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Re: [PSUBS-MAILIST] rib span



In brief. The "A" in A-516Gr 70 means that this particular material has been tested by the American Society for Testing and Materials (ASTM) and has been approved to be used for applications requiring a specific characteristic or property. This gives material manufacturers, the steel mills, a standard (chemically, mechanically, ect..) which must be met in order to provide the consumer/fabricator a material that is trustworthy. The "516" is a numbering system that in this particular case specifies the material as being a carbon steel suitable for pressure vessels subjected to moderate and lower temperature service.The nominal composition for this is C-Mn-Si which together give the material its ability to be used for applications such as submarines. Grade 70 means that the plate has a minimum specified tensile strength of 70 ksi (70-90,000 psi is the actual range) the highest for this particular alloy. The others are 55, 60, and 65 ksi depending on the heat treatment process, I think.
 
The American Society of Mechanical Engineers (ASME) has adopted this same numbering system except to show they didn't copy it directly they add an "A" to the beginning. So if you look this material up because you want to weld on it and you need to find filler materials or qualify the material, weld and/ or welder you would find this under SA-516Gr70 and a lettering system that helps you through the ASME standards. These materials come in different forms like plate and sheet. Sheet just being very thin <0.125 in. and sometimes it comes in coils. These forms are partially dictated by the demand and the physical ability to produce the material with the desired properties.
 
Adam
----- Original Message -----
From: Chris Nugent
To: personal_submersibles@psubs.org
Sent: Thursday, August 21, 2003 6:15 PM
Subject: Re: [PSUBS-MAILIST] rib span

   If no one minds me chiming in, I've a question.   "A516Gr70".  Obviously this is nomenclature referring to the grade and type of steel used, but I myself am foggy on it.  What is the difference between plate and sheet steel, and how is the above term "deciphered" into layman's terms?  Could someone break that down for me?
 
          Thanks,
 
               Chris Nugent

VBra676539@aol.com wrote:
K-350 1-man has 48" long cylinder, 2-man has 72"--the 600 is 72" in the 1-man
version just to float. Built like an anvil. The PC-8 is a 42" diameter hull,
3/8" A516Gr70 and rated at 800', so I'd say Captain Kittredge was being very
conservative. So would he.
Vance


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