20 Welding Issues
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The economizer in coal chemical plants is exposed to temperatures of over 600 degrees, and sulfur, hydrogen, and carbon monoxide are the main substances that can penetrate it. What type of welding rod should be used when repairing leaks in these pipes? I tried using 507, 317, and 422 rods, but none of them worked – the surfaces did not fuse together. I request an explanation.
1 It needs to be polished until a metallic shine appears, before it can be welded； 2 The welder must be certified under TS and highly skilled. 3 GTAW welding method shall be used, with J507 wire being dried first
The economizer cannot reach such high temperatures; the 20G model can no longer be used at 600 degrees. What do you think, OP?
Based on the material used in their construction, economizers can be divided into two types: those made of cast iron and those made of steel pipes. Non-boiling economizers are usually made of cast iron, although some are also constructed from steel pipes; on the other hand, boiling economizers must be made of steel pipes. Cast iron economizers are commonly used in boilers with a pressure of ≤2.5 MPa. If the pressure exceeds 2.5 MPa, a economizer made of steel pipes should be used. Can it be determined what material it is?
Is there an installation technical manual? As special equipment, boilers generally come with complete documentation
Flue gas temperature is not equal to the metal temperature of the economizer
Look for the certification, verify the material thoroughly before deciding on the type of welding material; using the method of testing based on the results of welding with electrodes can lead to problems