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I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

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Peter Ditzel
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I don't know for sure but I have to imagine it's a corrosion concern. High UTS in 304 could signify that maybe there's some residual stress or cold work (from cooling off the solution, solution cycle not being held long enough, etc.) that could impact corrosion resistance. This is also implied by the fact that AMS 5511 is for 304L (with the lower carbon facilitating welding by protecting against sensitization) and it has you do an ASTM A262 test. That said, I would bet that 100k was chosen as a neat round number rather than because it's a true inflection point where all of the sudden the material starts experiencing corrosion failures in service. Unless your application is particularly aggressive where you don't feel this would be prudent or justifiable, I feel like you could accept it on the basis that it's only 2ksi over, which as you mentioned might be explained by normal variation on a tensile test (E8 reports the reproducibility as 1.3% but I would take this as a grain of salt given that it was determined in optimal conditions, plus in your case the MTR reported 98ksi). Even little things like whether the tensile specimen was well-centered in the grips, or whether the technician measures the diameter of the specimen accurately (i.e. .250" vs. .251"), can bias the result by 1-2ksi (yield is generally more variable than UTS because the elastic region isn't always perfectly linear and that can affect the slope of the 0.2% offset line but still). Of course, this variation could just stem from heterogeneity in the material itself, rather than the testing parameters, but suffice it to say it isn't a resounding failure. If you're worried about it, you could re-heat treat the material or just take another 2-3 tensiles from the product and run a retest.

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

This is an interesting topic.  I always wondered the technical necessity of a cap on UTS, which sometimes causes compliance difficulties to users.  Has there been any incident that a structure failed sole because UTS was too high?  When a structure failed and it was also high in UTS, did the material have sufficient ductility and/or toughness?  If appropriate ductility, and if necessary also toughness, are required, is there any benefit/reason of capped UTS?

Shelly Tang

Lead Principal Metallurgical Engineer

Swagelok

Solon, OH 44139

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I work in extruded aluminum and have a few customers that are working with automotive crash management systems (bumpers, crash cans, side sill, etc.). They frequently have upper limits on strength to control the order and nature of the crumpling/energy absorption. You want a component that has a lot of strength and ductility in order to maximize energy absorption. However, if the part is too strong, it won't begin to fail/crumple and will instead transfer the forces farther into the system. Reducing the effectiveness of the system.

This is an interesting topic.  I always wondered the technical necessity of a cap on UTS, which sometimes causes compliance difficulties to users.  Has there been any incident that a structure failed sole because UTS was too high?  When a structure failed and it was also high in UTS, did the material have sufficient ductility and/or toughness?  If appropriate ductility, and if necessary also toughness, are required, is there any benefit/reason of capped UTS?

Shelly Tang

Lead Principal Metallurgical Engineer

Swagelok

Solon, OH 44139

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

Thanks, David, for your insights.  That seems to be a reasonable cause.  Then I wonder, in that case shouldn't the cap be on yield strength, instead of UTS?  

I work in extruded aluminum and have a few customers that are working with automotive crash management systems (bumpers, crash cans, side sill, etc.). They frequently have upper limits on strength to control the order and nature of the crumpling/energy absorption. You want a component that has a lot of strength and ductility in order to maximize energy absorption. However, if the part is too strong, it won't begin to fail/crumple and will instead transfer the forces farther into the system. Reducing the effectiveness of the system.

This is an interesting topic.  I always wondered the technical necessity of a cap on UTS, which sometimes causes compliance difficulties to users.  Has there been any incident that a structure failed sole because UTS was too high?  When a structure failed and it was also high in UTS, did the material have sufficient ductility and/or toughness?  If appropriate ductility, and if necessary also toughness, are required, is there any benefit/reason of capped UTS?

Shelly Tang

Lead Principal Metallurgical Engineer

Swagelok

Solon, OH 44139

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I don't know AMS 5511 at all, but the possible reason for the upper limit is related to the product being produced from this material. There may be a reason that they don't want the parts to be too strong. Which is to say they want "this" part to fail before another part will fail. 

I work in extruded aluminum and have a few customers that are working with automotive crash management systems (bumpers, crash cans, side sill, etc.). They frequently have upper limits on strength to control the order and nature of the crumpling/energy absorption. You want a component that has a lot of strength and ductility in order to maximize energy absorption. However, if the part is too strong, it won't begin to fail/crumple and will instead transfer the forces farther into the system. Reducing the effectiveness of the system.

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I don't know AMS 5511 at all, but the possible reason for the upper limit is related to the product being produced from this material. There may be a reason that they don't want the parts to be too strong. Which is to say they want "this" part to fail before another part will fail. 

I work in extruded aluminum and have a few customers that are working with automotive crash management systems (bumpers, crash cans, side sill, etc.). They frequently have upper limits on strength to control the order and nature of the crumpling/energy absorption. You want a component that has a lot of strength and ductility in order to maximize energy absorption. However, if the part is too strong, it won't begin to fail/crumple and will instead transfer the forces farther into the system. Reducing the effectiveness of the system.

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------

I recently had some material that was supplied and certified to AMS 5511 fail 3rd party tensile testing.  AMS 5511 specifies "Tensile Strength, maximum  100 ksi", the 3rd party testing showed 102 ksi. The mill certification shows 98 ksi.  Both test reports showed the material exceeding the ductility requirements. While I think that this is probably in the noise for tensile testing, I am looking for a basis to buy off the material. I don't see a specific orientation listed for the tensiles.

Now the question -   I am wondering why the tensile limit?  Is there a corrosion concern?  I have seen 304L exceed 100 ksi UTS on several occasions and on different product forms. I reviewed similar AMS and other standards and do not see a tensile maximum, so this seems to be unique to AMS 5511. I recognize that sometimes standards made by committees have compromises in them, just trying to understand if there might be an underlying metallurgical concern.

------------------------------
Peter Ditzel
------------------------------