We are looking for compatible weld filler to repair CD4MCu stainless steel casting. The welding process we are using is GTAW. Can you offer any guidance?
The matching filler metal is AWS A5.9 Class ER2553; however, it is not very readily available. An alternative would be ER2594, commonly known as Zeron 100X.

Be aware that as-cast CD4MCu is likely to be very brittle due to formation of sigma phase during casting. It may be necessary to anneal the casting (at temperatures above 1,900 degrees F), followed by water quenching before you weld. If you do not anneal, you run the risk of cracking the casting during welding.

Our fabrication shop has an angle shear that has the capacity to shear angles to thicknesses of 1 in. The sheared edge of thick angles typically has a rough, cracked edge. Commonly, these angles are welded for clip angles used on structural applications. Do you know of any code requirements or references for material trimming to clean up the edge quality for cyclically loaded structural applications? Any input or direction would be much appreciated.
You need to reference Section 5.15 "Preparation of Base Metal" in AWS D1.1-2006. This section refers to the general prep required for all surfaces used in structural applications. It states: "Surfaces on which weld metal is to be deposited shall be smooth, uniform, and free from fins, tears, cracks, and other discontinuities which would adversely affect the quality or strength of the weld." This statement really addresses the entire issue relating to structural applications. However, there are additional requirements cited under 5.15.3 in AWS D1.1-2006 for cyclically loaded structures that requires trimming for sheared materials thicker than 1/2 in. Additionally, under the same subsection, toes of angles or rolled shapes (excluding wide flange sections) thicker than 5/8 in. must be trimmed in cyclically loaded structures. Keep in mind that this subsection requires trimming to produce a satisfactory surface for welding whenever the weld is to carry calculated stress per the code.

I would suggest considering alternate cutting methods that would produce a better cut-surface to reduce the need to resurface of the sheared edge.

I am working on a project and would like some advise on stress relief requirements. The part we a making is a bracket for a camera that will be placed in a difficult environment. The material is 6061-T6 aluminum, code is AWS D17.1. It will be GTAW welded and we are not sure if there are any requirements for stress relief after welding. If there are, what are they?
There is no requirement to stress relieve aluminum welds. In fact, there is no practical method to stress relieve welds in 6061-T6 without significantly degrading the mechanical properties.

I would like your recommendations on which electrode to use when welding ASTM A706 rebar to ASTM A992 steel beams. I would like to know if the E80, low-alloy electrodes required by AWS D1.4 for joining A706 to itself will work on the A992 material?
Generally, it is customary to match the lower strength side of the weld connection, which in this case would be the A992 material, that can be welded with low hydrogen, E70 filler metal. This is a general guideline, and presumes that the load-limiting factor is the strength of the lower strength material. That is not always the case; therefore, sound engineering judgment should be followed.

As far as using E80 filler metal as recommended for the A706, there would be no significant issues with using it to join the A706 to the A992 base material. The strength would be an overmatch and may not add to the overall connection strength, but that depends on the specific conditions for the connection you are making. n

This column is sponsored by Penton and the Lincoln Electric Co., Cleveland. Dave Barton is a senior welding engineer in the Application Engineering Group of The Lincoln Electric Co. He oversees welding procedure development for both new technology and existing products, performs failure analyses for customers, and serves as a consultant on welding application problems. Barton has been with Lincoln Electric for 21 years. Send your questions for Mr. Barton in care of WDF by e-mail to: askdav@penton.com