Q/BQB 419-2003 is a Chinese enterprise standard developed by Baosteel, specifying technical requirements for seamless steel tubes used in mechanical and general engineering applications. It defines chemical composition, mechanical properties, dimensional tolerances, and testing methods.
Q/BQB 419-2003 tubes are widely used in the manufacturing of automotive components, hydraulic cylinders, precision machinery, and other applications requiring high dimensional accuracy and surface quality.
The standard covers cold drawn or cold rolled seamless tubes and allows for different delivery conditions such as normalized or cold finished. It emphasizes tight dimensional control and smooth internal and external surfaces.
This specification is commonly adopted in industries requiring reliable structural performance with strict tolerances, and it is often used as a benchmark in both domestic and export markets.
