How to prevent rust of large stainless steel butt welding flange?
As a sealing and fastening connector, large diameter flange is easy to install, flexible in position and long in service life. It is widely used in large vessels in aerospace, petroleum, chemical and other fields.
The welding seam of large diameter flange shall be subject to 100% ultrasonic or radio graphic testing. The surface of large diameter flange shall be free from cracks or other defects that reduce the connection or strength of flange. When the working pressure of large flange with long diameter is equal to or greater than 0.8 times of the maximum allowable working pressure specified in the standard, the butt welding seam of large diameter flange and circular pipe shall be inspected with 100% X-ray.
The gist of derusting:
Immerse the flange in hydrochloric acid, the reason is to restore the rust to iron, but this method has certain danger. Hydrochloric acid is corrosive material, which is not beneficial to human body. When controlling, it must be careful not to touch the human body. If there is a good flange, neutralize it with alkali, and don’t touch your hands happily.
Stainless steel butt welding flange is used to complete switch and flow control in pipeline. As a pipeline system, stainless steel butt welding flange is used to complete switch and flow control components. It has been widely used in many fields such as kerosene, chemical industry, metallurgy and hydropower. In the once well-known non-standard flange technology, sealing form closure planning, sealing materials for rubber, polytetrafluoroethylene and so on.
After welding, the non-standard flange pipe fittings are hard, and the American standard flange is large, and cracks occur randomly. If chromium stainless steel electrodes (G202 and G207) are accepted, preheating above 300 ℃ and slow cooling at 700 ℃ after welding are necessary. If post weld heat treatment is not available, stainless steel non-standard flange pipe welding rod (A107, A207) should be used.
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