Hello all,
Duplex and super duplex grades are prone for the forming of intermetallic phases that lower corrosion resistance and mechanical properties like impact strength.
These phases grow in a temperature range between 950-600 degC during heat treatment and/or welding. After metal fabrication...
Hello all,
Currently we are designing a few hp heat exchangers including NACE MR 0175 requirements.
Materials of construction will be S31803/S32205 DSS, material thickness up to 100mm.
Most of the requirements that are included are understood and can be achieved but the maximal hardness...
A Norsok M650 qualification test record holds a scope (qualification of process) and the tested and qualified thickness and weight.
In some cases a range of qualifcation is also given but in most cases this range is missing.
Can anybody inform me about the criteria that is applicable to...
Hello all,
My question relates to the different methods used for bending and heat treating duplex stainless steel (heat exchanger) u-tubes.
To avoid metallurgical problems with the duplex grade material it is prefered to bend the tubes cold. In some cases specifications prescribe solution...
Hello all,
Recently we booked an order for fabricating a super duplex heat exchanger.
Design code ASME VIII div 1 including U-stamp.
During the procurement stage we are facing some difficulties buying the correct S32750-F53 seamless tubes.
The only option we have at this moment is an...
Good day,
I have some questions that relates to whether or not to apply post weld heat treatment on carbon steel headers.
This question relates to the fabrication of pressure equipment.
Can somebody give me the main reasons for applying pwht by for example an carbon steel header of an air...
Dear All,
As pressure equipment fabricator we designed a new type of header for air cooled coolers that contains almost no welds.
Instead of welding plates together we have a design that consists our of a forged block.
The only welding there is for the nozzles and in some cases an endplate. In...
Hello All,
Recently we subcontracted the manufacturing (forging, machining) and overlay welding of some tubesheets under ASME VIII div 1 including ASME U stamp.
This supplier holds a ASME U stamp certification but subcontracted the overlay welding to a welding company also with U stamp...
Dear All,
Recently we received an order of an Air Cooled Cooler that is fabricated completely of Titanium.
This bundle is a replacement of an exact copy which was built several years ago by another fabricator.
The tubesheet is 25mm thick and the tubes haves a wallthickness of appr. 2,11mm, Dia...
Dear all,
I have a question about PED certification related to delivery of materials from example Asia to be used in pressure equipment were the PED is applicable.
Situation: We buy a complete machined forged tubesheet from an Asian company and use this in a heat exchanger were the PED is...
Dear All,
Can somebody help me to find the diagram that help me determine the needed cooling rate for duplex stainless steel (A182-F51), Like CCT or phase diagram? Showing melting temperature till room temperature. And can somebody also help me how to find a manner to calculate the needed...
Hello All,
Can somebody help me find the correct answer for my question.
What is the correct method for the use of welding symbols on drawing for ASME VIII div 1? Is this AWS D1.1?
Hoe about the size of fillet welds; is it standard to mention leg of throat?
I have seen some ASME design...
Hi Fellow members,
On a other forum http://www.eng-tips.com/viewthread.cfm?qid=311301 I have opened a thread because I wanted to know what the tolerances are according to TEMA standards. When answered I immediately got a new question, as below:
As producer of Shell and Tube Heat Exchangers we...
Hello,
Can somebody tell me if 9th edition TEMA standards describes tolerances of hole diameters in baffles for shell and tube heat exchangers? Meaning is their a maximum distance specified between tube and tube hole. I'm not an experienced STHE engineer but more experienced with Air Cooled...
Hello All,
I have a question about the holding time for PWHT of unalloyed carbon steel like (S)A-516-70. In the past I once have seen a procedure in which the holding time was miscalculated. As per ASME VIII div 1 UCS-56 is stated that the holding time is one hour per inch of the used material...
Hello All,
I have e question about the sequence and order of execution of pressure testing with paint according to PD5500.
In our company we have a design of a headerbox of an air cooled cooler that can only be hydrotested after applying paint. Otherwise we have to change the design and make a...
