7228 50 80: Diğer çubuklar: diğerleri

General

A. There is a number of ways of distinguishing between forged and rolled products, where this distinction needs to be made (headings 7207, 7214, 7216, 7218, 7224 and 7228).

If the whole piece is available, it should first of all be examined for the way the cross-section varies:

• if the variations are not regularly repeated, the product is forged;
• if, on the other hand, there are regularly repeated variations, or if the cross-section is constant, the product may be forged or rolled. In this case, all the following criteria should be examined:

1. dimensions of the cross-section

If these are large (cross-section with an area of more than 150 000 mm2), the product is probably forged. If they are small (minimum dimension less than 15 mm), the product is probably rolled;

2. shape of the cross-section

If it is simple (for example, square, rectangular, round, hexagonal, etc.), the product may be either rolled or forged, whereas products of a more complex shape are almost always obtained by rolling;

3. length

If a product is more than 5 m long, it is almost certainly rolled; if it is shorter, it may be either rolled or forged;

4. dimensional tolerances

The tolerances in the dimensions of the cross-section are stricter in rolled products than in forged products;

5. metallographic aspect

Since, normally, the reduction ratio of rolled products is significantly greater than for forged products, it is almost always possible to distinguish between them by examination under a microscope.

The principal factors to be examined are inclusions and structure:

(a) inclusions in rolled products are thin, very elongated and almost perfectly parallel to the direction of rolling; in forged products, on the other hand, they are less elongated (almost elliptical in shape) and are not perfectly parallel;

(b) the structure of rolled products examined after annealing, if the product has been hardened and tempered, has almost perfectly rectilinear division marks parallel to the direction of rolling. In forged products, on the other hand, this is much less common and sometimes almost non-existent;

6. quantity

Forged products are generally delivered in small quantities.

Rolling can be carried out either hot or cold. Depending on the shape of the piece to be rolled and on the shape and positioning of the rollers, the process can be used to produce flat products, such as sheet and plate or hoop and strip, or bars and rods of round or polygonal cross-section, or sections of varying cross-sections, tubes, pipes, etc.

B. For the definition of certain types of plastic deformation (such as rolling, forging, stamping), see the HS General Explanatory Note to Chapter 72, part (IV), (A) and (B).

C. For the difference between hot-rolled or hot-drawn products and products obtained or finished in the cold state, see the HS General Explanatory Note to Chapter 72, part (IV), (B), final paragraph.

Some of the above differences between hot-rolled and cold-rolled products may be diminished or eliminated when cold-rolled products are annealed; equally, in the case of hot-rolled products which have a light cold-finishing, the differences are limited to surface hardness and appearance.

Hot-rolled or hot-drawn bars, rods, shapes, angles and sections may be cold-finished by drawing or other processes — notably, rectification or calibration — giving the product a better finish. This operation renders them classifiable as ‘cold-formed or cold-finished’.

However, cold dressing and rough scaling are not considered to be rectification or calibration processes, and therefore do not affect the classification of bars, rods, angles, shapes and sections, not further worked than hot-rolled or extruded. Similarly, such bars and rods, when twisted, are not to be considered as cold-finished.

D. For the definition of cladding, see the HS General Explanatory Note to this chapter, part (IV), (C), (2), (e).

Base metals clad with precious metals, whatever the thickness of the cladding, fall in Chapter 71 (see the HS Explanatory Notes to Chapter 71).

E. For comments on surface treatments, see the HS General Explanatory Note to Chapter 72, part (IV), (C), (2), (d).

F. Unfinished forgings no longer having the rough appearance of pieces roughly shaped by forging of heading 7207, 7218 or 7224 are to be classified in the headings appropriate to the finished articles, which are generally in Chapters 82, 84, 85 and 87. Thus, iron or steel forgings for the manufacture of crankshafts are proper to heading 8483.