Weld Overlay in Anchor Windlass Gypsy

Compatibility for the expected physical requirements are important, there are a range of facing metals corrosion is not usually a problem for the hard facing metal itself and they have to be compatible with the base metal so there is no problem there . look at this link.

http://www.weldmold.com/index.php/products/hardfacing-weld-materials.html

Hard facing should not alter the structural integrity of which you are welding so a qualification is not normally required.

Thanks Garth for the tip.

Indeed there are a lot of Cast Iron item that is subject to wear and it is great if PQR is not needed to support any repair on this item.

Cheers.

Hardsurfacing is a specialty for many fabricators. Stoody Deloro is probably the oldest leading company that produces a variety of hardsurfacing products. They are also very good at sharing the technology.

One major factor is that if a very hard weld material is placed on a material that is soft, say ASTM A36 or any low yield material, the hard weld material will "check crack" and often cracks all the way down into the base material (A36). It is highly recommended that an intermediate layer of a material (called "buildup) that has a higher yield strength (maybe halfway between the A36 and the welding material) to minimize the possibility of base material cracking. The "check cracks" occur as the hardsurfacing material is self-relieving the internal stresses that take place when the hard material solidifies.

Be careful of your build-up material. Much of that is manganese based and will work harden, sometimes to more than the cover passes.

Dear D

Let me be a bit pedantic.

Normally I have seen in quite a few (more than I like ) posts, that we get too bogged down with codes and things like that.

The codes and procedures are guide-lines to achieve the minimum requirements and are not always precise definitions of what the equipment demands.

I will like to start from your process output angle. You are hard-facing a component.

The requirements are

- Base metal strength is not compromised.

- There is required bonding between the base metal and overlay

- The overlaid material provides the rquired properties (Hardness, wear resistance- impact/erosion/corrossion as the case may be)

- The overlaid material does not dislodge/ chip off under severest condition.

The necessary tests are to be designed for this.

The WPS/PQR are mandatory (as per at least our internal procedures) to ensure that once the process is stabilised to achieve the required as per above are documented for repeatability. We do not want to be limited to one welder/ one machine do we? And this is even more important for special processes (and welding is of course one of them) and that is irrespective of whether the codes demand/exist. These are our internal document and are part of the processes that we develope and used to guide our vendors for guidelines, however based on these they are to develope their WPS,PQR and WQR.

The hardfacing in one of our critical component (as part of the main equipmen, and not repair) we had introduced some times in early eighties. Then of course as we progressed, we changed over and it is no more there now.

For this we used Stoody-N electrodes and developed the procedures as mentioned above including the wear tests to optimise the parameters, heat treatments etc. The cracks as the previous post said are a part of the game in the hard facing overlay. We too had a lot of apprehension about it, but later got the exact clarification as in the prev post.

The bottom line is get the WPS/PQR done for yourself, not for code.

This Sb Guru has obviously been there and done that! I totally agree with his last statement that the WPS and PQR should be for the company and not for the code! We write the required WPS's and PQR's for the code and then a more precise step by step procedure for performing the work. This is especially true for repairs and surfacing for corrosion, erosion or wear problems in our shop. We deal with coal handling and all the above problems are involved.