For one of our clients we replaced existing bundle and channel 
Tubesheet vdTUV 377/3 explosion cladded with 254SMO
Tubes UNS N08926 – Hastelloy
Tube – Tubesheet strength welded and slightly expanded 
Channel vdTUV 377/3 + P460 internally cladded with Aloy 625 by Cold Wire TIG

Bundle and channel are connected by stud bolts with super nuts 3 ¼ – 8UN
and successfully hydro tested @ 357 Bar(g)