searc for fine grained steel plate with through thickness properties 1

[koen31]

Dear all,

I am searching for a fine grained steel plate, which should be normalised or thermo-mechanical treated, and should have a high impact toughness. The steel should have a minimum yield strength of 360 MPa and a tensile strength of 455 MPa, and should have controlled through-thickness properties.

Who can advise me ?

Thanks in advance,

Koen

 

[metengr]

koen31;
You don't provide enough information to really help narrow down your choices. What is the application? What about corrosion resistance? What about service temperature?

 

[koen31]

You can see the application here :

http://www.bil-ibs.be/eng/Research/research_2004_Friex.htm

The plates shall be used for welding trials to join pipes.
I would like to use a plate with a high impact toughness (the higher the better).
Since the rolling direction of the plate is perpendicular to the rolling direction of the pipes, I like to avoid segregation effects, therefor I would like to have normalised steel, with controlled through thickness properties (pure metals).
Corrosion resistance is not important.

I hope this is enough information ? If not, please ask.

Thanks,

Koen

 

[metengr]

Ok. I would say your best bet is the ASTM/ASME A/SA 533 plate steel, probably Type B, Class 1. This is a fine grain practice steel plate and is supplied in a quench and tempered heat treatment condition.

 

[koen31]

Do you think a quenched and tempered steel plate is better suitable than a normalised ?

 

[stanweld]

Since this involves welding research for normal pipeline thicknesses, I would advise using A 516-70, normalized, not as rolled, purchased to meet your specified impact properties. We readily purchase small quantities of this material with > 50 J absorbed energy at -50 F for impact test WPS qualification.

Purchasing API 5LX microalloyed skelp with appropriate properties would be great but is not not practical for your research. I suspect that, at some point, you will need to purchase microalloyed API 5LX pipe to complete your study.

 

[metengr]

Yes. Most of the quenched and tempered steel plates used for pressure vessel fabrication have consistent through thickness properties. Your stregnth requirements are such that the Q&T steel plate would be a better selection. Also, take a look at the Conclusion in your link, it was mentioned the steel plate was quenched and tempered.

Conclusion

The feasibility of the FRIEX welding process has been successfully proven. The study of this new variant of the friction welding process shows that the process is highly suitable for joining pipes. Using the experimental test set-ups, high quality welds could be produced for pipes (pipeline steel X42) with a maximum outer diameter of 5 inches. For the welding ring material, a high strength quench and tempered material was used.

There is another option. Make the weld ring material out of the same material as the pipeline. You can purchase an added pipe spool to machine the weld rings.

 

[koen31]

Stanweld,

What do you mean, that we should by pipes, and machine plates out of it ?

Metengr,
The quenched and tempered materials were used in the beginning, but not anymore. The impact toughness was too low in some cases.

Do you think it is possible to buy a plate X52 ?

regards,

Koen

 

[stanweld]

koen31,
I did not state that you should purchase pipe and machine plates out of it.

 

[metengr]

Koen;
The weld ring used for friction welding pipe spools should be similar to the pipe base materials. As I stated, and after reading the link you provided, why not machine weld rings out of extra pipe material? You can wafer cut the weld rings and optimize the length for this process.

 

[koen31]

That is indeed a possibility. Maybe we have a large-diameter pipe where we can cut plates from.
We did that by the way for welding X70.
But it's more labour intensive of course...
I'll try finding pressure vessel steel ASTM A517.

How about the option to use a thermo-mechanical treated steel ? I suppose it is lower alloyed than pressure vessel steel, so the risk exists that you loose all the mech. properties after welding...

 

[metengr]

koen31;
After thinking about this, I really don't see any benefit to using a weld ring material that is specifically made from micro-alloyed or TMCP steel plate.

 

[TVP]

koen,

Since it appears you are in Europe, you may prefer to look for EN steels rather than ASTM. EN 10028-2 is the standard for flat steel for pressure purposes, normalized. 10028-5 is for TM rolled, and -6 is for Q&T. Since this is solid-state welding and not arc welding, you may be able to use TM rolled steel and not suffer too much degradation in properties. I'm sure one of the divisions within Arcelor produces TM or Q&T steel for PV applications. Probably voestalpine too.

 

[koen31]

I found a pressure vessel steel, P460NL1.
It has a yield strength of min. 460 MPa, and is normalised.
I looked at this material through the microscope, but it has a banded structure. See :

http://www.bil-ibs.be/nl/p460NL1.jpg

I fear that the carbon rich zones (with the pearlite) will transform in bainitic microstructures, with a high hardness and a low impact toughness.
Would it be possible to obtain a material which has not this banded structure ?

thanks,

Koen

 

[TVP]

This type of banded microstructure is common for normalized, high Mn carbon steels such as P460NL1 according to EN 10028-3. It is one reason why Q&T treatments are used to improve the microstructure. Changing to a TM-rolled steel (P460ML1, etc. acc to EN 10028-5) may be an improvement, but really the Q&T grades according to EN 10028-6 will have the best microstructure and properties.