What are fixed length, indefinite length and double length?
The length dimension of steel such as steel pipe is the most basic dimension of all kinds of steel, which refers to the length, width, height, diameter, radius, inner diameter, outer diameter and wall thickness of steel such as steel pipe. The legal units of measurement for the length of steel such as steel pipes are meters (m), centimeters (cm) and millimeters (mm). In current custom, 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 many stresses on the calculation of steel length, so how to calculate the length of steel? Is it difficult? Let’s take a look at.
Length and dimension of steel:
Table of Contents
- 1 Length and dimension of steel:
- 2 Example of steel length dimension:
Range size of steel
It is an effective measure to save material to specify the range size of steel. Range sizing means that the length or the length multiplied by the width is not less than a certain size, or the length and length multiplied by width are delivered within the size range from how many to how many. The production unit can supply products according to the size requirements.
Where the product size (length or width), within the scope of the standard, and does not require fixed size is called indeterminate. The indefinite length is also called the normal length. The metal materials delivered according to the indefinite length can be delivered within the specified length range. For example, if the length of ordinary round steel not more than 25 mm is 4-10 m, the round steel with the length within this range can be delivered.
According to the order requirements cut into fixed size is called fixed length. When delivery is made according to the fixed length, the delivered metal materials must have the length specified by the demander in the order contract. For example, if it is specified in the contract that the delivery should be made according to the fixed length of 5 m, the delivered materials must be 5 m long, and those shorter than 5 m or longer than 5 m are unqualified. But in fact, the delivery can not be 5m long, so it is stipulated that positive deviation is allowed, but negative deviation is not allowed.
According to the order requirements of the fixed size cut into a full multiple is called a double ruler. In case of delivery according to the multiple length, the length of the metal material delivered must be the integral multiple of the length (called single scale) specified by the demander in the order contract (with additional saw). For example, if the buyer requires a single length of 2m in the order contract, then the length is 4m when it is cut into double ruler and 6m when it is cut into three times. One or two saws are added respectively. The sawing amount is specified in the standard. When delivery, only positive deviation is allowed, and negative deviation is not allowed.
If the length is less than the lower limit of the indefinite length specified in the standard, but not less than the minimum allowable length, it is called a short ruler. For example, it is stipulated in the standard for water and gas transmission steel pipes that 10% of the short steel pipes (calculated by the number of pipes) in each batch are allowed. 4m is the lower limit of indefinite length, and the shortest allowable length is 2m.
If the width is less than the lower limit of the indefinite width specified in the standard, but not less than the allowable narrowest width, it is called narrow ruler. In case of delivery according to the narrow scale, attention must be paid to the narrow scale and the narrowest scale specified in relevant standards.
The picture shows the production process of steel pipe
Example of steel length dimension:
Length dimension of section steel
- 1) the standard length of train track is 12.5m and 25m.
- 2) The dimensions of round bar, wire and steel wire shall be calibrated in millimeters (mm) of diameter d.
- 3) The dimension of square bar shall be calibrated in millimeters (mm) of side length a.
- 4) Dimensions of hexagonal bar and octagonal bar shall be calibrated in millimeters (mm) of the distance s from opposite sides.
- 5) The dimensions of flat bar shall be calibrated in millimeters (mm) of width b and thickness d.
- 6) The dimensions of I-beam and channel bar are calibrated in millimeters (mm) of waist height h, leg width b and waist thickness d.
- 7) The dimensions of equilateral angle bar shall be calibrated in millimeters (mm) with equal side width b and side thickness d. The dimensions of unequal angle bar are calibrated in millimeters (mm) of side width b, b and side thickness d.
- 8) The dimensions of H-beam are calibrated in millimeters (mm) of web height h, wing width b, web thickness t1 and wing thickness t2.
Length dimension of steel plate and steel strip
- 1) generally, it is calibrated in millimeters (mm) of the thickness d of the steel plate. While the steel strip is calibrated in millimeters (mm) of width b and thickness d of the steel strip.
- 2) Single steel plates have specified different sizes. For example, hot rolled steel plates include: 1mm thick steel plates with a width of 600× 2,000 mm; 650×2000mm; 700×1420mm; 750×1500mm; 900×1800mm; 1000×2000mm, etc.
Length dimension of steel pipe
- 1) generally, the diameter d, inner diameter and wall thickness s of the steel pipe are calibrated in millimeters (mm).
- 2) Each type of steel pipe has specified different sizes, for example, there are 15 kinds of seamless steel pipes with an outer diameter of 50mm and a wall thickness of 2.5-10mm; Or 29 kinds with the same wall thickness of 5mm and outer diameter of 32-195mm. Another example is that the wall of welded steel pipe with nominal diameter of 25mm has 3.25mm ordinary steel pipe and 4mm thick steel pipe.
Source: China Steel Pipe Manufacturer – Yaang Pipe Industry Co., Limited (www.steeljrv.com)
(Yaang Pipe Industry is a leading manufacturer and supplier of nickel alloy and stainless steel products, including Super Duplex Stainless Steel Flanges, Stainless Steel Flanges, Stainless Steel Pipe Fittings, Stainless Steel Pipe. Yaang products are widely used in Shipbuilding, Nuclear power, Marine engineering, Petroleum, Chemical, Mining, Sewage treatment, Natural gas and Pressure vessels and other industries.)
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