The length dimension of steel is the most basic dimension of all steel materials, which refers to the length, width, height, diameter, radius, inner diameter, outer diameter, and wall thickness of the steel material. The legal units of measurement for the length of steel are meters (m), centimeters (cm), and millimeters (mm). In current practice, inches (″) are also used, but they are not a legal unit of measurement.

1. Fixed-length steel: This is an effective measure to save materials. Fixed-length steel means that the length or width multiplied by the length is not less than a certain dimension, or that the length or width multiplied by the length is within a certain range. Production units can produce and supply according to this size requirement.

2. Variable-length (usual length): Products with dimensions (length or width) within the standard range but not requiring a fixed size are called variable-length steel. Variable-length length is also called normal length (standard length). Metal materials delivered in variable-length form only need to be delivered within the specified length range. For example, for ordinary round steel not exceeding 25mm, the normal length is specified as 4-10 m, and round steel within this length range can be delivered.

3. Fixed-length: Steel cut to a fixed size according to order requirements is called fixed-length steel. When delivering according to fixed-length steel, the delivered metal materials must have the length specified by the buyer in the order contract. For example, the contract specifies a fixed length of 5m. For delivery, all delivered materials must be 5m in length; lengths shorter or longer than 5m are considered unacceptable. However, in reality, deliveries are unlikely to always be 5m long; therefore, positive deviations are allowed, but negative deviations are not permitted.

4. Multiple Lengths Items cut to integer multiples of the fixed dimensions required by the order are called multiple lengths. When delivering in multiple lengths, the length of the delivered metal material must be an integer multiple of the length specified by the buyer in the order contract (called a single length) (plus the saw cut). For example, if the buyer requires a single length of 2m in the order contract.Therefore, when cut into double the length, the length is 4m, and when cut into triple the length, the length is 6m, with one or two additional saw cuts added respectively. The kerf length is specified in the standard. When delivering goods in multiple lengths, only positive deviations are allowed, and negative deviations are not permitted.

5. Short ruler: A ruler whose length is less than the lower limit of the standard length for irregular lengths, but not less than the minimum allowable length, is called a short ruler. For example, the standard for water and gas transmission steel pipes stipulates that 10% of each batch (calculated by the number of pipes) are allowed to be short-length steel pipes of 2 to 4 meters. 4m is the lower limit for the length of the variable length, and the shortest allowed length is 2m.

6. Narrow ruler: A ruler whose width is less than the lower limit of the standard width for unspecified rulers, but not less than the narrowest allowable width, is called a narrow ruler. When delivering goods according to narrow dimensions, attention must be paid to the narrow dimension ratio and the narrowest dimension specified in the relevant standards.

Time：21/10/2026 16:10:18

1. Non-fixed length (standard/random length). This refers to product dimensions (length or width) that fall within the range specified by standards but do not require a specific, fixed size. Metal materials delivered under this classification need only fall within the prescribed length range. For example, for ordinary round steel with a diameter of 25mm or less, the standard length range is 4–10m; therefore, any round steel within this range is acceptable for delivery.

2. Fixed length. This refers to material cut to a specific, fixed dimension as required by the order. When delivered as fixed-length material, the metal must match the exact length specified by the buyer in the contract. For instance, if the contract specifies a fixed length of 5m, all delivered material must be exactly 5m long; lengths shorter or longer than 5m are considered non-compliant. However, since it is practically impossible for every piece to be exactly 5m, standards permit a positive deviation but prohibit any negative deviation.

3. Multiple length. This refers to material cut to an integer multiple of a fixed dimension specified in the order. When delivered as multiple-length material, the length must be an integer multiple of the base length (single length) specified by the buyer (plus the allowance for saw cuts). For example, if the buyer specifies a single length of 2m, a double length would be 4m and a triple length would be 6m, with the addition of one or two saw-cut allowances, respectively. Saw-cut allowances are defined in the standards. For multiple-length deliveries, only positive deviations are permitted; negative deviations are not allowed.

4. Short length. This refers to material with a length below the minimum limit of the standard non-fixed length range but above the absolute minimum permissible length. For example, standards for steel pipes used for water and gas transport allow a batch to contain up to 10% (by piece count) of short-length pipes measuring 2–4m. Here, 4m is the lower limit of the non-fixed length range, and 2m is the minimum permissible length.

5. Narrow width. "Narrow-width stock" refers to material with a width below the minimum specified for random-length/random-width stock but not less than the minimum permissible width. When supplying such material, one must adhere to the standards regarding the allowable proportion of narrow-width pieces and the absolute minimum width.

Time：13/10/2026 16:23:13

Fixed-length seamless steel pipes: "Fixed-length" refers to pipes delivered at specific lengths requested by the user. The purchaser specifies the exact length in the contract, and the manufacturer processes and cuts the seamless pipes to those dimensions. The advantages of fixed-length pipes include uniform length, which facilitates subsequent installation, fit-up, and welding while reducing the need for on-site cutting; they are ideal for projects with precise length requirements, such as pipeline prefabrication and structural support applications. Due to the precision processing and material loss involved, their price is typically slightly higher than that of random-length products.

Random-length (or variable-length) steel pipes: This term refers to pipes delivered within a standard length range rather than at a single, fixed value. Delivery is usually based on a specific length interval, with actual lengths varying within that range. Production of random-length pipes offers greater flexibility and higher material utilization rates, and they are generally more cost-effective; they are suitable for applications where length requirements are less strict and on-site cutting is feasible.

Purchasers can make a choice based on project needs: fixed-length pipes are preferable for projects requiring minimized on-site processing and high installation efficiency, whereas random-length pipes are more suitable for scenarios with flexible length requirements where cost control is a priority.

Time：13/10/2026 06:24:12

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