Carbon steel elbow

Carbon steel elbow can also be called threading elbow, large radius elbow and boiler heating elbow

Carbon steel can be divided into three categories: carbon structural steel, carbon tool steel and free cutting structural steel according to the use. Carbon structural steel can also be divided into engineering construction steel and machine manufacturing structural steel. Carbon steel not only has good plasticity and weldability, but also has high strength and hardness. Therefore, carbon steel bends are widely used in power plants, electric power, concrete pump transportation and many other industries

In order to prevent cold cracks and hot cracks in welded joints, low hydrogen electrode is usually selected for arc welding, which not only makes the hydrogen content low, but also has the function of desulfurization and phosphorus to a certain extent. When the carbon content in the steel is low and the joint stiffness is not very large, the ilmenite type or titanium calcium type electrode can be selected for welding, but it is determined to adopt a strict process to cooperate with each other

Heating before welding is a useful process to prevent cracks when welding carbon steel bends. Heating can not only reduce the cooling rate of the joint, but also prevent the generation of austenite, reduce the welding stress and accelerate the escape of hydrogen dispersion. The selection of heating temperature and interpass temperature depends on the carbon equivalent of steel, the thickness of base metal, the structural stiffness, the type of welding rod, etc

The heating temperature can be checked by weldability inspection or by the calculation formula T0=550 (C-0.12)+0.4 δ Check. In the formula, T0 indicates the heating temperature (℃), and C indicates the carbon mass fraction (%) of the welding base metal, δ It indicates the thickness of steel plate (mm), and the weldment is more suitable for U-shaped or V-shaped groove, which can reduce the share of base metal melting into the weld

Other parameters of carbon steel elbow

Bending radius: R ≤ 6000 mm, and R ≥ 3D (R equals to 3D, 4D, 5D, 6D, 7D, 8D, 9D, 10D to represent the bending radius, and D is the outer diameter of the pipe)

Bending angle: θ It is usually 15 °, 30 °, 45 °, 60 °, 90 °, 135 ° and 180 °, and can also be bent according to the angle proposed by the customer

Length of straight section: the length L of straight section at both ends of the elbow is generally about 300 mm-1500 mm, or the length can be customized according to customer requirements

Executive standard: DL/T515& lt;& amp; lt; Power Station Bends& gt;& amp; gt;、 SY5257& lt;& amp; lt; Steel elbow& gt;& amp; gt; Implementation, or according to the standards or technical requirements proposed by customers

Product uses: petroleum gas pipeline engineering, gas pipeline engineering, chemical plant, power plant, chemical industry high-pressure pipeline, water conservancy, etc

There are five production methods of carbon steel elbow

1. Electrothermal method

Because the carbon recovery ability increases with temperature, many oxides and rare earth oxides that are difficult to recover can be recovered in the recovery furnace. In the recovery electric furnace, electric energy is used as the heat source, and carbon is used as the recovery agent to recover the ore to produce carbon steel