Thread: Hard Facing

Hi pipeclay
Put enough heat through welding into almost anything and it will distort to one degree or another.

A good size bucket should not present problems.

There is a bit more into hardfacing large areas than you might think.
Patterning so that the dirt cakes in between blocks of hardfacing saves time and money and overlay with a buttering layer of a flexible material come to mind.

Try doing a google search using the term hardfacing and earthmoving.

Finally be aware that the chromium content in the electrodes and wires are toxic stuff.Be warned.

Grahame

Thankyou,just wasnt 100% sure about the distortion,everything seems ok went with a cross hatch pattern.
Will have to search for (overlay with a buttering pattern I have no idea what that means at the moment).

Hi Pipeclay

Sorry did not have a lot of time this morning .Some ground engaging tools,buckets to mugs like us wear greatly around the lip area in particular.

The patterning idea is to get the chunks of dirt to build up between the hardfaced blocks so dirt wears on dirt and less hardfacing is required - saving money. The larger face shovels and the like are fitted with cast hard material blocks for this reason.

With the overlay ,the cutting edges are hard to begin with, and depositing hard materials on top of hard material causes cracking and peel off in some instances.

The trick has been to overlay the hard inflexible stuff with some flexible material like stainless and deposit the really hard on top.
When the bucket engages ( digs ) the stress and movement is taken up by the springy flexible overlay and less cracking occurs.

There are still small check cracks from contraction on the surface but there are necessary as a stress relief.

Again watch out for this stuff if you suck up some fumes it will make you sick as well as potentially give you cancer.

When I had to grind some of this S**T the dust in the air that settled on my lips made them sting.From that point I wore a respirator, even for grinding.

I remember seeing a lot of hardfacing info on one of the welding sites but can't remember which one .Earthmoving sites might be another area to look.
Attached is a piccy of chocky blocks fitted to a larger excavator bucket to give you an idea.The soil jams in between them and stays there.

Grahame

Just two other points to add to what Grahame stated. Be aware that you will need to use the barest minimum amps that will do the job, hard facing isn't meant to be pretty or smooth. the more that you burn it in the softer it will be from mixing with the parent metal. and the the other point is that you will need to have the correct build up on the first run, as it isn't advisable to do multiple runs over the top of each other. I have seen the second run peal off as quick as to went on. I wouldn't be worried about heat build up because you aren't confined the start at one end and finish at the other, if you feel that it is too hot move to another spot and go again.

Hope this helps

Robert

Thanks very much for the information from both,in regards to the layering and patterning I was thinking that it was some special welding type.
The buckets are only for a 7ton excavator so not overly big,did put the horizontal runs down at 115amps and the vertical at between 70 to 90,all have been single runs with rods of hardness 60.
Will take all that you both have mentioned on board for next time and incase there are any problems.
All the welding has been done in the open air so fume dissapation hasnt really been a problem.