Hold-backs for fillet welds

Date 06-18-2008 17:58

Bill, we typically use the weld size as the hold back...call for 5/16 fillet we start and stop 5/16 from the edge, but for returns it usually is 2X the weld size...ie 5/16 fillet gets a 5/8" return. According to that last sentence, it reads like if there is such a requirement, then it must be stated in the contract docs.

By Richard Cook (**)

Date 06-18-2008 19:41

The hold back is to assure that undercutting and encroachment of critical areas is avoided. D1.1 does specify the weld size or as specified on drawings for such hold back. this is extremely critical when approaching the "k-area" with the weld of a steel shape. be careful and not confuse "k" demension with "area" AISC is specific onthe two.

Simply, stated it is starting and stopping short of the edges, ends and critical areas.

By swnorris (****)

Date 06-19-2008 10:37 Edited 06-19-2008 10:40

Good point on the encroachment issue. This is due to cracks occurring in the 'k' area of hot rolled wide flange shapes. The shapes are produced from scrap iron in an electric furnace and continuously cast into a near shape configuration. It isn't the scrap iron or the continuous casting into near shape that's the problem, but rather the final cold straightening that alters the steel properties in the 'k' area. Extremely high yield stress almost equal to the elevated tensile strength occurs with corresponding lowered elongation and single digit CVN toughness.

I have an AISC advisory on this from 1997. If anyone would like a copy, just send me an email. I'll attach it and send it back to you.

By 803056

Date 06-22-2008 00:23

The attached file depicts the hold back.
Best regards - Al

Attachment: TerminationofFilletWeldsNearEdges23-July-07.wmf (35k)

By Bill M

Date 06-23-2008 17:46

to all above,
excellent replies as always - thanks