United States - 11/22/2019 (PRDistribution.com)
ST. LOUIS, MO - Paulo’s new hot isostatic press (HIP) is ready for service.
The HIP unit, a Quintus model QIH 122, was installed in Paulo’s expanded Cleveland Division earlier this year.
In hot isostatic pressing, parts are subjected to intense pressure and high heat. While the process was originally developed as a diffusion bonding technique, it’s an ideal method for densifying and eliminating porosity in cast or additive manufactured parts.
Customer orders can now be accepted following the successful completion of a battery of pre-production tests conducted this fall.
Intensive pre-production testing
The critical testing we conducted included making a detailed survey of dozens of process variables to help us fully understand what our HIP equipment is capable of.
This investigation was critical to helping us identify new opportunities for customers in sectors where HIP has made an important impact, including:
Below is a rundown of some of the tests we did, why we did them and what we learned.
Full-temp, full-pressure test
We did this test to verify the HIP unit could meet specs promised by the manufacturer. With the furnace fixtures we had on hand, we reached a maximum temperature of 2,282 F (1250 C). We’ll eventually be able to process at 2,480 F (1360 C) once updated fixtures are integrated.
The maximum pressure achieved was 30 ksi. That’s 30,000 pounds per square inch, or about 2,000 times the normal atmospheric pressure at sea level.
The goal during the quench portion of the test was to verify the vessel could cool at a rate of 360 F (200 C) per minute. This benchmark was met.
Temperature uniformity test
Temperature uniformity is critical to meeting requirements under SAE’s AMS2750 aerospace thermal processing equipment standard.
The test was composed of several cycles. Each cycle ran at a set pressure while the temperature was gradually increased. Temperature readings were taken from sensors placed in different parts of the chamber in 600 F (333 C) intervals.
We tested from 7 ksi up to the 30 ksi maximum. We started at 700 F (370 C) and climbed up to 2,282 F (1250 C) in each test.
In every condition we measured, we observed variations no greater than ±10 F. That’s an exceptional reading. We’re aware of competing HIP vessels that see temperature variations approaching ±50 F.
Maximum quench rate
In an earlier test, we verified the furnace could quench at 360 F (200 C) per minute. But specifications can stray quite a bit from that benchmark. The most impressive rate we observed was a staggering 900 F (500 C) per minute.
The only way to achieve that rate is if there are very few parts in the vessel. A full vessel has too much thermal mass to cool that quickly.
The testing described above ensured our HIP unit and its operators were ready to process customer orders, but there’s more we want to know. We’re running the tests listed below on an ongoing basis.
Testing thermocouples on parts – We know that because of the high-pressure environment inside a HIP vessel, thermal conductivity is very good. One of the benefits of HIP equipment is its ability to also solution treat parts. Comparing data from temperature sensors in the vessel to data from thermocouples on parts helps us determine just how wide an array of parts can be solution treated in addition to being HIP’ed.
Gas cleanliness – The argon used to pressurize HIP vessels is expensive. To reduce costs, we intend to recycle as much of it as we can. With the help of the gas chromatograph we’ve installed, we can more precisely gauge when it’s time to swap out old gas for new.
More about Paulo
Based in St. Louis, MO, Paulo provides advanced thermal processing for manufacturers in aerospace, automotive, power generation, medical, oil & gas, tool & die, firearms and other sectors.
Among Paulo’s locations are five plants strategically located in the U.S. as well as a new facility in Monterrey, Mexico.