Seamless pipe defects and causes

There are some common defects of seamless pipe for sharing.

1 Abscission
Characteristics of defects: in the steel pipe inner surface of the vertical distribution was raised spiral separation or rupture of bulk metal-like sandwich.

Causes: the material is caused by poor non-metallic inclusions, residual shrinkage, or severe osteoporosis.

2 Straight within the fold
Characteristics of defects:in the steel pipe inner surface of the vertical distribution is showing a symmetrical or single linear folded a long pass even local.

Causes:poor lubrication of the mandrel, the mandrel surface defects or surface with the oxide scale, scrap iron to make steel pipe inner surface of the program into the channel, the shortage of pipe in the rolling process, too full of rolling mill pass.

3 Wall contraction
Characteristics of defects:steel pipe horizontal thinnest section is surface depression located on the inner surface of the steel pipe and is local thinning of the wall thickness, even severe contraction of tear.

Causes:rolling mill extension in the hole sidewall part of the local pulled thin strip mill each rack pressure adjustment is improper and unreasonable extension coefficient distribution.

4 Within the rolling scars
Characteristics of defects:inner surface of steel pipe is vertical to nail-shaped scar, raised or block folding.

Causes:poor mandrel lubrication state is causing the mandrel local wear, damage, sticky metal, immediate serious wear and tear, stick the metal, the lack of meat or large cracks perforated ears were pressed on the steel pipe wall.

5 Rolling fold
Characteristics of defects:located on the partial or total length of the inner surface steel pipe was apparent grooves of the outer concave, convex folds or in the pipe outer surface longitudinal long pass prescribe symmetry is generally linear, individual slash-shaped.

Causes:rolling waste pipe outside diameter or waste pipe ovality is too large, bamboo control is not strong enough or lubrication conditions is poor, traverse device rolling touch the flat, rolling mill speed is error.

6 Double seam fold
Characteristics of defects:cracks in the steel pipe surface are sometimes scattered in the tube park weeks sometimes symmetrical.

Causes:Perforation capillary outside diameter is too large or irregular diameter is caused by folding.



Tech & Service of Seamless pipe

Seamless pipes are extensively applied for the nuclear device, gas, petrochemical, ship building and boiler industries. Seamless pipes dominates 65% of market share in Chinese boiler industry.

How to make seamless pipe(seamless pipe process)?
Hot Piercing Workshop
Piercing process
The cross roll piercing and pilger rolling process in the size range from approx. 250 to 660 mm outside diameter.
Precision cold drawn steel tube production process
Pipe weld cracks
often follow different mechanisms can be divided into two types of thermal cracking and cold cracking.
How to calculate a steel pipe and tube theoretic weight
Calculate a steel pipe?
Pipe fittings are necessary to join together pipes, or to change the direction of an existing pipe.
Pipe beveling
Pipe beveling is the process where an angle is formed between the edge of the end of a pipe or tube and a plane perpendicular to the surface.
Steel pipe cutting machine
Pipe cutting
Cutting tools have a grinding wheel piece cutting machine (also known as toothless saw), hand saw, cutter and other hand tools.
Packing the steel pipes
There are probably hundreds of different methods for packing a pipe, and most of them have merit, but there are two principles that are vital for any method.


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