The ASTM F3125 Grade A490 specification does not allow either hot-dip galvanizing (per ASTM F2329) or mechanical galvanizing (per ASTM B695) due to the risk of hydrogen embrittlement. The only coating currently allowed on A490 bolts is a zinc aluminum coating meeting ASTM F3393, which is itself a combination of three coating standards, F1136, F2833, and F3019.
ASTM Committee F16 is currently conducting additional research on the acceptability of hot-dip galvanizing on A490 bolts.
In my project ASTM A490M bolt in the exterior locations are corroded, kindly advise to overcome the issue. Whether I can use Zinc spray (Product Name: Zinga Spray) over the installed bolt to overcome the corrosion. I am expecting your quick response to concluded the isssue.
@Boopathy- There is no prohibition paint-type coatings for A490 bolts. You are able to use those to mitigate corrosion. The concern comes in when the bolts are plated by industrial methods, where solvents and chemical cleaners that the bolts are immersed in can cause the embrittlement issues. Simply painting is ok.
Dear Gary.
My name is Danfer De la Cruz I have some bolts 4140 Steel.
Please I need information about if this bolts is possible be Hot dip Galvanized.
Thank you
@Danfer- It depends on if and how the bolts are heat treated, and how they are being used. Bolts that are heat treated to a high strength level like A490s, and used in applications where they are stressed similarly to A490 bolts should not be galvanized. However, if the bolts are heat treated to a lower strength, or not heat treated at all, then they likely can be galvanized. The ultimate answer will depend on those factors.