Channel steel is divided into ordinary channel steel and lightweight channel steel. Hot-rolled ordinary channel steel has specifications ranging from 5# to 40#. Hot-rolled variable channel steel, supplied by mutual agreement between the supplier and the buyer, has specifications ranging from 6.5# to 30#. Channel steel is primarily used in building structures, vehicle manufacturing, other industrial structures, and fixed cabinets. Channel steel is often used in conjunction with I-beams.

Channel steel can be divided into four types based on shape: cold-formed equal-leg channels, cold-formed unequal-leg channels, cold-formed inner-flange channels, and cold-formed outer-flange channels. According to steel structure theory, the channel flanges should bear the load, meaning the channel should stand upright, not flat.

Channel Steel Specifications

Channel steel specifications are primarily expressed in terms of height (h), leg width (b), and waist thickness (d). Currently, domestic channel steel specifications range from 5# to 40#, corresponding to heights of 5 to 40cm.
At the same height, lightweight channels have narrower legs, thinner waists, and are lighter than standard channels. Channels ranging from 18 to 40 are considered large, while channels ranging from 5 to 16 are considered medium. Imported channels are marked with the actual dimensions and relevant standards. Import and export orders for channels are generally based on the required specifications after determining the corresponding carbon steel (or low-alloy steel) grade. Aside from the specification number, channels do not have specific composition or performance series.

Different properties
1. High-frequency welded steel pipe: After hot-rolled coil is formed in a forming machine, the skin effect and proximity effect of high-frequency current are used to heat and melt the edges of the tube. Pressure welding is then performed under the action of squeeze rollers to produce the product.
2. Straight seam welded steel pipe: including double-sided submerged arc welded straight seam welded steel pipe and high-frequency resistance welding. The English abbreviation of high-frequency resistance welding is ERW. Submerged arc welded straight seam steel pipe is divided into UOE, RBE, and JCOE steel pipe according to its different forming methods.

Different Materials
1. High-Frequency Welded Steel Pipe: High-frequency resistance welded steel pipe uses a different welding process than conventional welded pipe. The weld seam is formed by melting the base metal of the steel strip, resulting in greater mechanical strength than conventional welded pipe.
2. Straight seam welded steel pipe: The materials of straight seam welded steel pipe mainly include Q195, Q215, Q345, and X42 pipeline steel series. According to the specified wall thickness, straight seam welded steel pipes are divided into ordinary steel pipes and thickened steel pipes. According to the form of the pipe ends, steel pipes are divided into threaded and non-threaded types.

Different Features
1. High-frequency welded steel pipe: Smooth surface, high precision, low cost, and minimal weld height, making it suitable for 3PE anti-corrosion coating. High-Frequency Welded Steel Pipes differ significantly from Submerged Arc Welded Pipes in welding methods. Since welding is completed instantly at high speed, the difficulty of ensuring welding quality is much higher than that of submerged arc welding.
2. Straight seam welded steel pipe: The length of straight seam welded steel pipe is mainly divided into fixed length and variable length, which is mainly based on customer requirements. The length is generally 6-14 meters. Large-diameter straight seam welded steel pipe may require two steel plates for rolling, which also forms a double weld.

The pipeline anti-corrosion and thermal insulation layer consists of an anti-corrosion layer, a thermal insulation layer and an outer shell layer.
The anti-corrosion coating of a pipeline refers to a layer of special anti-corrosion material applied to the surface of the pipeline to protect the pipeline from erosion by external media. There are many types of anti-corrosion coatings; commonly used ones include paint, asphalt, polyurethane, epoxy, etc.
Different types of anti-corrosion materials are selected according to the requirements of different media and usage environments.

The insulation layer is designed to prevent rapid heat dissipation from the pipe and avoid temperature loss. Insulation materials include polystyrene, silicate, and polyurethane.
Choosing appropriate insulation materials and reasonable insulation layer thickness is very important for saving energy and improving pipeline efficiency.

Outer shell
The outer shell is designed to enhance the pipe's aesthetics, strengthen its strength, and provide protection. Common shell materials include steel plates, aluminum plates, stainless steel plates, UPVC, etc.
The thickness of the outer shell and the materials used should meet the requirements of the use environment and have certain compressive resistance and toughness.

This layer, applied around the exterior of a pipeline to provide insulation and heat insulation, generally consists of the following components:
1. Anticorrosion Layer: Two coats of anti-rust paint are applied to the outer surface of the pipeline.
2. Thermal Insulation Layer: A layer of thermal insulation and heat-insulating material;
3. Moisture-Proof Layer: This layer prevents moisture from entering the thermal insulation layer. Typically, this layer is wrapped with felt and has asphalt mastic applied to the seams. This layer is typically used for cold pipes.
4. Protective Layer: This layer protects the thermal insulation layer from damage. Typically, this layer is made of glass cloth wrapped around the protective layer.
5. Coloring Layer: This layer is painted a specific color to distinguish the fluid within the pipeline.
The purpose of corrosion protection is to isolate the metal surface of the pipeline from the corrosive environment, extend the life of the pipeline, and prevent leakage; reduce the heat loss of the medium in the pipeline (such as steam, hot water), or reduce the external heat transfer to the low-temperature medium (such as chilled water); maintain the medium temperature to meet process requirements or prevent the medium from solidifying.