ASME Torispherical Head

ASME code are developed by the American Society of Mechanical Engineers and are also widely used in the international industrial field. The ASME standards for heads are divided into two aspects: one is ASME SECC-1, which introduces the general properties and regulations of heads; the other is ASME VIII-1, which is a specification for the design of heads and pressure vessels. ASME VIII-1 stipulates the classification, size, material and manufacturing of dish heads, and requires all manufacturers to pass the review of the National Plate and Pressure Vessel Inspection Bureau (NB) of the United States to ensure product quality.

Dish head, Dalian Dingjin also known as spherical head with straight edges. It consists of a spherical surface, a straight edge of a cylinder at a certain height, and a transition part connecting the above two parts with a curvature radius smaller than the radius of the spherical surface. The dish head is a continuous curved surface. At the connection of the three parts, the radius of curvature of the meridian has a sudden change. Due to the change in curvature, there is bending stress.

1. Structural form

The dish heads formed by Dalian Dingjin could be divided into several forms such as spherical, elliptical, square and torispherical, and each form has its specific use occasion. For example, spherical heads are suitable for all media, including gas, liquid and solid, so they are widely used in various containers.

2. Material selection

The material of the ASME torispherical head should have the characteristics of corrosion resistance, high temperature and high pressure resistance, and impact resistance. Commonly used materials include stainless steel, alloy steel, plastic, etc. The specific material to be selected needs to be determined according to the use occasion and medium characteristics.

3. Advantages and characteristics

In addition to the above-mentioned structural forms and materials, the selection of the dish head also involves its wall thickness, installation form and whether it is equipped with gaskets and other aspects, so it needs to be considered comprehensively.

4. Use scenarios

Different containers require different heads, so it is necessary to carefully understand the nature and use occasions of the pressure vessels to select the appropriate dish head.

There are generally four methods of Dingjin to make ASME torispherical heads: manual forming, explosive forming, die forming and spinning. Among them, manual and die forming, Dalian Dingjin generally adopts hot pressing, that is, the head blank is heated to 800 ~ 1000℃, and then pressed on the mold by a press. However, with the rapid development of specialized production of pressure vessels in the chemical, brewing and other industries, the demand for heads is increasing, and the requirements for their internal quality (such as internal metallographic structure and pressure resistance, corrosion resistance, etc.) are also getting higher and higher. The specialized production of head cold pressing process and its mold design will gradually replace the hot pressing process, which has irreplaceable absolute technical and economic advantages over manual forming.