The Parting Shot - Pushing the Boundaries

Author:  Jack Champaigne
Source:  The Shot Peener magazine, Vol 18 / Issue 4, Fall 2004
Doc ID:  2004046
Year of Publication:  2004
Abstract:  
I attended the October SAE Fatigue Design and Evaluation Committee meeting at the University of Illinois. One of the most interesting topics covered in the meeting was the "weld challenge". The SAE Fatigue Design and Evaluation Committee asked for estimates of fatigue life of a weld test specimen. Actual pieces, fabricated by committee members, were fatigue tested. Two of the specimens were shot peened by Progressive Technologies in Grand Rapids, Michigan. Results: The unpeened specimen failed after 250,000 cycles. Testing was halted on the two peened specimens because they broke at the mounting flanges, not the expected weld point. There are plans to repair the flanges and continue the tests. One specimen had reached 2.5M cycles and the other, which had been duplexed peened, reached 3.5M cycles. Is shot peening helpful for welds? A three piece sample isn't much for statistics but more testing is planned. This project is in its early stages and 30 more specimens will be tested. For more information go to www. fatigue.org/Weld/weld.html.