Length of steel
Length of steel
How to calculate the length of steel such as steel pipe? What is: fixed-length, indefinite-length, double-length
The length dimension of steel such as steel pipe is the most basic dimension of various steels, which refers to the length, width, height, diameter, radius, inner diameter, outer diameter and wall thickness of steel such as steel pipe. The legal measurement units for the length of steel such as steel pipes are meters (m), centimeters (cm), and millimeters (mm). In current practice, it is also expressed in inches (〃), but it is not a legal unit of measurement. It's simple to say, in fact, there are still a lot of particularities in the calculation of steel length, so how to calculate the steel length? Is it difficult? Let's take a look together:
Steel length dimension:
1. Range of steel size
Specifying the range of steel size is an effective measure to save materials. The range of fixed-length is that the length or length multiplied by the width is not less than a certain size, or the length, length multiplied by the width from how many sizes to deliver the goods. The production unit can produce and supply according to this size requirement.
2. Indefinite length (usual length)
Any product size (length or width) that is within the range specified by the standard and does not require a fixed size is called an indefinite rule. Indefinite length is also called normal length (through ruler). For metal materials delivered according to an indefinite length, as long as they are delivered within the specified length range. For example, ordinary round steel with a length of not more than 25mm is generally specified as 4～10m in length, and round steel with a length within this range can be delivered.
3. Fixed-length
Cut to a fixed size according to the order requirements is called fixed-length. When delivering according to the fixed-length length, the metal material must have the length specified by the purchaser in the order contract. For example, if the contract states that the delivery is based on a fixed-length length of 5m, the delivered materials must be 5m long. Anything shorter than 5m or longer than 5m is not qualified. But in fact, it is impossible for the delivery to be 5m long, so it is stipulated that positive deviation is allowed, but negative deviation is not allowed.
4. Times the ruler
The fixed size cut into integral multiples according to the order requirements is called double ruler. When delivering in multiple lengths, the length of the metal material to be delivered must be an integer multiple of the length (called a single length) specified in the order contract by the buyer (plus saw cut). For example, if the buyer requires a single ruler length of 2m in the order contract, the length is 4m when cut into a double ruler, and 6m when cut into a triple ruler, plus one or two cuts respectively. . The amount of saw cut is specified in the standard. When the double ruler is delivered, only positive deviation is allowed, and negative deviation is not allowed.
5. Short ruler
The length is less than the lower limit of the indefinite length specified by the standard, but not less than the shortest allowed length is called short ruler. For example, the water and gas transportation steel pipe standards stipulate that 10% (calculated based on the number of pipes) of short-length steel pipes with a length of 2-4m are allowed per batch. 4m is the lower limit of indefinite length, and the shortest allowed length is 2m.
6. Narrow ruler
The width is less than the lower limit of the indefinite width specified by the standard, but not less than the narrowest width allowed is called a narrow rule. When delivering the goods according to the narrow rule, you must pay attention to the narrow rule ratio and the narrowest rule stipulated by the relevant standards.
Examples of steel length dimensions:
1. Length dimension of section steel
1) The standard length of the train track is 12.5m and 25m.
2) The dimensions of round steel, wire and steel wire are calibrated in millimeters (mm) of diameter d.
3) Square steel size is calibrated in millimeters (mm) of side length a.
4) The size of hexagonal steel and octagonal steel is calibrated in millimeters (mm) of the distance s from opposite sides.
5) The size of flat steel is calibrated in millimeters (mm) of width b and thickness d.
6) The size of I-beam and channel steel is calibrated in millimeters (mm) of waist height h, leg width b and waist thickness d.
7) The size of equilateral angle steel is calibrated in millimeters (mm) with equal side width b and side thickness d. The size of unequal angle steel is calibrated in millimeters (mm) of side width B, b and side thickness d.
8) The size of H-shaped steel is calibrated in millimeters (mm) of web height h, wing width b, web thickness t1, and wing thickness t2.
2. Length dimension of steel plate and steel belt
1) Generally calibrated by the millimeter (mm) of the thickness d of the steel plate. The steel strip is calibrated in millimeters (mm) of the width b and thickness d of the strip.
2) There are different sizes of single steel plates, such as hot-rolled steel plates: 1mm thick steel plate with width 600×length 2000mm; 650×2000mm; 700×1420mm; 750×1500mm; 900×1800mm; 1000×2000mm, etc.
3. Length of steel pipe
1) Generally calibrated by the number of millimeters (mm) of the outer diameter D, inner diameter and wall thickness S of the steel pipe.
2) Each type of steel pipe has different sizes, such as seamless steel pipes with an outer diameter of 50mm and 15 types with a wall thickness of 2.5-10mm; or 29 types with the same wall thickness of 5mm and an outer diameter of 32-195mm. Another example is a welded steel pipe with a nominal diameter of 25mm and a 3.25mm ordinary steel pipe and a 4mm thick steel pipe.
