Tubing

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K-Tube uses a proprietary process of Laserwelding to manufacture tubing. Laser-welded tubing is cleaner, more concentric and, unlike other methods, contains no filler materials. The smaller heat-affected zone means the weld itself will not interfere with dimensional or visual requirements, which results in a smoother finish. These characteristics make laser-welded tubing a top choice among design engineers.

Alloys

302/304 Properties: Essentially nonmagnetic, 302/304 becomes slightly magnetic when cold-worked. This means that medical devices that have been manufactured with large amounts of cold work need to be tested before being used in the MR environment.302 alloy is the same as 304 alloy except 302 has a .12% carbon maximum. In 304, the maximum carbon is .08%. Low carbon content means less carbide precipitation in the heat-affected zone during welding and a lower susceptibility to intergranular corrosion. Technically, 304 alloy meets the requirements of 302, except that 302 is harder than 304 with the same amount of cold work. Both hardness and tensile strength are increased when cold-worked. Additionally, 304 has better corrosion resistance than 302.Benefits: 302/304 are 18-8 austenitic Cr-Ni stainless steel alloys selected for their excellent strength, high ductility, and excellent drawing, forming and coiling properties. This alloy is also one of the least expensive medical materials.Applications for 302/304: Stylets, catheters, wire guides, springs and needles.
304L Properties: 304L is the same as 304 but with slightly higher nickel content (8%-12%) and lower carbon content. The lower carbon level increases weldability and lessens inclusions. 304L is slightly weaker than 304.Benefits: The chemistry of 304L makes it less susceptible to sensitization (i.e., the reduction in a material’s corrosion resistance due to exposure to elevated temperatures).

Applications for 304L: Catheters, wire guides, small parts made from straightened and cut wire, and orthodontic uses
316 Properties: 316 is an 18-8 Cr-Ni stainless steel modified by the addition of molybdenum. It is nonmagnetic in the annealed condition and not hardenable by heat treatment. This alloy has good ductility in the cold-worked condition. Fabrication characteristics are similar to those of 302 and 304.Benefits: 316 has high creep strength at elevated temperatures and good heat resistance. The 2%-4% molybdenum content increases resistance to marine environments.Applications for 316: Suture wire, orthopedic cables, skin closure staples, catheters, stylets, bone pins and many small machined parts. The alloy is biocompatible and possesses good corrosion resistance.
316L Properties: 316L has high creep strength at elevated temperatures, and its fabrication characteristics are similar to those of 302 and 304.Benefits: 316L has the superior corrosion resistance of 316 but also has superior resistance to intergranular corrosion following welding or stress relieving. It has good corrosion resistance to most chemicals, salts and acids. The low carbon content of 316L reduces the possibility of in vivo corrosion.Applications for 316L: Suture wire, orthopedic cables, skin closure staples, catheters, stylets and bone pins.
321 Properties: 321 is similar to 304 except its Ti content helps prevent chromium carbide precipitation resulting from welding or elevated temperatures. 321 has fabrication characteristics similar to 302/304 and 316/316L.Benefits: 321 resists scaling and vibration fatigue.Applications for 321: Aircraft exhaust stacks and manifolds, chemical processing equipment, welding equipment and jet engine parts.
430 Properties: 430 is one of the most widely used types of stainless steels. Because the alloy does not contain nickel, it is in the ferritic condition. Therefore, 430 does not respond to cold-working as the austenitic grades of stainless steel do. It is magnetic in all conditions. In the annealed condition the steel is ductile, does not harden excessively during cold work, and can be formed using a large variety of roll-forming or mild stretch-bending operations as well as the more common drawing and bending processes. Being a ferritic material, 430 is prone to brittle fracture at subzero temperatures; thus, it cannot be used in cryogenic applications.Benefits: The steel has good corrosion resistance in mildly corrosive environments and good resistance to oxidation at elevated temperatures. As the steel does not contain nickel or molybdenum, it is cheaper than any of the 300 series steels.Applications for 430: Automotive trim, interior architectural uses, nitric acid plant equipment, oil refinery equipment.
434 Properties: 434 is similar in chemistry and performance to 430 stainless steel. 434 has the addition of molybdenum to increase its resistance to corrosion. The alloy combines a ferritic structure with good fabricability and strength characteristics.Applications for 434: Automotive trim, interior architectural uses, nitric acid plant equipment, oil refinery equipment.
17-7 PH® Properties: 17-7 PH is a Cr-Ni stainless steel. 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. 17-7 PH should not be used in salt water or reducing environments. It has higher tensile strength compared to the 300 series when cold-worked, and is more expensive than 300 series alloy.Benefits: It is suitable for use in freshwater, industrial and marine atmospheres, and mild chemical and oxidizing environments.Applications for 17-7 PH: Very detailed, intricate parts due to its low distortion in heat treatment. Very stable.
Inconel® 625 Properties: Inconel is a nickel-chromium-molybdenum alloy with the addition of niobium. The niobium acts with the molybdenum to stiffen the alloy’s matrix—providing high strength without a strengthening heat treatment.Benefits: This alloy is an excellent general-purpose material for elevated temperatures. The alloy resists a wide range of severely corrosive environments and is especially resistant to pitting and crevice corrosion.Applications for I-625: Chemical processing, aerospace and marine engineering, pollution-control equipment and nuclear reactors.
Hastelloy® C-276 Properties: A versatile, corrosion-resistant alloy, Hastelloy does not usually need to be solution heat-treated after welding. Also, Hastelloy has vastly improved fabricability.Benefits: This alloy has excellent resistance to localized corrosion from both oxidizing and reducing media. It resists formation of grain-boundary precipitates and is therefore suitable for chemical process applications in the as-welded condition. C-276 has excellent resistance to strong oxidizers like ferric and cupric chlorides, hot contaminated media (organic and inorganic), chlorine, formic and acetic acids, acetic anhydride, seawater, brine solutions, sulfur compounds, wet chlorine gas, and hypochlorite and chlorine dioxide.Applications for Hastelloy C-276: Chemical process equipment and desulfurization of flue gas equipment.
Invar® 36 Properties: Invar 36 alloy is a 36% nickel-iron alloy possessing a rate of thermal expansion approximately 1/10th that of carbon steel up to 200°C.Benefits: This alloy has been used for applications where dimensional changes due to temperature variation must be minimized, such as in radio and electronic devices, aircraft controls, optical and laser systems, etc.Applications for Invar 36: Bimetallic thermostats and in rod and tube assemblies for temperature regulators.

Finishes

K-Tube offers a variety of finishes to suit your needs.

K-Tube offers three distinct inside diameter finishes. This is a degree of flexibility not offered by any other domestic tube manufacturer. These finish options provide solutions for a wide range of applications and budgets, and specific RMS/Ra values can also be achieved.

Each ID characteristic depends on the size and wall of your tubing, so please discuss your finish requirements with a customer service representative. Some ID finish requests will need to be reviewed by one of our engineers to determine the correct process.

 

Welded and Drawn

Welded and drawn tubing is the tube of choice when the inside diameter finish is not critical. These products are a prime example of high-quality tubing with maximized economics. Welded and drawn tubing is more flexible and resistant to breakage than any other stainless tubing and all tube sizes are supported by this option. The cleanliness of the surface is also a hallmark of this finish because no lubricants or solvents are used.

 

Plug/Mandrel Drawn

Plug/mandrel drawn tubing excels when your project needs thin to ultrathin walls or a specific feel. It also meets special stylet insertion requirements. This product combines our Laserweld technology and plug-draw capabilities to provide distinct advantages. Tube sizes of 32 gage and larger are supported by this option.

 

Plug/Mandrel Drawn (Premium ID Surface Finish)

Plug/mandrel drawn tubing with premium ID surface finish is for applications that require enhanced flow characteristics or reduced turbulence. This tubing is ideal when the inside diameter finish is critical. The floating plug-drawing process eliminates interior coarseness. Tube sizes of 23 gage through 10 gage are supported by this option.

Sizing

Gauge Wall Type OD Range ID Range Wall
6 RW .2020-.2040 .1700-.1760 .0150
TW .2020-.2040 .1800-.1860 .0100
7 RW .1790-.1810 .1470-.1530 .0150
TW .1790-.1810 .1570-.1630 .0100
8 RW .1640-.1660 .1320-.1380 .0155
TW .1640-.1660 .1420-.1480 .0100
9 RW .1470-.1490 .1150-.1210 .0155
TW .1470-.1490 .1250-.1310 .0100
10 RW .1330-.1350 .1040-.1080 .0140
TW .1330-.1350 .1120-.1160 .0100
ETW .1330-.1350 .1160-.1200 .0080
UTW .1330-.1350 .1200-.1240 .0060
MTW .1330-.1350 .1240-.1280 .0040
11 RW .1190-.1210 .0920-.0960 .0130
TW .1190-.1210 .0980-.1020 .0100
ETW .1190-.1210 .1020-.1060 .0080
UTW .1190-.1210 .1060-.1100 .0060
MTW .1190-.1210 .1100-.1140 .0040
12 RW .1080-.1100 .0830-.0870 .0120
TW .1080-.1100 .0890-.0930 .0090
ETW .1080-.1100 .0930-.0970 .0070
UTW .1080-.1100 .0970-.1010 .0050
MTW .1080-.1100 .1010-.1050 .0030
13 RW .0940-.0960 .0690-.0730 .0120
TW .0940-.0960 .0750-.0790 .0090
ETW .0940-.0960 .0790-.0830 .0070
UTW .0940-.0960 .0830-.0870 .0050
MTW .0940-.0960 .0880-.0920 .0030
14 RW .0820-.0840 .0610-.0650 .0100
TW .0820-.0840 .0660-.0685 .0080
ETW .0820-.0840 .0710-.0730 .0055
UTW .0820-.0840 .0730-.0760 .0045
MTW .0820-.0840 .0760-.0790 .0030
15 RW .0715-.0725 .0525-.0555 .0090
TW .0715-.0725 .0595-.0615 .0060
ETW .0715-.0725 .0615-.0635 .0050
UTW .0715-.0725 .0635-.0655 .0040
MTW .0715-.0725 .0655-.0675 .0030
16 RW .0645-.0655 .0455-.0485 .0090
TW .0645-.0655 .0525-.0545 .0060
ETW .0645-.0655 .0545-.0565 .0050
UTW .0645-.0655 .0565-.0585 .0040
MTW .0645-.0655 .0585-.0606 .0030
17 RW .0575-.0585 .0405-.0435 .0080
TW .0575-.0585 .0465-.0485 .0050
ETW .0575-.0585 .0490-.0510 .0040
UTW .0575-.0585 .0510-.0530 .0030
MTW .0575-.0585 .0530-.0550 .0020
18 RW .0495-.0505 .0315-.0345 .0085
TW .0495-.0505 .0375-.0395 .0060
ETW .0495-.0505 .0410-.0430 .0040
UTW .0495-.0505 .0430-.0450 .0030
MTW .0495-.0505 .0450-.0470 .0020
19 RW .0415-.0425 .0255-.0285 .0075
TW .0415-.0425 .0315-.0335 .0050
ETW .0415-.0425 .0340-.0360 .0035
UTW .0415-.0425 .0360-.0380 .0025
MTW .0415-.0425 .0380-.0400 .0015
20 RW .0355-.0360 .0230-.0245 .0060
TW .0355-.0360 .0255-.0270 .0050
ETW .0355-.0360 .0270-.0285 .0040
UTW .0355-.0360 .0290-.0305 .0030
MTW .0355-.0360 .0310-.0325 .0020
21 RW .0320-.0325 .0195-.0210 .0060
TW .0320-.0325 .0225-.0240 .0045
ETW .0320-.0325 .0245-.0260 .0035
UTW .0320-.0325 .0265-.0280 .0025
MTW .0320-.0325 .0285-.0300 .0015
22 RW .0280-.0285 .0155-.0170 .0060
TW .0280-.0285 .0190-.2050 .0040
ETW .0280-.0285 .0215-.0230 .0030
UTW .0280-.0285 .0235-.0250 .0020
MTW .0280-.0285 .0255-.0270 .0010
23 RW .0250-.0255 .0125-.0140 .0060
TW .0250-.0255 .0165-.0180 .0040
ETW .0250-.0255 .0185-.0200 .0030
UTW .0250-.0255 .0205-.0220 .0020
MTW .0250-.0255 .0225-.0240 .0010
24 RW .0220-.0225 .0115-.0130 .0050
TW .0220-.0225 .0135-.0155 .0040
ETW .0220-.0225 .0155-.0170 .0030
UTW .0220-.0225 .0175-.0190 .0020
MTW .0220-.0225 .0195-.0210 .0010
25 RW .0200-.0205 .0095-.0110 .0050
TW .0200-.0205 .0115-.0130 .0040
ETW .0200-.0205 .0135-.0150 .0030
UTW .0200-.0205 .0155-.0170 .0020
MTW .0200-.0205 .0175-.0185 .0010
26 RW .0180-.0185 .0095-.0110 .0040
TW .0180-.0185 .0015-.0130 .0030
ETW .0180-.0185 .0130-.0145 .0020
UTW .0180-.0185 .0145-.0155 .0015
MTW .0180-.0185 .0155-.0165 .0010
27 RW .0160-.0165 .0075-.0090 .0040
TW .0160-.0165 .0095-.0110 .0030
ETW .0160-.0165 .0115-.0130 .0020
UTW .0160-.0165 .0130-.0140 .0015
MTW .0160-.0165 .0140-.0150 .0010
28 RW .0140-.0145 .0065-.0080 .0035
TW .0140-.0145 .0085-.0100 .0025
ETW .0140-.0145 .0100-.0110 .0020
UTW .0140-.0145 .0110-.0120 .0015
MTW .0140-.0145 .0120-.0130 .0010
29 RW .0130-.0135 .0065-.0080 .0035
TW .0130-.0135 .0080-.0090 .0025
ETW .0130-.0135 .0090-.0100 .0020
UTW .0130-.0135 .0100-.0110 .0015
MTW .0130-.0135 .0110-.0120 .0010
30 RW .0120-.0125 .0055-.0070 .0030
TW .0120-.0125 .0070-.0080 .0025
ETW .0120-.0125 .0080-.0090 .0020
UTW .0120-.0125 .0090-.0100 .0015
MTW .0120-.0125 .0100-.0110 .0010
31 RW .0100-.0105 .0040-.0055 .0025
TW .0100-.0105 .0055-.0070 .0020
ETW .0100-.0105 .0070-.0880 .0015
UTW .0100-.0105 .0080-.0090 .0010
32 RW .0090-.0095 .0035-.0050 .0025
TW .0090-.0095 .0050-.0060 .0020
ETW .0090-.0095 .0060-.0070 .0015
UTW .0090-.0095 .0070-.0080 .0010
33 RW .0080-.0085 .0035-.0050 .0020
TW .0080-.0085 .0050-.0060 .0015
ETW .0080-.0085 .0060-.0070 .0010
34 RW .0070-.0075 .0025-.0040 .0020
TW .0070-.0075 .0040-.0050 .0015
ETW .0070-.0075 .0050-.0060 .0010
35 RW .0050-.0055 .0015-.0030 .0015
TW .0050-.0055 .0030-.0040 .0010
36 RW .0040-.0045 .0010-.0020 .0015
TW .0040-.0045 .0020-.0030 .0010
*Custom sizes available upon request. RW Regular Wall TW Thin Wall ETW Extra-thin Wall UTW Ultrathin Wall MTW Microthin Wall

Cut-to-Length Tubing

K-Tube offers cutting options to help you save cost.

K-Tube has capacity to produce millions of cut-to-length parts each week. We offer a number of different cutting options based on the demands of your application. The best cut for your application will vary based on length, tolerance, and specific use. By identifying the most cost-effective cutting technology for your tubing project, we may be able to help you attain significant cost savings.

If you need to make sure your choice is properly validated, we can manufacture a few small runs with different cut choices through our K-Tube Discover Center.

Review the cut options listed below to determine which is the right fit for your next project.

B – Score break cut (70-90% open ID, with rounded OD):

Score break cuts can be a very cost-effective method when downstream processing or fabrication will remove material from the ends. It is often chosen for applications where slight deformation to the ID is acceptable.

E, EF & ECG – Electrolytic cut (100% open ID, burr free with a natural edge break on OD):

Many medical applications require clean, burr free cuts. K-Tube’s electrolytic cutting centers offer the highest level of cut quality and capability available.

 

L – Laser cut (100% open ID, burr free with a minimal edge break on OD):

Laser cuts are ideal for very short parts requiring a clean burr -free cut or for applications where a sharp edge on the OD post-cutting is preferred.

 

S – Shear cut (0-5% open ID, pinched OD):

Most of the standard footage we sell has been shear cut to the desired length after the final straightening process is complete.

When ordering, please specify which cut type you’d like. If you are unsure which cut is best for your needs, give us a call, and we will guide you in the right direction.

Mechanical Properties

K-Tube’s expertise will ensure your final product will meet your requirements.

K-Tube has a metallurgy lab and advanced engineering resources on site to ensure that the characteristics of your miniature stainless tubing meet your performance criteria. By controlling the amount of cold work imparted to the tube, we can manufacture and test to your product’s exacting temper, tensile, yield, or hardness requirements

 

Temper

Tubing can be fully annealed or supplied as cold worked.  ¼, ½, and full hard conditions are commonly used industry terms, but we define these values by reporting in specific tensile strength ranges. We will report all associated tensile values in the material certifications supplied with each shipment, using test methods described in ASTM E8.

Tensile

When more control over the material strength is required than temper alone can give, ultimate tensile strength can be specified directly. Our standard tolerance is +/- 15 ksi around the specified strength, although we support applications that require tighter control. Tubing strength will increase when cold-worked, at the expense of toughness. Consider discussing your project with one of our engineers or metallurgists if your product will face strong compressive forces.

 

Yield, Elongation

The resistance to plastic deformation can be an important characteristic in many products. Yield strength increases along with tensile strength as the tube is cold worked, while elongation decreases. Because of their close relationship to tensile strength, these test results are typically reported for information only. When high ductility is required for forming or bending, consider use of a precipitation hardening alloy that can be heat treated to high strength after fabrication.

 

Hardness

In some high-wear applications, such as edge retention, hardness is a more appropriate measure of tube strength than temper or tensile strength. K-Tube reports hardness in Rockwell HRC or HRB units, and will typically verify that a minimum is met when paired with a tensile strength requirement. Micro-hardness testing can be used to verify that the mechanical properties are consistent throughout the cross section of the tube.