Drawing note with quotes

[Dale_Youngs]

I have an old drawing with a note that specifies the heat treatment of the part. Part of the information is in quotes - "H900". Does anyone know what quotes mean in a drawing note?

 

[mfgenggear]

Op
Is there an other note that specifies heat treat spec.

 

[Dale_Youngs]

The problem is the rest of the note gives some conflicting requirements in a hardness range and a BAC spec. I cant find any interpretation of quotes in a note that would indicate it would be reference or guidance, but I suspect it was the intent. The problem is that the drawing is so old I cant ask what the intent was.

 

[mfgenggear]

Op
The spec must specify the heat treatment and hardness. Regardless
If it is old ask customer engineering to clarify. Do not guess.
Parenthesis is reference. I believe it was on an old military spec.

 

[Dale_Youngs]

Thanks, just wanted to make sure I wasnt missing an old convention.

 

[WKTaylor]

Poster is seriously skimpy on info.

Obviously H900 is SStl PHT. There should be a general note or reference on the drawing to a Boeing spec of some kind... in the PL or general notes or 'stock-printed' block somewhere on the drawing face.

WHAT SStl Material/alloy?

/NOTE/ from my days working for USAF: if this is an old Boeing drawing, there may be areas that are illegible... might have to request a checked/verified legible copy of the vellum drawing in the archives.

/CAUTION/ My company no longer allows PHT H900 for 95% of SStl components. H900 = high strength/hardness, low ductility = low fracture toughness and poor SCC resistance. The ONLY exceptions I'm aware of are for parts in pure bearing/compression, like bushings and bearing races.

 

[mfgenggear]

AMS2759/3 precipitation harden

 

[WKTaylor]

mfg... RE OP post #3...

Mentions 'BAC'... suggests this is a Boeing drawing.

AMS2759/* would likely not apply. However, MIL-H-6875 might apply... if drawing is old-enough.

 

[mfgenggear]

Acknowledge will

 

[debodine]

My background is not structural so take my point with a grain of salt. You have probably already reviewed this, but MMPDS-15 Chapter 2 for Steel gives some information about H900, though it does not detail the exact process. It also supports Wil's CAUTION comment about fracture toughness.