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Carbon steel primarily refers to steel with a carbon content of less than 2.11%, without intentionally added alloy elements. Carbon steel is an iron-carbon alloy with a carbon content of less than 2.11%. In addition to carbon, carbon steel usually contains small amounts of silicon, manganese, sulphur and phosphorus.
|
Type |
Elliptical Head |
|
Inner Diameter |
1067mm |
|
Min Thk. A/F |
60mm |
|
Cutting Method |
Plasma Cutting |
|
Forming Method |
Spinning |
|
Heat Treatment |
Required |
|
Material Designation |
SA 516 Gr.70N |
Carbon steel dished heads are widely used in petroleum, chemical equipment, transportation, power, and nuclear industries. Learning about the 9 types of corrosion of carbon steel dished heads would be better to avoid or reduce the improper operation leading to various types of corrosion for related workers. Following 4 types mentioned for your reference, and the rest 5 types would be shared at ....
1. Uniform Corrosion: This type of corrosion occurs uniformly over the entire surface exposed to the medium or over a large area, resulting in macroscopic uniform corrosion damage.
2. Contact Corrosion: When two metals or alloys with different potentials come into contact and are immersed in an electrolyte solution, current flows between them. The metal with the higher potential corrodes more slowly, while the metal with the lower potential corrodes more quickly.
3. Selective Corrosion: Selective corrosion refers to the phenomenon where a particular element in an alloy enters the medium due to corrosion, preferentially.
4. Pitting Corrosion: Pitting corrosion is characterized by deep corrosion concentrated on individual small points on the surface of the carbon steel head, also known as small hole corrosion or point corrosion.
Heat treatment refers to thermal processes that can alter the micro-structure and properties of carbon steel heads after welding or reduce residual stresses.
To effectively slow down and prevent abnormal damage to carbon steel dished heads service for pressure vessel, improving metal properties, and eliminating residual stresses, heat treatment plays an important role beyond strict adherence to specifications and manufacturing procedures.
The specific objectives of heat treatment for carbon steel heads are as follows:
(1) Relieve residual stresses from welding;
(2) Stabilize the shape and dimensions of the head, reducing distortion;
(3) Improve the properties of the head material and the weld zone. This includes increasing the ductility of the weld metal; decreasing the hardness of the heat-affected zone; enhancing fracture toughness; improving fatigue strength; improving creep characteristics; restoring or increasing the yield strength reduced during cold forming;
(4) Enhance the head's resistance to stress corrosion;
(5) Further release harmful gases, particularly hydrogen, from the weld metal of the head to prevent delayed cracking.
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