5 Classifications of Stainless Steel Pipes

Stainless steel is the most versatile material in the world and is now an integral part of every industry. It consists of a steel alloy and a certain proportion of chromium. This addition of chromium provides the material’s ability to resist corrosion. This feature has earned the popularity and reputation of stainless steel in the market. Because stainless steel is low maintenance, resistant to oxidation, and does not affect other metals in contact with it, it is widely used in a variety of applications, especially in pipe manufacturing. Stainless steel pipes are divided into different types according to different classification.

By Material

Steel pipes are divided into ordinary carbon steel pipes, high-quality carbon structural steel pipes, alloy structural steel pipes, alloy steel pipes, bearing steel pipes, stainless steel pipes and bimetallic composite pipes, coatings and coated pipes to save precious metals and meet special requirements.

By Production Mode

According to the production method, stainless steel pipes are divided into two types: seamless pipes and welded pipes.

1. Seamless stainless steel pipe

A steel tube made of a single piece of metal with no seams on the surface and no welded joints called a seamless stainless steel pipe. Depending on the application, there are thick-walled tubes and thin-walled tubes. According to different production methods, it is divided into hot-rolled pipe, cold rolled pipe, cold drawn pipe, extruded pipe, and top pipe. Due to the metal itself, it can withstand high pressures and temperatures, which makes the seamless stainless steel tube quite versatile. Seamless stainless steel pipes are mainly used as petroleum geological drilling pipes, cracking pipes for petrochemicals, boiler tubes, bearing tubes, and high-precision structural steel tubes for automobiles, tractors, and aviation.

2. Welded pipe

Welded steel pipe, also called welded pipe, is a steel pipe made by welding a steel plate or a strip steel after being crimped. According to the welding process, it is divided into furnace welded pipe, electric welded pipe and automatic arc welded pipe. According to the welding form, it is divided into straight welded pipe and spiral welded pipe. According to the shape of the end, it is divided into a circular welded pipe and a special-shaped (square, flat, etc.) welded pipe. According to its material and use, it is divided into stainless steel welded steel pipe for mechanical structure, welded steel pipe for low-pressure fluid transportation, welded steel pipe for mining fluid, and welded steel pipe for fluid transportation.


Due to its flexibility, welded pipes can be used in almost all industries. Also, they are more resistant to corrosion than pressure. Due to the materials used and the lightweight nature of the welded pipes, they are more cost effective than most other pipe methods and offer you the best value.

By Section Shape

According to the cross-sectional shape, the stainless steel tube can be divided into a round tube and a shaped tube. The special-shaped tube has a rectangular tube, a rhombic tube, an elliptical tube, a hexagonal tube, an octagonal tube, and various cross-section asymmetric tubes. Shaped tubes are widely used in a variety of structural parts, tools, and mechanical parts.

By Crystal Structure

According to the crystal structure, it can be divided into austenitic stainless steel, ferritic stainless steel, martensitic stainless steel, duplex stainless steel. Huzhou GaoLin stainless steel pipe manufacturing Co., Ltd. is a professinal stainless steel pipes manufacturer.

1. Austenitic stainless steel

Austenitic stainless steel is the largest family of stainless steel, accounting for about two-thirds of all stainless steel production. They have an austenitic microstructure, which is a face-centered cubic crystal structure. This microstructure can be achieved by alloying with sufficient nickel or manganese and nitrogen to maintain the austenitic microstructure at all temperatures from the low-temperature region to the melting point. Since austenitic stainless steels have the same microstructure at all temperatures, they cannot be hardened by heat treatment. This limits their use in structural and other load-bearing components.

2. Ferritic stainless steel

Ferritic stainless steel has a ferrite microstructure like carbon steel, which is a body-centered cubic crystal structure and contains 10.5% to 27% chromium with almost no nickel. Due to the addition of chromium, this microstructure exists at all temperatures and they are magnetic like carbon steel. Because they do not contain nickel, they are less expensive than austenitic grades and are now widely used in a variety of industries.

3. Martensitic stainless steel

Martensitic stainless steels have a wide range of properties and are used as stainless steel engineered steels, stainless steel tool steels and creep resistant steels.

4. Duplex stainless steel

Duplex stainless steels are referred to as “dual-phase” because they have a two-phase structure composed of ferritic and austenitic stainless steel grains. It has good resistance to pitting and crevice corrosion and also has high strength and high resistance to stress corrosion cracking. Due to the lower alloy content, the cost of duplex stainless steel may be lower. Duplex steels are generally classified into three subgroups based on their corrosion resistance: lean duplex steel, standard duplex steel, and super duplex steel.

Today, the oil and gas industry is the largest user and has driven a higher level of corrosion resistance, leading to the development of super duplex stainless steel pipes. Recently, lean-oil duplex stainless steel pipes have been developed which are relatively inexpensive (and slightly less resistant to corrosion) and are mainly used in structural applications of buildings and buildings (concrete reinforcement, bridge decks, coastal engineering) and the water industry.

By Tube End Shape

According to the state of the pipe end, the stainless steel pipe can be divided into a light pipe and a wire pipe (thread pipe).

Wire tubes can be divided into ordinary wire tubes (transport water, gas, and other low-pressure tubes, using ordinary cylindrical or conical tube threaded connections) and special threaded tubes (oil, geological drilling tubes, important wire tubes). For some special tubes, in order to compensate for the effect of the thread on the strength of the end of the tube, the end of the tube is usually thickened (internal thickening, external thickening or internal and external thickening) before the welding wire.

By Purpose

According to the application, it can be divided into oil well pipe (casing, oil pipe, drill pipe, etc.), line pipe, heat exchanger tube, mechanical structure pipe, hydraulic pillar pipe, gas cylinder pipe, geological pipe, chemical pipe (high pressure fertilizer pipe, petroleum cracking pipe) as well as ships and other pipelines.

Stainless steel pipes are corrosion resistant, durable and environmentally friendly. Stainless steel tubes are a good choice both in life and in industry. Huzhou Gao Lin stainless steel pipe manufacturing Co., Ltd. is a professinal stainless steel pipes supplier. If you have any needs, please contact us.


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