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Recent content by cnuk

  1. cnuk

    A519 Wall Thickness Tolerance

    I have a question regarding ASTM A519 wall thickness tolerance. The wall thickness tolerance says - If OD is less than 3”, the tolerance is 12.5% when the WT < 15% of the OD and 10.0% when WT > 15% of the OD. - If OD is 3” to less than 6”, the tolerance is 10% when the WT < 15% of the OD and...
  2. cnuk

    &quot;Coeff of Friction&quot; for slips on a tube

    I have an application where I need to grip onto the OD of a tube with jaws/slips to resist an axial load that is applied to the tube. There will be three or five jaws equally spaced around the OD to clamp. In order to size the hydraulic cylinders that will provide the clamping force I need to...
  3. cnuk

    Stainless Steel for Cryogenic Application

    Excellent guys. Thank you very much for sharing your expertise.
  4. cnuk

    Stainless Steel for Cryogenic Application

    I need to select a stainless steel grade for a cryogenic application. We use liquid nitrogen to drop the temperature of a steel pipe in order to remove an lining inside the pipe (differential thermal expansion causes cracking & thus removal). We load the tank with steel tubes at room...
  5. cnuk

    Welding 50ksi Structural to Q&amp;T Plate

    Thank you for the help by sharing your knowledge. Very helpful.
  6. cnuk

    Welding 50ksi Structural to Q&amp;T Plate

    I am trying to redesign an existing piece of outdoor structural equipment and bring it in line with code. I have two options to rework a deficiency where a square HSS member joins to a plate with a fillet weld around the square HSS: 1. Replace an 1 1/4" A36 plate with a ~80 ksi plate. Likely...
  7. cnuk

    API %CT J55 to ASTM A??? Cross Reference

    This may be a simple question but it has me stumped. I am trying to find the equivalent ASTM Axxx number for API tubing/casing (eg:5CT J55). Does an equivalent ASTM number exist? I have reviewed the API specs I have and found no such cross reference. The reason I ask is that I am trying to...
  8. cnuk

    PTFE Seal Temperature

    Thanks for the reply. We don't have control over the preload with our design. As far as properties go, we ran the material on our DMTA and the modulus drops by a factor of 4 between 100C and 150C, both far lower than room temp obviously. We see what I would call creep at current operating...
  9. cnuk

    PTFE Seal Temperature

    I have a PTFE (graphite filled) seal that I am testing running on a 2" shaft @ 500 RPM, 500 Psi. Test fluid is water at 50°C. It is grease lubricated. We are measuring temperature near the seal of 150°C which seems ridiculously high to me. Are you surprised by the temperature? I would never...
  10. cnuk

    Wire Rope: spring constant

    I need to find the spring constant (or load vs. deflection curve) for a piece of wire rope (1/4" 7x19 in my case). Surprisingly this is not something that any vendors publish....only breaking strength. I suppose the published data makes sense for the typical application where you are...
  11. cnuk

    Casing/Wellhead Max Stress

    jte, Thanks for the response. I'm always impressed my the amount of knowledge shared on these forums. Greatly Appreciated.
  12. cnuk

    Is Impact test done only for Low temperature suitability?

    A related question. I thought I read somewhere (ASME BPVC?) that most plain carbon steels do not require impact testing if the operating temperature is above -29degC? The reason I ask is that I am designing a device that operated on an oilwell and is made of ASTM A36 plate and CSA G40.21 44W...
  13. cnuk

    Casing/Wellhead Max Stress

    Thanks roadapple. I started looking into API 6A but it quickly (section 4.3.3.2) refers to the ASME boiler pressure vessel code (ie: stress intensity). I don't have a copy of ASME so am still trying to figure out what exactly "stress intensity" is. It sounds like it is max principal - min...
  14. cnuk

    Casing/Wellhead Max Stress

    I have a device that is attached to the wellhead. It transmits a large bending moment, axial load, and some shear to the casing and wellhead. I would like to know what the max allowable load/stress for a given casing / wellhead flange combination is? I have looked over some of the API specs...
  15. cnuk

    Wellhead Equip: Low temp material spec ?

    Thank you for the response! I have 6A now and am reviewing it. Greatly appreciated

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