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FAQ: Are there any methods of improving the fatigue strength of welded joints?

   

Frequently Asked Questions

Fillet welded joints may be treated with a variety of techniques to increase the fatigue strength with respect to failure at the weld toe. The most common technique is weld toe grinding, preferably with a grinding burr rather than a disc. For joints in structural steels, the UK standard BS7608 states that the allowable stress range may be increased by 30% for fillet welds treated in this way. Other methods include peening, or remelting the toe by TIG or plasma dressing. All these techniques require definition of a detailed method statement and appropriate training for the operator.

If fatigue failure occurs in the throat of a fillet weld, simply increasing the weld size or changing to a full penetration weld will give an improvement.

Further information can be found in:

  • 'Fatigue Strength of Welded Structures', 2nd Edition by S J Maddox, Abington Publishing, 1991. (ISBN 1 85573 013 8)
  • 'Improving the Fatigue Performance of Welded Joints', TWI, 1983, available from Abington Publishing. (ISBN 0 85300 164 2

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