Working pressure range of API 5L seamless steel pipe

　　API 5L Seamless pipe is widely used in high, medium and low pressure fields. Among them, the high pressure field refers to the occasion where the working pressure is greater than 10MPa; the medium pressure field refers to the occasion where the working pressure is between 1.6~10MPa; the low pressure field refers to the occasion where the working pressure is not more than 1.6MPa. According to different working pressure ranges, seamless steel pipes can be divided into three types: high pressure seamless steel pipes, medium pressure seamless steel pipes and low pressure seamless steel pipes.

　　Factors affecting the working pressure of seamless pipes:

　　The working pressure of seamless pipes depends on multiple factors such as its material, wall thickness, diameter and use environment. The working pressure of ordinary carbon steel seamless pipes at room temperature can reach about 20MPa, while stainless steel seamless pipes may have stronger pressure bearing capacity due to their higher material strength.

　　1. Material: The material of seamless pipes has a crucial impact on their pressure bearing capacity. For example, seamless pipes made of carbon structural steel, stainless steel and alloy materials have significant differences in pressure bearing capacity.

　　2. Diameter and wall thickness: The diameter and wall thickness of seamless pipes are also important factors in determining their pressure bearing capacity. Generally speaking, seamless pipes with smaller diameters and thicker walls have higher pressure bearing capacity.

　　3. Use environment: The environmental conditions in which seamless pipes are located, such as temperature, humidity, corrosive media, etc., will affect their pressure bearing capacity. In harsh environments, the pressure bearing capacity of seamless pipes may be reduced.

　　Comparison of working pressures of API 5L seamless pipes of different materials:

　　‌Ordinary carbon steel seamless pipes‌: The working pressure at room temperature is about 20MPa.

　　‌Stainless steel seamless pipes‌: Due to the higher material strength, their pressure bearing capacity is stronger. The specific value needs to be determined based on the actual situation and the technical data provided by the manufacturer.

　　Classification and specifications of API 5L seamless steel pipes:

　　Depending on the manufacturing process, seamless pipes can be divided into cold-drawn and hot-rolled types. Among them, the manufacturing cost of cold-drawn seamless steel pipes is low, but the production speed is slow; the production cost of hot-rolled seamless steel pipes is high, but the production speed is fast. The specifications and sizes of seamless steel pipes are mainly determined by two parameters: outer diameter and wall thickness. Different specifications and sizes can be selected according to different application requirements.

　　Example and data analysis:

　　Take a certain model of seamless steel pipe as an example. Its outer diameter is 48 mm, the wall thickness is 3.5 mm, and the material is 20# carbon structural steel. Under normal temperature and pressure, after testing, the pressure bearing capacity of the seamless steel pipe can reach 60 MPa. However, under high temperature and high pressure environment, its pressure bearing capacity may be reduced.

　　Calculation of pressure bearing capacity of seamless steel pipe:

　　Seamless pipes are widely used in the industrial field, and their pressure bearing capacity is a key indicator. Generally speaking, the pressure range that seamless pipes can withstand is between 10 MPa and 80 MPa. However, this is only a rough range, and the actual pressure bearing capacity needs to be evaluated according to specific circumstances.

　　The pressure-bearing formula of seamless steel pipe: P = 2 * t * S * Y / (D - t)

　　Wherein, P is the bearing pressure (in MPa), t is the wall thickness (in mm), S is the Poisson's ratio, Y is the yield strength (in MPa), and D is the pipe diameter (in mm).

　　For example: What is the bearing pressure of a 20G seamless steel pipe with a length of 89mm and a wall thickness of 12mm? 20G seamless steel pipes are usually made of high-quality carbon structural steel. After hot rolling, cold drawing and other processes, they have good mechanical properties and corrosion resistance.

　　According to the known specifications of 89*12mm, we can substitute t=12 into the formula for calculation. At the same time, we need to know the yield strength Y of the 20G seamless steel pipe. Usually, the yield strength of carbon structural steel is around 235MPa, so we can substitute it into the formula for calculation.

　　Substitute the relevant values for calculation: P = 2 * 12 * 0.3 * 235 / (89 - 12) = 27.6MPa.

　　API 5L Seamless steel pipe (smls pipe) is a common pipeline material. Compared with welded steel pipe, it has higher strength and tensile strength, as well as better high temperature resistance. Seamless steel pipe is widely used in petroleum, chemical, natural gas, electricity and other fields. In the fields of petroleum, chemical and natural gas, seamless steel pipe is mainly used to transport high temperature and high pressure fluids, such as oil, natural gas and chemical media.