Is there anything special I need to do to weld forged steel? Such as pre-heating or anything? I need to repair some Model A wishbone yokes that got a little damaged due to some very stubbon spring perches. If it's not such a great idea to weld on the wishbone yokes, does anyone repop them?
I hope not. I just welded mine up and refinished them. It's just steel that's been smashed into shape by a real heavy hammer, not like cast. I'm no metallurgist and I could be wrong but the only problem I can see is if you welded on a part like an axle it would / could affect the ductility.
IF you are a GOOD welder, there should not be a problem, just approach it like any mild steel project!---------Don
Cool, just wanted to make sure there wasn't a step I was missing. I searched and didn't really find any info. Thanks guys
in my opinion , on thick steel like an axle or wishbone forgings it doesn't hurt to preheat it a bit. it doesn't have to be red hot , just uncomfortable to touch. i was taught this by a guy who was a pipefitter for 40 years...and worked on the Alaska pipeline. you will pleasantly surprise how more smoothly your weld will go but what do i know
36-3window has the right idea. Preheating the forged part will help you get a more even weld especially if you are using something other than a tig. Due to the forging process, the steel molecules are more uniformly and tightly packed than regular cold steel, so it requires more heat to get a certain volume of material to the same temperature. If you are starting with more heat in the forging then it will be easier for the welding arc to bring the temperature of both parts to the melting point and give you better, more even penetration into both parts.
Pre heating is a very good idea for the welding of heavier forged pieces like you are writing about. A large tiger torch is commonly used as a heat source. To check temperature I now use an infra red thermometer, point at the area digital reading tells you how hot. In the past we used to use tempra sticks which look like a large crayon you would heat up the area and mark it with the stick if it melted then you were at the correct temp for that range of stick
Ok cool, I'll pre heat to be safe. What temp. would you recomment to pre heat to? I just need to repair the part where the spring perch goes in so it's not real thick there.
You'll be surprised at how much better penetration your MIG with .035 wire will achieve when you preheat. Even when you use the higher viltage setting, cold steel absorbs the heat from the arc so fast that the weld bead tends to just "lay" on top.
The TIG will make a huge difference. I would still preheat the forging, but with the mismatched heat absorption in the two pieces of metal you've got, using a TIG will allow you to focus the heat on the forging without simultaneously adding filler metal. Just make sure that you've got a good view of what you are doing and pay close attention so that you can keep the puddle centered on the joint. It will tend to spread toward the thinner, non-forged metal.
heat it up until you can spit on it and it evaporates within 2 seconds........shouldn't be a problem.......take yourtime...keep things clean..........
I ground a deep Vee in both parts, then layed in a hot MIG weld aiming the heat at the bottom of the vee then layering over it in one slow pass. The resulting weld looked good and seems to work fine.
HAMB metallurgist here, most forgings are low carbon and no real special welding technique is needed. Pre-heat is good because of the thicker section and mass, not necessarily because of the carbon content. If medium carbon steel is the base metal of the forging then pre-heat is definitely required. TIG is more forgiving than MIG for the welding, but the carbon content rule for preheat still stands. Medium carbon is anything above 0.35% carbon to about 0.75% carbon. Above 0.75% is high carbon and even more difficult to weld, hence why welding cast iron is so difficult to do. Tempil (brand name) sticks or paint melts at the indicated temp, or use the cheap infrared guns. Either one is good method and 300-400F is a good preheat temp to shoot for. Higher is even better, in general no such thing as too much pre-heat. Just still air cooling is fine, no need for insulation or slower cooling.
Any of y'all familiar with spark testing? Its a great and accurate way of determining what type of steel you're dealing with. Different steel alloys give different yet signature spark patterns when you grind them. Figure out the pattern then cross reference your trusty copy of the machinery hand book (if you don't have a copy get one-the older the better) and you will find all you needto know about the proper heat treatment of the metal yer working with.
V it out and if it is cracked heat it to find the end of the crack and make a radius on the end of the crack (drilling works well for that). Preheat if it is blue cold out, I never like to weld anything that is at freezing point for water. One thing that I have learned over the years is that preheating is not heating to the melting point of the material. 400-800 degrees will suffice for most of what any of us is going to weld. you can buy heat sticks but @ 400 degrees +/- water will bead up and roll off.
They're called tempilstiks, made by Tempilstik. One place I worked for had an assortment that we used for annealing and preheating parts. http://www.tempil.com/products/tempilstik-original/
I know this is an old thread, but I want to take this oortunity as a newly member to compliment this very informative forum. So many times I have searched how to do stuff or whatever, and you guys are always right on the money and so respectful. Thanks to this thread I have learned how to mig weld forged steel perfectly. Many thanks to all who have posted in this thread and so many other ones that have helped me over the years. I will be following this forum and try to make suggestions for others when I'm able to.
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