Butt weld elbows, Butt weld elbow pipe fittings

What is a butt-weld elbow?

Butt-weld elbow is a steel hot-pressed or forged pipe elbow. Its connection form is to directly weld the elbow to the steel pipe. Butt-weld elbow is a commonly used steel pipe fitting, mainly used to connect the curved part of the pipeline. Butt-weld elbow consists of the elbow itself and the connecting pipe, and is usually used in high-pressure, high-temperature and high-flow pipeline systems.

Manufacturing standards:

The main manufacturing standards for butt-weld elbows are generally ASME B16.9, EN 10253-2, SH3409, GB/T13401-2005, GB/T12459-2005, HG/T21635, HG/T21631, SY/T0510, GB/T10752-1995, ISO 15590-2:2009.

Classification of butt-weld elbows:

(1) Butt-weld elbows can be divided into long radius butt-weld elbows and short radius butt-weld elbows according to their curvature radius. The curvature radius of the long radius butt-weld elbow is equal to 1.5 times the outer diameter of the pipe, that is, R=1.5D. The curvature radius of the short radius butt-weld elbow is equal to the outer diameter of the pipe, that is, R=1D. In the formula, D is the diameter of the butt-weld elbow and R is the curvature radius. If there is no special explanation, the 1.5D elbow is generally selected.

(2) According to the pressure level, there are about seventeen types, which are the same as the pipe standards in the United States, including: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, Sch100, Sch120, Sch140, Sch160, XXS, among which STD and XS are the most commonly used.

(3) According to the angle of the elbow, there are 45-degree butt-weld elbows, 90-degree butt-weld elbows, 180-degree butt-weld elbows and elbows of other different angles.

(4) The manufacturing materials of butt-weld elbows are: carbon steel, alloy steel and stainless steel. The choice of these materials depends on the specific application environment and requirements. For example, carbon steel elbow is suitable for general industrial pipelines, alloy steel elbow is suitable for high temperature and high pressure environments, and stainless steel elbow has good corrosion resistance.

Characteristics of butt-weld elbow:
Steel butt welding elbow is a kind of pipe connector, which is generally used to connect pipes in different directions of the same pipe or connect pipes of different diameters. It has the following characteristics:
1. Corrosion resistance: Steel butt welding elbow is made of high-quality steel, has good corrosion resistance, and can be used for a long time in harsh environment.
2. High temperature resistance: Steel butt welding elbow can withstand high temperature and high pressure, is not easy to deform, and has good high temperature resistance.
3. Pressure resistance: Steel butt welding elbow is made of high-strength steel, has good pressure resistance, and can withstand high-pressure pipeline system.

4. Compact structure: Steel butt welding elbow has a compact structure, occupies little space, is easy to install, and can greatly save space and cost of pipeline system.

Manufacturing process:
The manufacturing process of steel butt welding elbow mainly includes forging, die pressing, cold drawing, welding, etc. Among them, forging and die pressing processes are suitable for manufacturing large-size, high-pressure pipe elbows; cold drawing process is suitable for manufacturing small-size, high-precision pipe elbows; welding process is suitable for manufacturing various elbows.

Large-diameter butt-weld elbows: 

Large-diameter butt-weld elbows are mainly used to connect two sections of pipes with different end face radii, or for pipe diameter change. This type of elbow generally needs to be produced according to specific project requirements or specific drawings. In addition to meeting the requirements of the pipe diameter, the specific conditions of the pipe must also be considered, such as pipe delivery pressure, fluid viscosity, abrasiveness, corrosiveness, fluid delivery temperature and other factors. Usually, butt-weld elbows are welded at the pipeline construction site. This is because the welding standards of various types of pipes are different, and on-site welding is required according to the grade of the pipe weld.

Application range of butt-weld elbows:

Butt-weld elbows are widely used in petrochemical, shipbuilding, papermaking, food, electricity, construction and other industries.
In the petrochemical industry, butt-weld elbows are generally used to connect pipeline systems for transporting oil, natural gas, and chemical products;
In the shipbuilding industry, butt-weld elbows are generally used to connect various pipeline systems of ships;
In the papermaking industry, butt-weld elbows are generally used to connect various pipeline systems of papermaking machines;
In the food industry, butt-weld elbows are generally used to connect the pipeline systems of food processing machinery;
In the power industry, butt-weld elbows are widely used in boilers, heat exchangers and other equipment in power plants, and can adapt to harsh environments such as high temperature and high pressure;
In the construction industry, in the building water supply and drainage system, butt-weld elbows play the role of connecting pipelines, with the advantages of easy installation and good sealing, and are widely used in building water supply and drainage systems.

Advantages of butt-weld elbows in construction:

Butt-weld elbows not only save space and reduce weight. More importantly, it ensures that there will be no leakage and has good sealing performance.

Butt-weld elbows use resistance heat to weld two pipe fittings together along the entire end face at the same time. On-site installation usually adopts two methods: resistance butt welding and flash butt welding. The butt-weld elbow is a type of elbow formed by hot pressing of steel or by forging technology. The connection method is to weld the elbow to the steel pipe, which has high productivity and is easy to automate, so it has been widely used. The following is a detailed introduction to the characteristics of butt-weld elbows in construction.

Feature 1:
Butt-weld elbows are mainly used to connect two sections of pipes with different radii, or to change the diameter of the pipe. This type of elbow is usually required to meet specific requirements or specific drawings. In addition to meeting the pipe diameter requirements, the situation in the pipeline should also be considered. Such as pipeline pressure, fluid viscosity, abrasives, corrosive fluid transportation and many other factors.

Feature 2:
Butt-weld elbows have welds. The elbow welding rust or corrosion is after the welding operation, or the environment outside the pipeline is rust-proofed to avoid bending rust or corrosion during welding.

Feature 3:
Usually when welding butt-weld elbows at the pipeline construction site, due to the different welding standards of various pipelines, it is necessary to perform on-site welding according to the welding level of the pipeline. It is necessary to perform on-site welding for different pipeline welding levels, which is another feature of welded elbows.

At present, butt-weld elbow fittings can already meet the automation process of mass production, and the construction effect is relatively stable. The existing elbow connection materials have certain design standards and can meet the current butt-weld manufacturing effect. In short, butt-weld elbow fittings have become one of the indispensable parts in various industrial fields due to their excellent performance and wide application fields.

Read more: Pipe Elbow Material Selection or Pipe Elbow Size Selection