Introduction
The polishing grade of the flanged and dished polished heads supplied by Dalian Dingjin is an important indicator to measure its surface quality. Different applications have different requirements for the polishing grade. When choosing a polished dished heads, it is necessary to determine the appropriate polishing grade based on the specific application requirements and industry standards. At the same time, the correct polishing and maintenance methods are essential to maintain the surface quality of the end cap and extend its service life.

Parameter
|
Type |
Hemispherical Head |
|
Manufacture Standard |
As per ASME Ⅷ-1,2023 UG79, &UG81 |
|
Inner Diameter |
900mm |
|
Min Thk. A/F |
20mm |
|
Straight Flange |
50mm |
|
Cutting Method |
Plasma Cutting |
|
Forming Method |
Cold Forming |
|
Heat Treatment |
Not Required |
|
Material Designation |
316L |
|
Material Standard |
As per ASME II-A,2023 |
|
Surface Treatment |
Polishing |
|
NDT Method & Acceptance Creteria |
Not Required |
Polishing Method
Mechanical polishing:
The surface of the elliptical head is polished by mechanical force and abrasives to achieve a certain degree of smoothness. Mechanical polishing can be further divided into different levels such as rough polishing, semi-finishing polishing and fine polishing.
Electrolytic polishing:
The surface of the torispherical head is polished by electrochemical reaction to obtain a very smooth surface, which is suitable for occasions with high precision requirements.
Chemical polishing:
The surface of the hemispherical head is corroded by chemical reagents to make it smooth. Chemical polishing is suitable for heads with complex shapes.

Category
Polishing grades of flanged and dished head are usually divided according to surface roughness (Ra value). Common polishing grades include as below:
|
Grade |
Description |
Features |
|
2B |
Cold-rolled bright surface |
The surface is smooth and shiny, suitable for general use |
|
No. 4 |
One-way brushed surface |
There are obvious brush marks, good corrosion resistance, suitable for occasions with high decorative requirements |
|
No. 8 |
Mirror polished surface |
The surface is very smooth and reflects light like a mirror, suitable for occasions with high cleanliness requirements |
|
Ra value |
Surface roughness |
The smaller the value, the smoother the surface |
Choosing the right polishing grade depends on the following factors:
Use environment:
Different use environments have different requirements for the corrosion resistance and cleanliness of the head.
Aesthetic requirements:
For some occasions with high decorative requirements, you may need to choose a mirror-polished head.
Cost considerations:
The higher the polishing grade, the higher the cost.

