Zhishang H-section steel

H-beam steel is an economical and efficient profile with more optimized section area distribution and more reasonable strength-to-weight ratio, so it is named because its section is the same as the English letter "H". Because all parts of H beam are arranged at right angles, H beam has been widely used for its advantages of strong bending resistance, simple construction, cost saving and light structural weight in all directions.

The section shape is similar to the capital Latin letter H of an economic section profile, also known as universal steel beam, wide edge (edge) I beam or parallel flange I beam. The cross section of H-beam usually includes two parts: web and flange plate, also known as waist and side.

Features and uses

The inner and outer flanges of H-beams are parallel or nearly parallel, and the ends of the flanges are at right angles, hence the name parallel flanged I-beams. The thickness of the web of H-beam is smaller than that of ordinary I-beams with the same height of the web, and the width of the flange is larger than that of ordinary I-beams with the same height of the web, so it is also named wide rim I-beams. Determined by the shape, the section modulus, moment of inertia and corresponding strength of H-beam are obviously better than that of ordinary I-beam with the same single weight. Used in different requirements of the metal structure, whether under bending moment, pressure load, eccentric load show its superior performance, can greatly improve the bearing capacity than ordinary I-steel, metal saving 10% ~ 40%. H beam has wide flange, thin web, many specifications and flexible use, which can save 15% ~ 20% metal in various truss structures. Because the flange is parallel inside and outside, and the edge end is at a right Angle, it is easy to assemble and combine into various components, which can save about 25% of the welding and riveting work, and greatly accelerate the construction speed of the project and shorten the construction period.

Due to the above advantages, H beam is widely used in: various civil and industrial building structures; A variety of long-span industrial plants and modern high-rise buildings, especially in areas with frequent seismic activity and high temperature working conditions; Large Bridges with large bearing capacity, good cross-section stability and large span are required; Heavy equipment; A highway; Ship skeleton; Mine support; Foundation treatment and dam engineering; Various machine components.

Model and specification

There are many product specifications of H beam, and the classification methods are as follows.

(1) According to the flange width of the product, it can be divided into wide flange, middle flange and narrow flange H-beams. Flange width B of wide and middle flange H-beams is greater than or equal to web height H. The flange width B of the narrow flange H-beam is equal to about half of the height H of the web.

(2) According to the use of the product, it is divided into H-type steel beam, H-type steel column, H-type steel pile, H-type steel beam with very thick flange. Sometimes parallel leg channels and parallel flange T-bars are also included in the scope of H beam. Generally, narrow flange H-beam steel is used as beam material and wide flange H-beam is used as column material. Therefore, it is also known as beam H-beam and column H-beam.

(3) According to the production mode, it can be divided into welded H-beam and rolled H-beam.

(4) According to the size specification, it is divided into large, medium and small H-beam steel. Usually the web height H above 700mm products called large, 300 ~ 700mm called medium, less than 300mm called trumpet. By the end of 1990, the largest H-beam in the world had a web height of 1200mm and flange width of 530mm.

Internationally, H beam steel product standards are divided into British system and metric system two categories. The United States, the United Kingdom and other countries adopt the British system, and China, Japan, Germany and Russia and other countries adopt the metric system. Although the British system and the metric system use different units of measurement, most H-beam steel uses four dimensions to express their specifications, namely: web height H, flange width b, web thickness d and flange thickness t. Although countries around the world have different ways of expressing the size and size of H-beam steel. But the product size specification range and size tolerance are not different.

Mode of production

H-beam steel can be produced by welding or rolling. H-beam welding is done by cutting strips of suitable thickness to suitable widths and welding flange and web together in a continuous welding set. The welding H beam has some disadvantages such as large metal consumption, not easy to ensure uniform product performance and limited size. Therefore, H - beam is mainly produced by rolling method. In the modern rolling production, the universal mill is used to roll H - beam steel. The web of H-beam is rolled between the upper and lower horizontal rolls, and the flange is rolled simultaneously between the side of the horizontal roll and the vertical roll. Since the flange end cannot be pressed with only universal rolling mill, it is necessary to set up an edge rolling machine behind the universal frame, commonly known as edge rolling machine, in order to press the flange end and control the width of the flange. In the actual rolling operation, the two stands are taken as a group to make the rolled parts reciprocate several times (FIG. 2a), or to make the rolled parts pass through a continuous rolling mill consisting of several universal stands and one or two edge end stands. A certain amount of pressure is applied at each pass to roll the blank into the product of the required specification shape and size. At the flange of the rolling part, the wear of the roll is relatively large because of the sliding between the horizontal roll side and the rolling part. In order to ensure that the roll can be restored to the original shape after heavy rolling, the sides of the upper and lower horizontal rolls and the corresponding vertical roll surface of the roughing mill should be inclined to 3° ~ 8°. In order to correct the dip Angle of the finished flange, the finished universal rolling mill, also known as the universal finishing mill, is set. The horizontal roll side is perpendicular to the horizontal roll line or has a small inclination Angle, generally no more than 20 ', and the vertical roll is cylindrical.

When the universal mill is used to roll H-beam steel, the rolling section can be extended more evenly, and the speed difference between the inner flange and outer roll surface is small, which can reduce the internal stress and appearance defects of the product. The H beam steel of different specifications can be obtained by changing the pressing amount of horizontal roll and vertical roll of universal mill appropriately. Universal rolling mill roll shape, simple shape, long life, roll consumption can be greatly reduced. The biggest advantage of universal rolling mill rolling H-beam is that only the thickness of web and flange is changed in the same size series, while the other parts are fixed. Therefore, the same series of H beam rolled with the same universal pass has a variety of web and flange thickness size specifications, which greatly increases the number of H beam specifications and brings great convenience for users to choose the right size specifications.

In the absence of universal rolling mill, sometimes in order to meet the urgent need of production and construction, the ordinary two-high rolling mill can also be installed with vertical roll frame to form universal pass rolling H-beam. In this way rolling H beam, product dimensional accuracy is low, flange and web is difficult to form a right Angle, high cost, few specifications, rolling column with H beam is very difficult, so there are not many users.