1, Performance of different types of seamless steel pipes at low temperatures
Carbon steel seamless steel pipe:
Carbon steel seamless steel pipes are suitable for general industrial fields, with operating temperatures generally ranging from -29 ℃ to 425 ℃. When the temperature approaches the low temperature limit of -29 ℃, the toughness of carbon steel will decrease and the material will become brittle, which may lead to cold brittleness problems. In this low-temperature environment, if subjected to external impact or other conditions, steel pipes may undergo brittle fracture, affecting their normal use and safety.
Q355 seamless steel pipe:
Q355 seamless steel pipe has excellent comprehensive performance and can withstand low temperatures. However, the specific low-temperature performance will also be affected by its level (such as the impact temperature represented by the five levels A, B, C, D, and E). At low temperatures, its mechanical properties (such as yield strength, tensile strength, etc.) can still be maintained at a certain level to maintain the structural stability of the steel pipe. However, as the temperature decreases, its properties may also change. For example, the trend of yield strength gradually decreasing with the increase of pipeline wall thickness still exists at low temperatures, and low temperatures may have a certain impact on its toughness.
106B seamless steel pipe:
106B seamless steel pipes are typically used within a temperature range of -20 ℃ to 400 ℃. In cold regions below -20 ℃, that is, in low-temperature environments, the toughness of steel will weaken and brittle fracture is prone to occur. Although it can still be used normally at low temperatures, attention should be paid to the issue of cold brittleness, and suitable materials and processes should be selected to ensure its cold resistance.
2, Performance of different types of seamless steel pipes at high temperatures
Carbon steel seamless steel pipe:
Carbon steel seamless steel pipes may undergo oxidation and corrosion at high temperatures. Its operating temperature is generally between -29 ℃ and 425 ℃. When it approaches or exceeds the upper limit of this temperature range, the oxidation resistance of carbon steel decreases due to the influence of high temperature, which accelerates the oxidation process and leads to the formation of an oxide layer on the surface of the steel pipe, affecting its performance and service life. At the same time, high temperatures may cause deformation of steel pipes due to factors such as thermal expansion coefficient. If under pressure, it may affect its structural stability and even lead to dangerous situations such as rupture.
Alloy steel seamless steel pipe:
The temperature range for alloy steel seamless steel pipes (such as 10CrMoAl seamless steel pipes) is generally between -29 ℃ and 593 ℃, suitable for high temperature and high pressure working environments. Taking 10CrMoAl seamless steel pipe as an example, it is a low-alloy steel with multiple characteristics in high temperature environments:
High temperature strength: It can maintain high mechanical properties and tensile strength under high temperature conditions, ensuring that the steel pipe structure is stable and not easily deformed or damaged in working environments with high temperature and possible pressure.
Oxidation resistance: The chromium element in it can form a dense oxide layer, providing excellent oxidation resistance, thereby delaying the oxidation rate of the steel pipe and reducing the impact of oxidation on the performance and service life of the steel pipe.
Creep behavior: At high temperatures, the creep behavior of the material increases, but 10CrMoAl steel pipes have a lower creep rate, ensuring stability and reliability in high-temperature environments, that is, they are not easily subjected to slow and irreversible deformation due to long-term stress.
Coefficient of thermal expansion: This type of steel pipe has a low coefficient of thermal expansion, which can reduce stress and deformation caused by thermal expansion, and avoid problems such as damage to the steel pipe structure or affecting its connection with other components due to stress caused by thermal expansion and contraction.
Stainless steel seamless steel pipe:
The temperature range for the use of seamless stainless steel pipes varies depending on the material and alloy composition of the stainless steel. Common stainless steel materials include 304, 316, etc., and their temperature range is generally between -254 ℃ and 816 ℃. Stainless steel seamless steel pipes have good corrosion resistance and high-temperature stability in high-temperature environments, making them suitable for some special industrial fields. For example, in industries such as chemical engineering, when dealing with high-temperature and corrosive substances, stainless steel seamless pipes can resist corrosion and maintain their structural and performance stability at high temperatures.
Seamless steel pipe 513:
Seamless steel pipe 513 has high temperature resistance and is typically used within a temperature range of 300 ° C to 700 ° C. Within this temperature range, it can be applied to high-temperature working environments in fields such as petroleum, chemical, and energy. For example, in high-temperature reaction processes in petroleum extraction and chemical production, as well as in high-temperature and high-pressure steam pipelines in thermal power plants, it can withstand the pressure of high-temperature environments, ensuring the safe transportation of various media (such as petroleum, steam, etc.) or the normal operation of equipment in high-temperature reactions.
Cold drawn seamless steel pipe:
Cold drawn seamless steel pipes have a high melting temperature, can withstand pressure and temperature changes in high-temperature environments, and are not easily deformed or broken. Due to the use of cold drawing technology, the structure of steel pipes is denser, which helps them maintain good structural stability in high temperature environments. After special anti-corrosion treatment, they can also have strong corrosion resistance in environments with high temperatures and possible corrosive media.
