SCH 80 pipe elbow

What is a pipe elbow?

Pipe elbow refers to a pipe fitting that changes the direction of the pipeline in the pipeline system. According to the angle, there are three most commonly used elbows: 45° elbow, 90° and 180° elbow. In addition, according to project needs, other abnormal angle elbows such as 60° are also included. Elbow materials include cast iron, stainless steel, alloy steel, malleable cast iron, carbon steel, non-ferrous metals and plastics, etc. SCH 80 refers to the wall thickness of the elbow.

The methods of connecting to pipes include: direct welding (the most common method) flange connection, hot melt connection, electrofusion connection, threaded connection and socket connection, etc.

According to the production process, it can be divided into: welding elbow, stamping elbow, push elbow, casting elbow, butt welding elbow, etc. Other names: 90-degree elbow, right-angle bend, etc.

The purpose of pipe elbow:

A commonly used connecting pipe fitting in pipeline installation. It connects two pipes with the same or different nominal diameters to make the pipeline turn at a certain angle. The nominal pressure is 1-1.6Mpa.

What is SCH 80?

SCH 80 (Schedule 80) represents the wall thickness, which refers to XS thickened pipes with a pressure wall thickness less than DN200mm. Usage scenarios generally involve high temperature, high pressure, and highly corrosive conditions. The wall thickness of SCH 80 grade pipes is relatively thick, and the pressure and temperature in the use environment must comply with ASME/ANSI standards to ensure the safety and reliability of the pipeline system. SCH 80 grade piping systems are often used in the manufacture of chemical equipment, high-pressure pipelines, high-temperature heaters and some special piping systems. When designing and installing a steel pipe system, it is necessary to select the appropriate pipe number according to the actual use environment to ensure the stability and safety of the pipeline system.

Standard specification for SCH 80 pipe elbow:

The standard specification for SCH 80 carbon steel pipe fittings is an important guarantee for ensuring the safety and quality of pipeline system operations. Various standard-setting organizations at home and abroad have formulated corresponding standards, such as the international pipe fitting standard ASME B16.9, the domestic steel pipe fitting standard GB/T12459, etc. There are corresponding regulations on the specifications, dimensions, surface treatment, pipe wall thickness, etc. of pipe fittings.

The internationally accepted pipe flange standards can be summarized into two different and non-interchangeable pipe flange systems: one is the European pipe flange system represented by Germany; the other is the American pipe flange system represented by the United States. 

Classification of pipe elbows:

1. Divide by material
Carbon steel: ASTM/ASME A234 WPB, WPC
Alloy steel: ASTM/ASME A234 WP 1-WP 12-WP 11-WP 22-WP 5-WP 91-WP911, 15Mo3 15CrMoV, 35CrMoV
Stainless steel: ASTM/ASME A403 WP 304-304L-304H-304LN-304N
ASTM/ASME A403 WP 316-316L-316H-316LN-316N-316Ti
ASTM/ASME A403 WP 321-321H ASTM/ASME A403 WP 347-347H
Low temperature steel: ASTM/ASME A402 WPL3-WPL 6
High Performance Steel: ASTM/ASME A860 WPHY 42-46-52-60-65-70
Cast steel, alloy steel, stainless steel, copper, aluminum alloy, plastic, argon phosphate, PVC, PPR, RFPP (reinforced polypropylene), etc.

2. According to the production method, it can be divided into pushing, pressing, forging, casting, etc.
3. According to manufacturing standards, it can be divided into national standard, electric standard, ship standard, chemical standard, water standard, American standard, German standard, Japanese standard, Russian standard, etc.
4. According to its radius of curvature: it can be divided into long radius elbow and short radius elbow. A long-radius elbow means that its radius of curvature is equal to 1.5 times the outer diameter of the pipe, that is, R=1.5D; a short-radius elbow means that its radius of curvature is equal to the outer diameter of the pipe, that is, R=1.0D. (D is the elbow diameter, R is the radius of curvature).
5. If divided by pressure level: there are about seventeen types, which are the same as the American pipe standards, including: Sch5s, Sch10s, Sch10, Sch20, Sch30, Sch40s, STD, Sch40, Sch60, Sch80s, XS; Sch80, SCH100, Sch120, Sch140, Sch160, XXS; the most commonly used ones are STD and XS.
6. According to different shapes and uses, it can be divided into: grooved elbow, ferrule elbow, double-bearing elbow, flange elbow, reducing elbow, dead seat elbow, internal and external tooth elbow, stamping elbow , push elbow, socket elbow, butt welding elbow, inner wire elbow, etc.

How to make SCH 80 elbow?

There are three ways to make elbows: hot pushing forming, stamping forming and medium plate welding.

1. Hot push forming
It requires the use of a pushing machine, a mandrel and heating equipment. The finished tube blank is placed on the mandrel and pushed, heated and shaped at the same time. This production speed is fast, suitable for mass production, and the manufactured elbow is , beautiful appearance and relatively uniform thickness.

2. Stamping molding
Depending on the material, you can choose cold pressing or hot pressing. Put the tube blank into the outer mold. After the upper and lower molds are merged, under the push of the press, the tube blank moves along the gap reserved between the inner mold and the outer mold to complete the forming process.

3. Medium plate welding

Medium plate welding is for the production of large elbows. First, cut two middle plates, then use a press to press half of the elbow section, and then weld the two sections together, so that the manufactured elbow will have two welds. Therefore, the welds must be inspected after production to ensure that they meet the standards.

Quality control of pipe elbow fittings:
Quality control of pipe elbow fittings is the key to ensuring the quality and safety of the pipeline system. The quality inspection of pipe fittings includes appearance quality inspection, chemical composition analysis, physical performance testing, non-destructive testing and other aspects. Only pipe fittings that have passed the inspection can be put into use to ensure the safe and effective operation of the pipeline system.

SCH 40 pipe vs SCH 80 pipe elbow fittings:
The main difference between SCH 40 and SCH 80 pipe elbow fittings is the wall thickness. SCH 40 pipe has a thinner wall thickness and is often used in low-pressure applications such as residential plumbing or irrigation systems. SCH 80 pipe elbow fitting has thicker walls and is used in high-pressure applications such as industrial processes, hydraulic systems and underground piping. They are designed to handle higher pressures and withstand greater stresses than SCH 40 pipe.

Looking at specific dimensions, the wall thickness of SCH 40 pipe is approximately 0.109 inches, while the wall thickness of SCH 80 pipe is approximately 0.154 inches. This means that SCH 80 pipe is approximately 30% thicker than SCH 40 pipe. While SCH 80 pipe is stronger and more durable than SCH 40 pipe, they are also more expensive.

SCH 80 pipe has thicker walls and requires more material and more manufacturing time, which increases costs. When selecting pipe for a specific application, it is important to consider the pressure requirements and the cost-effectiveness of selecting thicker, more expensive pipe.