Earl and the Aboveground Storage Tank Forum for fuel tanks, plastic tanks, fuel oil storage tanksWelcome to the aboveground storage tank forum, a bulletin board dedicated to tanks, fuel tanks, plastic tanks, fuel storage tanks, and above ground storage tanks (AST) API650, API653 & UL142 aboveground storage tanks (AST) and chemical plastic tanks. Remember the forum is made up of volunteers from experts to beginners. Unfortunately, we cannot allow free commercialism that promotes products, services, or sites.
 
Sponsored by:
Contact us about advertising
Earl   AST Forum  

Amine Service Tank

Friday, March 04, 2005   By: Josias Tatontos
The cylindrical tank OD 6100 mm, Height 7700 mm, Plate A 283 C, design pressure 0.427 psig, temp 200 F service : Amine with sp gr 1.002. If the tank use plate 6 mm, the hardness 200 BHN (weld) 225 BHN (HAZ) after PWHT. Our question is if we do the PWHT anybody know how to PWHT this tank, it is use the electric heater type to all the weld seam simultaneously, what is the temperature because the plate is only 6 mm. Thank you

Post a Reply...
Viewed 827 times

Sunday, March 06, 2005   By: www.thill.biz
Postweld Heat Treatment This operation can be defined as the heating of weldments immediately after welding in order to temper, stress relieve, or provide controlled cooling. It prevents the formation of hard or brittle structures prone to cracking in services. Postweld heat treatment is mandatory for certain alloys, combinations or alloys, and material thicknesses as outlined in the various codes and standards, such as ASME Section VIII Pressure Vessel Code. Consequently, welding procedures for such materials and/or thickness will contain the provisions for heat treatment. Fabricators may have difficulty with prostweld heat treatment due to shop practices rather than the treatment itself. Cracking can occur in vessels that are held for heat treating until a full furnaces load is ready. In general, at normal heat treating temperatures the time at temperature is specified as one hour per 1 in. (25 mm) of maximum thickness for vessels up to 2 in. (50 mm) thickness fabricators may suggest that since the component is being heated form both sides half-an-hour at temperature for each 1 in. (25) thickness is sufficient – but the one hour requirement should be maintained. For vessels over 2 in (50 mm) in thickness, the usual holding time is two hour plus 15 minutes for each additional 1 in. (25 mm) over the 2 in. (50 mm) thickness. Again, some fabricators may want to cut this time by half since the component is being heated form all sides. Holding time may be an accumulation of multiple heat-treat cycles. It dose not necessarily have to occur all at one time. Care must be taken to ensure that the accumulated time at the correct temperature equals that required to effect the desired treatment. There is a maximum furnace temperature for introduction of the vessel. This varies with the alloy but is generally 800º F (426º C) for carbon steels. Heating rate vary with alloy as well but are usually in the 200 to 400º F (93 to 204º C) range. Some manufactures will try to heat as rapidly as possible in order to reduce the time required. Cooling is normally performed in the furnace at a controlled rate unless the component si to be quenched. If quenching is performed then the component must be removed form the furnace and quenched as quickly as possible. Delays will cause such problems as carbide precipitation in austenitic alloy and reheat treatment will be necessary.

Post a Reply...
Viewed 838 times

Saturday, March 05, 2005   By: Stephen H
As far as I know, a "Stress Relief" would generally be at the same temperature, that is about 1200 F. You normally vary the time required to adjust for plate thickness, but temperature doesn't vary that much. If you're trying to maintain a maximum hardness on the welds, you should be able to make some weld samples, and try PWHT in a lab furnace to see if it gets the results you want.

Post a Reply...
Viewed 782 times

Saturday, March 05, 2005   By: ADI HAR-SHOSHAN
What is the reason that you have done PWHT?.

Post a Reply...
Viewed 775 times

Saturday, March 05, 2005   By: Josias Tatontos
Ownel spec call for it. Also In The OSHA technical manual Setion IV Chapter 3 there is possibility of cracking of carbon steel in an amine environment.

Post a Reply...
Viewed 809 times

Friday, March 04, 2005   By: Stephen H
I've never been involved on that kind of job. But I do recall quoting a tank or two that was to be stress relieved. Seems like there was a company called Cooperheat that we got pricing from. If I remember right, they quoted either the electrical heaters like you are mentioning, or the alternative to insulate the outside of the tank and heat the whole thing with fuel-fired heater through a manway. This was on a somewhat smaller tank than yours, but still field-erected. And this was maybe 15 years ago.

Post a Reply...
Viewed 791 times

Saturday, March 05, 2005   By: Josias Tatontos
Thank you for the response. Yes we can fired through the manway, several weeks ago i saw in Jambi Indonesia, CBI doing the stress relieve by firing through the manway but the tank is spherical and the thickness about 50 mm. Our question is if the plate is only 6 mm what is the temperature for stress relieve. thank you

Post a Reply...
Viewed 787 times

Sunday, March 06, 2005   By: Lawrence
The temperature cannot exceed critical temperature otherwise the ferrite begins to transform to austenite; of course it will transform back on cool down, but if this is not done right you could end up with martinsite or banite. Since the tank is very thin there is a higher probability. You tank wall is thin and will heat up very quickly. Must have excellent contols. Never exceed 1100F with this material and you must keep it at 1-hour and 15-minutes to be effective. Consult with a metallurgist who has experience with heat treatment. Lawrence

Post a Reply...
Viewed 787 times

Monday, March 07, 2005   By: Stephen H
API-650 specifies 1200 F for 1 hour/ inch, for stress-relieving insert plates or nozzles. This is not necessarily aimed at producing a specific hardness in welds, however. But that range should be acceptable for any of the allowable plate materials in API-650.

Post a Reply...
Viewed 787 times

Published on ast-forum.com

 

Featured
Atmospheric Design Pressure
By: Fathi [46]

The whole story is to avoid brittle fracture=

Test temperature shall be equal or warmer than Minimum Metal Design temperature at Test pressure.
------------------

I would limit my minimum testing temperature for a tank (or even for a vessel or a piping system) by the =

Temp = maximum of [ Min(lower shell) , Min(shell# 2) ....Min (Upper shell) ]

For a Shell# i the minimum is function ( of shell tickness , Material group ) and this can be found in API 650 , Fig 2-1

A similar a....   Read All
 
fiogf49gjkf0d

It's hard not to look at this ad at least once, then you go to the next page an notice it again. Maybe you will not read the message, but you will be thinking about the brand and we call that brand impressions.

About 2/3 of internet traffic is useless traffic and consist of malicous-bad-robots.  However, there are good robots too.  We block bad-robots, and allow the good one's through, but we just do not count the good one's.  We want good straight-brand impressions for our advertisers!

Imagine your static or animated display advertisement placed here, and if that is not enough you can include text too to expound on the virtues of your services and or products.    In addition, you can benefit by using our new advertisement feature to have your video included in your ad space.  Wow, make an infomerical with text and a display by combining all features to enhance the readers or audience's experience using your brand.  Ads can be much more than a static display ad. Here is an example of how your video could be used or position in this ad space

 

Caption: Public domain video from CommTank on NDE of aboveground tanks using Magnetic Flux Leakage (MFL) scanner and Ultrasonic Test (UT) methods. The author of the video is not an advertiser and is being used to show how the video ad can be of value to the reader since you have already being viewing the video.  It is hard not to think about the authors brand after viewing the video ad.  This is the benefit of Branding.

 

 

 

A Long-game that Earns Tomorrow's Sales


 Click on this Promotional Advertisement to Contact Us Today!

Good Branding Puts Your Brand or Company in the Front of a Decision-Maker’s Mind for a Purchase either Months from Now or Five-Years in the Future.

Good branding makes your brand or company the leader in a crowded field of other brands or companies vying for your potential or existing client's attention. 

An invitation to the buyer's table to negotiate potential sales from $thousands to $millions of dollars in any of these: Systems sale, Capital Equipment, Upgrades & Modifications,  Repairs, or Capital Project becomes easier now with a recognized brand that thinks forward by brand advertising.

Your advertising will cost you an unbelievable low amount, so ask for our Media Kit that has Specs and Rates. 

Below is some of our demographic data for ast-forum users will speak for itself:

Bus Sector Percent   Education Percent
Manufacturing 18%   College+ 70%
Power Gen 2%      
Chemical 4%      
Petroleum 40%      
A&E 6%      
Construction 12%      

Our network works hard for you with placements for full coverage on part of the network, or full network placement.  Brand yourself today and don’t miss-out on being invited to your client or future client's table because they forgot you.  Be the leader they will remember and be part of their capital project.  Tomorrow’s clients are your future.

 

Advertising and Marketing Agency for the ast-forum
PE Marketing, LLCBranding.jpg
Sponsors/Advertisers
Industrial Training School - Basic Electricity
 
ITS - Maintenance
 
Industrial Training School - Steel Making Tutorial
Steel Maiking Tutorial
Industrial Training School - Instrumentation
5% Off Enter TV0901
Confidentiality, Disclaimer & Policy
AST FORUM
© 2001 to AST (Aboveground Storage Tank) Forum, All Rights Reserved.
PE Marketing LLC is representing the steamforum for advertising and marketing
Valid XHTML 1.0 Transitional