Chapter 73 covers "Articles of Iron or Steel" in the Harmonized System, specifically including iron and steel pipe fittings, pipe accessories, structural components, containers, wire products, etc. The scope of this chapter ranges from sheet piling under 7301 to other articles of iron or steel under 7326, and it is an important chapter for the classification of iron and steel commodities in international trade. Its core lies in distinguishing the degree of processing and use of iron and steel articles, such as casting, forging, welding, and other processes. Goods in this chapter are widely used in construction, machinery, energy, and other fields, and classification requires comprehensive judgment based on material, shape, and processing method. Heading 7307 specifically covers "Tube or pipe fittings (for example, couplings, elbows, sleeves), of iron or steel," mainly including iron and steel fittings used to connect, branch, reduce, or close pipelines. This heading is subdivided into cast iron fittings (7307.1), stainless steel fittings (7307.2), and other iron or steel fittings (7307.9). Pipe fittings are usually made by casting, forging, machining, or welding, but care must be taken to distinguish them from the pipes themselves under 7304 to 7306. This heading is a key classification node for pipeline engineering, petrochemical, water treatment, and other industries. HS code 730799 is a six-digit subheading, broken down digit by digit: the first 2 digits "73" represent Chapter 73 (Articles of Iron or Steel), covering all manufactured articles of iron or steel, but excluding iron and steel raw materials or primary forms. The 3rd-4th digits "07" represent heading 7307, namely tube or pipe fittings of iron or steel, clearly pointing to fittings used for pipeline connection. The 5th-6th digits "99" are the subheading, meaning "other," namely fittings of carbon steel or other alloy steel other than cast iron fittings (7307.11, 7307.19) and stainless steel fittings (7307.21, 7307.22, 7307.23, 7307.29). Therefore, 730799 specifically refers to iron or steel fittings that are neither cast iron nor stainless steel, such as carbon steel elbows, tees, reducers, etc. This commodity is a carbon steel pipe fitting, neither cast iron (classified under 7307.1) nor stainless steel (classified under 7307.2), and is therefore classified under 7307.9 "Other tube or pipe fittings of iron or steel." If it were made of stainless steel, it should be classified under 7307.2; if made of cast iron, under 7307.1. In addition, if the fitting and pipe have been assembled into specific equipment, it may be classified under Chapter 84 or Chapter 85. This code applies to general carbon steel pipe fittings, such as butt-welded elbows and threaded couplings, and is one of the most common classifications among pipe fittings.
Chapter
Chapter 73 covers "Articles of Iron or Steel" in the Harmonized System, specifically including iron and steel pipe fittings, pipe accessories, structural components, containers, wire products, etc. The scope of this chapter ranges from sheet piling under 7301 to other articles of iron or steel under 7326, and it is an important chapter for the classification of iron and steel commodities in international trade. Its core lies in distinguishing the degree of processing and use of iron and steel articles, such as casting, forging, welding, and other processes. Goods in this chapter are widely used in construction, machinery, energy, and other fields, and classification requires comprehensive judgment based on material, shape, and processing method.
Heading
Heading 7307 specifically covers "Tube or pipe fittings (for example, couplings, elbows, sleeves), of iron or steel," mainly including iron and steel fittings used to connect, branch, reduce, or close pipelines. This heading is subdivided into cast iron fittings (7307.1), stainless steel fittings (7307.2), and other iron or steel fittings (7307.9). Pipe fittings are usually made by casting, forging, machining, or welding, but care must be taken to distinguish them from the pipes themselves under 7304 to 7306. This heading is a key classification node for pipeline engineering, petrochemical, water treatment, and other industries.
Digit Breakdown
HS code 730799 is a six-digit subheading, broken down digit by digit: the first 2 digits "73" represent Chapter 73 (Articles of Iron or Steel), covering all manufactured articles of iron or steel, but excluding iron and steel raw materials or primary forms. The 3rd-4th digits "07" represent heading 7307, namely tube or pipe fittings of iron or steel, clearly pointing to fittings used for pipeline connection. The 5th-6th digits "99" are the subheading, meaning "other," namely fittings of carbon steel or other alloy steel other than cast iron fittings (7307.11, 7307.19) and stainless steel fittings (7307.21, 7307.22, 7307.23, 7307.29). Therefore, 730799 specifically refers to iron or steel fittings that are neither cast iron nor stainless steel, such as carbon steel elbows, tees, reducers, etc.
Classification Basis
This commodity is a carbon steel pipe fitting, neither cast iron (classified under 7307.1) nor stainless steel (classified under 7307.2), and is therefore classified under 7307.9 "Other tube or pipe fittings of iron or steel." If it were made of stainless steel, it should be classified under 7307.2; if made of cast iron, under 7307.1. In addition, if the fitting and pipe have been assembled into specific equipment, it may be classified under Chapter 84 or Chapter 85. This code applies to general carbon steel pipe fittings, such as butt-welded elbows and threaded couplings, and is one of the most common classifications among pipe fittings.
📝 Declaration Elements
Product Name: The specific name of the declared commodity, such as "carbon steel elbow," "carbon steel tee," etc., which must be consistent with the actual goods and avoid broadly writing "pipe fitting." Material: Clearly specify the steel type, such as "carbon steel," "alloy steel," and indicate the grade (such as A234 WPB) or chemical composition (carbon content, etc.). Type: Specific fitting type, such as "elbow," "tee," "reducer," "coupling," "cap," etc., which must correspond to the HS subheading. Specification/Model: Includes nominal diameter, wall thickness, angle (such as 90° elbow), connection method (butt welding, threading, socket welding), and other dimensional parameters. Processing Technique: Explain the manufacturing method, such as "casting," "forging," "welding," "machining," which affects classification (cast fittings may be classified under 7307.1). Use: Briefly describe the application scenario, such as "for oil pipeline connection," "water treatment system," but use generally does not affect classification under this code. Brand: If there is a brand, the brand name must be declared; if there is no brand, fill in "no brand" to avoid omission. Quantity/Weight: Declare the actual quantity and weight (kilograms), which must be consistent with the packing list and used for statistics and inspection. Product Name: Carbon steel butt-welded elbow; Material: Carbon steel (A234 WPB); Type: Elbow; Specification/Model: DN100, 90°, butt-welded connection; Processing Technique: Forging; Use: Oil pipeline connection; Brand: No brand; Quantity: 100 pieces; Weight: 250 kilograms. Mistakenly declaring carbon steel as stainless steel, resulting in classification under 7307.2 instead of 7307.9. Failure to indicate the connection method (butt welding/threading), which may lead to incorrect classification under other subheadings. Misreporting cast carbon steel pipe fittings as forged; however, cast carbon steel is still classified under 7307.9, which does not affect the subheading but affects inspection.
Product Name
The specific name of the declared commodity, such as "carbon steel elbow," "carbon steel tee," etc., which must be consistent with the actual goods and avoid broadly writing "pipe fitting."
⚠️ Incorrectly declaring as "stainless steel elbow" or "cast iron fitting," resulting in classification errors.
Material
Clearly specify the steel type, such as "carbon steel," "alloy steel," and indicate the grade (such as A234 WPB) or chemical composition (carbon content, etc.).
⚠️ Writing only "steel," without distinguishing carbon steel from stainless steel, affecting subheading determination.
Type
Specific fitting type, such as "elbow," "tee," "reducer," "coupling," "cap," etc., which must correspond to the HS subheading.
⚠️ Misreporting a "coupling" as a "joint," or confusing an "elbow" with a "bend."
Specification/Model
Includes nominal diameter, wall thickness, angle (such as 90° elbow), connection method (butt welding, threading, socket welding), and other dimensional parameters.
⚠️ Failure to indicate the connection method, resulting in confusion with other subheadings under 7307.
Processing Technique
Explain the manufacturing method, such as "casting," "forging," "welding," "machining," which affects classification (cast fittings may be classified under 7307.1).
⚠️ Misreporting forged fittings as cast, resulting in incorrect classification under cast iron subheadings.
Use
Briefly describe the application scenario, such as "for oil pipeline connection," "water treatment system," but use generally does not affect classification under this code.
⚠️ Overemphasizing use while ignoring material and type, resulting in classification deviation.
Brand
If there is a brand, the brand name must be declared; if there is no brand, fill in "no brand" to avoid omission.
⚠️ Brand inconsistent with the actual goods, or failure to declare the brand causing customs questioning.
Quantity/Weight
Declare the actual quantity and weight (kilograms), which must be consistent with the packing list and used for statistics and inspection.
⚠️ Misuse of "ton" or "pound" as the weight unit, causing data errors.
Mistakenly declaring carbon steel as stainless steel, resulting in classification under 7307.2 instead of 7307.9.
Failure to indicate the connection method (butt welding/threading), which may lead to incorrect classification under other subheadings.
Misreporting cast carbon steel pipe fittings as forged; however, cast carbon steel is still classified under 7307.9, which does not affect the subheading but affects inspection.
🎯 Classification Logic
The core basis for classification is material and type. First, the fitting must be of iron or steel and used for pipeline connection. Second, distinguish by material: cast iron fittings are classified under 7307.1, stainless steel fittings under 7307.2, and other iron or steel (including carbon steel and alloy steel) under 7307.9. Finally, under 7307.9, further subdivision is based on type and processing method, but the six-digit subheading 730799 is the residual "other." Note that if the fitting has been assembled with a pipe into specific machinery or equipment, it may be classified under Chapter 84 or Chapter 85. 730711 Cast iron pipe fittings: The material is cast iron, whereas 730799 is carbon steel or other alloy steel. They can be distinguished by material reports or appearance (cast iron is usually rougher). 730721 Stainless steel flanges: The material is stainless steel, and the type is flange, whereas 730799 is other fittings of carbon steel. Flanges and pipe fittings have different uses but are easily confused. 730729 Other stainless steel pipe fittings: The material is stainless steel, whereas 730799 is carbon steel. If declared as stainless steel but actually carbon steel, it will result in classification error. 730793 Other butt-welded fittings of carbon steel: In the subdivisions of some countries, 730793 specifically refers to butt-welded fittings, while 730799 is other. However, China Customs does not subdivide them, and both are classified under 730799. 730799 Other carbon steel pipe fittings: This code itself; care must be taken to distinguish it from 730791 (flanges), 730792 (threaded fittings), etc., but in the Chinese tariff, 730799 is the residual. Is the material carbon steel or alloy steel? Is it clearly a pipe fitting rather than a pipe? Is it neither cast iron nor stainless steel? Has it not been assembled with equipment? Is the specification/model complete?
Basis
The core basis for classification is material and type. First, the fitting must be of iron or steel and used for pipeline connection. Second, distinguish by material: cast iron fittings are classified under 7307.1, stainless steel fittings under 7307.2, and other iron or steel (including carbon steel and alloy steel) under 7307.9. Finally, under 7307.9, further subdivision is based on type and processing method, but the six-digit subheading 730799 is the residual "other." Note that if the fitting has been assembled with a pipe into specific machinery or equipment, it may be classified under Chapter 84 or Chapter 85.
Confused Codes：
730711 - Cast iron pipe fittings
The material is cast iron, whereas 730799 is carbon steel or other alloy steel. They can be distinguished by material reports or appearance (cast iron is usually rougher).
730721 - Stainless steel flanges
The material is stainless steel, and the type is flange, whereas 730799 is other fittings of carbon steel. Flanges and pipe fittings have different uses but are easily confused.
730729 - Other stainless steel pipe fittings
The material is stainless steel, whereas 730799 is carbon steel. If declared as stainless steel but actually carbon steel, it will result in classification error.
730793 - Other butt-welded fittings of carbon steel
In the subdivisions of some countries, 730793 specifically refers to butt-welded fittings, while 730799 is other. However, China Customs does not subdivide them, and both are classified under 730799.
730799 - Other carbon steel pipe fittings
This code itself; care must be taken to distinguish it from 730791 (flanges), 730792 (threaded fittings), etc., but in the Chinese tariff, 730799 is the residual.
Self-Check：
✓ Is the material carbon steel or alloy steel?
✓ Is it clearly a pipe fitting rather than a pipe?
✓ Is it neither cast iron nor stainless steel?
✓ Has it not been assembled with equipment?
✓ Is the specification/model complete?
❓ FAQ
How are carbon steel pipe fittings and cast iron pipe fittings distinguished in HS codes? Carbon steel pipe fittings are classified under 730799, and cast iron pipe fittings under 730711 or 730719. The key difference lies in the material: cast iron has a high carbon content (usually >2%), while carbon steel has a low carbon content (<2%). When declaring, material proof such as a chemical composition report must be provided. If misreported, it may lead to classification errors and customs penalties. Which code are stainless steel pipe fittings classified under? Stainless steel pipe fittings are classified under 730721 to 730729, depending on the type (such as flanges, threaded fittings, butt-welded fittings, etc.). Carbon steel pipe fittings are classified under 730799. When distinguishing, it is necessary to confirm whether the material is stainless steel (containing chromium ≥10.5%) and pay attention to type subdivision. What is the difference between 730799 and 730791? 730791 specifically refers to carbon steel flanges, while 730799 covers other carbon steel pipe fittings (such as elbows, tees, etc.). Flanges are used for pipeline connection and are flat in shape; pipe fittings are used to change direction or branch. When declaring, the type must be accurately described to avoid misreporting flanges as pipe fittings. Should carbon steel butt-welded elbows be classified under 730799? Yes, carbon steel butt-welded elbows belong to other carbon steel pipe fittings and are classified under 730799. However, note that if they are stainless steel butt-welded elbows, they are classified under 730723. When declaring, the material, type, and connection method must be indicated to ensure accurate classification. If the fitting has already been assembled with a pipe, can it still be classified under 730799? No. If the fitting has been assembled with a pipe into specific machinery or equipment, it may be classified under Chapter 84 or Chapter 85. For example, a fitting assembly with a valve may be classified under 8481. When classifying, it is necessary to determine whether it has an independent function rather than being a simple pipe accessory. What documents are required when declaring 730799? Usually, a packing list, invoice, contract, material certificate (such as a chemical composition report), and product specification sheet are required. Customs may require supplementary explanation of processing technique or a declaration of use. It is recommended to prepare in advance to ensure consistency between documents and goods. How can the tariff rate for 730799 be checked? The tariff rate must be determined according to the destination country and country of origin. It can be checked through the website of the General Administration of Customs of China, the International Trade Single Window, or by consulting a customs broker. Note that the rate may change due to trade agreements (such as RCEP), and the latest tariff schedule should prevail. Is there any difference in classification between carbon steel pipe fittings and alloy steel pipe fittings? No difference. Carbon steel and alloy steel (other than stainless steel) are both classified under 730799. However, note that if the alloy steel contains specific elements (such as chromium or nickel), it may be regarded as stainless steel and thus classified under 7307.2. Accurate material composition should be provided when declaring.
Q: How are carbon steel pipe fittings and cast iron pipe fittings distinguished in HS codes?
A: Carbon steel pipe fittings are classified under 730799, and cast iron pipe fittings under 730711 or 730719. The key difference lies in the material: cast iron has a high carbon content (usually >2%), while carbon steel has a low carbon content (<2%). When declaring, material proof such as a chemical composition report must be provided. If misreported, it may lead to classification errors and customs penalties.
Q: Which code are stainless steel pipe fittings classified under?
A: Stainless steel pipe fittings are classified under 730721 to 730729, depending on the type (such as flanges, threaded fittings, butt-welded fittings, etc.). Carbon steel pipe fittings are classified under 730799. When distinguishing, it is necessary to confirm whether the material is stainless steel (containing chromium ≥10.5%) and pay attention to type subdivision.
Q: What is the difference between 730799 and 730791?
A: 730791 specifically refers to carbon steel flanges, while 730799 covers other carbon steel pipe fittings (such as elbows, tees, etc.). Flanges are used for pipeline connection and are flat in shape; pipe fittings are used to change direction or branch. When declaring, the type must be accurately described to avoid misreporting flanges as pipe fittings.
Q: Should carbon steel butt-welded elbows be classified under 730799?
A: Yes, carbon steel butt-welded elbows belong to other carbon steel pipe fittings and are classified under 730799. However, note that if they are stainless steel butt-welded elbows, they are classified under 730723. When declaring, the material, type, and connection method must be indicated to ensure accurate classification.
Q: If the fitting has already been assembled with a pipe, can it still be classified under 730799?
A: No. If the fitting has been assembled with a pipe into specific machinery or equipment, it may be classified under Chapter 84 or Chapter 85. For example, a fitting assembly with a valve may be classified under 8481. When classifying, it is necessary to determine whether it has an independent function rather than being a simple pipe accessory.
Q: What documents are required when declaring 730799?
A: Usually, a packing list, invoice, contract, material certificate (such as a chemical composition report), and product specification sheet are required. Customs may require supplementary explanation of processing technique or a declaration of use. It is recommended to prepare in advance to ensure consistency between documents and goods.
Q: How can the tariff rate for 730799 be checked?
A: The tariff rate must be determined according to the destination country and country of origin. It can be checked through the website of the General Administration of Customs of China, the International Trade Single Window, or by consulting a customs broker. Note that the rate may change due to trade agreements (such as RCEP), and the latest tariff schedule should prevail.
Q: Is there any difference in classification between carbon steel pipe fittings and alloy steel pipe fittings?
A: No difference. Carbon steel and alloy steel (other than stainless steel) are both classified under 730799. However, note that if the alloy steel contains specific elements (such as chromium or nickel), it may be regarded as stainless steel and thus classified under 7307.2. Accurate material composition should be provided when declaring.
⚠️ Disclaimer: HS code classification, declaration elements, tariff rates and regulatory conditions on this page are for reference only and do not constitute legal advice on customs classification. Tariff rates and regulations are subject to change; the latest announcements from the General Administration of Customs and on-site determinations shall prevail. Please consult professional customs brokers or customs authorities before import/export.