![]() |
|||||
|
|
|
|
|
||
|
|
|
|
|||
|
|
|||||
The Importance of First and Last Welds There are few things more disappointing than putting over twenty hours into a blade only to have a flaw show up while grinding, or worse after heat treating. Avoid what I call the "Heartbreak of Damascus"by paying scrupulous attention to the smallest details while in the midst of your process. 1. Watch for dark spots on the surface of your billet when it comes out of the forge and begins to cool. Flaws will show as dark spots due to incomplete heat transfer from improperly bonded layers. 2. Small jets of yellow flame on the ends or edges of the billet. These are caused by escaping gases in sinuses and fissures that have exit routes along the edges of the billet, it is a sure sign of an improperly closed weld. Take the time to fix these things immediately upon discovery. Do not move forward until they have been eliminated.
The last weld deserves close attention as well. Time, temperature and mechanical manipulation(repeated drawing out and folding)serve to strengthen welds. The final weld has had the least amount of these things.Do not attempt to finish your billet with your final fold too close to your ending size.
Start your final weld with two(or three)oversized pieces that you can draw down to the appropriate finished size,thereby giving the weld the necessary time,temp and working factors so important to weld strength. And finally, always thermal cycle your billet to ensure an easy time with any cold work you might need to do on it. For more articles like these, sign up for our free weekly newsletter. |