Chanute has unmatched experience fabricating HRSG headers and manifolds. We have manufactured every type of HRSG pressure part from reheater to feedwater heater. We understand the design details and have experience in fabricating every OEM’s header joint styles. The most common joint styles found in natural circulation HRSG’s are:
Full strength (stick-through)
This is the most common joint style utilized today and can be applied to a variety of coil designs. The joint is utilized in single or multiple row harp configurations and for both straight tube sidehill and bent tube radial layouts. A variety of hole bevels are used depending on joint configuration. They range from step bevels to constant depth bevels.
The full penetration tube to header weld is also a common joint style, particularly in superheaters and reheaters. The full penetration (full tube wall thickness) is accomplished by either a straight tube bore with the tube saddled on to the header or by spot face machining of the header to allowing more of a butt weld configuration.
The socket seat tube to header weld is also a common joint style, particularly in upper headers to guard against crevice crack corrosion. The socket seat is accomplished by machining a seat to prevent the tube from sticking completely through the header.
Fabrication Expertise That makes a Difference
With 25 years of header fabricating experience, Chanute knows the design and workmanship procedures that are required to successfully manufacture high alloy headers. Some material types must also be processed very carefully, in particular P91 Cr-Mo and 2205 duplex stainless. Both of these material types are susceptible to weld cracking during fabrication unless special care and fabrication techniques are employed. Additionally, trace elements must be controlled in the base and weld-filler materials to ensure proper metallurgy.
Chanute’s engineering staff can upgrade your replacement headers to resolve operating and mechanical issues. It is also common for our customers who are experiencing Flow Accelerated Corrosion (FAC) to upgrade material types to improve reliability and extend the life of the header. Chanute's engineers are qualified to evaluate flow distribution, thermal expansion and perform the applicable code calculations.