Requirements for straightness of seamless pipes

Seamless pipe (SMLS) is a commonly used material in industrial production. Its straightness is a crucial quality indicator. Seamless steel pipes should have a certain degree of straightness to avoid adverse effects on their use. The country has formulated standards for the straightness of seamless steel pipes, which will be detailed in this article.

1. Measurement method

Seamless pipes can be measured for straightness using simple tools such as metal gauges. National standards typically express measurement results in millimeters or other length units. A ruler can be used for smaller diameter pipes, while more precise measuring instruments are required for larger diameter pipes.

2. Limit deviation

To ensure the quality of seamless pipes, the country has set clear limits for straightness deviation.  These limits are divided into different levels based on the pipe's diameter, with larger pipes having a greater allowable deviation. National standards provide specific deviation values. In special circumstances, the national standards allow for some deviation requirements. For instance, longer pipes may have a larger allowable deviation.

3. Level requirements

The national standards specify the grade requirements for the straightness of seamless pipes. The level requirements are divided into level two or level three. The requirements for first-level straightness are relatively high, while the requirements for third-level straightness are relatively low. In actual projects, different grades of steel pipes can be selected to meet specific usage requirements.

The quality of seamless pipes is indicated by their straightness. National standards and requirements have been defined for this characteristic. To ensure the quality of seamless steel pipes, it is important to select the appropriate grade for specific usage requirements and conduct measurements and inspections in accordance with national standards.