Hey what’s up guys! This is Michael from Michlin Metals and guess what today is? INCONEL DAY!!!! Today we’re going to talk about Inconel. However, before we get into it, I think it’s time we talk about you….SUBSCRIBING! Hit that little MMI button right here. If not, how about a quick thumbs up? Either way, I am grateful for you watching! Let’s get into it!

Todays’ video introduces you to the family of alloys that carry the Inconel name….Inconel is a trade name of Special Metals Corporation. Other metal producers of generic material cannot use the Inconel trademark. Five of the more popular of the Inconel family are Inconel Alloy 600,  601, 625, 718, and X-750.  The first three are not hardenable by heat treatment.  The others are grades that can be strengthened by ” Precipitation Hardening” heat treatment.

Nickel and Chromium are the major elements of these alloys and they have strength, corrosion and oxidation resistance over a wide range of temperature and environments.

This family of alloys finds numerous uses in chemical processing equipment as well as many high temperature applications requiring resistance to oxidation such as furnace fixtures and retorts. Inconel alloys are found in aerospace applications including jet and rocket engine components.

Special versions are found in Nuclear reactor components.

Inconel 600 UNS designation N06600 has a minimum  of 72%Ni  (plus cobalt).

As we noted in our earlier videos, these two metals are metallurgically similar and are considered as one element in this composition. Cr is 14 to 17% and Fe 6 to 19 % of this alloy.  Carbon is restricted to a maximum of point 15%, Manganese to a maximum of  1.0 %, Sulfur to a maximum of point 015 % ,  Si and Cu to a maximum of  point 50 % each.

This alloy is not hardenable by heat treatment.

Inconel 601 UNS designation N06601 has increased high  temperature oxidation resistance due to an increase in Cr content to 21 to 25% and 1.0 to 1.7% Al.  Ni (plus Co) is 58-63%.  C maximum is point 10, S point 015 % maximum, Si point 50 % maximum,  Mn and Cu are each 1.0% maximum. The remainder is Fe.

This alloy is also not hardenable by heat treatment.

Inconel 625 UNS N06625 is used for higher strength applications. It is strengthened by the addition of Mo (Molybdenum) and Cb (Niobium). Mo also contributes to resistance to corrosion and high temperature oxidation.  Composition is 58% min Ni (plus Cobalt), 20 to 23% Cr, 8 to 10% Mo, and 3.15 % to 4.15 % Niobium (Cb) (plus Ta (Tantalum)).   In this application the elements Niobium (Cb) and Tantalum (Ta) are considered one element of the composition. Restricted elements are allowed to a maximum %….. Fe 5.0%, Carbon point 10%, Manganese point 50% ,Si point 50%, Al point 40%, Ti point 40%, Phosphorous (P) point 015% and Sulfur point 015%.

Some specifications restrict any Co present to a maximum of 1.0 %

This alloy is not hardenable by heat treatment.

Inconel 718 UNS N07718 is a high strength alloy with useful properties from minus 423 to 1300 degrees F. Composition requires 50 to 55% Ni (plus Co),17 to 21% Cr, 4.75 to 5.50% Niobium + Tantalum Cb(plus Ta), 2.80 to 3.30% Mo, point 65 to 1.15% Ti, and point 20 to point 80% Al.

Restricted elements and the maximum  of each allowed are  C point 08 %, Mn point 35%, Si point 35%, P point 015%, S point 015%, Boron point 006% Cu point 30%, and Co 1.0%.   Fe is considered to be the remainder. This alloy can be precipitation hardened. Solution treatment is typically between 1750 and 1950 deg F  followed by an ageing treatment at 1325 deg  for 8 hours with slow cooling to 1150 deg F and holding for 8 hours.

Inconel  X-750  UNS N07750 composition is 70% minimum Nickel (plus Cobalt), 14 to 17 % Cr, 5 to 9 % Fe, 2.25 to 2.75 % Ti, point 4 to point 7% Al, and point 7 to 1.20% Niobium + Tantalum Cb (plus Ta) . Restricted elements are Mn  to 1.0 % , Si  to point 5%,Cu to point 5 %, Sulfur to point 01 %, Carbon to point 08 % and Cobalt to 1.0 %

This alloy responds to precipitation heat treatments, typically in three steps. Solution heat treatment is accompanied by an intermediate ageing , followed by final ageing. Times and temperatures depend on the properties for the specific application.

Remember these are complex materials and specifications can modify the basic material compositions as well as determine the product form, thermal condition, and test requirements.  So as we always say  Check the Specs!

Thanks for watching, and if you made it this far, you obviously like metal! You like information about METAL, and if that’s the case, just click right here and subscribe so you won’t miss any more of my videos. If you have missed previous videos (and I’m not sure how) click here. Thanks for tuning in, this is Michael with Michlin Metals. I’m out!