Abstract
Surface quality of nuts used in gas pipe joints is an important issue because the surface state affects the fatigue characteristics. Surface defects of nuts produced by warm forging from a stainless steel are observed and the cause of defect generation is discussed based on the numerical results of FEM simulation. It is revealed that there exists the lap defect on the drawn wire surface with an opened end and the surface defects on the forged nut are generated by the tensile stress during forging since there exists a moment at almost the whole area of the billet surface that a tensile stress over 200MPa is generated during nut forging.
Highlights
Nuts under investigation in the present paper are used in gas pipe joints (Figure 1) for experimental devices and buildings
Serious accidents occur if the gas pipe joint in the service had been broken
The nut is produced from a drawn wire of SUS316 by four stages forging; upsetting, 1st extrusion, 2nd extrusion and piercing
Summary
Nuts under investigation in the present paper are used in gas pipe joints (Figure 1) for experimental devices and buildings. These gas pipes serve mainly for poisonous gases and flammable gases. A few check marks exist almost on a straight line These defects on nut surface perhaps become the start point of fatigue crack and cause failure under repeated stress [3]. The purpose of the present work is to clarify the generation cause of surface defects on forged nuts.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
