About the Pump Shaft Material Selection In Boiler Water Pump

[Jackelmo]

As per the API 610 standard Table H.1 material class for pump parts, for boil water shaft, it is recommended in S-6 to use the 12% chrome steel.
Due to the urgent need from our customer, I would like to use the 42CrV6 (carbon alloy SAE6140)instead of the martensitic A276 S42000 to make the new shaft. But I am worried about the corrosion problem will happened later. what about your opinion?
Thanks.

 

[Artisi]

If it's that urgent use the closest material available and schedule a change out some time into the future and fit a shaft of the correct material.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

 

[Jackelmo]

I want to persuade our customers to use 42CrV6 material shaft permanently.And I would like to know why the API610 standards require the 12% chrome steel in the boil water pump.

 

[EdStainless]

What type of guarantee are you willing to offer?
Especially if the new 'permanently' is much shorter than the original life.
This material selection is based on long and hard gained experience.
There are a number of other alloys much closer to 420 that should be considered first.

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P.E. Metallurgy, consulting work welcomed

 

[JJPellin]

The corrosive nature of boiled feed water depends on many variables. Has it been deaerated? Has it been chemically treated? What residual oxygen is present? Other factors should be reconsidered. What is the metallurgy of the impeller(s)? What is the operating temperature?

Johnny Pellin

 

[MJCronin]

I believe that we are at the point where it would be wise to call in an experienced pump consultant, pay his fee and take his advice..

IMHO, it would be money well spent, despite what your MBA boss may tell you

Boiler Feed pumps are dangerous and very expensive .... BFP failure can mean a forced outage

I would not trust the musings of a bunch of elderly strangers on the internet ....

MJCronin
Sr. Process Engineer

 

[Jackelmo]

Thanks all.

The impeller material for the pump is CA6NM and the medium is well deaerated in power plant. The temperature for medium is about 175 degree.
After discussed with our custumers, they consider the 42CrV is carbon alloy and the CA6NM is stainless material. There is the ferrite contamination problem.
So we decide to order the martensitic A276 S42000 for the new pump shaft and fullfill the API requirement.

 

[MJCronin]

Jackelmo ..

Thank you for completing this thread and helping out ENG-TIPS ...

Thread completion and the respect for technical participants is not often done around here ....

Best Regards and GOOD LUCK !!!

MJCronin
Sr. Process Engineer

 

[BSMEclassof2012]

Jackelmo:

A very common shaft material (and the one we always use) for boiler feed pumps is 410 SST Cond T. This may be cheaper and readily available than the one you are considering (A276 S42000). In case you haven't bought your shaft material, you can get a quote for 410 SST Cond T. Just my 2 cents! Good luck!