I want to weld the base of a jack to a steel plate for a tool I'm making. How can I tell if the base is cast iron or cast steel? The jack is like those used in an engine cherry picker.
Here's something from Google: Hit it with a grinder. Cast iron will throw small red/orange sparks. Cast steel is almost the same as mild steel with yellow to white sparks.(larger than cast iron)
Probably better to make a bolt down retainer frame for a jack, obviously going to be a replaceable repair part at some time.
I have welded it with a MIG before it holds ok but not well enough for anything you are lifting with it. When i did it it was on exhaust for diesel driven compressors and we would fire it up after i welded it to make it cool evenly that is the key to keep it from cracking. If you are welding on something cast you have to make it cool down evenly or it will crack on you. In the past when i did not have Kaowool to wrap it in I have taken small pices and either bury them or put them in a bucket of sand (buried) to make it cool evenly.
Depending on what you are going to do with it, maybe you could br*** braze it. I have a Dodge 4 with a cracked water jacket, on the outside, and I am wondering why I can't braze it. Seems like it would be more doable that weld and less likely to leak. Not a high stress area, I think.
Another way to check cast iron vs steel is to tap with a hammer. If it rings, it is steel, if it kind of thud sound it is cast iron. Welding cast iron is difficult because the high carbon content. MIG will work, but with any welding the risk is cracking along the fusion line. Lots of preheat and slow cooling helps, as well as peening the weld and ductile nickel rod are other means to help. Brazing will not crack and that is probably the easiest for a cracked part. make sure the surface is clean as possible before you braze.
I do not know how big the part is, but I have had success in the past like this. Clean it real good, then clean it even better. Set your oven, (when your ol' lady isnt home) all the way and stick the part in it for about 30 minutes. Take the part out and leave the oven on. Im not sure about mig, but weld it up with Ni Rod after cleaning it again real quick, I have also heard of guys using coat hanger because of the high nickle in it. As soon as you are done put it back in the oven and lower the temp to about 300 for about 20-30 minutes then down to 200 or so for the same amount of time then take it out and let the ambient temp take over. Let it cool slow and evenly. This has worked for me in the past, but believe me, it took alot of failures (cracking from cooling unevenly) from being impatient for me to learn this. Good luck!!!
Often times it is better to braze the thing than trying to weld it.Welding cast iron is a skill you have to practice,but all of the tips given are valid,I employ all of them when I weld cast except I use a rosebud on my torch,I grind a large notch to feather out the boundry line of fill to base material,I use a sand box to slow cooling after post weld heat treatment
If you're talking about welding the base of a hydraulic jack (you said engine cherry picker jack) make sure you dis***emble the jack before welding. Too much heat will cook the seals in it. And also remember that heating a vessel containing fluid can be VERY dangerous if there is no room for the fluid to expand.