What are the factors affecting the annealing of stainless steel pipelines

In the process of demolition of old
buildings, the removal of stainless steel pipeline is an area requiring
special attention. This article mainly talks about the construction methods
under the demolition of stainless steel pipelines.

When removing the old pipelineline of
stainless steel pipelineline, most of them first use plasma cutting machine to
cut the pipelineline, then remove the pipeline by hand. If the caliber of
stainless steel pipeline is larger than DN200, you can also use hand hoist to
help lift and unload. The disassembled pipelines need to be cleaned out in time
so that the new pipelines can be prefabricated.

When the new stainless steel pipelineline is
prefabricated, the pipelineline can be lined up on the ground according to the
original pipelineline. During the prefabrication period, the location should be
based on the actual situation of the site. Before that, we need to see the
qualification certificate, chemical composition and mechanical properties of
the stainless steel pipeline and fittings manufactured by the company. We also
conduct heat treatment and intergranular corrosion tests for pipelines. Also
check the appearance of the pipeline to ensure that there are no cracks and
heavy skin defects on the surface of the stainless steel tube. It is usually
cleaned before the pipeline is installed to remove oil and other dirt.

Prohibited the use of oxygen acetylene
cutting of stainless steel pipeline, and should use the saw, hand saw, grinding
wheel cutting machine, plasma cutting machine, pipeline cutting, grinding wheel
with special grinding wheel.

Attention should also be paid to the use of
welded joints and fittings for 18-8 stainless steel pipelines, because the 18-8
stainless steel belongs to austenitic stainless steel, so the suitable way of
welding is manual argon arc welding.

Stainless steel pipelines need to be
installed after the support is fixed, and the pipelines can not directly
contact with the carbon steel support. Instead, stainless steel sheets,
chloride free plastic sheets and rubber plates should be inserted between
pipelines and supports.

According to the difference between the
conveying medium and the operation temperature, the flange gaskets shall be
selected according to the specifications, and the contents of chloride ions in
the non-metallic gaskets can not be greater than 50*10-6. When the pipelineline
of stainless steel pipeline is long or the temperature of the conveying medium
is high, the compensator should be added to the pipelineline.

Finally, after the installation of the
pipelineline, the test pressure test should be done according to the design or
specification requirements. In water pressure test, the content of chlorine ion
in water should not be higher than 25*10-6.

Source: China Stainless Steel Pipelines
Manufacturer – Yaang Pipe Industry Co., Limited (www.yaang.com)