This is a bit late now but I figured I'd give you my input on this for future reference.First, I have to go along with Steve U.S. Alloys with the pre-heat. 400F is good for all general purpose uses in heavy equipment attachments. 400F will not even be a dull red, the best way is to use a "color stick" or "heat stick" as they are commonly called unless you are good at "feeling" the heat. (8 years of working in plastic extrusion, you get to know the "feel" of how hot something is within 10 to 20 degrees) Going any higher than 500F and you run the risk of inducing sub surface crystalization and fractures along the heat effected zone that exceeds this temp. I've done hundreds of repairs such as this one. The first thing you need to do is remove the cutting edge from the blade if the crack is within 3" of the crack. If the cutting edge is cracked (read the post quick and don't recall the exact details you gave) you need to repair it off the blade to get a good weld. For the cutting edge, you need to place it on a flat surface such a welding table or concrete floor that it smooth. Bevel both sides of the break to within 1/8" of the center thickness wise. Allign both pieces to there proper position. To keep them in place for the repair, I tack weld a piece of bar stock to each edge. Pre-heat the weld area and 1" to either side to 400F. For rod alloy, you should select a rod that is as close to the base metal as possible. From experience, these cutting edges are not usually different from those used on snow plows and loader buckets if at all. They are generally a low to medium manganeze alloyed steel. For the root pass I use regular 1/8" E7018. (usually, 3 passes are sufficient for the fillet) The second and third pass I will usually use either 1/8" or 3/16" E8018 or E9018 depending on the appearance of the base metal hardness using the grinder spark test. These alloy rods will help increase the tensile strength of the weld without making an overly hard spot. Run a 1" long root bead on one side to one edge of the piece in a normal weaving manner. Flip the part and put another 1" weld opposite the first one. Allow at least 15 minutes cool time for these welds then using 1" long stiches, flipping after each one, finish the root pass. For second and third pass, use a deep cutting weave action to get a good mix of the weld puddle and base metal. Once the root is done, run weaving cover passes to finish the fillet in the same manner with 1" stiches and flipping after each one. Once the weld is complete and still hot, you need to pein the weld hard. The best way to do this is with an air hammer and a ball point bit 1/4" in diameter. If you don't have this, use at least a 32oz ball pein hammer and beat the snot out of the weld bead and 1" to either side of it. This will stress relieve the weld and heat effect zone. When the peining is done, you need to re-heat the weld bead evenly till it is dull red color, about 1000 to 1200 degrees. Allow it to air cool until the red color is gone peining lightly with hand hammer on both sides while cooling. Once it has cooled to around 400F drench cool it with luke warm water. This will help return the weld/heat area the original temper without creating any stress areas or brittle points. The biggest thing you need to watch with the blade is warping it with the weld. Groove the crack as like with the cutting edge instructions. You need to weld this in the same manner as well. Pre-heat only to 400F max, in reality, 200F is sufficient for the blade alloy. The root pass should be done with 3/32" E6011 assuming this is a normal sized machine with a blade metal thickness of 3/8" to 1/2". The use of the smaller diameter rod in a vertical up bead will help control the heat placed into the work and allow you to make an clean easy root without overheating the base metal. As with any type repair like this, use stitch welds (one full rod if using the 3/32 diameter) and flip flop sides between beads so you don't warp the blade. Clean the root pass and use 1/8" E-6011 V-up for the second pass using the same manner as the root bead but working in an opposite sequence. Don't try to fill too much on the second pass with the E6011, run a normal thickness bead. Now use the E7018 for the cover pass using a wide weave and getting a good mix with the base metal and also using opposite sequence as the prior bead. Pein these cover passes as you finish each stich with the air hammer or ball pein. Don't be afraid of beating on it, the more you pound it, the better it will be in the end. Deforming the hot bead is fine when doing this work, don't worry about it being pretty looking when done. No one cares what it looks like as long as it holds. I think you also asked about the E6013LV rods. These are designed to work best when used on AC current buzz box type machines like the little Lincoln 225, Sears 225, older Miller Thunderbolt and the like. The "LV" stands for Low Voltage. These machines usually allow the weld voltage to drop off signifigantly when the arc is struck as compared with machines like the heavy duty production machines. Unlike the standard E6013 rods like 1/8" which are usually run on the 75 to 90 amp settings, the "LV's" need to be jacked up to 115 or 130 amp range in order to get a good weld bead. These LV rods also differ in the manner in which you will run the bead. The standard E6013 rods will be run like an E6011 maintaining an arc gap from the base metal equal to the diameter of the rod no matter if using AC or DC weld current. The LV's will be run like an E7018 on DC electrode positive. You want to drag the rod touching the base metal lightly. If you allow an arc gap greater than a few thousanths of an inch, you will get slag inclusion into the weld. Always start the arc out of the weld area or you will get slag inclusion as well. Once the arc starts, get the rod touching the base metal, if it sticks, you need to increase the current range until it runs smooth. These rods will run a very smooth arc like a 7018 on DC with little sparks and quiet sound, nothing like a standard 6013. Keep the rod angle to work around 80 degrees, no less but closer to 90 degrees is OK, if you need to, even for V-up welds. These are excellent rods and will run on any AC machine perfectly and produce high quality welds if done correctly. To be quite honest, they won't run for crap on DC machines especially production machines. I learned all these tricks after years of trial and error and doing a lot of free repairs to correct mistakes I made. As for the E6013LV rods, I used these too thus is why I know how to run them and what machines they will work on and what ones they won't. The tech manuals and text books give you a lot of basics but not as much as getting out there knee deep in the mud, butt deep in the snow and twisted into 10,000 directions the human body should never possibly be expected to get twisted into without breaking things that hurt. Been there, done that, got the scars to prove it.
|
