Castable steel to weld to SA-213-T11

[johntrhodes81]

Would anyone care to recommend a steel for casting parts that will be welded to SA-213-T11 seamless pressure pipe and have simmilar properties? This is for casting return bends on a locomotive superheater setup. The pressure is 310PSI and the maximum temperature is 850F. This temperature is a little hot for SA-178 boiler tube which should stay under 700-800F.

Thanks for the recommendations.
John R.

 

[metengr]

ASME SA 217 WC9.

 

[johntrhodes81]

Thanks. What temperature is SA 217 WC9 rate for in a pressure application? I saw 1,100F in one resource.

I have seen some return bends made of SA-216 WCA but I think it is best to keep them below 800F. Opinions?

Thanks much. I really appreciate it.
John R.

 

[arunmrao]

johntrhodes
your reference to WC9 - 1100F is correct.

@metengr,
Why would you select WC9 over WC6 please?

_____________________________________
"It's better to die standing than live your whole life on the knees" by Peter Mayle in his book A Good Year

 

[metengr]

arun;
In my experience with boilers and pressure vessels for pressure-retaining material on gas touched surfaces, I found WC9 is more suitable, available (sometimes lower cost) and has better creep design margin (higher Mo) for elevated temperature service in comparison to WC6. I limit both T11/P11 wrought products and the cast version of WC6 to 900 deg F.

 

[johntrhodes81]

Group,

I had another engineer friend recommend using:
SA-217-WC6 or SA-217-WC11 with SA-213-T11 and
SA-217-WC9 with SA-213-T22.

Said those pairs of metals were more similar in composition. Any opinions?

Thanks, John R.

 

[metengr]

johntrhodes81;
You can use the SA 217 WC6 to pair with T11. However, you will not have the added margin with service temperature as you would with WC9 material. There is no requirement where T11 must be paired with WC6. I prefer having the non-pressure part material be slightly more rugged in design, thus my rationale for recommending WC9 versus WC6.

 

[johntrhodes81]

OK, Got it no SA-217-WC6. Also you don't suggest WC11 either?

You said non-pressure. Actually the return bends are basically cast 180 degree pipe fittings usually with the outside radius side thickened and tapered. As you may know a Locomotive Type "E" superheater setup consists of 2 superheater elements connected by a return bend inside of a fire tube. The return bend experiences full boiler pressure, 310 PSI in this case, and also extreme temperatures. The return bends are only inches from the furnace/firebox. If steam flow is cutoff abruptly in can take a period of time for the furnace temperature to reduce so the return bends take the brunt of the temperature. Also they can be effected by abrasion since they are the first thing that is in the flow of combustion gases and any unburned fuel particles present.

Sorry I didn't go into more explanation at the beginning. Not sure if this changes anything.
John R.

 

[metengr]

Based on the additional information, I would still use WC9 for the bends.

 

[johntrhodes81]

Thanks, I appreciate it.
John R.