What is SA-106Gr.C alloy steel pipe commonly used in high-temperature and high-pressure environments

First, what are the chemical composition characteristics of SA-106Gr.C alloy steel pipe?

Carbon: Content is generally between 0.27% and 0.33%. Carbon is one of the key elements determining the strength of steel. An appropriate carbon content allows the alloy steel pipe to achieve good strength after proper heat treatment, helping it withstand higher pressures.

Manganese: Content is approximately 0.87% to 1.13%. Manganese has a solid solution strengthening effect in steel, significantly improving the strength and toughness of the alloy steel pipe, enabling it to withstand greater stress and reducing the likelihood of breakage under complex working conditions.

Silicon: Content is between 0.10% and 0.30%. Silicon is mainly used for deoxidation and also improves the strength of steel to a certain extent, enhancing the overall performance of the alloy steel pipe.

Impurity element restrictions: There are strict limits on the content of phosphorus and sulfur, with phosphorus not exceeding 0.035% and sulfur not exceeding 0.035%. Because phosphorus and sulfur form harmful inclusions in steel, these inclusions reduce the toughness and corrosion resistance of alloy steel pipes, potentially leading to premature failure during use.

Second, what are the mechanical properties of SA-106Gr.C alloy steel pipes?

(1) Tensile strength: Typically between 483 and 648 MPa. In practical industrial applications, such as in boiler piping systems, when internal steam generates high pressure and exerts axial tension on the pipe, this high tensile strength ensures that the alloy steel pipe will not easily break, thus guaranteeing the safe operation of the piping system.

(2) Yield strength: Not less than 276 MPa. Yield strength is the stress at which a material begins to undergo significant plastic deformation. During the pressure-bearing process of the pipe, sufficient yield strength ensures that the alloy steel pipe will not undergo irreversible deformation within a certain pressure range. Especially under high temperature and high pressure environments, this property is crucial for maintaining the normal shape and function of the pipe, effectively preventing pipe deformation and avoiding safety accidents caused by pipe deformation.

(3) Elongation: Not less than 22%. Elongation reflects the toughness of alloy steel pipes. Higher elongation allows alloy steel pipes to deform to a certain extent without breaking under external impact or complex stress conditions. For example, during equipment startup, shutdown, or changes in operating conditions, pipelines experience thermal stress due to temperature changes. Sufficient elongation allows the alloy steel pipe to effectively adapt to these stress changes, preventing cracking due to stress concentration.

Third, how is the heat treatment process of SA-106Gr.C alloy steel pipe implemented?

Generally, normalizing is used, with normalizing temperatures typically between 870 and 940℃. During normalizing, the alloy steel pipe is heated above its critical temperature and then cooled in air. The main function of normalizing is to refine the grains, making the microstructure of the alloy steel pipe more uniform, thereby improving its strength and toughness. After normalizing, the microstructure of the alloy steel pipe is mainly pearlite and ferrite. This microstructure helps the alloy steel pipe maintain stable performance at high temperatures and withstand greater pressure and stress.

Fourth, how is the manufacturing process of SA-106Gr.C alloy steel pipe made?

Hot Rolling Process: Hot rolling is a commonly used manufacturing process. After heating the steel billet to a suitable temperature, it is gradually transformed into a seamless steel pipe through the rolling action of rolls. Hot rolling has high production efficiency and can guarantee the basic mechanical properties of the alloy steel pipe. However, the dimensional accuracy of hot-rolled alloy steel pipes is relatively low, requiring subsequent finishing processes to meet dimensional accuracy requirements.

Cold Drawing Process (Optional): For applications with higher dimensional accuracy requirements, cold drawing can be used. Cold drawing involves drawing the alloy steel pipe at room temperature using dies to achieve more precise dimensions for the outer diameter and wall thickness. Cold drawing can produce alloy steel pipes with high dimensional accuracy and good surface quality, but its production efficiency is lower, and the cost is relatively higher.

Fifth, what are the temperature resistance properties of SA-106Gr.C alloy steel pipes?

Temperature Resistance: SA-106Gr.C alloy steel pipes have excellent high-temperature resistance and can operate normally within a temperature range of -29℃ to 427℃. Within this temperature range, the mechanical properties and chemical stability of the alloy steel pipes can meet the requirements of various industrial applications, and their performance will not decrease drastically due to temperature changes.

Sixth, what are the application areas of SA-106Gr.C alloy steel pipes?

(1) Petrochemical Industry: In petrochemical plants, they are used to transport high-temperature, high-pressure petroleum products, chemical raw materials, and steam. For example, in crude oil distillation units of oil refineries, as part of the pipeline system, they transport crude oil to different distillation towers for fractionation, and can also withstand the high-temperature steam generated during the fractionation process.

(2) Power Industry: Widely used in boiler systems of power plants, mainly for manufacturing components such as superheater tubes and reheater tubes. These components need to withstand the effects of high-temperature steam. SA-106Gr.C alloy steel pipes, with their excellent high-temperature resistance and mechanical properties, can ensure the safe and stable operation of boiler systems.

(3) Other industrial fields: They are also used in pipeline systems and equipment that require the transport of high-temperature media or operate in high-temperature environments, such as heating furnace pipelines in the metallurgical industry and steam transmission pipelines in the papermaking industry.