Brief Introduction
A storage tank is a container used to hold liquids, semi-solids or solids.
Storage tanks Dalian Dingjin's dish heads applied can be divided into metal storage tanks, non-metallic storage tanks, and composite storage tanks according to the material;
According to the corrosion resistance, they can be divided into anti-corrosion (corrosion-resistant) storage tanks, ordinary carbon steel storage tanks, and stainless steel storage tanks;
According to the working environment, they can be divided into normal pressure storage tanks, normal temperature storage tanks, high pressure storage tanks, high temperature storage tanks, low temperature storage tanks, and negative pressure tanks; According to the shape and size, they can be divided into vertical storage tanks, horizontal storage tanks, cone-bottom storage tanks, elliptical (dish-shaped) head storage tanks, special-shaped storage tanks, large storage tanks, and small storage tanks;
According to the use function, they can be divided into fixed storage tanks, movable storage tanks, transport storage tanks, and mixing tanks.
In terms of the cost-effectiveness of storage tanks, steel-lined polyethylene storage tanks are now the most superior. They have excellent corrosion resistance, high strength, and long life. The appearance can be manufactured into multiple varieties such as vertical, horizontal, transport, and mixing.
ASME storage tanks need to use heads produced according to ASME standards.
Parameter
|
Type |
Elliptical Head |
|
Manufacture Standard |
As per ASME Ⅷ-1,2023 UG79, &UG81 |
|
Inner Diameter |
1500mm |
|
Min Thk. A/F |
6mm |
|
Straight Flange |
50mm |
|
Cutting Method |
Gas Cutting |
|
Forming Method |
Cold Forming |
|
Heat Treatment |
Not Required |
|
Material Designation |
SA 516Gr.70 |
|
Material Standard |
As per ASME II-A,2023 |
|
Surface Treatment |
Sand Blasting |
|
NDT Method & Acceptance Creteria |
Not Required |
Cold Forming Advantages
Advantages of cold forming
Cold formed heads have precise dimensions and stable quality, no surface roughness and oxidation caused by heating, and beautiful appearance of the heads; in addition, there is no need to worry about material degradation caused by heating.
Applicable Heat Treatment
The standards and specifications of pressure vessels in various countries around the world determine whether heat treatment is required after processing based on the degree of processing deformation.
Judging from the more than 8 million heads produced by Hokkaido Iron Works in Japan over the past few decades and the more than 1 million heads produced by our company over the past decade, it is feasible to define whether heat treatment is required for cold-formed heads based on ASME specification UCS-79.
Therefore, it is necessary to consider whether heat treatment is required based on the design and use conditions and the degree of processing deformation.
The ASME specification stipulates that when the maximum fiber elongation of the processing degree exceeds 5% and any of the five conditions is met at the same time, carbon steel and low alloy steel cold-formed heads must be heat treated.
Five conditions:
The medium used is extremely or highly hazardous;
The material requires impact testing (which can be determined according to ASME VIII-1UCS-66);
The thickness of the cold-formed steel plate is greater than 15.9mm;
The plate thickness reduction rate after cold forming is greater than 10%;
The forming temperature is within the range of 120-482℃.
