength, MPa||Tensile strength, ksi|
|Cold worked||Aged||Cold worked||Aged|
The weldability is good. Suitable welding methods are TIG, MIG and MMA. It can be welded without filler metal (autogenously) using the TIG process, but filler metal is preferable. For TIG and MIG welding, Sandvik 19.12.3.LSi or 19.12.3.L can be used, or if a higher strength is desired, Sandvik 22.8.3.L.
For MMA, the corresponding electrodes Sandvik 19.12.3.LR or Sandvik 22.9.3.LR are suitable.
The martensitic content in HAZ of the material, decreases after welding resulting in a typical annealed microstructure with an austenitic matrix and a small amount of ferrite. This means that the tensile strength will be lower for the weld compared with the high strength base material. Therefore, welds in the material are not suitable for active parts of a construction, when extremely high strength is required.