4140 bushings

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I am installing new bushings for the pivot on a dump bed. Bushings are 3" OD x 2" ID, the machine shop made them out of 4140. The hinge pin is standard 2" cold roll. I will be welding them into standard A36 channel. Just to double check my plan of attack, I wanted to run it by you guys. I will be preheating the bushings to between 350F and 500F, probably closer to 500. I will be using 7018 filler (straight out of the rod oven), peening with an air scaler while welding. After I am done, post-heat between 500F and 1000F, then wrap in Kaowool insulation to cool slowly. One issue I have is I do not have a temp stick for 1000. I need to check the thermocouple on my meter to see if it goes that high. Am I forgetting anything? Thanks in advance.
Reply:Myself?I would pre heat the bushings..Weld in place..Post heat the bushings and call it a day.No need for all this insulation or stuff like that..In..Out.Done....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Originally Posted by rancher76I am installing new bushings for the pivot on a dump bed. Bushings are 3" OD x 2" ID, the machine shop made them out of 4140. The hinge pin is standard 2" cold roll. I will be welding them into standard A36 channel. Just to double check my plan of attack, I wanted to run it by you guys. I will be preheating the bushings to between 350F and 500F, probably closer to 500. I will be using 7018 filler (straight out of the rod oven), peening with an air scaler while welding. After I am done, post-heat between 500F and 1000F, then wrap in Kaowool insulation to cool slowly. One issue I have is I do not have a temp stick for 1000. I need to check the thermocouple on my meter to see if it goes that high. Am I forgetting anything? Thanks in advance.
Reply:Originally Posted by zapsterMyself?I would pre heat the bushings..Weld in place..Post heat the bushings and call it a day.No need for all this insulation or stuff like that..In..Out.Done....zap!
Reply:Originally Posted by lars66Better check the pin clearance in the bushing before welding around them and shrinking  them on the inside.
Reply:Originally Posted by rancher76The machine shop said they took this into account and left "extra" clearance to compensate. But I will definitely check when I am done.
Reply:Zap, you getting snowed in back there??
Reply:Originally Posted by akpolarisZap, you getting snowed in back there??
Reply:Preheat to 500 is plenty.  Bare steel turns blue at around 500.... at 400 it is straw brown.  Before welding and after just lightly grind a few spots then watch to see the colour when heating with your torch.