×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

Slurry pump impeller casting

Slurry pump impeller casting

Slurry pump impeller casting

(OP)
This question is about manufacture of high chrome dredger pump impeller casting.

I have received a customer's casting with no drawing for reengineering.

The casing is a simple job, but with the impeller I have a challenge.

Normally, the internal threads for engaging the shaft, is machined on a in situ cast mild steel insert or a cast thread using ceramic cores.

In this case, there is a mild steel insert used with a cap/flange on top.

Normally, there exists a vertical split in the insert during casting ( a "C" section), so that while the casting cools, this insert also closes, like a spring, thus avoiding cracking.

But, I am seeing an insert, without this slot, I am stumped.

Look for some insights or tips about manufacturing such castings.

The casting weighs about 1160 kilos and the material is high chrome iron.

Thanks in anticipation.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Slurry pump impeller casting

Just a random thought, if the shaft / impeller is threaded right hand, think about cutting a coarse thread left hand on the outside of the insert with the insert cast into the impeller.

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.)

RE: Slurry pump impeller casting

We used to machine flutes into the OD of the inserts, and made sure that there were no square corners.
We also made sure that the inserts were hot (usually by making sure that molten metal flowed over them.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Slurry pump impeller casting

(OP)
Is the insert cryo fit (liquid Nitrogen)? I am leaning towards that idea?

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Slurry pump impeller casting

I hesitate to shrink fit the steel, Ni-Hard does not like being under tensile stress.
This is a large casting, you could almost make the steal insert in two pieces.
Cast in a fairly thin wall part, then mechanically insert the thicker threaded one.

= = = = = = = = = = = = = = = = = = = =
P.E. Metallurgy, Plymouth Tube

RE: Slurry pump impeller casting

(OP)
EdStainless,

Thanks, and that is how I have been manufacturing impellers. Though a few have moved away from cast inserts, by having ceramic cores with threads. Thus the bore would have cast threads and they are just cleaned on a lathe.

I pursued this technology, but failed , and then gave up as business moved away.

Now, once again after 20 years, I see an impeller that has a whole insert!!. I was stumped.

"Even,if you are a minority of one, truth is the truth."

Mahatma Gandhi.

RE: Slurry pump impeller casting

arunmrao, I should have added "and machine the impeller hub internal thread after casting"

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.)

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources

White Paper - Effects of AIA Quick Guide to UL 489 or UL 1077
The function of a circuit breaker is to provide overload (thermal) and short-circuit (magnetic) protection to a circuit and its downstream components. A circuit breaker functions like an airbag in a car, protecting circuit components and people by tripping the circuit to interrupt the current flow if it detects a fault condition in the control system. Download Now
White Paper - Guide to Integrate Large-Format Additive
As with any new technology, getting into large-format 3D printing begins with investigation. The first question may be a simple one: what does “large-format” mean? For 3D printers, “large” is a relative term. Many extrusion-based (FFF) 3D printers are referred to as desktop machines, because they fit on table space. Some of these have very respectable build volumes – but when it comes to “large-format,” the machines will need their own dedicated floor space. Large-format 3D printers have significant build volumes and are most often found in professional settings, like manufacturing facilities and R&D centers. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close