Post By johnoder
Post By Mark McGrath
Weld Prep Cost Question
What would be your idea of cost (in time) to to track burn and hand grind 2.5" wide and 2.5" deep weld bevel on 4130 plate per inch? I have about 8500 inches aggregate to do on about 30 pieces of 5" plate about half curves and half straight.
This is a how long`s a piece of string question.A 45 deg bevel is roughly 3.5" through the cut.A oxyacetylene burner will run at 3-5 feet/min on that thickness.
How many stop starts will he have?
How good a worker is he?
What quality of cut is he going to leave for the grinding?
If I was costing it I would allow 12-16hours.
OTOH,I have a man here who would do it in 10-12 hours.
Sorry can`t be more specific.
The company i use to work for switched to milling weld preps on a large 50 taper bridge mill.
Firstly you can't have some one running a grinder over here under health and safety law. Hand arm vibration levels.
Secondly the accuracy - Finnish was superb. Practically no post burn clean up We were in high strength steels and cutting haze was a issue. Till then we had done profile burning of weld preps which is slow, but a lot faster - easier than track cutting that much.
Third and most crucially everything went from a V prep to a J prep. Thats a significant reduction in the number - amount of passes to fill the joint back up on heavier plates. Hence massive welding cost savings as well as a reduction in weld induced stress. Ie products should have a lot longer fatigue life in the field.
I know its not answering your question but its food for thought, a 45 degree bevel is way to wide IMHO for most joints needs.
Thanks gents. Roughing in a quote on a 120,000 lb weldment that will consume about 6500 lbs of filler metal. Thinnest plate is 4".
You got a sub arc? That said melting that much fillers going to need lots of coins fed into the electric meter, heck better employ some one just to feed them in :-)
Well worth having a j bevel machined in 1/2 the filler metal.
If xray inspected prolly need to figure on a back gouge also.
What process sub arc, shield arc, shield arc wire. hard wire?
funny talk for a man retired years ago
Roughing in a quote on a 120,000 lb weldment that will consume about 6500 lbs of filler metal. Thinnest plate is 4".
Originally Posted by Heavey Metal
I'm with adama and Heavey..."J" prep would surely be best from a productivity standpopint as long as your code of construction allows it. If you are going to SMAW that mess, you have a lot of hours ahead, even sub arc you can probably only get 20-25#/hr down, unless you have a schnazzy multi-wire SAW running 5000 amps, then I'm really jealous!