Diferencia entre tubería de acero dulce y tubería de acero al carbono

Mild steel seamless pipe

Mild steel pipe is made of carbon steel with a carbon content of less than 0.25%. Mild steel is a type of carbon steel in which the carbon content is very low. Approx. 0.16–0.29% by weight. This steel is cheap and the most commonly used. It is malleable and malleable, but has low tensile strength. Low carbon cannot be hardened by heat treatment.

Mild steel is the mildest type of carbon steel and has a relatively low carbon content. Mild steels may also contain other elements such as manganese, silicon and traces of phosphorus. These additional elements protect the integrity of the metallic iron structure by preventing dislocations within the iron crystals. Carbon acts as a hardening agent and the percentage of carbon added is directly proportional to the strength of the steel; the strength of steel generally increases with the percentage of carbon added. Mild steel has a very low carbon content compared to other carbon steels. Mild steel has high ductility and ductility, while other carbon steel types have low ductility. Mild steel cannot be hardened by heat treatment, but other types of carbon steel can be hardened by heat treatment. Mild steel has lower strength and hardness than other carbon steel types. It is usually expressed by the surface roughness Ra of steel.

The surface roughness of the pipeline is mainly manifested in the following aspects: The surface roughness of the wearing parts. The rougher the surface, the smaller the effective contact area with the bearing, the greater the pressure, and the faster the wear.

Low carbon steel seamless pipe has the following characteristics:

1. Low carbon steel seamless steel pipe is a carbon steel with a carbon content of less than 0.25%. Because of its low strength, low hardness, and low softness, it is also called low carbon steel.
2. The annealed structure of low-carbon steel seamless pipe is ferrite and a small amount of pearlite, with low strength and hardness, but good plasticity and toughness.
3. Low carbon steel seamless pipe has good cold forming performance, and can be cold formed by crimping, bending, stamping and other methods.
4. Low carbon steel seamless steel pipe has good weldability. It is easy to accept various processing such as forging, welding and cutting.

Seamless carbon steel pipe

Carbon steel pipes are made of steel ingots or solid round steel through perforation into capillary tubes, and then made by hot rolling, cold rolling or cold drawing.

The raw material for carbon steel pipe is round tube billet, and the round tube embryo should be cut by cutting machine to grow billets with a length of about 1 meter, and transported to the furnace by conveyor belt. Billet is fed into the furnace to heat, the temperature is about 1200 degrees Celsius. The fuel is hydrogen or acetylene. The temperature control in the furnace is a key issue. After the round tube is out of the furnace, it must be pierced through a pressure piercer. Generally, the more common piercer is the cone roll piercer. This kind of piercer has high production efficiency, good product quality, large perforation diameter expansion, and can wear a variety of steel types. 

After piercing, the round tube billet is successively cross-rolled, continuous rolled or extruded by three rolls. After extrusion, the tube should be taken off for sizing. Sizing by high-speed rotary cone drill holes into the billet to form a tube. The inner diameter of the steel pipe is determined by the length of the outer diameter of the drill bit of the sizing machine. After the steel pipe is sized, it enters the cooling tower and is cooled by spraying water. After the steel pipe is cooled, it will be straightened. After straightening, the steel pipe is sent to the metal flaw detector (or hydraulic test) by the conveyor belt for internal flaw detection. If there are cracks, bubbles and other problems inside the steel pipe, they will be detected. After the quality inspection of steel pipes, strict manual selection is required. After the quality inspection of the steel pipe, paint the serial number, specification, production batch number, etc. with paint. And hoisted into the warehouse by crane.

Seamless carbon tube is the most commonly used material for process piping. It has the advantages of wide availability, high strength and various connection possibilities, such as screw connections, socket welding and butt welding. Steel pipe should be selected based on the strength and durability required for the application and the ductility and workability required to join the steel pipes and form them into spools. Piping must withstand the pressure, temperature and corrosive conditions of the application. It is used for liquid, gas and steam service in above-ground and underground services.

What is the difference between low carbon steel pipe and carbon steel pipe?

1. Different carbon content

Carbon content: low carbon steel is generally less than 0.25%; medium carbon steel is generally between 0.25 and 0.60%; high carbon steel is generally greater than 0.60%.
In addition to the carbon (C) element and a certain amount of silicon (Si) (generally not exceeding 0.40%) and manganese (Mn) (generally not exceeding 0.80%, up to 1.20%) alloying elements for deoxidation, the steel contains Contains no other alloying elements (except residual elements). Usually, those with a carbon content of less than 0.02% are called wrought iron, those with a carbon content of more than 2.11% to 4.3% are called pig iron, and the ones in the middle are steel.

2. Different applications

Low-carbon steel is generally rolled into angle steel, channel steel, I-beam, steel pipe, steel strip or steel plate, and is used to make various building components, containers, boxes, furnaces and agricultural machinery. High-quality low-carbon steel is rolled into thin plates to make deep-drawn products such as automobile cabs and engine covers; it is also rolled into bars to make mechanical parts that do not require high strength. Low-carbon steel is generally not heat-treated before use, and those with a carbon content of more than 0.15% are carburized or cyanided, and are used for shafts, bushings, sprockets and other parts that require high surface temperature and good wear resistance.

Some common applications of high carbon steel include: railroad tracks, prestressed concrete, wire rope, tire reinforcement, knives, saw blades, gears, chains, and more.

3. Different costs

Carbon steel contains approximately 0.05-1.70% carbon by weight. Increasing the percentage of carbon in steel gives it extra strength and is also considered the most economical way to increase the strength of steel. However, steel also tends to become brittle and less ductile due to the addition of more carbon. Therefore, a proper balance of carbon must be added to obtain the extra properties of the steel. The carbon content of high carbon steel is between 0.3-1.70%, and the carbon content of low carbon steel is between 0.05-0.15%. Mild steel is the most commonly used grade of steel today due to its relatively low manufacturing price.

4. Different in nature

Mild steel has a very low carbon content compared to other carbon steels. Mild steel has high ductility and ductility, while other carbon steel types have low ductility. Mild steel cannot be hardened by heat treatment, but other types of carbon steel can be hardened by heat treatment. Mild steel has lower strength and hardness than other carbon steel types. High carbon steels can be heat treated better than mild steels and are therefore useful in many applications. Other elemental impurities can also give steel very interesting properties; namely sulfur.