Chapter 73 covers articles of iron or steel, but excludes raw materials for iron and steel smelting (Chapter 72) and finished products of specific machinery, vehicles, and other chapters. This chapter includes pipe fittings, structural parts, containers, fasteners, springs, chains, needles, nails, etc. The core characteristic is that they are made of iron or steel and are general-purpose base metal articles, not constituting complete machinery or equipment of other chapters. Heading 7318 covers screws, bolts, nuts, coach screws, screw hooks, rivets, cotters, cotter pins, washers and similar articles, of iron or steel. It includes threaded articles and non-threaded articles with fastening functions. It is key to distinguish from Chapter 82 tools and Chapter 83 miscellaneous articles of base metal. This heading specifically refers to threaded or similar fasteners used for connecting, fixing, or transmitting loads. First 2 digits 73 = Chapter for articles of iron or steel, covering all basic iron and steel articles. Digits 3-4: 18 = Heading 7318, specifically screws, bolts, nuts, coach screws, screw hooks, rivets, cotters, cotter pins, washers and similar articles, of iron or steel. Digits 5-6: 13 = Subheading 731813, which refers only to hook head screws, i.e., screws with a hook-shaped or bent hook head, used for hanging, tensioning, or special connections. Note: Hook head screws differ from ordinary screws, eye screws (7318.15), and screw hooks (7318.19) in that their head shape is a hook, not a ring or ordinary slotted head. Hook head screws, because their heads are hook-shaped, are specifically used for hanging or tensioning, and their function differs from ordinary screws (with slotted or cross heads) and eye screws (with ring heads). Classification is based on their iron or steel material, threaded structure, and hook-shaped head characteristics, meeting the specific naming under subheading 7318, and therefore classified under 731813, rather than 731815 (other screws) or 731819 (other threaded articles not elsewhere specified).

Product Name: The common name of the declared commodity should accurately reflect the hook head feature, such as 'hook head screw' or 'hook bolt', avoiding simply writing 'screw'. Material: Specific type of iron or steel, such as 'carbon steel', 'alloy steel', 'stainless steel', and indicate the grade (e.g., Q235, 304). Specifications and Dimensions: Thread diameter, length, hook dimensions, etc., such as 'M8×50mm, hook inner diameter 10mm'. Thread Type: Indicate whether it is fully threaded, partially threaded, or self-tapping, and the thread standard (e.g., metric, imperial). Head Shape: Clearly state 'hook-shaped head' and describe the opening direction, angle, and other features of the hook. Use: Main usage scenarios, such as 'for hanging cables', 'for construction tensioning', 'for mechanical connection'. Surface Treatment: Such as 'galvanized', 'black oxide', 'painted', 'stainless steel natural finish', etc. Brand and Model: Manufacturer's brand and product model; if no brand, fill in 'no brand'. Product Name: Hook head screw; Material: Carbon steel Q235; Specifications: M10×80mm, hook inner diameter 12mm; Thread: Fully threaded, metric; Head Shape: Hook-shaped, opening upward; Use: For construction formwork tensioning; Surface Treatment: Galvanized; Brand: No brand. Mistakenly declaring hook head screws as ordinary screws, leading to incorrect codes. Material only written as 'iron', without distinguishing iron or steel type, affecting classification. Ignoring thread information, may be classified as non-threaded hook nails (7317).

Core classification basis: 1) Material is iron or steel; 2) Has a threaded structure (if non-threaded, classify under 7317); 3) Head is hook-shaped, different from ring head or ordinary head; 4) Used for connecting, hanging, or tensioning. Need to combine with the Explanatory Notes to heading 7318; hook head screws fall within the scope of 'screws and bolts', and due to the hook head feature, are specifically named under subheading 731813. If made of stainless steel, still classified under 731813, but note the material's impact on tax rates. 731815 Other screws and bolts: 731815 is for screws and bolts with ordinary heads (slotted, cross, hex socket, etc.), without hook-shaped heads; hook head screws, due to their special head shape, are classified under 731813. 731819 Other threaded articles: 731819 is for threaded articles not specifically named, such as eye screws, screw hooks, etc.; hook head screws are already named under 731813, not classified here. 7317 Nails, tacks, drawing pins, etc., of iron or steel: 7317 is for non-threaded nails, including hook nails; if hook head screws are non-threaded, they are classified under 7317, not 7318. 732690 Other articles of iron or steel: 732690 is for iron or steel articles not elsewhere specified; if hook head screws are non-threaded and not nails, they may be classified here, but usually priority is given to 7318 or 7317. 741533 Copper screws, bolts: Material is copper or copper alloy; if made of iron or steel, classify under 7318; if copper, under 7415. Is the material iron or steel? Is there a thread? Is the head hook-shaped? Is it used for connecting or hanging? Is it excluded from Chapters 82 and 83?

What is the difference between hook head screws and eye screws? Are the HS codes the same? Hook head screws have a hook-shaped head with an open opening; eye screws have a closed ring head. Their HS codes differ: hook head screws are classified under 731813, eye screws under 731815 (or other screws) or 731819. When declaring, accurately describe the head shape. Are stainless steel hook head screws classified under 731813? Yes, material does not affect the applicability of subheading 731813; as long as they meet the definition of hook head screws, stainless steel ones are also classified under 731813. However, note that stainless steel material may involve different anti-dumping duties or regulatory conditions; material should be stated when declaring. If hook head screws have no thread, which code should they be classified under? If hook head screws are non-threaded, they do not belong to 7318 (threaded articles) and should be classified under 7317 (nails of iron or steel). The specific subheading depends on head shape and use, such as 73170090 (other nails). When declaring hook head screws, how should specifications and dimensions be filled in? Fill in thread diameter, length, and hook dimensions, e.g., 'M8×50mm, hook inner diameter 10mm'. Diameter and length are important parameters for classification; hook dimensions help distinguish from other similar products. Does the use of hook head screws affect classification? Use itself does not directly determine classification but can assist judgment. If the use is special, such as exclusively for automobiles or aviation, it may involve other chapters. General industrial hook head screws are still classified under 731813. How to inquire about the import tax rate for hook head screws? You can check through the General Administration of Customs website or the International Trade Single Window, and determine the applicable rate based on origin, trade agreements, etc. Note that rates change; it is recommended to refer to the latest announcements. How to distinguish hook head screws from screw hooks (731819)? Screw hooks usually refer to rods with a hook at one end and a thread at the other, but the head is not a screw head; hook head screws have a screw head (hook-shaped) and a threaded shank. If the product has no screw head and only a bent hook at one end, it should be classified under 731819. When declaring hook head screws, are brand and model mandatory? Brand and model are not required for classification, but declaration elements require filling. If no brand, fill 'no brand'; if no model, fill 'no model'. If intellectual property is involved, declare truthfully.