stainless steel type 304, 316, 316l

[olympios]

The cargo pipe installation on one of our ships should be made of these materials. Is there a way to find out if the yard complied? I put a magnet and on some of them stuck. Is this enough evidence that these are not made of the above materials?

 

[PAN]

The magnet can stick at weld joint. The nonmagnetic property should be found at parent metal (austenitic stainless steel).

 

[shooter45]

Depending on where the specific batch of material falls within the specification chemical analysis ranges all three of these alloys can be magnetic. The only way to be certain is to use one of the portable analysis machines and carry out a Positive Material Identification (PMI.

 

[rustbuster1]

For 304 ,316 or 316L to be magnetic they must be excessively cold worked (I presume you are not talking about welds joining pieces of pipe) Therefore you have good reason to suspect that they are not these materials. However, depending on what they are you might even be better off (e.g., if they are duplex SS like 2304 or 2205). So, it would be wise to take some filings and get chemistry or to use a field analyzer, although this test will not tell you the C content.

 

[olympios]

I want to thank everybody for your answers. Your help is greatly appreciated.