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Recent content by RCMRon

  1. RCMRon

    Fine thread bolts - do they back off

    Desert fox, thanks for the article, and again, thank you everyone for hte great feeback. a lot of my investigation was dependent on that article and other published material including national standards on stud welding. Our failure seem to be classical with respect to the examples shown in this...
  2. RCMRon

    Fine thread bolts - do they back off

    Hello desert fox I am told that regardless of the stresses put on the studs, the break should always be in the stud material and not at the weld. From what I can see, and others, the break is clearly in the weld area. We don't weld ourselves, we buy these from a machine shop that cuts the...
  3. RCMRon

    Fine thread bolts - do they back off

    On an earlier reply, someone wanted to see a cross section of the weld interface, I have this picture of one of the welds that did not fail before the backing plate let go. http://files.engineering.com/getfile.aspx?folder=b4320355-6b2a-4b6a-bc85-f666e3690d14&file=IMGP0293.JPG
  4. RCMRon

    Fine thread bolts - do they back off

    Here is a picture of a failed stud end of the failure Hope this helps ROnhttp://files.engineering.com/getfile.aspx?folder=03864a8e-1807-4548-a485-40458aaafb38&file=IMGP0298.JPG
  5. RCMRon

    Fine thread bolts - do they back off

    Hello desert fox, thanks for the reply. When I sent in the pictures to a stud manufacturer (Different one than the studs used) the consensus was that it was a weld failure. This is a stud weld done with an old TR-1600 nelson stud welder. Our torqueing procedures are inadequate so I can not tell...
  6. RCMRon

    Fine thread bolts - do they back off

    again, thanks for the assistance. To provide a few answers to the questions, what damaged the liner was that fact that it tore off of the blade at 720 RPM. Operating temperature is approx 250 DegC, Diameter is 80" I showed the pictures of the stud to a stud manufacturer, his assessemnet was...
  7. RCMRon

    Fine thread bolts - do they back off

    All of the answers given have been very helpful Hydtools mentonned that that double nutting was not a choice any more. Why is that, is it because there are better solutions Tunalover just suggested a prevailing torque. In oiur applications, the operating temperature of the fans, minimum 80" in...
  8. RCMRon

    Fine thread bolts - do they back off

    With the rotation and vibration be enough incentive. Should they be tak welded or double nutted?
  9. RCMRon

    Fine thread bolts - do they back off

    These are 5/8 " fine hread studs holding 70 lb fan blade liners on a 500HP fan rotating at 712 RPM. the liners are held in place with 20 1 1/2 inch studs. When properly torqued, will the nuts back off and or shouyld they be tack welded or double nutted? Does anyone know of others that use stud...
  10. RCMRon

    recfractory anchor brick failure - could water cause this?

    Russell, would these bricks me more tolerant to water caused thermal streesses and if so , how? They are different. Ron
  11. RCMRon

    anchor brick failure - could cause be water

    Thank you Ron. It is a PR 85 that we use. Yes the failure is localized to the area under the roof leak. the bricks are held in place on the beams in a manner in which they can move due to thermal expansion / contraction. Even though the brick has a 2500 lb tensile strength at 68 deg F, whan...
  12. RCMRon

    anchor brick failure - could cause be water

    Yes, I should not have used the word bolt because we have anchor bricks and not anchor bolts. Yes, all of the anchorbricks were broken. They snapped of at the interface with the roof and 5" of the brick was left hanging. Vesuvius are strugling with this and want to blame everything on water...
  13. RCMRon

    recfractory anchor brick failure - could water cause this?

    Thanks for the insight. What you all described above fits perfect with the failure. Even without water, can i assume that quick heat up and cool down caused by othe reason such as a burner gun flame directed right at the refractory, would have the same result? Is there a better way these days...
  14. RCMRon

    anchor brick failure - could cause be water

    Corus, thanks for the information, in one of my postings, about 5 or 6 up from this one, i attahed a picture of how our refractroy roof is suspended. It is suspended by anchor bricks. the bricks themselves are held to beam with steel anchors. It is the bricks that broke at the contact point with...
  15. RCMRon

    recfractory anchor brick failure - could water cause this?

    We operate the inside of the furnace at 2200 degF so I would suspect that a tthe point wher the anchor meets the refractory is is very close to this. large quantities of water laned in the area of the colapse s=due toa hole in the roof although there were signs of longer term thermal crack in...
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