case hardened repair
RSS | Subscribe | Contact Us | Advertise | About Us
Results 1 to 8 of 8
  1. #1
    Join Date
    Jan 2008
    Posts
    3,397

    case hardened repair

    i have a 1" diameter case hardened steel bar that has had a section removed by o-a cut. how do i replace the missing section(8" long) and keep or return the case hardening to the welded area? this is in a correctional facility and the original integrity of the bar needs to be returned as part of the repair.

  2. #2
    Join Date
    Oct 2007
    Location
    Vandalia, Ohio near Dayton
    Posts
    1,705

    Re: case hardened repair

    It's probably not practical to restore the original case hardening; can you describe the part and how large the whole assembly is?

    Most case or surface hardening is done inside a controlled atmosphere furnace...Do you know how the original part was manufacturred?

    Knowing nothing else, I do have an alternative suggestion. You could weld the repair in as normal. Then grind the weld and heat affected zone down below flush. Finish by building the repairs back up with a hardfacing rod. You'll still wind up wiht some areas of the case that are softened in the HAZ surrounding the hardfacing deposits. But the repair will have a hardened surface like the rest of the bar. That might suffice, but without knowing more about the thing being repaired and the customer's requirements I can't say for certain...
    Mobile Welding at your worksite or place of business. Serving Dayton, Ohio and the surrounding metro areas.
    AWS Certified Welding Inspector (#XXX10731) and Certified Welding Educator (#XXX1008E)
    www.bensonmobilewelding.com

  3. #3
    Join Date
    Sep 2006
    Location
    NJ, USA
    Posts
    3,357

    Re: case hardened repair

    Without KNOWING specifics of what is there material AND process wise, it's all just guessing.

    Sort of like someone saying they have a piece of aluminum and need it welded. There are a lot of different types of aluminum, and some just aren't weldable.

    The original bar could have been case hardened, but what is the base material and how deep is the case hardening and what hardness is needed on the surface and the core, etc, etc.

    It could be repairable to meet the functional needs of the customer in some manner, or it might just need to be replaced as a whole bar. Depends on the customer and the needs of the piece.

    Just a surface hardening a couple thou deep? Maybe just an O-A torch running rich on the acetylene to put some extra carbon onto the surface of the steel. Then you have to quench it.

    Interesting idea of putting some hardface on it. But that could be kind of ugly looking without going back and grinding it smooth and round.

    It depends.
    The best laid schemes ... Gang oft agley ...

  4. #4
    Join Date
    Dec 2007
    Location
    Los Angeles
    Posts
    5,209

    Re: case hardened repair

    Quote Originally Posted by weldbead View Post
    i have a 1" diameter case hardened steel bar that has had a section removed by o-a cut. how do i replace the missing section(8" long) and keep or return the case hardening to the welded area? this is in a correctional facility and the original integrity of the bar needs to be returned as part of the repair.
    You really shouldn't let the Shop doods take the O/A back to their cells
    Ed Conley
    http://www.screamingbroccoli.net/
    MM252
    MM211
    Passport Plus & Spool gun
    TA 185
    Lincoln SP135 Plus- (Gone to a good home)
    Miller 125c Plasma 120v
    O/A set
    SO 2020 bender
    Beer in the fridge

  5. #5
    Join Date
    Oct 2007
    Location
    Vandalia, Ohio near Dayton
    Posts
    1,705

    Re: case hardened repair

    I was guessing since this was a bar in a prison that it was hardened just to keep the inmates from wearing away at it with whatever pot metal and nail files they can scrounge up.

    Some of the hardfacing compounds can be machined/ground, even though they're very hard. So you could restore the bar to it's original ID, if you put the hard facing on to build the repair weld back to the same OD as the original bar. Then paint over the repair to match the existing color(if any). This would camoflage the repair and still maintain at least some hardened surface in and around the repair....Just speculating....

    Depending on the nature of the part and the value of the job it might also be worth looking at Castweld's O-A powder spray coatings. Those go on at a pretty low temperature, and pretty quickly. You might be able to overspray a thin, hard layer ontop of the repair welds and get the same end result.

    Moonrise is right when it says it's all guesswork without more information...
    Mobile Welding at your worksite or place of business. Serving Dayton, Ohio and the surrounding metro areas.
    AWS Certified Welding Inspector (#XXX10731) and Certified Welding Educator (#XXX1008E)
    www.bensonmobilewelding.com

  6. #6
    Join Date
    Jan 2008
    Posts
    3,397

    Re: case hardened repair

    the bar i need to repair is one of about 50 in a large window, bars are all one unit. i am thinking of getting a test lab to do some rockwell tests on existing bars to see what is there, and compare that to some new steel bar. i am aware of a product called cherryred which may be similar to the castweld stuff.i have little chance of getting any info from the prision itself as the bars were installed along with the rest of the place in 1920.records are few .

  7. #7
    Join Date
    Oct 2007
    Location
    Vandalia, Ohio near Dayton
    Posts
    1,705

    Re: case hardened repair

    Window bars in a prison...good candidate for being made tamper resistant...

    I hope the job pays well enough to cover the lab testing. Checking the case could be done with a small cross-section polished and etched. This is probaby $50-$100 depending on where you're located. Be careful with hardness testing. Some of the test methods are not reliable with case hardened surfaces.

    I have some prior experience with this, but won't spout off here. Feel free to send me a PM if you need some detailed advice on the type of testing that would serve you best.

    Quote Originally Posted by weldbead View Post
    the bar i need to repair is one of about 50 in a large window, bars are all one unit. i am thinking of getting a test lab to do some rockwell tests on existing bars to see what is there, and compare that to some new steel bar. i am aware of a product called cherryred which may be similar to the castweld stuff.i have little chance of getting any info from the prision itself as the bars were installed along with the rest of the place in 1920.records are few .
    Mobile Welding at your worksite or place of business. Serving Dayton, Ohio and the surrounding metro areas.
    AWS Certified Welding Inspector (#XXX10731) and Certified Welding Educator (#XXX1008E)
    www.bensonmobilewelding.com

  8. #8
    Join Date
    Sep 2006
    Location
    NJ, USA
    Posts
    3,357

    Re: case hardened repair

    Find out what the customer actually wants or needs.

    Just because the original bar was casehardened doesn't necessarily mean the replacement has to be case hardened.

    Simple looking and sounding job, just weld in an 8" piece of 1" diameter steel bar. But, oh by the way, it's case hardened.


    Maybe use a different material for your replacement bar, maybe flame-harden a mild steel bar using an O-A torch running rich on the acetylene, maybe hard-face it.

    Then you have the effect of your weld repair and the previous torch cut on the existing bar. And beveling and full-pen welding a replacement section in, and then grinding it all smooth and making the repair disappear. Forty bucks in materials and $600 in labor?
    The best laid schemes ... Gang oft agley ...

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
RSS | Home | Penton Media | Contact Us | Subscribe | For Advertisers | Terms of Use | Privacy Statement