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Stainless Steel Instrumentation
Fractional / Metric Tubing
TS-04-S
2011
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www.dklok.comTubing benefits
Tubing has many benefits against piping.
Pipe threading or welding is difficult to disassemble
and re-assemble.
Piping requires skilled worker for welding & threading.
Piping is bulky.
Tubing is assembled by simple wrench make-up on
DK-LOK tube fittings reducing assembly time and the
overall cost of installation.
Tubing is bendable, allowing lower pressure drop with
fewer connections. This in turn reduces costs with
less fabricating manpower.
For safe, reliable and leak-free tubing system for use with
DK-LOK fittings, tubing should be considered as one of
fitting components.
The following parameters should be considered when
ordering instrumentation bright annealed seamless and
welded tubing.
1. Tubing Selection
2. Tubing Handling
3. Tubing Installation
4. System Pressure
5. Welded Tubing Working Pressure
DK-LOK Tubing Features
For the best performance with DK-LOK fittings, DK offers
ASTM A269 and A213 bright annealed DK-LOK tubing 1/8
in. to 1 in. OD with the following features:
Seamless and suitable for bending and flaring.
Free of scratches, drawing, dirt, and dust and other
contamination.
Chemically cleaned and passivated surface.
Cold drawn and bright annealed.
Hardness 80 HRB or less.
DK-LOK tubing marking and packaging
Marking on tubing includes OD, wall thickness(WT),
material grade, specification, heat code, and country
of origin.
Tubing ends to be capped.
A certain quantity to be packaged in a protective
cover and then packed in a wooden crate.
DK-LOK tubing standard length
6 meter tubing cut length variations as per the requirement
of ASTM A450 standard.
DK-LOK tubing ovality in OD and variations in WT
ASTM A269 specifies permissible variation in tubing OD
and WT, reads:
Tube O.D.
In.
Permissible
variation in OD,
In. (mm)
Permissible variation
in WT, %
Up to 1/2
+/- 0.005 (0.13)
+/- 15%
1/2 to 1 1/2, excl.
+/- 0.005 (0.13)
+/- 10%
Tubing ovality variation in OD as per the requirements of
ASTM A269. For tubing OD 1/8 in. and smaller, DK
supplies +/- 0.003 inch variations for the leak-free
performance with stainless steel 316 DK-LOK fittings.
Tubing WT variations as specified in the ASTM A269
standard. See Table 4 and 5.
Heat Treatment
Solution annealed.
Surface Condition
Bright annealed with thermocouple clean level on the
inside surface as per ASTM A632 S3.
1). Tubing Selection
Hardness
1. Tubing must be softer than fitting material. The metal
tubing must be fully annealed and suitable for bending
and flaring.
2. Tubing hardness must be selected according to the
information in the table 4 and 5.
Surface
3. Tubing must have a surface free from scratches, draw
mark, dirt, durst and flat spots.
Ovality
4. Tubing in oval or out-of-roundness may not fit into the
fitting. Do not force the tubing into the fitting; it may
damage the fitting sealing system on the nut, ferrules,
and body.