Hi Kix!
I was reading the brochure that Scott posted in this thread, and what I read on page 4 states:
"The following alternatives are available when selecting the yield strength of the filler material:
1) Undermatching weld metal (the weld metal has a lower yield strength than the parent metal).
2) Matching weld metal (the weld metal and the parent metal have the same yield strength).
3)Overmatching weld metal (the weld metal has a higher yield strength than the parent metal).
So, after reading that, have you tried welding with say a E10XT-X, E11XT-X, or a E12XT-X wire yet to see if you may get closer to what you're looking for in your tensiles? Of course, I would first try to contact SSAB Oxelosund and find out if this would make a difference or not. ;) I would also incorporate a tempering bead technique similar to what is performed when welding HY-80, HY-100 steels and their equivalents... Are you absolutely sure that the required tensile strength must be at least the same as the parent metal???
Finally, I would double check that the filler metal has a hydrogen content less than 5ml/100g of weld metal before concluding that it's safe not to preheat the joint prior to welding. I would also use PWHT in order to get close to what you're looking for in tensile strength if possible. Edit! Forget the PWHT because I just found the data sheet for Hardox 500 which recommends no further heat treatment yet, I do'nt know for sure if they are including PWHT in their statement... Interesting in the fact that it does'nt list the yield or tensile strengths of this grade as opposed to the other data sheets that do... I wonder why???
http://apps.ssabox.com/pdf/datasheets/us_datasheet_hx_500_v1.pdfAnywho, we got a US Corporate office right here in Coraopolis (Less than 5 miles from my residence) and I guess a Hardox distribution center in Pittsburgh, on Neville Island:
http://ssabhardox.openfos.com/I'm going to call them tomorrow and find out what's the correct tensile strength for the Hardox 500, and here's an e-mail addy for the Area Technical Manager - Kjell Backman: kjell.backman@ssabox.com
Maybe this person can shed some light for you on your situation.
The thing that bothers me most about this problem is why this Hans Konradsson writes you stating:
"There is no weld method today that can match that strength and the Hardox wear resistant plates are not meant (he spelled it incorrectly :) ) to be welded with matching strength" yet, it clearly states in the .pdf that alternatives are available besides using undermatching filler metal... Then he continues by writing: "To avoid problems with mainly hydrogen cracking it should be welded with soft filler material of 500 MPa or 70 ksi." In the .pdf that Scott posted it clearly shows in the chart on the first page on the left hand side that Hardox 500 calls for at least an E80XT-x wire and can go as high as an E90XT-X so, where does his logic fit in with using a "soft filler material of 500 MPa or 70 ksi"???
If this is true then who in the Sam Hill came up with these specs in the first place??? Somebody should've known beforehand that these tensiles could'nt be achieved realistically!!!
If you ask me??? Someone is trying to bury this FUBAR, and hand it over to your lap!!! I have one suggestion for you: CYA - PERIOD!!!
Now, I've heard in the past that with the suggestions I gave above, that one can achieve significant improvements in their tensile limits by incorporating all of the above mentioned practices, although I personally have'nt tried it on Hardox 500. I wish you all the best on this one Kix!!!
Try this link from SSAB Oxelosund, it has many"Technical recommendations" .pdf's on welding weldox & hardox:
http://www.ssabox.com/templates/brochures/InformationMaterial____10048.aspxRespectfully,
Henry