Pressure vessel head pipe cap

Pressure vessel heads have a very wide range of applications. They are equipment that plays an important role in various sectors of the national economy, such as the petrochemical industry, energy industry, scientific research, and military industry. A pressure vessel body is generally composed of six main parts: a cylinder, a head, a flange, a sealing element, openings and nozzles, and supports.

## 1. Scope

1. In terms of materials, the new standard is not limited to pressure vessel heads made of steel (carbon steel, low-alloy steel, high-alloy steel, and qualified steel plates), but also applies to pressure vessel heads made of other metallic materials (aluminum, titanium, copper, nickel, and nickel alloys).

2. In terms of type parameters, the new standard applies not only to elliptical, dished, spherical cap, and conical heads, but also to hemispherical and flat-bottomed heads. In addition, the new standard renames "flanged conical head" as "conical head".

3. In terms of manufacturing methods, the new standard applies not only to heads formed by stamping, spinning, and rolling, but also to heads formed by segmental fabrication.

A pressure vessel head is a type of boiler component. It is usually used at both ends of a pressure vessel and also serves as a plug at the end of a pipeline. There are many different types of head configurations.

Among pressure vessels, compared with other types of heads, spherical heads have superior stress distribution. They require a smaller thickness under the same diameter and pressure, saving materials, so they are often used in high-pressure vessels. At the same time, among all connections between heads and cylinders, the thickness difference between a spherical head and the cylinder is relatively large. The connection structure between them not only affects the manufacturing of the equipment but is also one of the important factors determining whether the vessel can operate safely. In GB150-1998, the butt circumferential weld between the cylinder and the spherical head is also defined as a Type A welded joint.

The practice of processing customer-supplied materials for head manufacturing has a long history and covers a wide range. To effectively control the entire process of head manufacturing, promote large-scale and specialized head production, regulate the head market, and ensure the absolute safety of special equipment such as pressure vessels, it is necessary for the Special Equipment Safety Supervision Bureau to uniformly arrange local safety supervision, supervision and inspection, as well as pressure vessel management. Head manufacturing enterprises shall strictly control the input and output of material-supplied processing, clarify respective legal responsibilities, put an end to counterfeit and shoddy products and illegal manufacturing, and continuously purify and standardize the market for heads used in special equipment such as pressure vessels.