Monster Truck Steering Knuckles 4140 as forged 1

[MonsterShop]

Ive taken on this job recently and Im ready to start the welding process. These are 14" dia rings approx 2" wall thickness 4140 as forged mtl (not annealed - about rc35) with flat pads milled on each side. The pads have slots milled across them where I will slip in steel plates to be ARC welded in place. These plates constitute steering arms for the knuckle. The plates will be plasma cut from two sizes: .375" and .625".

I realize of course pre and post heating are necessary. I could really use some help with the temperatures and times, recommended Arc welding electrodes and type of steel to use for the plates. Remember the rings are as forged at rc35, I went with that material to provide max durability and by machining it I know its tuff as hell.

I really appreciate any advice. Thanks in advance!

 

[metengr]

MonsterShop;
Is this for a hobby car? Also, are you sure about the design, strength requirements and weld joint detail?

Have you ever welded before with low alloy steel, do you have a welding procedure, what is the welding process you selected, what is the pad material that will be joined to the 4140 alloy steel????

I believe you can tell from my specific questions you need to better explain what you going to do before someone gets hurt

 

[MonsterShop]

Thanks for your questions. It is for a test vehicle. The design, stregth and weld are uncertain until tested however my 12 years of manufacturing experience in machining, and axle assembly tells me that it will exceed the expectations of the customer.

My welding experience includes mainly stick welding of stainless, and alloy steel. I have welded 4140 proir however for non critical jobs.

The process is smaw. The pad is machined on the 4140 ring so its 4140 mtl. I thought I would use 4140 mtl for the plates but could use a recommedation for something less expensive that would work. Also will use low hydrogen electrodes but could use a recommendation for type.

Thanks again

 

[metengr]

Preheat for 4140 base material; 400 deg F

Your PWHT (post weld heat treatment) will depend on the original heat treatment condition of the 4140 material that you purchased. Typically, you try to remain 50 deg F below the original tempering temperature of the 4140 ring and pad material for PWHT. The original tempering temperature can be determined from the material test report for the forging and the pad material.

Filler metal; E8018 B2 H4

Suggested nondestructive testing - wet fluorescent magnetic particle testing

 

[MonsterShop]

Originally I thought Id use 4140 for the steering arm plates to match the pad area on the ring. Can you recommed an alternate more readily availible material and if so would the filler metal change?
Mag particle inspection has been added to our inspection process for this job.
Thanks