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Manufacturing Process / Major Equipment

Manufacturing Process / Major Equipment

Out of all its numerous features, Nippon Steel & Sumikin Pipe is most proud of its integrated production control system covering tube manufacturing, drawing, heat treatment, and cutting. Whereas many steel tube manufacturers outsource the drawing process, this is yet another area where we exhibit our user-focused characteristics and commitment.

Moreover, as an example of our application of new technology, we are attracting attention for our practical application of a high ductility mill, which produces steel tubes with good workability.

Manufacturing Process

1.Forming

Rollers with various curvatures are used to bend flat steel strip into a tubular shape.

Forming Forming

2. High frequency electric resistance
welding

A high frequency induced current is used to hot pressure weld the edges of the steel strip formed into a tubular shape.

High frequency electric resistance welding High frequency electric resistance welding

3. Eddy current or ultrasonic testing

The integrity of the raw material and weld zone is completely inspected online in a non-destructive means.

Eddy current or ultrasonic testing Eddy current or ultrasonic testing

4. Sizing

Rollers with various curvatures are used to squeeze the welded tube, adjusting its outer diameter. Rectangular or square tube can be formed in addition to round tubes.

Sizing Sizing

5. Cutting

Cutters are used to cut the continuously formed tube into defined lengths.

Cutting Cutting

6. Heat treatment

The metallic structure of the high frequency electric resistance welded tube is standardized and softened through heat treatment in a continuous furnace.

Heat treatment Heat treatment

7. Pickling, Surface treatment

The surface is roughened through pickling and the tube is put through chemical treatment and dipped in oil.

Pickling, Surface treatment Pickling, Surface treatment

8. Swaging

The end of the tube is swaged, reducing the outer diameter so that it can be inserted into the dies for cold drawing.

Swaging Swaging

9. Cold drawing

The tube is drawn through plug dies, creating steel tube with excellent dimensional accuracy and smoothness.

Cold drawing Cold drawing

10. Straightening

The straightness of the tube is increased.

Straightening Straightening