Metal Talk Archives
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Is Inconel® 625 the same as Nickel 625?

The answer, not surprisingly, is yes and no. The chemistry, mechanical properties, and range of uses are within the same standards of quality, but Inconel® is a trademark that can only be used by one mill-Special Metals Corporation.

There's still some confusion among buyers, engineers, and machinists when it comes to superalloy grades. Why does the print say Inconel® 600 and the mill test reports refer to it as Nickel 600 or "ATI"® 600? Can one be substituted for the other? The answer to this is a definite yes. ASTM and AMS specifications guide the manufacturing of these high performance alloys. Reputable mills make absolute sure that the material they produce meets these strict standards. What's important in the name is not what comes before the alloy number, but the alloy number itself.

Why the Names?

Most of the high temp alloys were formulated after 1940 to support the high demands of aerospace engines. Jets needed to become more powerful, reliable, and durable. This required machined metal parts that surpassed the current technology. The nickel superalloys were developed to stand up to high pressure, highly corrosive, and high kinetic energy uses. The mills that developed these alloys trademarked them when granted their patents. Those trademarked names are still commonly used today, even though the patents have long expired.

Confusion and concessions

Your print might still say Inconel® and not Nickel. Airplanes last a long time. The end user can be slow to change the language used to purchase accepted components. Alloys can be referred to by the old trademarks out of habit.

All that can cause a problem, especially in Department of Defense contracts. The DOD contractor will often have to get a customer concession on the alloy name. For example, Inconel® 625, by that trademark, is not available in the metal distribution network. The name is currently owned by Special Metals Corporation, and they will only produce the alloy as a mill run quantity of 2000 lbs minimum. If you need less than that, like most machine shops we deal with do, you have to buy from a metal distribution center. We may or may not buy the product from Special Metals. More often than not material comes from a mill like Allegheny or Allvac. The same holds true for the Hastelloy® trademarks owned by Haynes International.

End Results

Vincent, and most other distributors, quote to generic names like "Nickel 400" instead of "Monel® 400", or "Alloy C-276" instead of "Hastelloy® C-276". We do this because the patents are no longer in effect on these high performance nickel alloys. We might be stocking nickel alloy rod made by any one of the high quality, tightly controlled DFARS-compliant mills that roll equally good product.

What really matters is that the material in the supply chain, the material that goes into products that have a huge impact on all our lives, are made to the highest standards of quality. And that they are mill tested and certified to accepted internationally recognized specifications.


All Trademarks are held by their respective owners

I've been in this business for awhile, but I still think of rain when I hear the phrase "Precipitation Hardened". I picture drops of some chemical raining down inside the heat treating furnace, magically changing the properties of the metal. I know I'm wrong, so what is precipitation hardening?

To begin to understand it, we first need to define a couple of terms:

Precipitate
A distinct solid mass created within another mass.
Crystal Lattice
The blueprint of how matter is repeated to form a crystal. My favorite explanation is found at the King's College website. I like it because not only is it very clearly written, but it has graphics from the beginning of the world wide web. It reminds me that we're learning about things that don't change.
Crystal Structure
What fills in the lattice. Again, hat's off to King's College and the page's author Professor Barbara Sauls for an easy to understand explanation.
Dislocation
An irregularity within the crystal lattice
Supersaturation:
When there is more of a substance in a solution than can be dissolved. This changes based on the temperature of the solution (in our case the bar of metal). This is commonly explained using rock candy.

Disclaimer!

I'm not a metallurgist or a scientist of any kind, so what I say should be taken with a precipitate of salt. There's a lot of very technical explanations out there if you're interested in that side of things.

So, here goes the simplest explanation I can come up with:

Dislocations create weak points within the structure, in our case the metal. If you reduce dislocations you make the metal stronger. Precipitation hardening does this in a three stage process.

Stage 1. Solution treatment:

First the metal is heated up to the point that things start dissolving and moving around. This is called the "solution" phase of the heat treatment. I used to think that the metal sat in a liquid solution, like in a bathtub, but the metal itself becomes the solution when it is heated.

Stage 2. Quenching:

The metal is brought down to room temperature relatively quickly, or "quenched". This forces a state of supersaturation. Sort of how like carbonation bubbles just waiting to blow out the top of your soda bottle when you open it.

Stage 3. Aging:

Reheating the metal to something in between the solution treatment temperature and the quenching temperature and letting it sit for awhile (the "aging" phase) gets everything moving again. Particles that don't have a place to fit (because supersaturated) start to find particles like themselves to join up with. The lump they make is a "precipitate".

Now the real fun starts. Where things would normally have the potential to break through the weak points in the lattice (the dislocations) these precipitates get in the way--like a bumper in a bumper pool table. A lot of times they bounce around long enough to create a new part of the lattice that doesn't have a dislocation. They become a part of a stronger crystal structure.

And that's what makes the precipitation hardened metal stronger.

 

Further Reading:

A more detailed, but still easy to understand, explanation can be found on Reddit, courtesy of user terevos2. Some really great graphics are included, including a youtube video that demonstrates dislocations within a crystal lattice. I highly recommend reading it for a short, but accurate understanding of the process.

M. Vincent & Associates is proud to have been awarded the "Oro" Supplier Award. The award was presented at Sandia National Laboratories Production Supplier Conference, 2009.

We are committed to maintaining our recognized quality standards to all of our customers.

M. Vincent & Associates presented with Sandia National Laboratories Oro Supplier award

Did you know that common magnesium alloys are one quarter the weight of steel, and two thirds that of aluminum?

They also machine 50% faster than aluminum, six times faster than steel, and seven times faster than titanium. But still magnesium alloys offer high strength.

Magnesium can be used as a tough but lightweight electromagnetic interference shield in laptop computers, cell phones, and hospital equipment.

It is also safely absorbed into the human body. Soon you may see magnesium alloys being used for repairing broken bones and other internal medical procedures.

And--magnesium is fully recyclable!

Give us a call for magnesium alloy sheet, plate, rod, and custom extruded shapes.

What is a machine ready blank?

A machine ready, custom cut and ground blank is time and effort saved. You determine what dimensions and tolerance that will best reduce set-up, milling and machining time for your most important jobs. You pass that need on to us. We deliver flat, square and parallel blanks you can load with the comfort of knowing every piece will be equal.

How is this achieved?

Through precision cutting, Blanchard grinding, double-disc grinding and/or duplex milling.

Why take on the extra up-front costs?

  1. Reduce premachining costs
  2. Free up machine operators to prepare for the next job.
  3. Use less experienced machinists to oversee jobs using our blanks, saving your top talent for the toughest jobs.
  4. Cut part production time, allowing you to make more parts, or move through jobs faster.
  5. Reduce liability and part loss based on clamping errors
  6. Save money in the long run.

puzzle

We can produce blanks out of most metal alloys we sell. Please use our general quote form to request more information or get a job quote.