Manufacturing Process of Elbow

Elbow is a pipe fitting that changes the direction of the pipeline. It is a common connecting pipe fitting in pipeline installation. It connects two pipes with the same or different diameters to make the pipeline turn at a certain angle. According to the production process, it can be divided into: stamping elbow, welding elbow, push elbow, butt welding elbow, casting elbow, etc. According to the angle, there are three commonly used elbows: 45 °, 90 ° and 180 °. Of course, 60 ° and other abnormal angles can be customized according to the needs of the project.

The connection methods of elbow and pipe include: direct welding (the most commonly used method), flange connection, electric fusion connection, hot fusion connection, threaded connection, socket connection, etc.

Elbow materials include stainless steel, cast iron, malleable cast iron, alloy steel, carbon steel, non-ferrous metals and plastics. Because nickel alloy material has good corrosion resistance, mechanical performance and process performance, nickel alloy elbow is usually used in high concentration oxidized acid (nitric acid, sulfuric acid) and other transmission pipelines. It can be widely used in seamless water transmission pipe, steam pipe, seawater exchanger and evaporator, sulfuric acid and hydrochloric acid environment, marine equipment and other fields. The use of these materials can reduce the corrosivity during equipment operation, improve the operation stability and production efficiency, and have good cost performance. Therefore, nickel alloy materials are more and more used in industry, and the production of nickel alloy elbow is more and more common. Now the more popular products are Hastelloy C276 elbow, Inconel 718 elbow, Inconel 625 elbow, etc.

How are elbows made? Let's take a look:

Method 1: stamping forming

Stamping forming is the earliest forming process for batch production of seamless elbows. It is characterized by low cost and is suitable for small batch and special specification production. Nowadays, most elbows of common specifications are produced by hot pushing method or other forming processes. The pipe blank used for stamping needs to be equal to the outer diameter of the elbow, and the press is used to directly press and form in the mold. Before stamping, the pipe blank is placed on the lower die, the inner core and end die are installed into the pipe blank, the upper die moves downward and begins to press, and the elbow is formed through the constraint of the outer die and the support of the inner die. Since the outer arc is in the tensile state during forming and there is no excess metal in other parts to supplement, the wall thickness at the outer arc will be about 10% thinner.

Method 2: Hot push molding

The hot push elbow forming process is the most common process. It is a process in which the blank sleeved on the die moves forward under the push of the push machine with a special elbow pushing machine, core die and heating device, and is heated, expanded and bent during the movement. The principle of hot pushing elbow is to determine the diameter of pipe blank according to the plasticity of metal material and the law of constant volume before and after deformation. The diameter of pipe blank used needs to be less than the diameter of elbow. The deformation process of blank is controlled through core die to make the compressed metal at the inner arc flow and supplement to other parts thinned due to diameter expansion, so as to make the wall thickness of elbow more uniform.

The forming process of hot push elbow has uniform wall thickness and beautiful appearance, which is suitable for mass production. Therefore, it has become the main forming method of carbon steel and nickel alloy steel elbow, and sometimes it is also used in the forming of some specifications of stainless steel elbow.

The heating methods of the forming process include medium frequency or high frequency induction heating (the heating ring can be multi circle or single circle), reflection furnace heating and flame heating. The specific heating method is determined according to the specific conditions of the formed product requirements.

Wudenalloy has focused on the production and manufacture of nickel alloys for more than ten years. We are a principal worldwide supplier of corrosion-resistant alloy and other superalloy metals. We have a professional technical team and after-sales service, so we can offer high-quality Hastelloy®, Incoloy®, Inconel®, Monel®, Duplex Stainless Steel and other alloy material. These materials are available in bar, sheet&plate, pipe&tube, flange, forging, and other forms to meet the needs of our customers. you can send emails to sales@wudenalloy.com at any time, Wudenalloy is your trusted supplier of special alloy material.