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some people can wreck an anvil with a can of spray paint


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One of my customers dropped this off  last week and said he had a new operator and first day the guy busted this bucket.

He was pretty up set, said his machinic had just welded in  a new base edge  shanks and teeth into it

After looking over the seen of the crime I looked at Jeff and said I hope you didn't get after the operator to much , It was not he's fault.

I then explained what happened was hydrogen cracking,  the cause no or not enough pre heating .

any one that has worked with steel  has noticed when you heat steel water will come to the surface, the thicker the steel the more water it will produce

On mild steel  of 1/2" and under welding won't show  hydrogen cracking. but when you get into heavy plate 3/4" and up Per heating is a good idea and with heat treated steels it's a must.

Pre heating  needs to be done correctly , depending on the grade of steel 275 -325 degrees  F is good but its important to heat all the way through  I call it soaking , we heat it to 275 cover it with a heat blanket and keep checking  and re heating till it's 275 all the way through the plate . At this point the water and hydrogen are expelled from the plate and your ready to weld when we are finished welding we  cover and let it cool over time

 

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25 minutes ago, Rawleigh99 said:

Cool!  Post pictures of the repair as it progresses!  It is always nice to learn from the professionals!

Yes. Please do.I'd like to see that too!

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"any one that has worked with steel  has noticed when you heat steel water will come to the surface, the thicker the steel the more water it will produce"

 

 Steel does not contain water. Copy this and paste it to your bathroom mirror, so you can see it every day.

 The dampness seen on steel from the initial preheat is the water produced by the combustion of the fuel gas.

 Until the steel is over 212 degrees, water will condense out of the flame, and show its presence on the metal.

 This is not to discount the phenomenon of hydrogen embrittlement, which is something to be concerned about when welding high strength steels.

 I teach welding at the local community college, this is one of my pet peeves.

 I had a student who swore up and down that water came out of steel when it was heated. I saw this as a teaching moment.

 We setup an experiment where two identical pieces of metal were heated to 300 degrees.

 One was heated with a rather large electric element, the other with a torch.

 The piece heated electrically did not 'bleed' water.

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...yes..... I remembered  the  heating   and the 'water'   ...from my imformative years, being taught to weld .....at the Caterpillar dealership.....many moons ago......and the absolute requirement   for heating the high carbon,  ground engaging  'steel'

Mike

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1 hour ago, supermechanic said:

 

This is not to discount the phenomenon of hydrogen embrittlement,

I became aware of this in the early '90s when I worked for a place that remanufactured process control equipment.  Stainless steel pancakes (diaphragm sending units to send signals to a pressure transmitter) that had been subjected to hydrogen became brittle and not suitable for remanufacturing, at least as far as I can remember.  That was almost 30 years ago, though, so I could be wrong.

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I welded a ripper tooth bracket on the backside of a Case 9020? Excavator 15 years ago when we rented it. I pre heated it and used 12018 rod to attach it. Last I heard it was still attached to it and this was a rental machine

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2 hours ago, supermechanic said:

 

"any one that has worked with steel  has noticed when you heat steel water will come to the surface, the thicker the steel the more water it will produce"

 

 Steel does not contain water. Copy this and paste it to your bathroom mirror, so you can see it every day.

 The dampness seen on steel from the initial preheat is the water produced by the combustion of the fuel gas.

 Until the steel is over 212 degrees, water will condense out of the flame, and show its presence on the metal.

 This is not to discount the phenomenon of hydrogen embrittlement, which is something to be concerned about when welding high strength steels.

 I teach welding at the local community college, this is one of my pet peeves.

 I had a student who swore up and down that water came out of steel when it was heated. I saw this as a teaching moment.

 We setup an experiment where two identical pieces of metal were heated to 300 degrees.

 One was heated with a rather large electric element, the other with a torch.

 The piece heated electrically did not 'bleed' water.

Bingo. The fuel used is a hydrocarbon. What do you get when you burn HC? H20 and CO2, which then condenses on the surface. I like your teaching moment. I had an argument with one of our weld inspectors over the same thing and we did the same test.

Preheating is necessary to reduce the thermal shock of the welding process. It also slows down the cooling of the weld puddle which in turn makes the weld less brittle. Try welding a 10" disk of 1045 without preheating. It will never stay together.

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Welded a 19' long 5" thick spade nose cutting edge on a Cat 994 loader bucket back in my welding days. A TON of preheating was involved lol, hours and hours. I believe I welded it at 400 degrees. Then I had to bore about 50 holes through it to bolt the wear plates to it (it was a quarry machine). Had to heat it local around each hole to anneal it enough to bore the holes through it. Got to weld on some real interesting things back when I worked at the construction dealer as a welder.

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7 hours ago, nomorejohndeere said:

have you used electric blankets to heat and control the cool down ?  where the process can be stepped down and controlled over a period of time.

 

 

Yes we did a job in a paper mill on a lime kiln  the mill brought in a company called Copper Heat  as I recall they were from England or Scotland 

In 20 hours they had it rapped and up to temp 12' in dia, 275' long 17 men welded for 2 weeks it in the dead of winter and when they started heating it up it was like a sanna for the first 10 hours as they pulled the cold out of the steel

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12 hours ago, supermechanic said:

 

"any one that has worked with steel  has noticed when you heat steel water will come to the surface, the thicker the steel the more water it will produce"

 

 Steel does not contain water. Copy this and paste it to your bathroom mirror, so you can see it every day.

 The dampness seen on steel from the initial preheat is the water produced by the combustion of the fuel gas.

 Until the steel is over 212 degrees, water will condense out of the flame, and show its presence on the metal.

 This is not to discount the phenomenon of hydrogen embrittlement, which is something to be concerned about when welding high strength steels.

 I teach welding at the local community college, this is one of my pet peeves.

 I had a student who swore up and down that water came out of steel when it was heated. I saw this as a teaching moment.

 We setup an experiment where two identical pieces of metal were heated to 300 degrees.

 One was heated with a rather large electric element, the other with a torch.

 The piece heated electrically did not 'bleed' water.

I agree with your water  from fuel gas,  But explain to me when I heat a  base edge say 1.5 to 2" thick why do I see moisture on the back side of the plate? it is very little but it there

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8 hours ago, RBootsMI said:

Welded a 19' long 5" thick spade nose cutting edge on a Cat 994 loader bucket back in my welding days. A TON of preheating was involved lol, hours and hours. I believe I welded it at 400 degrees. Then I had to bore about 50 holes through it to bolt the wear plates to it (it was a quarry machine). Had to heat it local around each hole to anneal it enough to bore the holes through it. Got to weld on some real interesting things back when I worked at the construction dealer as a welder.

Here's a chance for me to learn something. Where I used to work they always welded the wear plates on, then some beads of hard face. I have a couple ideas but don't know if I'm right. So my question is, why do you bolt them on?

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37 minutes ago, 51cub said:

Here's a chance for me to learn something. Where I used to work they always welded the wear plates on, then some beads of hard face. I have a couple ideas but don't know if I'm right. So my question is, why do you bolt them on?

Bolted on cutting edges are easier to change.

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3 minutes ago, 1586 Jeff said:

Bolted on cutting edges are easier to change.

 

4 minutes ago, 1586 Jeff said:

Bolted on cutting edges are easier to change.

On bigger machines and wheel loaders have bolt on wear parts making for quick change outs, machines working 24/7 wear out a lot of iron

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10 hours ago, nomorejohndeere said:

have you used electric blankets to heat and control the cool down ?  where the process can be stepped down and controlled over a period of time.

 

 

 

2 hours ago, m.c.farmerboy said:

Yes we did a job in a paper mill on a lime kiln  the mill brought in a company called Copper Heat  as I recall they were from England or Scotland 

In 20 hours they had it rapped and up to temp 12' in dia, 275' long 17 men welded for 2 weeks it in the dead of winter and when they started heating it up it was like a sanna for the first 10 hours as they pulled the cold out of the steel

 

 

It’s called induction heating.  there are newer ways now but some still use blankets and “chick lets”.   We use Miller Proheat 35’s at work all the time.  Not cheap but very effective and powerful. Ours use Litz cables and we wrap the pipe, but we do have some blankets

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Preheat, first we do it to avoid hydrogen issues. What this video if the link works

The preheat allows the weld to stay hot longer and allow the hydrogen diffuser from the weld.  
 

Second, preheat slows the cooling of the weld so you have less stress on it. Think of dumping cold water into a hot glass, it can crack from the sudden change in temperature. So can your weld

there are more reasons to preheat, but what it really comes down to is if your using higher strength steels, alloys  or working in a  critical application preheat is a good practice.  

finally.  Knocking the sweat out of it, or preheating the steel. If you use heat sources that don’t produce water vapor you don’t get the water.

 

 

just a couple observations to consider.  

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1 hour ago, AKwelder said:

 

 

 

It’s called induction heating.  there are newer ways now but some still use blankets and “chick lets”.   We use Miller Proheat 35’s at work all the time.  Not cheap but very effective and powerful. Ours use Litz cables and we wrap the pipe, but we do have some blankets

are you a pipe line welder? I almost went up there in the 70's but ended up in the army 

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56 minutes ago, lightninboy said:

Can weld a cutting edge onto a farm loader bucket without preheating, though, right? 

you might get away with it But I don't recommend it , most base edges are hi tensil steel  

Before I sold that part of the company off we were building  125 to 150 buckets a year of all types, the few problems we had over 30 plus years where mostly related to per heating 

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10 hours ago, m.c.farmerboy said:

are you a pipe line welder? I almost went up there in the 70's but ended up in the army 

Yes, at least I was. Work in the office more now a days 

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