1 / 13

Formed rolled internal threads

When a part is cold formed the grain flow lines are neither cut nor broken but follow the contour of the upset. This process increases the tensile strength of the part. Cold formed parts as compared to machined parts are stronger and tougher both statically and in fatigue, therefore producing a high

lidia
Télécharger la présentation

Formed rolled internal threads

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

    1. Formed (rolled) internal threads

    2. When a part is cold formed the grain flow lines are neither cut nor broken but follow the contour of the upset. This process increases the tensile strength of the part. Cold formed parts as compared to machined parts are stronger and tougher both statically and in fatigue, therefore producing a higher quality end product. www.metal-working-online.com Thread Performance

    3. Thread Performance (test results)

    4. Thread Performance (continued)

    5. Whether cutting or rolling threads the preformed hole should be sized to produce a thread percentage between 60% to 75%. A thread height higher than 75% may result in engagement interference. Thread strength studies and tests have proven that there is no appreciable increase in thread strength with an increase thread percentage above 60%. Similarities

    6. Common misunderstood characteristic of rolled threads is the discontinuity or dip in the crest of the thread. Since forming taps rearrange the metal and the proper height of the thread is between 60 to 75%, the crest of rolled threads have a concave shape due to the flow of the metal. When observed by one not familiar with thread formation or type, the concave crest of a rolled thread is often interpreted as thread damage and/or a manufacturing error. www.filtercouncil.com Technical Service Bulletin 94-3R1 - Spin-On Filter Threads (see attached article) Misunderstood characteristics

    7. Other Articles

    8. Other Articles

    12. Summary Rolled threads and cut threads are completely interchangeable. Rolled threads and cut threads gage identically. Oversize holes are not as common as when a cutting tap is used, because the thread is formed very close to the size of the tap. Fewer problems with undersize holes, because the roll-form taps do not shave the threads during tap reversal like cutting taps do. Rolled threads are at least as strong as cut threads

    13. Recommendations

More Related