I am using a 9cr1Mo alloy steel pipe and that is the dilemna of going for the next higher diameter which will have cost implications. We have never bothered about surface roughness till one of our pipe manufacturers came up with the option of a better surface finish, that poses the question what...
Thanks katmar for your frank comments. I have a situation in hand where I have worked out dropfor various roughness factors. My vendor has now come up with an option of a better surface finish at a higher cost. That is now prompting me to raise this question. I am at the border of my pressure...
Can somebody please tell me what is the normal surface finish expected of a pipe as per good industrial practice. Some vendors extrude pipes and give without machining ID while others machine the ID and give good finish based on the manufacturing process.I am talking about high wall thickness...
Vendors are giving surface finish of Internal dia ranging from 6.4 Micron (Ra) - 250 RMS to 15 Micron (Ra) - 500 RMS
My doubt is whether the surface finish given by Pipe vendors can be treated equivalent to a hydraulic roughness of 0.05 mm as specified in CRANE Handbook, or should I take a...
For pressure drop calculations, Crane's Handbook and many software give the absolute roughness of Pipes as 0.05 mm for clean commercial steel pipes
What is the surface finish (RMS or Ra) to be specified to the pipe manufacturer to attain the above absolute roughness.
Is there any correlation...
I came across a literature that FRITZCHE formula is more appropriate for Superheated steam lines than the conventional Crane or Darcy formulae for pressure loss in Piping.
Can this formula be used for sizing piping in a Power Plant like Main Steam Piping, Reheat Piping
How is the pressure loss in Main steam piping assumed while fixing the Boiler Super heater outlet pressure, to start with the initial fixing of parameters. Is it expressed as a percentage of HP Turbine inlet pressure.
I have seen in some Power Plant engineering books that 5% of Turbine inlet...
For one of our projects for an EQUAL TEE OF SA234WP91 material, with 20" OD and thickness of 4 ", Vendor has proposed a block forged and machined tee instead of formed one
1. Above what thickness can we accept Forged tees instead of Formed, and are there any disadvantages associated with it ...
Thanks for your valuable comments
For a Supercritical unit with a Main steam pressure of 270 bar and temperature of 573 deg C, an F91 Y-Piece of Seamless Forged construction has a crotch thickness of nearly 210 mm, where as a Spherical Welded Y-Piece has a maximum thickness of only 125 mm...
I am attaching the pictures of the two wye pieces for your understanding (courtesy MEGA fitting)
The left side Y-Piece (larger one) is a spherical Y-Piece which is of welded construction widely used in Germany and Europe. Design is done mostly based on German TRD-301
The right side Y-Piece...
If you plan to do Dynamic analysis of piping , also find a compatible software with your Piping Stress Analysis software to facilitate seamless linking
EN 13480-3 piping code that Cylindrical Y-Pieces (Seamless) are not recommended in High temperature creep lines
One of the reason could be that forged and machined Y-Pieces have very high thickness in the crotch area (almost three to four times) compared to spherical welded Wye pieces. This can...
