If this spring is external as they are normally are I can see exposed to is a little splash which would be washed off prior to shipping. Our standard procedure on covers of this type is to fill, close, and rinse off where you have a waster drain. We got a fine years ago because there was white stuff reported around a cover on a tanker truck. This was recorded as a leak when in reality it was material that wasn't rinsed off and was reacting with CO2 in the air.
What is the container made of?
Could you post a picture of the hatch and cover?
edStainless,
Normally this is a very big spring probably weighing around 10-15 pounds so making it from any of C-22, Elgiloy, or MP35N would be extremely expensive $450 US ea. for a 1 1/2" by 3/4" dia. of .016 wire for use in a pump in Cupric Bromide service. The order was for 10 springs.