SAE 4041 galvanizing 1

[capablanca]

Sirs:
Does anybody knows if there is a problem to hot dip galvanize SAE 4041 anchor bolts.I have an opinion on this
that says that this treatment reduces strongly the strength
of the bolt.

Thanks,Capablanca.

 

[NickE]

Yes I think there's a problem with hydrogen induced embrittlement.

(do a search, there were some good disscussions on this topic like ~6mo to 1year ago)
nick

(you probably want to have them mechanincally plated.)

 

[unclesyd]

It is done. The problem come in the acid cleaning and fluxing prior to the Hot Dip process.

You migh check the following website and get an RFQ.

http://www.ktbolt.com/KTGalvanizing.htm

 

[BillPSU]

Hot dipping also adds about .007 on a side on a flat surface. The thread would be unusable even if it wasn't embrittled by the acid dip.

 

[capablanca]

Thanks all.Do you think that the same happens with SAE 1045
steel?
Capa.

 

[capablanca]

Me again.Thanks Nicke;I found all discusions on this question.My question is if in general terms which "normal"
steel have less problems in hot dip galvanizing embrittlment:SAE 4041,1045 or say 1020?Shall I avoid
SAE1045 in my anchor bolt design?
Capa.

 

[Flesh]

What is the strength class of your bolts? Failure via hydrogen induced embrittlement has a direct relationship with material strength. Depending on the reference source, I believe low-alloy steels that are <35Rc are immune. Need confirmation on this.

 

[TVP]

The requirement in SAE/USCAR-5 is that embrittlement relief is required for steel parts that have a core hardness greater than 320 HV (~ 32 HRC), or a surface hardness greater than 350 HV (78.0 HR15N). Property class 9.8 and higher fasteners must have embrittlement relief, and 8.8 fasteners > M16 also require embrittlement relief. The requirement in ASTM B 850 is similar: tensile strength > 1000 MPa, hardness > 300 HV10, 303 HB, or 31 HRC.

 

[metman]

capablanca is probably not interested to go this deep but others might be interested. My friend, Ed Cook, did his masters thesis at MIT on Hydrogen embrittlement of steel circa 1968.

Jesus is THE life,
Leonard

 

[SMF1964]

Additional consideration: if the material is heat treated to a very high hardness, can the hot dipping process afterwards temper the steel somewhat and reduce the strength.

 

[CoryPad]

SMF1964: yes, overtempering can occur.

Regards,

Cory

Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.