The chemical composition of steel: The chemical composition of steel is a critical factor affecting the performance of seamless steel pipes, and it also serves as a primary basis for determining the rolling processing technology and heat treatment methods of steel pipes.

Aluminum alloy raw materials: Heart-added based on primary application.

Residual Elements: Iron in place, operation moderate.

(c) Hazardous Elements: Strictly Controlled (As, Sn, Sb, Bi, Pb), Gases (N, H, O)

Out-of-furnace refining or electroslag remelting: Improves the uniformity of the steel liquid's chemical composition and purity, reduces the contamination of non-metallic materials inside the tube, and enhances the steel's shape.

Specs for steel pipe geometry, precision, and design aesthetics.

The steel pipe diameter: Depending on the sizing (reduction) method of the pipeline, the operating condition of the machinery and equipment, and the regulations of the processing technology.

Allowable error: Diameter ±mm.

Di: Nominal Diameter mm.

Steel pipe wall thickness accuracy: Related to the heating quality of steel pipe billets, main technical parameters and adjustment parameters of various deformation process flows, tool quality, and lubrication quality.

Thickness Allowable Tolerance: The thickness variation on the cross-section, either larger or smaller.

One: Wall thickness mm.

Ovality of steel pipes: Indicates that the steel pipe is not perfectly round in the horizontal direction.

(d) Tube Length: Standard Length, Fixed (Multiple) Lengths, Allowable Length Tolerance.

Pipe Bend Radius: Indicates the curve of the pipe: bend per meter of pipe length, total bend of pipe length.

Pipe inner hole cutting slope: Refers to the horizontal slope between the inner hole of the pipe and the cross-section of the pipe.

(g) Welding angle and radius of the pipe inner hole.

Five: Steel pipe surface quality: Specify smooth surface.

(a) Hazardous Factor Defects: Cracks, inward and outward folds, curling, delamination, scabbing, pulled-in dents, bulges, etc.

General Defects: Surface rust, blue lines, scratches, dings, minor internal and external straight lines, rolling marks, etc.

The reason is:

Defects caused by surface or internal defects in the billet.

Secondly, issues caused during the production process, such as incorrect design of the main parameters for cold rolling processing technology, uneven surface of the mold, insufficient lubrication standards, and unscientific design and adjustment methods for the plate holes.

3. During the heating, cold rolling, heat treatment, and straightening processes of the billet (steel pipe), improper temperature control can lead to uneven deformation, or unscientific heating and cooling rates, or excessive straightening deformation, resulting in excessive internal stress. This can also significantly increase the risk of surface cracks in the steel pipe.

6. Steel Pipe's Physical and Chemical Properties: Mechanical properties at room temperature, structural mechanical properties at high temperatures, ultra-low temperature properties, and corrosion resistance. The key to the physical and chemical properties of pipe materials lies in their chemical composition, microstructure, purity of the steel, and the heat treatment methods of the pipes.

Section 7: Tube Processing Techniques: Extrusion, expanding, rolling, bending, electric welding, etc.

8. Steel pipe alloy composition: High multiplier (macro economy), low multiplier (external economy) M, B, P, F, A, S.

9. Special Requirements for Pipe Material: Contract Annex, Technical Proposal.