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Precision Tubing and Wire

Unimed’s quality tubing and wire products offer a combination of desired characteristics :

  • dimensional accuracy
  • clean and smooth surface quality
  • high corrosion and heat resistance
  • excellent tensile properties
  • good machinability

Unless otherwise specified all our tubings are welded and cold drawn. Welded tubes have similar mechanical strengths compared with seamless tubing, but offer, in general,

  • Superior concentricity of OD and ID
  • Better ID surface quality
  • Availability in a larger range of sizes and wall thicknesses
  • Lower costs and shorter delivery times

Welded tubing originates from sheet material that is formed into its round shape and welded. The tubes are redrawn to obtain the desired dimensions and temper. This makes the weld practically homogeneous and difficult to differentiate from seamless tubing.

Austenitic Stainless steel is practically non magnetic in the annealed condition but slightly magnetic when cold worked (redrawn). The lower the carbon content of a stainless steel material, the less magnetic it is.

Unimed supplies stainless steel tubing and wire in the following configurations :

  • In straight random lengths

of up to 2 meters, cut-off without deburring. In view of the high cost of packing and shipping two meter long tubes/rods, we recommend the supply of one meter lengths. Unless a greater precision is requested we apply a +/- 5 mm tolerance on the one and two meter lengths.

  • In precision cut lengths with deburred ends

clean (degreased) and passivated, starting from as small as 0.5 mm length. Our standard tolerance for cutting is +/- 0.5mm but we can meet your required precision of as tight as +/- 0.02 mm, on request.

  • As precision parts and components

Unimed can offer a wide variety of metalworking services for prototyping and small to medium production runs. These include Grinding, Bending, Machining, Laser Welding, Surface Finishing and Coating, Final Assembly, etc. You are invited to submit your drawings for quotation and expert advice.

 

 

  • Materials

    Unimed obtains full length tubing and wire from selected manufacturers who have been producing them to our exacting specifications for a very long time. Over 50 years of know-how in fabricating medical needles allows us to provide stainless steel tubing and wire of a consistently high quality in the austenitic materials listed below.

    These selected stainless steels can be used, according to ISO 9626 (1991) International Standard, in the manufacture of hypodermic needle cannulae, and according to ISO 7153-1 (1991) International Standard in the manufacture of surgical instruments.

    AISI 302 (DIN 1.4310)
    This material has been selected for its excellent mechanical properties for most of our solid wires and wire components.

    AISI 303 (DIN 1.4305)
    Unimed offers this material in form of solid wire in certain sizes and manufactures a variety of components from it.

    AISI 304 (DIN 1.4301)
    We offer this material in a wide range of tubing sizes and also in certain solid wire diameters.

    AISI 316L (DIN 1.4404 ou 1.4435)
    This material, available from Unimed in a wide range of tubing sizes, is particularly suitable for analytical, chemical and pharmaceutical applications.

    Certain tubing and solid wire dimensions are also available in other materials, and we can fabricate components from these materials as well. You are invited to contact us for further details and for advice regarding the choice of material for a specific application.

    Click on Selection of available materials for chemical composition and mechanical properties of the above materials and a list of other materials that we can offer.

  • Hardness / Strength

    Hardness and strength are achieved by cold working the tubing after the welding process. The more cold working (re-drawing) that is applied to the tubing the harder it becomes.

    Various terms are used to specify the hardness (temper) of stainless steel tubing and wire and they can have different meanings within certain medical and industrial markets. The following explanations may help to avoid confusion::

    Hardness Test is a test designed to assess the resistance to penetrate. The surface is indented under a defined load and the depth or area of penetration is measured.

    Stiffness Test is the measure of a tube’s ability to resist bending. Stiffness is determined by applying a force to the center of a tube which is suspended across a span, and then the deflection is measured. ISO 9626 sets standards for certain tubing sizes with regular and thin wall but there are no stiffness performance criteria available for many tubing sizes.

    Tensile Strength is a measure of the resistance that a material offers to tensile stress. It is expressed as the force per unit cross sectional area that is required to break it.

    A certain amount of hardness is required to meet stiffness specifications. However, increasing the hardness by additional cold work has a minimal effect on the stiffness beyond a certain point. The greatest impact on the stiffness of tubing comes from changes made in the cross section (OD, wall thickness) of the tubing.

    Unimed stipulates Tensile Strength rather than Hardness for their tubing. In fact, it is difficult or even impossible to carry out correct hardness testing by penetration from a load, on thin wall tubing in particular.

    Unimed’s stock of tubing and solid wire is generally carried in full hard condition, with the exception of AISI 303 and AISI 316LS which are half-hard. However, random length and cut tubings and wire can also be provided in bright annealed condition, or produced in half-hard temper, on request.

    For more details, click on:

  • Surface roughness

    Unimed tubing and wire are produced with a smooth finish that is consistent in appearance. Various ratings are used in the measurement of surface roughness, but Ra expressed in micrometers or microinches is the generally accepted parameter. Ra is the arithmetic average roughness (arithmetic mean of the deviations of the roughness profile from the mean line).

    As a rule, Unimed tubings have the following roughness ratings :

    OD 0.4 μm = 16 µinch (N5) 

    ID 0.8 to 1.6 µm = 32 to 63 µinch (N6 – N7)

    However, certain tubing sizes are available or can be produced with a superior finish: :

    OD 0.1 µm = 4 µinch (N3)

    or

    ID 0.4 µm = 16 µinch (N5)

    Please request the corresponding N3 or N5 finishes to obtain these smoother surfaces.

     

  • Certifications

    On request, Unimed will supply Material Certificates or Certificates of Compliance with the goods. Please make sure to indicate such requirements in your enquiries and purchase orders.

    Illustrated below is our standard Inspection Certificate (Certificate of Compliance). We can also issue Compliance Certificates according to your form.

    Download certificate

Unimed tubings are precision drawn to tight tolerances in metric dimensions ranging from as small as OD 0.10 mm to about OD 10 mm. Wall thickness ranges from 0.03 mm to about 1.00 mm, and in many cases we can offer several wall sizes for a same ID. Practically all our tubes have an ID tolerance that allows a wire (mandril, stylet) of the same nominal size to pass freely inside the tube, with a close fit.

Please note that the tolerance on the outer diameter of the tubing once it is a sub-contracted finished component can be different from the one of our tubing raw material due to polishing operations.

We can also offer the possibility to reduce the OD of a tube by centerless grinding, maintaining tight tolerances. In this way a custom sized tube can be produced by selecting a standard ID and then grinding it to the required OD.

In addition to the many listed standard sizes, we have on stock a number of special dimensions which may suit your prototyping or small production needs. On receipt of an enquiry with a specific tubing/wire size, we will usually give you the nearest available stock dimension.

Your custom sizes can be produced within a few weeks, for quantities as small as 100 meters per size.

  • AISI 304 Tubing

    Tubing hard drawn, welded, straightened, AISI 304
    Outer diameterAvailable inner diameters
    mmTol. mmmmmmmmmmTol. mm
    0.30+/- 0.010.17+ 0.03
    0.40+/- 0.010.20+ 0.03
    0.45+/- 0.010.25+ 0.03
    0.50+/- 0.010.250.38+ 0.03
     
    0.55+/- 0.010.250.30+ 0.03
    0.60+/- 0.010.35+ 0.03
    0.65+/- 0.010.150.35+ 0.03
    0.70+/- 0.010.400.470.50+ 0.03
    0.80+/- 0.010.350.50+ 0.03
    0.90+/- 0.010.600.70+ 0.03
    1.00+/- 0.010.700.75+ 0.03
     
    1.10+/- 0.0150.700.800.90+ 0.04
    1.15+/- 0.0150.99+ 0.04
    1.20+/- 0.0150.700.801.00+ 0.04
    1.30+/- 0.0151.00+ 0.04
    1.40+/- 0.0151.001.20+ 0.04
    1.50+/- 0.0150.901.001.20+ 0.04
     
    1.60+/- 0.0150.951.101.30+ 0.04
    1.65+/- 0.0151.301.40+ 0.04
    1.70+/- 0.0151.20+ 0.04
    1.80+/- 0.0151.551.60+ 0.04
    1.85+/- 0.0151.55+ 0.04
    1.88+/- 0.0151.70+ 0.04
    1.90+/- 0.0151.15+ 0.04
    2.00+/- 0.0151.401.50+ 0.04
     
    2.09+/- 0.021.91+ 0.05
    2.30+/- 0.021.151.80+ 0.05
    2.40+/- 0.021.902.21+ 0.05
    2.50+/- 0.020.50+ 0.05
    2.80+/- 0.020.602.00+ 0.05
     
    3.00+/- 0.020.500.602.202.40+ 0.07
    3.00+/- 0.022.80+ 0.07
    3.20+/- 0.051.702.60+ 0.07
    3.25+/- 0.053.05+ 0.07
    3.30+/- 0.052.30+ 0.07
    3.50+/- 0.052.70+ 0.07
    3.55+/- 0.053.30+ 0.07
    3.63+/- 0.053.46+ 0.07
    3.95+/- 0.053.60+ 0.07
    4.00+/- 0.051.502.50+ 0.07
     
    4.37+/- 0.054.15+ 0.07
    4.50+/- 0.052.503.00+ 0.07
    5.00+/- 0.052.002.503.404.50+ 0.07
    6.00+/- 0.055.005.50+ 0.07
    6.05+/- 0.054.98+ 0.07
    6.27+/- 0.056.01+ 0.07
    7.00+/- 0.056.406.50+ 0.07
    7.50+/- 0.057.00+ 0.07
     
    8.00+/- 0.057.007.50+ 0.07
    8.05+/- 0.053.98+ 0.07
    8.08+/- 0.057.81+ 0.07
    9.00+/- 0.056.008.50+ 0.07
    9.47+/- 0.059.19+ 0.07
    10.00+/- 0.057.959.50+ 0.07
    10.54+/- 0.0510.02+ 0.07
    12.00+/- 0.0511.00+ 0.07


    The tolerances mentioned above are given for information purpose only. The contracted tolerances can be adapted to your needs and will be confirmed in our offers.

    Download PDF

    Updated July 6, 2016

  • AISI 316L Tubing

    Tubing hard drawn, welded, straightened, AISI 316L (or *AISI 316 Ti)
    Outer diameterAvailable inner diameters
    mm Tol. mm mm mm mm mm Tol. mm
    0.11 +/- 0.01 0.02 + 0.03
    0.20 +/- 0.01 0.09 + 0.03
    0.25 +/- 0.01 0.12 0.16 + 0.03
    0.27 +/- 0.01 0.17 + 0.03
    0.30 +/- 0.01 0.15 + 0.03
    0.35 +/- 0.01 0.17 + 0.03
    0.39 +/- 0.01 0.22 + 0.03
    0.40 +/- 0.01 0.30 + 0.03
    0.41 +/- 0.01 0.26 + 0.03
    0.48 +/- 0.01 0.12 + 0.03
    0.50 +/- 0.01 0.15 0.25 0.30 0.35 + 0.03
     
    0.60 +/- 0.01 0.19 0.35 0.40 0.45 + 0.03
    0.63 +/- 0.01 0.35 + 0.03
    0.70 +/- 0.01 0.30 0.40 0.45 0.50 + 0.03
    0.72 +/- 0.01 0.13 + 0.03
    0.80 +/- 0.01 0.20* 0.40 0.50 0.60 + 0.03
    0.90 +/- 0.01 0.20 0.35 0.40 0.43 + 0.03
    0.90 +/- 0.01 0.51 0.55 0.60 0.71 + 0.03
    0.96 +/- 0.01 0.57 + 0.03
    0.98 +/- 0.01 0.46 + 0.03
    1.00 +/- 0.01 0.20 0.25 0.30 0.35 + 0.03
    1.00 +/- 0.01 0.40 0.50 0.65 0.70 + 0.03
    1.00 +/- 0.01 0.80 + 0.03
     
    1.05 +/- 0.015 0.84 + 0.04
    1.10 +/- 0.015 0.58 0.70 0.74 0.80 + 0.04
    1.10 +/- 0.015 0.90 + 0.04
    1.20 +/- 0.015 0.30 0.47 0.60 0.70 + 0.04
    1.20 +/- 0.015 0.80 + 0.04
    1.25 +/- 0.015 0.37 1.11 + 0.04
    1.27 +/- 0.015 0.81 + 0.04
    1.30 +/- 0.015 0.65 0.75 0.90 1.10 + 0.04
    1.34 +/- 0.015 1.11 + 0.04
    1.35 +/- 0.015 1.00 + 0.04
    1.40 +/- 0.015 0.80 1.00 1.20 + 0.04
    1.50 +/- 0.015 0.40 0.50 0.70 0.90 + 0.04
    1.50 +/- 0.015 1.12 1.21 + 0.04
     
    1.60 +/- 0.015 0.51 0.56 0.67 0.71 + 0.04
    1.60 +/- 0.015 0.76 0.79 0.95 1.06 + 0.04
    1.60 +/- 0.015 1.10 1.20 1.30 + 0.04
    1.60 +/- 0.015 1.40 + 0.04
    1.70 +/- 0.015 1.20 + 0.04
    1.73 +/- 0.015 1.56 + 0.04
    1.75 +/- 0.015 1.00 1.36 1.50 + 0.04
    1.80 +/- 0.015 1.10 1.26 1.30 1.40 + 0.04
    1.80 +/- 0.015 1.50 + 0.04
    1.90 +/- 0.015 0.61 1.40 1.50 1.60 + 0.04
    1.90 +/- 0.015 1.64 + 0.04
    2.00 +/- 0.015 0.30 0.50 0.61 0.71 + 0.04
    2.00 +/- 0.015 0.81 0.90 1.00 1.20 + 0.04
    2.00 +/- 0.015 1.37 1.40 1.50 1.60 + 0.04
    2.00 +/- 0.015 1.70 1.80 1.90 + 0.04
     
    2.05 +/- 0.02 0.61 + 0.05
    2.10 +/- 0.02 1.10 1.30 1.60 1.80 + 0.05
    2.20 +/- 0.02 1.40 1.70 2.00 + 0.05
    2.30 +/- 0.02 1.80 + 0.05
    2.40 +/- 0.02 1.50 1.60 1.80 2.10 + 0.05
    2.50 +/- 0.02 1.50 1.60 1.90 2.00 + 0.05
    2.50 +/- 0.02 2.20 + 0.05
     
    2.60 +/- 0.02 1.00 2.00 + 0.05
    2.70 +/- 0.02 2.20 2.50 + 0.05
    2.80 +/- 0.02 1.67 2.20 + 0.05
    3.00 +/- 0.02 0.30 1.00 1.20 1.50 + 0.05
    3.00 +/- 0.02 2.00 2.10 2.50 2.60 + 0.05
     
    3.05 +/- 0.05 1.84 + 0.07
    3.10 +/- 0.05 2.00 + 0.07
    3.30 +/- 0.05 2.40 2.80 + 0.07
    3.40 +/- 0.05 1.00 2.90 + 0.07
    3.50 +/- 0.05 1.00 1.10 1.80 2.50 + 0.07
    3.50 +/- 0.05 3.00 3.10 + 0.07
    3.60 +/- 0.05 3.10 + 0.07
    3.90 +/- 0.05 3.30 + 0.07
    4.00 +/- 0.05 1.50 2.00 3.00 3.30 + 0.07
    4.00 +/- 0.05 3.50 + 0.07
     
    4.10 +/- 0.05 3.60 + 0.07
    4.50 +/- 0.05 3.50 4.00 + 0.07
    4.80 +/- 0.05 4.20 + 0.07
    5.00 +/- 0.05 2.50 3.00 4.00 4.50 + 0.07
     
    5.05 +/- 0.05 4.80 + 0.07
    5.18 +/- 0.05 4.34* + 0.07
    5.45 +/- 0.05 5.00 + 0.07
    5.50 +/- 0.05 4.50 + 0.07
    6.00 +/- 0.05 2.00 2.50* 3.00* 4.00* + 0.07
    6.00 +/- 0.05 5.00 5.50* + 0.07
    6.50 +/- 0.05 6.00 + 0.07
    7.00 +/- 0.05 5.00* 6.00 + 0.07
     
    8.00 +/- 0.05 6.00 7.00* + 0.07
    8.10 +/- 0.05 7.20 + 0.07
    8.50 +/- 0.05 8.00 + 0.07
    9.00 +/- 0.05 7.00* 8.00* + 0.07
    10.00 +/- 0.05 7.48 9.00* + 0.07


    The tolerances mentioned above are given for information purpose only. The contracted tolerances can be adapted to your needs and will be confirmed in our offers.

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    Updated July 6, 2016

  • Stainless steel wire

    Straightened stainless steel wire
    DiameterToleranceMaterial
    mmmmAISI
    0.15-0.01304
    0.20-0.01304, 316L
    0.25-0.01304
    0.30-0.01304
    0.35-0.01304
    0.40-0.015302
    0.45-0.015302
    0.50-0.015302, 316L
    0.52-0.015302
      
    0.55-0.015302
    0.60-0.015302, 316L
    0.65-0.015302
    0.66-0.015302
    0.67-0.015302
    0.70-0.015302
    0.75-0.015302
    0.80-0.015302
    0.85-0.015302
    0.90-0.015302
    0.95-0.015302
    1.00-0.015302, 316L
      
    1.10-0.015302
    1.20-0.015302
    1.30-0.015302, 316L
    1.40-0.015302, 316L
    1.50-0.015302, 316L
    1.60-0.015302
    1.70-0.015302
    1.80-0.015302
    1.90-0.015304, 316L
    2.00-0.015302, 316L
       
    2.10-0.015302, 316L
    2.20-0.015302
    2.25-0.015304
    2.30-0.015316L
    2.40-0.015302, 316L
    2.50-0.015303, 316L
    2.60-0.015303
    2.80-0.015303
    3.00-0.015303, 316L
    3.50-0.02303, 316L
    4.00-0.02303, 316L


    The tolerances mentioned above are given for information purpose only. The contracted tolerances can be adapted to your needs and will be confirmed in our offers.

    Download PDF

    Updated July 6, 2016