I have a client that had an axle break on a dolly. The client said that the axle was ASTM 1045. I took a look at the setup and it appeared that the axle fractured in shear. When I took a look at the axle, I noticed that it had been welded at the fracture location. I was wondering if welding this material could have contributed to the cause of the failure.
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ASTM 1045 Weldable?
- Thread starter DWHA
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DWHA;
Yes. In general, 1045 carbon steel can be welded provided preheat requirements are followed closely. In some cases a stress relief or post weld heat treatment may be required. The lack of preheat is normally the cause of most weldability problems with higher carbon grades of steel. Did the failure occur along the edge of the weld? If so, this would most likely be cause by lack of proper preheat during welding.
Yes. In general, 1045 carbon steel can be welded provided preheat requirements are followed closely. In some cases a stress relief or post weld heat treatment may be required. The lack of preheat is normally the cause of most weldability problems with higher carbon grades of steel. Did the failure occur along the edge of the weld? If so, this would most likely be cause by lack of proper preheat during welding.
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StructMech
Structural
I was discussing welding 1045 steel with another engineer yesterday and he indicated the quality and integrity of welds on 1045 is poor at best. Both of us know about pre-heating. Is there a grade of weld wire or something else that has worked well for you in this application?
Bottom line is the weld most certainly played a factor. However, it is not necessarily a material factor as you state in your thread.
It is generally accepted that all welded structures are put into service with some type of discontinuities. But we also have to remember that not all discontinuities rise to the level of defects that need to be repaired.
Even with proper preheat, welding procedures and good NDE you very likely had some type of discontinuity in the toe or edge of the weld that created a stress raiser which contributed to the failure. Examination of the fracture origin in the SEM will tell you a lot.
The material become more of a factor here if improper welding procedures were used because then not only do discontinuities play a factor, but microstructure and phases can play a factor due to differences in fatigue or fracture initiation resistance.
It is generally accepted that all welded structures are put into service with some type of discontinuities. But we also have to remember that not all discontinuities rise to the level of defects that need to be repaired.
Even with proper preheat, welding procedures and good NDE you very likely had some type of discontinuity in the toe or edge of the weld that created a stress raiser which contributed to the failure. Examination of the fracture origin in the SEM will tell you a lot.
The material become more of a factor here if improper welding procedures were used because then not only do discontinuities play a factor, but microstructure and phases can play a factor due to differences in fatigue or fracture initiation resistance.
StructMech
Structural
I found a book called "Metals and How to Weld Them". The James F. Lincoln Foundation website jflf.org sells it. This book explains the how's and why's of welding medium and high carbon steel. I've been looking all over the place trying to gather enough understanding to feel comfortable welding ASTM 1045 and other medium or high carbon steels. This book is amazingly clear. I recommend this book to anyone looking for a "practical how to" on welding metals.
If you use a filler material with similar chemistry to the parent metal and preheat and weld between 1000°F and 1500°F, cool slowly, anneal and heat treat the required hardness you will limit everything but grain structure differences. It is mandatory to over weld and machine back to original size.
For 1045 this is going to be difficult because of filler material availability. In the mid 1980’s we fabricated a prototype high speed track out of C1026 and C1040 and used a .30 carbon weld wire, annealed and heat treated the blocks and none cracked. The C1026 did stretch past yield under load. We have had good success using an E80SD2 welding wire C1045 to 8620.
Ed Danzer
For 1045 this is going to be difficult because of filler material availability. In the mid 1980’s we fabricated a prototype high speed track out of C1026 and C1040 and used a .30 carbon weld wire, annealed and heat treated the blocks and none cracked. The C1026 did stretch past yield under load. We have had good success using an E80SD2 welding wire C1045 to 8620.
Ed Danzer
Are you sure it was a clear shear failure? There is no apparent edge galling, or galling on the "hump" near the top. Any possibility of bending failure or combination torsional/bending failure?
Poor weld profile could have contributed to fatigue crack propagation, however, there does not appear to be any significant fatigue progression. Single event overload more likely.
Is the weld there just to keep the axle stub from sliding out? If so, why not key it and do away with the weld?
Poor weld profile could have contributed to fatigue crack propagation, however, there does not appear to be any significant fatigue progression. Single event overload more likely.
Is the weld there just to keep the axle stub from sliding out? If so, why not key it and do away with the weld?
The remaining weld looks like it was welded a little cold. It looks like the weld is still there and it failed at the toe/HAZ. If you look at toe between 12 and 1 o'clock you can see the weld looks to have been under-filled or undercut the base metal. Also, in this area the weld has convexity this is an indication of the volts being to low. The root toe in this area show no signs of shearing. The surface is smooth and looks as if it was not bonded well during failure(this is also seen in other areas of the root toe). At about 3 o'clock it's hard to tell but it looks like you can see the outline of the weld pass (poor fusion).I'm no expert just stating what I'm seeing.
Sure looks like you've got a small fatigue crack right at 6 o'clock. That's right where you'd expect it to start.
Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling
Gold is for the mistress - silver for the maid
Copper for the craftsman cunning in his trade.
"Good!" said the Baron, sitting in his hall
But iron - cold iron is the master of them all.
Rudyard Kipling
Take a second look at your second photograph. I see clear evidence of ratchet marks around the perimeter of the fracture surface. This suggests some torsional component to the failure.
It's tough to tell what definitely happened after the fracture surface was painted???
There are several spots of undercut visible in the toe lines of the weld at 12 o'clock.
Any one of those undercut defects/discontinuities could have been the point of origin for the fatigue failure that occurred here.
You can reweld this successfully. A previous poster mentioned ER80 solid wire. This is probably sufficient to the task. Given a choice, I'd find some ER90 filler or stick weld it with E9018 low hydrodren rod. Given a choice I'd TIG weld this, but any skilled welder should be able to make this repair with whatever process is available.
Were I doing this, I'd start by grinding, gouging, or machining out the old weld and remove any fatigued metal at the fracture surface. Try not to recess the joint below the surface of the surrounding plate any more than necessary, as this will complicate welding. That is, unless it's practical to remove the entire shaft to repair it.
Prep the new shaft stub by beveling it at ~30° angle, using a double bevel prep. Blunt the tapered end of the joint tip slightly, to facilitate welding a full penetration root pass. I'd pre-heat the joint to ~400°F before commencing welding. Then fill each side of the bevel, alternating sides to minimize distortion. Allow the joint to cool to an interpass temperature of 500°F max between passes. Once welding is complete, Pack the joint in glass fiber insulation to slow cooling.
It's tough to tell what definitely happened after the fracture surface was painted???
There are several spots of undercut visible in the toe lines of the weld at 12 o'clock.
Any one of those undercut defects/discontinuities could have been the point of origin for the fatigue failure that occurred here.
You can reweld this successfully. A previous poster mentioned ER80 solid wire. This is probably sufficient to the task. Given a choice, I'd find some ER90 filler or stick weld it with E9018 low hydrodren rod. Given a choice I'd TIG weld this, but any skilled welder should be able to make this repair with whatever process is available.
Were I doing this, I'd start by grinding, gouging, or machining out the old weld and remove any fatigued metal at the fracture surface. Try not to recess the joint below the surface of the surrounding plate any more than necessary, as this will complicate welding. That is, unless it's practical to remove the entire shaft to repair it.
Prep the new shaft stub by beveling it at ~30° angle, using a double bevel prep. Blunt the tapered end of the joint tip slightly, to facilitate welding a full penetration root pass. I'd pre-heat the joint to ~400°F before commencing welding. Then fill each side of the bevel, alternating sides to minimize distortion. Allow the joint to cool to an interpass temperature of 500°F max between passes. Once welding is complete, Pack the joint in glass fiber insulation to slow cooling.
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