Fact or Fiction

[Terry Frank]

Over the course of a lifetime I have heard many times that a weld is stronger than the metal welded. Can anyone shed some light on this?

Fact or Fiction? Thanks

[Buju]

Generally, depends on the quality of the weld as well.

[CaptPatrick]

If the proper filler is used for a specific alloy, the weld has full penetration, and no impurities are present within the weld, and the correct amperage is used, and accurate cooling & retempering is done, then a weld can, and often is, stronger than the weldament pieces. It takes a real good professional hand welder years to attain that kind of perfection. CAD/robotic welding is where you'd regularly see a weld as strong as the weldaments.

[Harry Babb]

Ditto on what Buju and Pat stated.
Speaking of basic mild steel like A36 plate, angle or flat bar....the yield strength is about 36000 PSI and the Tensile strength is 60,000/70,000.

If you use a 6011 filler rod the weld filler metal is 60,000 PSI and if you use my favorite 7018 the filler metal is 70,000 PSI.

The weld metal is as strong or stronger than the parent metal. When the failure occurs it will usually be in the heat affected zone on either side of the weld.

The base metal is a forged or rolled material and the weld is basically a cast metal with different grain structure and that is where the failure will occur.

Harry