Galvanizing - AS2312 and AS4680

[keenaseng]

Does anyone know why Table 5.2 in AS2312 calls up HDG900 which has a coating thickness of 125um as an option, when table 1 in AS4680 indicates that a maximum of HDG600 (coating thickness of 85um) is achievable for steel thicker than 6mm?

As outlined in table 1 of AS4680, the thickness of galvanized coating is proportional to thickness of the steel being dipped. I.e. the thicker the steel, the thicker the coating.

At what steel thickness would you get 125um thick coating?

No point specifying HDG900 if I don't know when I could get it... I have been caught out before specifying HDG600 to thin walled SHS and RHS!!

 

[apsix]

You're probably best asking your local galvaniser what they can achieve.

 

[hokie66]

keenaseng,

The thicknesses listed in Table 1 of AS4680 are minimums, not maximums. So you could expect a minimum of 85 microns for 6 mm thick steel. The zinc thickness will increase with thicker steel. There is a lot of useful information on the attached site, although maybe not exactly what you want. As apsix says, talk to your local galvaniser.

http://www.ingal.com.au/IGSM/01.htm

 

[keenaseng]

Cheers for the link. I'll have a chat to Ingal.

 

[asixth]

I have always called up the minimum 600g/sq.m as recommended in AS4680. I was at an engineers australia presentation recently conducted on Hot Dipped Galvanizing.

http://www.engineersaustralia.org.a...ivision/Events/2010/20100713 - structural.pdf

The presenter at this event was very knowledgeable and they are the general manager for the Galvanizers Association of Australia. I'm sure if you can get hold of this person they would be more than willing to help (maybe).

http://www.gaa.com.au/index.html

This gaa website also looks like it has plenty of information that may help. If you go to the side menu and select 'FAQ' then select 'Coating Thickness' it comes up with a downloadable pdf. It references AS4680 and says [highlight]minimum[/highlight] thickness of 600g.sq/m for steel sections greater than 6mm thick.

I have said on jobs that the general protective coating is to comply with AS2312 and galvanized structural sections are to comply with AS4680 with a minimum coating of 600g/sq.m.