Results 1 to 10 of 10

Thread: Removing inside weld line of a pipe

  1. #1
    Associate Engineer
    Join Date
    Aug 2020
    Posts
    5

    Removing inside weld line of a pipe

    What is the best and fastest way to remove the inside weld line of pipes with 16mm outside diameter and 1m thickness so a piston can reciprocate easily inside it? I have two options in mind. one is to have the inside of LSAW pipes machined, which might be laborious. The other option is to cold draw ERW pipes (I think cold drawing LSAW pipes would not result in smooth and accurate enough inside surface). I'm not sure whether either of these methods works. Is there a better way to to this? The end product is 12cm Cylinders which will be produced at least 1000 in quantity per day.

  2. #2
    Technical Fellow jboggs's Avatar
    Join Date
    Mar 2011
    Location
    Myrtle Beach, SC
    Posts
    851
    When I read the word "piston" I assume some fluid or air will be involved. I also assume you will want the piston to seal against the walls of the cylinder and not leak as it moves. If that is correct, you are going to have to do MUCH more than just remove a weld seam. You are going to have to finish the inside of the cylinder to some very precise requirements.

    Also, you did not say how long these pipes are.

  3. #3
    Associate Engineer
    Join Date
    Aug 2020
    Posts
    5
    Thank you for your reply. You got all the parts right. The cylinder is filled with nitrogen under about 10bar pressure, and of course the piston should be sealed. What processes should I go through then? I mentioned the end products are 12cm cylinders, but I buy them as 6m or 3m Tubes.

  4. #4
    Technical Fellow jboggs's Avatar
    Join Date
    Mar 2011
    Location
    Myrtle Beach, SC
    Posts
    851
    Have you built prototypes? Did they work well? Go from there, one step at a time.

    I doubt that this is the place to get all your engineering and process information for the successful manufacture of pressurized cylinder actuators.

    To answer your original question, no I cannot tell you a good way to remove the internal weld seam. But I can tell you that I would not think that a welded tube is a good candidate for the raw material. I would expect an eventual split or failure at the seam after repeated exposure to internal pressure. If it does fail, that's where it will be. I am not in the cylinder manufacturing business so I could be wrong. But I have bought and used thousands of them over the years, and I have seen my share of failures.

  5. #5
    Administrator Kelly Bramble's Avatar
    Join Date
    Feb 2011
    Location
    Bold Springs, GA
    Posts
    2,349
    ID of pipe smaller than required on build then drill/ream to size for accuracy and consistent cylindrical surface.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

  6. #6
    Principle Engineer
    Join Date
    May 2015
    Posts
    188
    Did you look at drawn over mandrel tubing? (D.O.M.)

  7. #7
    Associate Engineer
    Join Date
    Aug 2020
    Posts
    5
    I agree that seamless pipes are much bether choices, but in order to be abale to compete with price of similar products I have to use welded pipes.

  8. #8
    Associate Engineer
    Join Date
    Aug 2020
    Posts
    5
    I have considered D.O.M, but I'm not sure whether I would get a smooth and accurate surface from a tube with an inside weld seam. I would appriciate sharing any similar experience.

  9. #9
    Technical Fellow jboggs's Avatar
    Join Date
    Mar 2011
    Location
    Myrtle Beach, SC
    Posts
    851
    "I'm not sure whether I would get a smooth and accurate surface from a tube with an inside weld seam".

    You have your answer from Kelly:
    "ID of pipe smaller than required on build then drill/ream to size for accuracy and consistent cylindrical surface."

    No raw pipe is going to give you a good enough internal surface to do what you want to do without fully machining a precise and smooth bore. The ID of the pipe or tube you purchase must be under size so you can machine it to produce a true, straight, precise, and smooth bore.

    In your original post you said the pipe thickness is "1m". I think you meant 1mm. That leaves you almost no material to machine away. I don't think a 1mm wall will be stiff enough or strong enough.

  10. #10
    Administrator Kelly Bramble's Avatar
    Join Date
    Feb 2011
    Location
    Bold Springs, GA
    Posts
    2,349
    I've seen tubes that were deep drawn and then polished internally used for shock absorbers / McPherson Struts.

    Build or maybe find an existing tube diameter.
    Tell me and I forget. Teach me and I remember. Involve me and I learn.

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •