In December 2017, SAE released an updated and much-needed version of AMS 6931. Before we dig into some major changes in AMS 6931D, let’s take a look at where AMS 6931C left off.

AMS 6931 is a specification for titanium bar, forgings, and forging stock. AMS 6931 is specific to the 6AL-4V alloy.

AMS 6931C covered products up to 6” in diameter or least distance between parallel sides. However, it is commonly requested for products larger than 6” to be certified to AMS 6931. Since larger sizes were not specifically covered in the specification, AMS 6931C left it up to the purchaser and producer to determine what mechanical requirements could be satisfied for any products outside of the range identified in the specification. Usually manufacturers interpreted this as either (1) product manufactured in a size outside of the range of AMS 6931C would be manufactured to meet the properties of the largest size that is covered, or (2) since there are no specific requirements for products outside of the range of the specification, test results would be for information only, and not cause for rejection.

AMS 6931D recognizes that purchasers and end users are looking for assurances of what mechanical properties can be achieved in larger section sizes, by extending the coverage to 10” in diameter or least distance between parallel sides.  Also, while AMS 6931C defined properties for products with a maximum cross-section of 48 square inches, AMS 6931D extends to 79 square inches.  This allows titanium AMS 6931D products in this extended range to be certified without a “for information only” caveat; we now have firm requirements. For products larger than 10” diameter or least distance between parallel sides, and beyond a 79 square inch cross-section, the spec still does mandate the purchaser and producer to agree on the properties. [Read more…]

In December 2017, SAE released an updated and much-needed version of AMS 4928. Before we dig into some major changes in AMS 4928W, let’s take a look at where AMS 4928V left off.

AMS 4928 is a specification for titanium bar, wire, forgings, flash-welded rings, and drawn shapes. AMS 4928 is specific to the 6AL-4V alloy.

AMS 4928V covered products up to 6” in diameter or least distance between parallel sides. However, it is commonly requested for products larger than 6” to be certified to AMS 4928. Since larger sizes were not specifically covered in the specification, AMS 4928V left it up to the purchaser and producer to determine what mechanical requirements could be satisfied for any products outside of the range identified in the specification. Usually manufacturers interpreted this as either (1) product manufactured in a size outside of the range of AMS 4928V would be manufactured to meet the properties of the largest size that is covered, or (2) since there are no specific requirements for products outside of the range of the specification, test results would be for information only, and not cause for rejection.

AMS 4928W recognizes that purchasers and end users are looking for assurances of what mechanical properties can be achieved in larger section sizes, by extending the coverage to 10” in diameter or least distance between parallel sides.  This allows titanium AMS 4928W products in this extended range to be certified without a “for information only” caveat; we now have firm requirements. For products larger than 10” diameter or least distance between parallel sides, the spec still does mandate the purchaser and producer to agree on the properties. [Read more…]

MIL-T-9047 is a classic titanium specification covering aircraft quality Titanium and Titanium Alloy Bars (Rolled or Forged) and Reforging Stock.  It was cancelled in 2005 but it is so ingrained in the titanium industry, it seems it will never truly go away. This specification tends to be confusing to users, because it covers so many different types of titanium and different conditions. Rather than calling out an alloy, an old drawing may call out just a Type or a Composition.  We hope the following table will aid you in procuring the right type of titanium for your requirements.

The above table appears in the back of MIL-T-9047G (available for free download at http://quicksearch.dla.mil/qsSearch.aspx), but we like our version better. If you agree, you are welcome to email us at sales@performancetitanium.com and we will gladly share a copy.

Specification MIL-T-9047 was cancelled in February 2005. The last active revision was “G”. In the cancellation notice, future acquisition was directed to SAE AMS-T-9047, which is also now cancelled. If your contract requires use of the superseding specification, refer to this discussion for help.

Since the MIL-T-9047 specification has been used for decades, often times a drawing will call out an old Composition such as MIL-T-9047 Comp 6. Using the table above, we can determine that Comp. 6 is related to the alloy 6Al-4V, and the drawing is pulling from an older revision of the specification, either Revision D or F. It is unusual to procure material whose certifications will still use these older revisions, types and compositions. The certs will most likely display this alloy as 6AL-4V, MIL-T-9047G (the most recent revision of the cancelled specification).  Check with your Sales Rep if you have questions or reach us at Sales@performancetitanium.com.