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  4. Ultrafine Grain Stainless Steel nanoSUS™

Ultrafine Grain Stainless Steel nanoSUS™

nanoSUS 301, nanoSUS 304


nanoSUS™ is a stainless steel that has ultrafine grained (UFG) microstructures with average grain sizes smaller than 1 μm.
Compared to normal material, various property improvements can be expected, such as improved strength, fatigue properties, and workability by controlling the microstructure.

Supported Shapes


Supported Range (COIL,SHEET)

Thickness : 0.010mm-0.60mm *Contact Sales if your need 0.20mm-0.60mm.

Width          : 3.0mm-300mm

Length        : COIL or SHEET less than L2000mm

Strengths of nanoSUS™

The following advantages can be expected with grain refinement.

  1. High Strength
    • Strength can be enhanced by ultrafine elongated grain structure due to severe plastic deformation (SPD). This allows lightweighting through lower height and thinner thickness of parts. 
  2. Improvement of Strength-Ductility Balance
    • Heat-treatment after severe plastic deformation (SPD) makes an equiaxed fine-grain microstructure, and the strength-ductility balance.
      Various processing is possible without sacrificing strength.
  3. High Fatigue Properties
    • Fatigue properties are improved compared to normal grains.This also contributes to longer service life of parts.
  4. High Workability
    1. Surface roughness improvement

      Due to ultrafine grained (UFG) microstructures, roughness on the surface of bending parts are improved during metallic materials processing.

    2. Stable shear surface during pressing

      Normal materials with large crystal grains may not have a smooth shear surface due to grain dropout when fine pressing is performed.
      Ultrafine grain steels can stabilize the contour shape of the fine-pressed shear surface.

Fatigue Properties

Improved fatigue properties enable longer service life of parts. The fatigue limit of SUS301 normal grain is about 50% of the proof stress (YS) while nanoSUS™ has a fatigue limit of 62% of YS, which is about 10% higher than that of normal grain.
s-n curve of nanoSUS301EH and normal SUS301EH


Compared to ordinary 2B material, nanoSUS™ 2B has higher hardness and higher resistance (YS), but has almost the same performance in terms of stretch formability. 
Formability of ordinary 2B material and nanoSUS™ 2B 

Spring Limit Value

High spring limit values can be obtained by low temperature annealing (HT:Heat Treatment). In particular, nanoSUS™ 301 can achieve extremely high spring properties exceeding 1600 MPa in the rolling direction and 2000 MPa in the transverse direction, making it suitable for high-strength spring material applications.



Fine grain structure minimizes skin roughness and dripping during etching, also enables finer and more precise etching process.

Evaluation of Minimum Drilled Hole Diameter t0.18mm

When making etched holes with a hole diameter of 0.22 mm, stainless steel normally does not penetrate, but nanoSUS does.
Evaluation of Minimum Drilled Hole Diameter t0.18mm

Evaluation of Micro-Slitability t0.18mm

Normally, stainless steel is insufficiently etched in the center of the slit, but nanoSUS provides a good etched shape over the entire area.
Evaluation of Micro-Slitability t0.18mm

 ■Evaluation of Round Hole Half Etchability

It can be seen that nanoSUS has less skin roughness after half etching and that the edges of the round holes are machined with high precision.
Evaluation of Round Hole Half Etchability

Advantages of TOKKIN

TOKKIN's nanoSUS ultrafine grained material has the following advantages.

  1. A Wide Variety of Steel Grades
    • We can manufacture custom-made products in a wide range of steel grades and materials, not only in limited grades such as SUS301 and 304.
      Please feel free to contact us for trials.
  2. Grain Size Control
    •  It is possible to create different sizes of crystal grains.
      <Control Range> nanoSUS 3μm or less (normal grains 10μm or more) *Depends on the finish.
  3. Ultra-Thin Foil Production
    • We can manufacture ultra-thin foils with thicknesses down to 0.010mm (10μm).
  4. Small Lot Sizes
    • We can supply custom-made products in tens of kilograms.

Related Pages

Stainless Steels Foils

We can make it to foils (less than 0.10 mm thick) in all the stainless steels we manufacture.

We welcome your questions and inquiries regarding materials.