G48 Corrosion Test, 1

[zulsaid]

How is the temperature influnce the corrosion rate? Which is give more higher rate of corrosion, either at +20 celcius or at +25 celcius?

 

[GRoberts]

The specimens will experience more pitting and weight loss at higher temperatures.

 

[zulsaid]

GRoberts,
Any big difference if I carried out the corrosion test at +20 celcius and +25 celcius? Because I have received a raw material grd F51/2205, in the mill cert stated the supplier carried out G48 Mtehod A at +20 celcius/24hrs, weight loss is 0.266g/m2. But our specification is +25 celcius/24hrs, weight loss is 4g/m2. Is the supplier value can supercede our specification? Or I need to carry out another test at +25 celcius.

 

[GRoberts]

The 20C test is not valid for a 25C requirement as the results will degrade with the rise in temperature. Sometimes dramatically. The test should be repeated at 25C to verify.

 

[zulsaid]

GRoberts,

Is bar product also can claim as forging product? Is 1.4462 UNS S31803=F51?

 

[EdStainless]

Which chemistry does it meet, 31803 or 32205?

Either way if your spec is 25C then it must be tested at 25C.

Though I must say that a spec that is based on significant corrosion is like yours is is not good practice. You should select condition that result in near zero corrosion so that detection is better. 4g/m2 is clearing because of pitting attack.
Surface prep is critical in G48. If you acid clean the samples you can get some very low test results.

I would suggest that you consider moving to method C and using a lower temp.
Do you require A923 also? You should on a duplex. They are two different tests.

= = = = = = = = = = = = = = = = = = = =
Plymouth Tube