Max. working temp / pressure of 4130 pipe?

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Hi all,I have been searching all night and I can't seem to find the answer. I was wondering if anyone had a reference for the maximum working temperature for 4130 pipe. My application is low pressure and high temperature (650 degrees F). If anyone has a link to a reference for this, I'd greatly appreciate it.Thanks in advance
Reply:I found this on 4130 not sure if it'll help  ... Highest tempering temperature i see on the chart is 1200 degrees Fahrenheit there's a chart if you scroll down a bithttp://www.pacificalloys.com/4130_ba...loy_steel.htmlLast edited by aav1996; 02-28-2013 at 08:07 PM.
Reply:Well, pressure will be dictated by the wall thickness of the material. If it's pipe, it will have a rating for pressure. If it's tube, it might not. But, suffice to say, seamless 4130 is very strong, and has good working temps and pressure capability. Also, remember that heat MAKES pressure- so, if the system runs a fluid at say 20PSI at 650 degrees......... and the system stops and is sealed/ not vented or relieved, that pressure inside WILL rise as the temp is constant without material movement or venting.And then, when the heat rises and in turn builds pressure, you need to start looking for which way is the nearest exit........And then, after so much work...... you have it in your hand, and you look over to your side...... and the runner has run off. Leaving you holding the prize, wondering when the runner will return.
Reply:It is a little tough sometimes to get strength data at temperature.  My metallurgist buddy says that mild steel goes to half strength at about 600 degrees C.  Alloy steel should be better than that.  I assume that you meant 650F, which is not nearly as hot as 600 C, so the steel would lose less than half its strength at 650F.  You said low pressure.  Just make sure that the pipe is rated for, say, double the expected pressure.   As others have said, one has to consider the possibility of temperature or a malfunction causing an increase in pressure.   A well designed system would have some kind of overpressure relief system, and perhaps more sophisticated protection schemes.I have never seen 4130 pipe.  4130 tube is probably not rated for internal pressure, as it is generally used as a structural element.   Can you use tubing as pipe?  Probably, but I would be thinking of an additional safety factor to compensate for any unknowns.The other consideration is corrosion, which could reduce wall thickness and strength.  Beware of galvanic corrosion if you mix metals in any liquid environment.These are some of the engineering considerations that I might apply in this situation.RichardSculptures in copper and other metalshttp://www.fergusonsculpture.comSyncrowave 200 Millermatic 211Readywelder spoolgunHypertherm 600 plasma cutterThermal Arc GMS300 Victor OA torchHomemade Blacksmith propane forge
Reply:You need to be wary of embrittlement with alloy steels operating at high temperatures.  Some grades of material are extremely brittle within certain temperature ranges, after sitting at those temperatures, or when cycled up and down through certain temperature bands.I know you said this was low pressure, but that's not nearly enough information to make an informed decision about what's appropriate.  Not sure what the end result is, but you need to do a lot more research before you settle on 4130 steel for high temp pressure applications.There are special filler metals used for welding Cr-Mo steels that are used at high temperature.  You need to use and follow very specific welding procedures and post weld heat treatment procedures in order to achieve the right properties in the finished weldments.Suggest you consider if you really need to use Cr-Mo steel; or if you can get by with a material that's simpler to fabricate and for which there is plenty of high temperature performance data available.Benson's Mobile Welding - Dayton, OH metro area - AWS Certified Welding Inspector
Reply:Not enough info supplied.The only info you have supplied so far are "4130" and "650F" and "low pressure".What condition is the 4130 in?  Annealed, or normalized, quenched and tempered, what?650F, OK.  Constant, temperature cycling, what?'Low pressure' is not enough info.  5 psi, 50 psi, 500 psi, 5000 psi, what?Pressure rating of a 'pipe' depends on the material, and the condition of the material, and the wall thickness, and the diameter, and the temperature.  Add in the material in the 'pipe' and any corrosion issues there.  Account for any pressure spikes or surges.  Etc, etc.If the application is in any way "critical", get a licensed Professional Engineer involved.  Temperature and 'pressure vessel' is one of the reasons that there are safety codes and Professional Engineers around.  Because back in the late 1800's to early 1900's, there were many catastrophic boiler (pressure vessel) failures with property damage and injuries and fatalities every year (one example: March 20, 1905, Grover Shoe factory in Brockton, Mass. Boiler failure and explosion and resultant fire  killed 58 and injured 150.  The explosion and resultant fire leveled the factory. The boiler went through three floors of the factory (vertically), knocked over a water tower which fell onto the factory and further collapsed it.  Flammable solvents, natural gas, and coals from the boiler all added to the fire and damage.  The boiler flew vertically through the factory and ended up going over 200 ft away, where it smashed into the house of Mary Pratt and knocked the house off its foundation.http://en.wikipedia.org/wiki/Grover_...ctory_disaster  )   Between 1880-1890, there were over 2000 boiler explosions in the US alone. 159 boiler explosions listed for 1880 in the US.ASME founded in 1880.  Massachusetts enacts boiler code requirements in 1907.  The best laid schemes ... Gang oft agley ...
Reply:Mr. MoonRise gives a good answer.  Best to consult a PE, who will in turn consult this code:https://law.resource.org/pub/us/code...b31.1.2007.pdf(assuming it's steam and not chemicals)
Reply:We use either Stainless or Inconel for our test set ups here at my work.  Some test set ups are 1200 degrees, and flow air at 1200psi.  I'm a test technician for an aerospace company here in Arizona, and have been dealing with this stuff for 27+ years now.    What is fun to watch is what liquid nitrogen does to a 12" dia pipe that is about 40' long.---No good deed goes unpunished---
Reply:Thank you all so much for the replies and the help. I greatly appreciate it. After doing a lot more research, I decided to use P-5 pipe for my application. which is chrome-moly, but not 4130 per se. It does exceed the temperature / pressure requirements.Again,I greatly appreciate all of your help.