Heat treat 800H steel to 1600F -- any contractors that can do this?

[Rob Inks]

I have a 40' tall 126" ID reactor that has some weld cracks. I need to pre heat this vessel to roughly 1600 F to drive impurities out of the grain before welding and also needs to be post treated. Has anyone ever done something similar on this large of a scale? I need to find a contractor capable of such a job.

 

[SteamKing]

I have a 40' tall 126" ID reactor that has some weld cracks. I need to pre heat this vessel to roughly 1600 F to drive impurities out of the grain before welding and also needs to be post treated. Has anyone ever done something similar on this large of a scale? I need to find a contractor capable of such a job.

You should at least do a search for companies experienced in pressure vessel repairs.

Try some of the companies at this link:

http://www.thomasnet.com/products/pressure-vessel-repair-services-91722207-1.html

 

[Rob Inks]

Thanks for your help. I have used contractors in the past but they are not capable of such an enormous project. I know that we can't be the first company to need to do a vessel this big. Just throwing feelers out there to see if maybe anyone had been involved in a similar project.

 

[SteamKing]

Thanks for your help. I have used contractors in the past but they are not capable of such an enormous project. I know that we can't be the first company to need to do a vessel this big. Just throwing feelers out there to see if maybe anyone had been involved in a similar project.

It's not clear where the vessel is welded. Are the cracks located such that the entire vessel needs preheating? Clearly, someone had to make this thing in the first place. Have you talked to the fabricator?

I've worked in shipyards where two large castings were welded together to form one large piece. The process was officially observed to make sure proper pre-heating of the zone to be welded was accomplished, but the whole piece did not need preheating. IIRC, the minimum preheat was about 1200 °F, which was to be confirmed by using a temperature indicating stick, such as this one:

http://www.tempil.com/products/tempilstik-original/

The welding zone of the cast pieces glowed an orange-reddish color when tested, and the heat coming from them was so intense that the person wielding the temp stick had to wear a welding glove and some extra insulation just to get close enough to check the piece.

It's also not clear what your experience is in such matters. I think you should consult with a welding engineer who has experience in the relevant ASME codes governing the construction of this device. Also, it doesn't cost anything to discuss this project with various individuals or companies. The people you talk to may not be able to handle a project this size, but that does not mean they can't steer you toward someone who might be able to manage it. You might also want to consider putting together a brief request for quotation which can be sent out for people to examine.