Heat exchanger tubes are made using the cold
rolling process and the semi-finished product for these are
usedrolled
steel tubes. Heat
exchanger tubes are used in energy and chemical industry for
heating the buildings, water etc. The heat exchanger tubes make it
possible to transfer thermal energy from one media to another. The
heat transfer may be linked with phase transformation of the media.
Overview of the dimensional standards and the technical-delivery
conditions according to which these tubes are manufactured and
supplied is shown in aseparate overview. Dimensions of the heat exchanger
tube The
outside diameter of the heat exchanger tubes ranges from *6 mm to
*1 mm according toDIN
****0and
from ½ inch (*2.7 mm) to 4 inches (**4.3 mm) according
toASTM
A**9The
tubes for the heat exchangers may be supplied also in compliance
with other standards starting with 4 mm. Detailed overview is shown
in tables and according toBS, NF
A, UNI, STN, ČSN, GOST standards,
according toEN
****6and
according toJIS
standards. Types of steel for heat exchanger
tubes Tubes
for the heat exchangers are made of the following steels according
to EN ******2: P**5GH, according to DIN ***9: St *7.0, DIN ****5:
St*5.8, *5Mo3, DIN ****3: TTSt*5N and according to ASTM A**9.
Additional types of steel according to BS ***6, NF A *****5, UNI
***2, GOST **0, GOST ***0, JIS ***1, JIS ***2, STN *2 ***1 and ČSN
*2 ***1 together with its chemical composition and mechanical
properties are shown in aseparate overview. Steel
is manufactured in electric arc furnace and it is killed. Other
types of steel are possible to deliver upon
request.
Delivery condition and tubes surface of the
heat exchanger tube Tubes
are supplied according to agreed standards. The cold drawn tubes
after the final forming go through thermal processing in shielding
gas normalizing.
Tubes length destined of the heat exchanger
tube Upon
request the heat exchanger tubes may be supplied in length up to
*8.3 meters.
Straightness of heat exchanger
tube Straightness deviation for the whole length
of a tube L can not exceed value of 0.***5 x L. In conversion to
the 1 meter length it can not exceed 3
mm.
Ends of the heat exchanger
tube The
ends of the tubes are vertical to the longitudinal axis and are
without burrs.
Marking of the tubes and tube
bundles Tubes
are marked by spraying the agreed upon data. Tube bundles are
marked with labels with the agreed upon
data.
Surface protection of the heat exchanger
tube The
inner and outer surface is protected by a light oil application.
Upon request it may be protected with and easy removable oil
application on the outer side. The tube ends may be enclosed by a
plastic plug.
Packaging of the heat exchanger
tubes The
tubes are usually packaged into bundles of a hexagonal
cross-section and are bound with a steel band that has a paper
underneath. The package is wrapped with a plastic sheet. Upon
request the tubes may be supplied in wooden
crates.
Testing of the heat exchanger
tube Besides
the prescribed mechanical tests, each tube is tested with leak
tightness test by eddy current. Based on an agreement it is
possible to do the hydrostatic testing or ultrasound
testing.
Certified test reports EN
****4 2.2, 3.1 or 3.2 ASTM/ASME
A**0 DIN ****9
2.2, 3.1.B