A36 Steel Plate Porosity
A36 Steel Plate Porosity
(OP)
I am manufacturing a part from a 19" OD x 4.25" thick piece of A36 plate and while machining it, porosity was opened up. I am used to seeing this in castings but not in A36 plate. We performed a liquid penetant test on the machined surface and the porosity was visually worse. Can anyone speak to A36 plate and porosity? I always thought a plate material could have laminations but not porosity. Is this correct?





RE: A36 Steel Plate Porosity
rp
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
I didn't intend to doubt your use of the word, only that there are many causes. Porosity is the presence of voids in the material. It does not address how they got there.
Yes, porosity is more common in castings. You can also see it in weldments. As weldstan pointed out, it can exist in wrought materials due to insufficient hot work. It can also result from poor steelmaking practice. The list goes on.
rp
RE: A36 Steel Plate Porosity
The porosity in the plate can be as a result of failure to close the defect from a continuously cast slab during rolling . It is not surprising that the plates are tested (ultrasonic testing) before sourcing from the dealers or mills.
RE: A36 Steel Plate Porosity
19" OD plate? Is this plate or a tube form?
As others noted, A36 steel plate is often produced starting from a continuous cast slab that is repeatedly hot rolled to your 4.25" thickness. I don't have a copy of ASTM A36 handy, but I believe it references other ASTM specs that cover specific metallurgy and quality requirements for rolled A36 plate. These ASTM documents will help you determine whether your material is non-conforming.
If your material delivery included certs or a CofC from the vendor stating the material conformed to ASTM A36 standards, and you make a determination it does not, then you should take up the issue with the vendor. On the other hand, if you simply purchased a piece of steel plate with no guarantee of pedigree or quality and you find it to be defective, then caveat emptor and chalk it up to experience.
Look at the bright side, at least you discovered the problem during manufacturing rather than after the component was put into service.
Good luck to you.
Terry
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
Are you sure the raw shape was cut from a plate?
Do you have a certified material test report that can be verified to be for the material you received?
Did your company cut the raw shape from plate or was it supplied by a vendor?
Best regards - Al
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
RE: A36 Steel Plate Porosity
Even if you specify NDT by the supplier, I wouldn't hold my breath.
I would agree that it is worthwhile performing UT upon receipt. If it doesn't pass, send it back. Once you start machining it, you own it.
Best regards - Al
RE: A36 Steel Plate Porosity