Allowable Deviation Values of Wall thickness and Outer Diameter of Seamless Tubes
Date:2024-02-22 keywords: seamless tube wall thickness and outer diameter allowable deviation, seamless pipe choose
Allowable deviation values of wall thickness and outer diameter of seamless tubes (SMLS tube):
International standards:
According to international standards, the allowable deviation value of seamless tube wall thickness should comply with the following regulations:
1. For seamless steel tubes with wall thickness > or = 20mm, the allowable deviation value should be within plus or minus 10%;
2. For seamless steel tubes with 2.5mm ≤ wall thickness ≤ 20mm, the allowable deviation value should be within plus or minus 12.5%;
3. For seamless steel tubes with wall thickness less than 2.5mm, the allowable deviation value should be within plus or minus 0.5mm.
Generally speaking, international standards have strict requirements on the allowable deviation value of seamless steel tube wall thickness.
Chinese standard:
According to the relevant provisions of the domestic standard GB/T 8163-2008 "Seamless Steel Pipe", the allowable deviation value of the wall thickness of seamless tubes should meet the following requirements:
1. For seamless steel tubes with wall thickness > or = 20mm, the allowable deviation value should be within plus or minus 12.5%;
2. For seamless steel tubes with a wall thickness of 2.5mm ≤ 20mm, the allowable deviation should be within plus or minus 15%;
3. For seamless steel tubes with wall thickness less than 2.5mm, the allowable deviation value should be within plus or minus 0.45mm.
Domestic standards have relatively loose tolerances on the wall thickness of seamless steel tubes, but they still need to meet the requirements of relevant standards.
The meaning of the allowable deviation value:
The allowable deviation value of seamless tube wall thickness refers to the allowable gap between the seamless steel tube wall thickness and the actual wall thickness during the production process. The scope of this gap is specified by relevant standards, and its purpose is to control the quality of seamless steel tubes and ensure their stability and reliability during use.
What is the national allowable error value for seamless tubes?
The national standards for seamless steel tubes stipulate the allowable errors, which are generally divided into two aspects: outer diameter error and wall thickness error. According to standard regulations, the outer diameter error of seamless steel tubes is generally between 0.10mm~0.75mm, while the wall thickness error is between 0.10mm~12.5%. The specific value depends on factors such as the specifications, material, and process of the steel pipe. Different steel pipes may have different allowable errors.
Reasons and effects of allowable deviations in size of seamless steel tubes:
1. Allowable deviation of outer diameter: The allowable deviation of outer diameter of seamless steel tube is mainly caused by factors such as rolling and straightening during the production process. A deviation in the outer diameter will affect the connection performance of the steel pipe, while a smaller outer diameter will affect the strength and sealing performance of the steel pipe.
2. Allowable deviation of wall thickness: The allowable deviation of wall thickness of seamless steel tube is mainly affected by uneven factors such as rolling and wall straightening. The strength and stiffness of the steel pipe will also affect the sealing performance of the connection part.
3. Length tolerance: The length tolerance of seamless steel tubes is mainly caused by factors such as sawing and inspection. If the length is too short, it will affect the overall use effect of the steel pipe, while if the length is too long, it will cause material waste.
What is the impact of the allowable error of seamless steel tubes on the quality of steel pipes?
The allowable errors for seamless steel tubes stipulated by the state are to ensure the qualification and stability of steel pipe quality. When producing and using seamless steel tubes, the existence of errors may affect the performance and service life of the steel pipes.
Steel pipes with large outer diameter errors are prone to oil leakage, air leakage and other problems during use. If the wall thickness error is too large, it will affect the load-bearing capacity, pressure resistance, wear resistance and other performance indicators of the steel pipe. Therefore, in the process of using seamless steel tubes, it is necessary to strictly comply with national standards for testing and selection.
How to avoid the impact of the allowable error of seamless steel tubes on quality?
In order to avoid the impact of the allowable error of seamless steel tubes on the quality of the steel pipe, the following points need to be paid attention to when selecting and testing steel pipes:
1. Choose seamless steel tubes that meet national standards and avoid using steel pipes with excessive outer diameter errors and wall thickness errors;
2. During the processing and installation of steel tubes, operate in strict accordance with national standards to avoid secondary errors;
3. Regularly conduct non-destructive testing to detect and deal with quality problems in a timely manner to ensure the continuous and stable performance of seamless steel tubes.
Conclusion:
The allowable deviation value of seamless tube wall thickness and outer diameter is a very important parameter. Different countries and regions have corresponding standards and regulations. Manufacturers and users should strictly abide by them to ensure that there is no The quality and safety of seamed steel tubes.
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