Hot Galvanized Corrugated Steel Pipe with A Good Performance of Anti Corrosion

Request of hot galvanization for corrugated steel culvert pipe

As we know, the corrugated steel pipe is buried under soil, it has a support function for the road. After calculation we can get what thickness and what corrugation to meet the load request, but if the steel rust, it will affect on the strength of the corrugated steel pipe directly.

So we have take measures to prevent the steel to rust. Hot dip galvanization is a good choice, after test lots of times, based on the test result and data, we get a conclusion, the hot dip galvanization can meet the design.

Request of zinc coating on the corrugated steel pipe standard

All of corrugated steel pipe standard, they have a detail request only for the zinc coating. Because it is so important to the corrugated steel pipe quality. If a bad galvanization, the corrugated steel culvert can only have a working life in 10-20 years, it is big difference to the design working life 50-70 years. So before we shipping our product, the inspection on zinc coating is the one of the most important jobs.

All of us know, thicker steel plate is easy to be with thicker zinc coating, but thinner steel plate is difficult to be with a thick zinc coating, though we try to make the zinc coating thicker, it will be easy to peel off.

So In America standard, there is a difference request on difference thickness of the culvert.

Normally thin steel plate, the zinc coating request is 600g/m2, and thick steel plate, need zinc coating 900g/m2. also some thicker steel plate will be 1200g/m2. I think this standard is reasonable. But in Chinese standard, it only have one index for galvanization, only 1200g/m2.

Galvanization problem we suffered

In China, there are many small factory, they even do not understand standard clearly, but they have machines to produce corrugated steel pipe. Years ago, one of my customer from Africa, he asked many factories quality and price of the corrugated steel pipe, he inquired the culvert in thickness 2mm, but some factories told him, the zinc coating thickness should be 1200g/m2.

Finally, the customer chose our factory to produce culvert for him, and he insist us to offer him zinc coating 1200g/m2. I told him the steel is thin, if 1200g/m2 zinc coating, it will be easy to peel off, but the customer still request 1200g/m2 zinc coating. Then the problem is there are crack on the zinc coating, after that, my customer only request the zinc coating 600g/m2.