Alloy MP35N®

General Description

MP35N® Alloy, with its nickel-cobalt-chromium-molybdenum content, has a special combination of high strength, ductility and corrosion resistance. In the annealed state, it has the same easy-to-work characteristics of the 300 series alloys, yet it is capable of being hardened by a simple heat treatment. It has higher tensile strength/hardness and even ductility compared to the 300 series when cold-worked. After the aging heat treatment, it has one of the highest strengths on any currently produced alloys. The unique properties of MP35N® allow for it to be used in applications where other alloys have failed.

MP35N is a registered trademark of SPS Technologies, LLC.


  • Stents
  • Device delivery systems
  • Biopsy needles
  • MRI compatible devices

Reference Standards

  • AMS 5758
  • AMS 5844
  • AMS 5845
  • ASTM F562
  • BS 7252
  • ISO 5832


  • Cold working will achieve higher tensile strengths.
  • Aging Heat treatment will result in the highest strength available for miniature stainless steel tubing.
  • Many combinations of properties available based on processing method to suit many applications.
  • Excellent corrosion resistance–extensive use in stents and implants

Typical Chemistry

Carbon 0.03%*
Manganese 0.15%
Phosphorous 0.015%
Sulfur 0.01%
Silicon 0.15%
Chromium 19.00% 21.00%
Nickel 33.00% 37.00%
Molybdenum 9.0% 10.5%
Titanium 1.0%
Iron 1.0%
Boron .01%
Cobalt Balance Balance

Possible Mechanical Properties

Hardness HRC 44 HRC 54 HRC
Tensile Strength 140 ksi 220 ksi 290 ksi
Elongation 40% 5% 2%
Tensile Strength

General Properties

Density 0.304 lb/in3
Elastic modulus 34,000 ksi
Shear modulus 12,100 ksi
Thermal conductivity (70F) 88 BTU-in/hr-ft2 - F
Mean CTE (70-1000F) 8.7 x10-6 in/in/F
Electrical resistivity 80 microohm-cm
Magnetic Permeability (Annealed) 1.0009

Tubing-specific Requirements

  • Lengths: Tubing is normally furnished in mill lengths of 5 ft, but can be supplied in up to 20 ft lengths with a shear cut end.
  • Cut End Finish: Precision cut-to-length pieces with burr-free ends can be furnished when specified.
  • Roundness: Difference in minimum and maximum OD measurements must be equal or less than half the OD tolerance.
  • Surface Finish: OD and ID surface finish (Rq or RMS) limits may be specified. ID and OD surface finish values are only reported for dimensions >0.020".
  • Typical OD Surface: < 20 μin Rq.
  • ID Surface finish: Depends on the reduction (drawing) method. Free sunk tubing has a typical ID surface finish <150 μin Rq. Plug drawn tubing can have an ID surface finish range with values as low as < 20 μin Rq.
  • Straightness: No deflection greater than 5% of the outside diameter for tubing with OD ≥ 0.020” or 0.001” maximum deflection for tubing with OD <0.020”. Any special straightness requirements shall be agreed upon between the purchaser and supplier. Tubing should not “wobble” as defined per ASTM F2819.

Additional tubing specification information can be found in K001-15a Standard Specification for Miniature Laser Welded and Drawn Stainless Steel and Nickel-Chromium Alloy Tubing for General Use.

Available dimensions

K-Tube has the capability to make tubing with the wall thickness and outside diameter combinations in the chart below. Tubing with an OD/Wall ratio lower than 20:1 can be drawn to the final dimensions. Tubing with an OD/Wall ratio between 20:1 and 40:1 must be centerless ground to the final dimensions. K-Tube's capabilities are constantly improving, please inquire if your dimensions are outside of the listed dimensions.

Download The MP35N K-Tube Stainless Technical Sheet

Download the MP35N K-Tube Technical Data Sheet (PDF) to easily share all the details on this page with your team.

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