1. Classification by production method:

(1) Seamless tubes - cold drawn tubes, extruded tubes, cold rolled tubes.

(2) Welded pipe:

(a) Classification by process - gas shielded welded pipe, arc welded pipe, resistance welded pipe (high frequency, low frequency).

(b) According to welding seam - straight seam welded pipe, spiral welded pipe.

2. Classification according to cross-sectional shape: (1) circular steel pipe; (2) rectangular pipe.

3. Classification by wall thickness - thin-walled steel pipes, thick-walled steel pipes

4. Classification by use: (1) Civil pipes are divided into round pipes, rectangular pipes, and floral pipes, which are generally used in decoration, construction, structure, etc.;

(2) Industrial pipes: steel pipes for industrial piping, steel pipes for general piping (drinking water pipes), mechanical structure/fluid delivery pipes, boiler heat exchange pipes, food hygiene pipes, etc. It is generally used in various fields of industry such as: petrochemical, papermaking, nuclear energy, food, beverage, pharmaceutical and other industries that have high requirements for fluid media.

2. Seamless steel pipe

Stainless steel seamless pipe is a long steel material with a hollow section and no seams around it.

1. Seamless steel pipe manufacturing technology and process:

Smelting＞Steel ingot＞Rolling＞Sawing＞Peeling＞Perforation＞Annealing＞Pickling＞Ashing＞Cold drawing＞Head cutting＞Pickling＞Storage

2. Features of seamless steel pipe:

From the above process flow, we can easily see that: first, the thicker the wall thickness of the product, the more economical and practical it is; the thinner the wall thickness, its processing cost will increase significantly; secondly, the product The process of the product determines its limitations. Generally, seamless steel pipes have low precision: uneven wall thickness, low brightness on the inner and outer surfaces of the pipe, high cost of sizing, and pitting and black spots on the inner and outer surfaces that are difficult to remove; thirdly, its Detection and shaping must be processed offline. Therefore, it reflects its superiority in terms of high pressure, high strength, and mechanical structural materials.

3. Welded steel pipe

Welded steel pipe, referred to as welded pipe, is a stainless steel pipe welded by steel plates or steel strips after being curled and formed by a unit and a mold.

1. Steel plate > Slitting > Forming > Welding > Induction bright heat treatment > Internal and external weld bead treatment > Shaping > Sizing > Eddy current testing > Laser diameter measurement > Pickling > Warehousing

2. Characteristics of welded steel pipes:

It is not difficult to see from the above process flow: First, the product is produced continuously online. The thicker the wall thickness, the greater the investment in the unit and welding equipment, and the less economical and practical it is. The thinner the wall thickness, the lower its input-output ratio will be; secondly, the process of the product determines its advantages and disadvantages. Generally, welded steel pipes have high precision, uniform wall thickness, and high internal and external brightness of stainless steel pipe fittings (determined by the surface grade of the steel plate) The surface brightness of the steel pipe) can be arbitrarily cut to length. Therefore, it reflects its economy and aesthetics in high-precision, medium and low-pressure fluid applications.