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Hey Glen, A spiral made steel tube was used for the Malan subs conning tower section. Perhaps the main hull as well. But I've never heard if that is a ok way to go or not. There are so many types and thicknesses of them, that it might be hard to generalize. I'm sure the group will have some good impute for you. I would just go with the basic rolled plate design as specked in the plans. From what I understand A516 GR70 has the same carbon and iron make up as T1 steel, which is called A514, but is tempered to be more brittle then A516 GR70. So the A516 GR70 has excellent notch toughness for cold temperatures like you might have when diving or at the surface in some cases. Meaning that if you hit some thing really hard that the steel will dent, rather then crack, and if there was a crack it wouldn't travel as easily. I don't know what the GR70 really means, or what other grades there are. Perhaps it has to do with the carbon content, and/or the type of annealing or normalizing that was done to it. George Kittredge has said that you can use A-235C, or A-36 mild steel if your not going have you sub certified and be just fine for recreational purposes. But that the A516 GR70 was a great up grade. He was at the time talking about K-250's so take that into account. I'll send his quote to you off list. Your resident pipe dreamer ;)' Regards, Szybowski From: glenbrown@vodamail.co.za To: personal_submersibles@psubs.org Subject: Re: [PSUBS-MAILIST] k350 plans Date: Thu, 4 Sep 2008 20:31:26 +0200 Any Psuber.
Could someone answer the following is astm a certain standard?.Is STD=standard.and if so what is a standard 10'' wt pipe thickness?.does wt =water ?does GR70=grade 70?what does astm516 mean? What else could this metal be called i.e. rocktough ect I am busy building a K350 and
not getting any joy with our south African pipe suppliers in getting materials.Can a spiral manufactured pipe be used.
Please excuse my ignorance your
advice or any suggestion will be much appreciated .
Thanks Glen
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