Basic knowledge of hot rolled channel steel

Intro

Hot-rolled channel steel is a long hot-rolled steel with a groove section and an oblique leg inside.

Use

Mainly used in building structures, vehicle manufacturing and other industrial structures, 14# below are mostly used for construction projects as purlins; More than 16# is used as the chassis of the vehicle and the frame of the mechanical structure; More than 30# can be used for bridge structures as tension bars, can also be used as beams, columns and other components of industrial plants, channel steel is often used with I-steel.

Channel section diagram and marking symbol

Channel steel symbol: height =h, leg width =b, waist thickness =d, at present, China's channel steel is generally 5-40 specifications. Even if the height is the same, the light weight will be lighter than the ordinary weight, and the legs are narrow and the waist is thin, the number of large is 18-40, and the number of medium is 5-16. If it is imported, the actual specifications and related standards will also be marked. Its composition and performance are not specific ingredients. In terms of the length of delivery, it is generally divided into two kinds of fixed size and double size, and there is a permissible difference. The length can be selected into three kinds, one is 5-12, and 5-19, and one is 6-19, and the progress is generally 6-15.

Specifications and models

Specification representation

It is expressed by the main contour size of its cross section (mm), that is, the number of millimeters of waist height (h) * leg width (b) * waist thickness (d).

The specification expression method, such as 120*53*5, represents a channel steel with a waist height of 150 mm, a leg width of 63 mm, and a waist thickness of 10 mm.

Channel steel with the same waist height, if there are several different leg width and waist thickness, it is also necessary to add a b c to the right side of the model to distinguish, such as 25a# 25b# 25c#.

Moment of inertia

the moment of inertia (I= mass X vertical axis twice) the moment of inertia

Static moment

Static moment

Moment of inertia of section

Section moment of inertia (I= area X inner axis quadratic)

Polar moment of inertia of section

Polar moment of inertia (Ip= area X vertical axis 2).

Polar moment of inertia

The integral of the area of each element of the section and the quadratic product of each element to a specified axis perpendicular to the section Ip = P↑2dF.

Description of the channel steel type

The channel steel can add the symbol "[" in front of the model, and the symbol" # "can be added to the upper right corner of the model, such as [32c#].

In the ordinary channel steel, the channel steel of 16# ~ 22#, if there is no code on the right side of the model, can be regarded as B-type channel steel.

I-steel is divided into ordinary type and light, compared with the same type of ordinary I-steel, light I-steel waist thickness size is smaller, lighter weight.

The specification of the channel steel is expressed by the model and the standard code, which is simple and convenient, but the size of the leg width and waist thickness can not be visually seen, and the number of millimeters of the waist height * leg width * waist thickness is still required when necessary.

Weight

Channel steel is delivered according to theoretical weight or actual weight.

When calculating the theoretical weight of the channel steel, the density of the steel is 7.85g/cm3.