Slightly different take: Heavy welding repair

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Hello folks, over my spring break (teach at a CC) I had an opportunity to participate in a repair to a platen on a 24,000 ton extrusion press. Initially the cracks were located by a third-party inspection company and then we came in and excavated and repaired the cracks. Utilized 2 induction heating machines to bring the part up to temp (400 to 450 degrees F, more like 550 to 600 degrees in reality). Then gouged, ground and welded for 10 days, 24 hours a day. SMAW process, E7018 5/32" and 1/8" electrodes, around 450 to 500 lbs. worth. Here are a few pictures. Best regards. Allan Attached Imagesaevald
Reply:Have a couple more photos to include: Best regards, Allan Attached Imagesaevald
Reply:Wow... that is an awesome project.  Many thanks for sharing.... Can I ask a few questions?On your first photo, there is a brown area around each of the cracks..Is that rust, or is that some sort of dye penetrant to highlight the cracks in the first place?How do you get in there to stick weld (oops, sorry... Shielded Metal Arc Welding -SMAW), without burning yourself on the hot block of steel?  How many times did you cuss and say dang, I burned myself again...?What material are they extruding?  Plastic, aluminum or perhaps some other sort of metal?How did you clean up all the flux.. wirebrushes?  It doesn't look like any grinders were used...and finally, it looks like the molten material being extruded will flow thru the oriface right over the weld beads without additional machining work.  Is what we see the final product or is there more machining to do?Again, many thanks for sharing this mega project.
Reply:Just curious - why using such small electrodes?  I would think with that much material to deposit it would pay off in short order to have a bigger machine capable of pushing 1/4" rod (or larger) or does that cause other problems?
Reply:Hello zipzit, the coloring of the "cracks" was mainly due to the inspector using a paint pen to roughly mark them out. The heating of the part caused the paint to change color to more of a brown hue. There was also some yellowish dust that you can see in some of the pictures, this is the iron powder that was used for the mag-particle inspection to better see and determine whether the cracks were fully removed or not before welding and filling began to complete the repair.      You asked about the heat, there is a product that I know of as K.O. Wool, it is essentially a type of ceramic insulating material that has some pretty amazing heat-retention and protection abilities. This was used for both protection from the heat for the welders and for helping to maintain a proper preheat and when it was all done, to provide the proper postheat welding procedure. I did spend a lot of time welding in a very hot environment for the duration of the repair process. Lost a fair amount of weight, drank a lot of fluids and didn't make a lot of trips to the restroom. Perspiration was the primary method of fluid loss.      The part that you are seeing there is 24" thick, the large hole is roughly 10" in diameter, the two partial side holes are probably around 4" diameter. Had to reach into the hole, start the beads and draw them outward in order to see where you were going. Also bent a lot of rods in order to achieve the proper rod angle to make a weld without having a shower of spatter while welding. This was definitely not your average welding challenge nor the same as most of the welding that a structural welder might see. The key was to try to weld it in a structured progression that would prevent un-needed starts and stops or starts that might leave porosity. Most starts were made with "new" electrodes, thus there was a lot of stub loss. That part kind of goes against my grain, yet, the cost of a few electrodes isn't worth the rework that could result either. Hope this answers some of what you were questioning. Best regards, AllanEDIT: this was for aluminum extrusion, this is the plate that holds the dies in place while the extruding is taking placeLast edited by aevald; 04-11-2012 at 07:43 PM.aevald
Reply:Hello greenbuggy, a lot of what you are seeing was welded in the horizontal position, overhead position, and other odd contorted ways. 5/32", by our experience and that of others, would provide the best opportunity for success for this particular repair. I do understand your question. Best regards, Allanaevald
Reply:Nifty!
Reply:Out of curiosity,  I have been in situations that used high number of electrodes due to having to bend them.  until one job where we were able to break out the 12 inch long reach fluxcore gun.  Once you have tried it you will wonder why it took you so long to pull the trigger on it.  I know much of the process it determined by some engineer, but it look like it would have been able to do what you were wanting to do.  any thoughts?  by the way I love the stringers.  Very consistent!
Reply:Hello Scott, I believe that low hydrogen electrodes were specified on this one. Another problem was the depth and space that everything was happening in, a full-length rod did or a long necked wire gun could have put the welding arc at such a low angle that spatter/arc blow was or would have been a serious problem. Overhead at a low electrode/gun angle is typically even a more difficult situation to contend with. So that is the main reason for the process choice and some of the applications of bent-rod welds. Rod choice was additionally influenced by a pre-repair analysis of the material. A sample was sent to a metallurgical laboratory for analysis and testing and the basic WPS was determined based on their findings. Thanks for your comments and suggestions. Best regards, Allanaevald
Reply:How long did it take you to complete the work and were there any interpass temp limits or concerns, or did you just go to town on it?"Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Hello kolot, the gouging and welding started on a Monday afternoon at 1:00pm, proceeded non-stop for approximately 8/24 hour shifts and then was treated to a post weld treatment for roughly another day and a half. About the time that they were going to sign it off, they found another crack in a different spot on the casting and had to implement another repair regimen, roughly another 5 days worth. Yes, interpass temps were a concern and monitored, yet the size of this thing didn't present much of a danger of exceeding those limits. We implemented a log system to track temps. Additionally the two induction heaters each had 4 thermocouples to provide additional temperature monitoring and control of temps. Hope that answers your questions. Best regards, Allanaevald
Reply:NNNNICE UNIFORM BEADS!WE use the KOWool on a regular basis for insulating too. Did you notice a scatching in the throat or where you wearing a respirator also? I'll give you credit-that would have been hot!
Reply:Thank you, and that is a lot of work, more time than I had thought but I'm having a hard time figuring the scale of that , it does look pretty sizable and with stringers to fill that I can see where it takes a lot of time.Nice work, sorry to hear you found a second crack. Keep everybody working though."Si Vis Pacem Para Bellum"Lincoln Idealarc 250 AC/DCMillermatic 251   Syncrowave 300   30A spoolgunLincoln MP210Hypertherm 45(2) LN 25(2) Lincoln Weldanpower 225 CV(4) SA200   1 short hood    SA250    SAM 400
Reply:Thats some cool work. Way beyond my skill level. After all the welding was done was there a considerable amount of mill work to get the opening back to the original dimension. If you have any pics of the machine work I would like to see those to. Very interesting post.
Reply:Hello bhardy501, I understand that they brought in another company to do some of the profiling by milling. I believe they use a portable Climax milling machine. I have not seen the "finished" product. I usually end up going in every now and then to do additional work at this facility. If I can get in there I will see about getting a look at how it was finished. In the past the profiling was done with a carbon arc and grinders. I'm glad that wasn't the case this time. I am at home right now and don't have access to my full library of pictures. If you have never seen some of these portable milling units I will try to find some pictures that I have of milling flanges on wind tower sections. They will give you an idea of the size of some of these machines and their capabilities. Thanks for the comments and questions. Best regards, Allanaevald
Reply:Thanks.
Reply:Hello bhardy501, here are some pictures of a Climax milling machine that they are preparing to attach to the end flange of a wind tower section to machine it flat. I have seen various Climax equipment for portable machining purposes, I believe them to be a very innovative company and provide some really top-rate equipment. Hope you enjoy the pictures. Best regards, Allan Attached Imagesaevald
Reply:Hello EliasFaust, if you are asking about the powder, it's the iron powder that was used during the mag-partical inspection phases of the repair. You can get this medium in different colors for various uses and so that it can be seen better depending upon what you are inspecting. Best regards, Allanaevald
Reply:Wow, thats a cool peice of equipment. Never saw anything like that, especially in operation. I did see a lathe one time in operation that had such a long bed travel that the operator had a seat mounted to the carriage, I think it had a 60 ft bad and a swing of 6 ft. it was used to turn shafts for power plant motors. Thanks for the photos.