The report may have been referring to what is now called austempering?
Normal quench into a fluid of 100-200°F of a hardenable steel produces a crystal structure called martensite.
Austempering is when the quench fluid starts at 450-750°F and produces a crystal structure called bainite...
Thank you for the time and temperature estimates. I am guessing both the top and bottom plates had the Al2O3 coating? How was the coating applied (would be nice if it were simple like painting it on)?
Thanks for the tip on vapor pressure, I will look that up.
We had an issue with (lack of)...
Hi Ed - Thank you for the process description, it looks like we would need some specialized fixturing if this customer wanted to work with us, and they would need to do any rolling themselves. Our vacuum furnaces usually run around 50 microns of pressure, which is roughly equivalent to hydrogen...
I work at a commercial heat treater with vacuum furnace equipment. We had a local manufacturer contact us to ask if we could sinter together nickel wire mesh sheets (product as described in this paper).
The manufacturer's current supplier sinters stainless steel sheets for him, but they have a...
Yes. My previous employer re-bricked one of their furnaces incorrectly and had thousands of pounds of wrong-hardness parts after.
Do you have a way to survey temperature in the furnace? If you can attached thermocouples to sample locations (usually 3 around the top, 3 around the bottom, and 1...
EdStainless - the material is carburized at 1700°F, normalized at 1900°, stress relieved at 1300°, hardened from 1900°F, sub-zero treated at -110°F for 2.5 hours, then tempered at 350°F. As far as the Cr, the part is copper plated over all the surfaces that need to maintain corrosion...
I work at a commercial heat treat company that has an opportunity to vacuum carburize CX13VDW material; we have never worked with this particular chemistry before.
We have established processes to carburize other stainless steels such as Pyrowear 675, and my first process was based on this...
Not sure if you plan on outsourcing the rehardening after the parts are straight. If you plan to do it in house, note that going back to the T6 state requires a solutioning furnace with a water quench tank.
Nitrocarburizing is a (comparatively) low-temperature process that results in a very shallow layer (~.005") on the surface becoming very hard (>60 HRC)
Carbonitriding is a higher temperature process (with the associated extra distortion) that results in a shallow layer (~.020") on the surface...
What type of treatment (stress relieve, through harden, case harden, etc.) are you looking at?
Also, what hardness or mechanical requirements must be met on the final product?
Kenneth - In addition to the blasting option, also consider treating one part at ~800°F for an hour or so in an air draw before carburizing. As I note in my earlier post, I've had success with this workaround and it has the advantage over blasting of less impact on the part appearance.
I've had this problem occur sporadically on certain parts over my heat treating career (~15 years) without satisfactory root cause determination.
It might be related to the surface finish.
Usually treating in an air draw at 700-1000° to develop an oxide layer prior to the carburizing process...
I appreciate all the comments, the conversation is very insightful.
I passed on to our customer that there is no current industry standard for "gun quality" and that any certifications to that effect are referencing a specific agreement between that mill and that purchaser. It sounds like, as...
Today I had a customer contact me asking if "regular" 8620 steel would respond to heat treat any differently than "gun quality" 8620 steel. I speculated that "gun quality" steel might have tighter alloy and cleanliness tolerances but for their application (a small part with a shallow case...
My previous experience has been consistent with EdStainless's statement: that with our hardness results the original age must have been too cold or too short. But in this case we run monthly TUS (±10°F) and weekly SAT on the aging furnace and are very confident the logged temperature of 900°F...
My company has aged at 900° for 1 hour some small pieces of 17-4 material (120 pieces of 1.9" long bolts that weigh 0.022 lb each). Our customer says these parts were machined from the same bar as the two previous orders we processed, where the hardness results were as expected.
On the current...
The white microstructure component is definitely ferrite by the shape.
Undissolved ferrite (from too low an austenitizing temperature or too short an austentitizing time) tends to be more blocky whereas quench ferrite (from the insufficient alloys in the steel to transform or from too slow of...
We ran the anneal cycle over the weekend, both on already annealed parts (but too hard for the end user's preference) and on parts that had been below spec and were hardened before the anneal.
All the annealed parts are 85-89 HRB. I've told the customer that is the closest we can get to the...
I work at a commercial heat treater, and have a customer with about a hundred cone rings (small ones - about 1/2 pound and 2-3 inches across) made of 52100 material. The end user is going to press fit these parts and wants them a particular hardness for best conformance to the press fit...
