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What are the technical requirements for tube billets?

What are the technical requirements for tube billets in the production of seamless steel pipes for medium and low pressure boilers?

The quality of the tube billet is the basic factor that determines the quality of seamless steel tubes for medium and low pressure boilers. In order to ensure the smooth progress of the perforation process and obtain high-quality medium and low pressure boiler tubes, strict requirements must be put forward on the chemical composition, geometric dimensions, surface quality, macrostructure, macrostructure, physical properties, and chemical properties of the tube blank:

(1) The surface quality of the tube blank determines the surface quality of seamless steel pipes for medium and low pressure boilers. Because the surface of some tube blanks are not allowed to have visible defects, such as cracks, inclusions, scars, pores, iron sheets, joint marks and sharp scratches, pits, and indentations with a depth of more than 1.00mm.

(2) The macrostructure defects of the tube blank are directly related to the internal quality of seamless steel pipes for medium and low pressure boilers. Including center porosity, shrinkage cavity, subcutaneous crack, middle crack, center crack test and subcutaneous bubbles.

(3) Geometric size and shape requirements.

Diameter: 3087 boiler tube blanks of different specifications are delivered according to different outer diameter tolerances.
Ovality: The ovality should not be greater than 0.75 of the diameter tolerance.
Curvature: The bend per meter of the tube blank shall not be greater than 6mm, and the total bend shall not be greater than 0.6% of the total length.

Tips: A53 steel pipe is intended mechanical and pressure applications, but is also acceptable for and widely used in air, water, steam, and gas lines. A53 pipe is suitable for welding.

 

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