Hello All, I am a mechanical designer who is new to the heavy equipment industry. My experience is in camera/lighting systems for the glass industry. I am trying to get up to speed as fast as possible so I don't have to ask so many questions and so that I can add value to my work. I am looking for help understanding common materials used in various parts of excavators and similar equipment. If anyone could chime in on what alloys they are familiar with for various elements of heavy equipment, or let me know of some resources that they would recommend, that would be awesome. Thanks!
Generally the materials used for structures fall into the category of a welded steel structure with castings as reinforcement in critical areas. 1. The steel plate for fabricated box sections is generally a 290 MPa structural steel to a specification something like ASTM A513/A519/A572. 2. The castings would be generally malleable steel and fully weldable when combined with the steel plate as specified above.
occasionally you will see some crane booms and low beds manufactured with T-1
I know this is a pretty old thread but thought i would start here. So if we were going to make repairs on an excavator boom, the above mentioned would be ideal so as to match the original factory metal, correct ? Thanks for any help
Most everyone uses 7018 rod or E70T wire to repair excavator booms. There is nothing exotic in that steel.
50000lb yield plate on most excavator booms , frame components and buckets ive worked on. Qt 400 plate cutting edges and wear bars, 4340 pins induction hardened.
Appreciate that guys. Sounds like with 50000lb plate it would be overkill and possibly a good place for a fracture if a guy used 8018 on that type of plate? I will stick to the 7018 or ER70s-6. As far as plate goes in the 50000lb range, which one of these would be most commonly used or easier to purchase ? ASTM A513/A519/A572.
We just found some 3/8" astm 572 at our local steel supplier for a small fee of $38.30 square ft. This should be comparable to the boom steel ?
Ive alway bought my steel by the lb wheather its plate ,sheetpile,structural steel or pipe. Rule of thumb i keep in mind is 1" plate = 40.84 lbs/sq.ft. divide by 8 = 5.10 lbs/sq ft. X3 = 15.3 for/lbs./sq.ft. your 3/8" PL. Thats 2.50/lb for your 3/8" PL if my math isnt messed up. I have not bought steel for a few months now but that sounds like full retail for a small piece. Im going to call my supplier and get an update on pricing today. If you can get your hands on a steel suppliers hand book they are very handy as they list a lot of grades ,sizes and structural member specs and weights.They used to give them away,I found one from Carnegie Steel printed in 1910 which is still very handy today. I would alway ask for the mill certification on the specific steel i was ordering,lots of times ,especially with structural steel the yield strength would come up higher than spec. This was particularly handy when looking for angle iron for boom repair on my American cranes ,the inspector i have dealt for 30 years with would ask for 50000 yield Angle iron for angle boom chords when we were doing a repair.
Thank ya Tugger .. Thats some good info. and i like the old school stuff for sure. i will have to look that Carnegie steel book up see if i can find one. I have an old Norton tool room grinding hand book. We do some of our own machining and tool sharpening for our machines. That ole book was printed back in 1947 and is just about handier than pockets on a shirt. Appreciate your time.
I'd wouldn't use ER70S-6 solid wire Mig unless it was in spray transfer mode. Penetration/fusion could be suspect. E71-T1 (all position) dual shield flux-core is the closest wire to compare with 7018 stick. Sometimes for additional strength you could use 8018 (8018C3) which has 1% nickel for extra toughness. It is often specified for repairing crane booms unless they are T1. T1 requires 11018 or an equivalent flux-core wire. It is not advisable to use rods such as 11018 on mild steel because it has different properties than the base metal and can crack. Preheat on heavier sections and peening while hot can help relief stress from the welding process.
I worked at a place that made grapples, booms and such for excavators. Like Nige mentions above. Mostly A572 was used.
Sure expensive stuff now.
I have always kept solid wire for doing light gauge materials . Dual shield wire like Lincoln 71 Elite with C o 2 for anything structural on machines. Ive used that wire for QT 100 or QT 400 plate on buckets with no problems.
Solid wire is OK for general repairs that aren't subject to stresses like booms and dozer frames are under.
I have a data book from A J Forsyth (Vancouver BC) that my Dad gave me 30 yrs ago. Cam
Roger that guys.. will use either 8018 or the 71. May be easier to just get 8018 although i like my mig. Also Welder Dave on the preheat what do you like to shoot for as far as temps go ? just enough to fry any egg but not too hot...300 - 400 deg ? Really do appreciate all the info from you guys. Good to know there is still some good ole boys left out there !!
The thing about any welding with flux, is the heat needs to be enough to keep it out of the joint. Very easy to get porosity if you are not an expert at welding. Does the Cat factory use fluxed welding wire for their welds? I have never welded mig with flux. But only use mig on small materials not over 1/4 inch thick. Any thick materials I have always used stick.
One would normally only want an expert welding on booms and sticks. We used both hard wire and dual shield for heavy welding. Hard wire was used a lot for clean metals and high deposition. Dual shield was mainly used for repair welding and a lot of out of position stuff. We used .045 wire with both wire types but only used dual shield for the 1/16" machine. There was a Hobart Handler mig for the small fineness stuff and we only used hard wire. As I recall it had .023 wire in it. The was a roll of inner shield for it but no body touched that stuff. It smelled terrible and coated you nose and throat when using it. Stick was for the most part used for crane booms or something special when I moved out of the shops. The field trucks kept a ten pound sealed tube of 7018 on the truck all the time. When I started in the business the only industry using squirt guns was the ship yards. Critical welds were only done with stick and the exotic stuff was in the aircraft industry or for the piping systems on ships. Now it seems everything is done with a squirt gun.
Around 300 deg's. is usually fine for preheat but it depends on the material. Done properly flux turns to slag and comes to the top. No different than stick welding but usually very easy to remove. I think someone said back in the day Cat used solid wire but in spray arc mode (flat and horizontal welds only). Dual shield flux-core and sub-arc for larger weldments has pretty much taken over. There is metal-core wire that is kind of a cross between solid wire Mig and dual shield without slag but I don't think it's used for heavy equipment much.
The 80K wire on 50K steel isn't as much as a mismatch as it appears. The 80K rating on the wire is ultimate tensile strength, or when it breaks. The 50K on the steel is elastic limit, or where stress loads cause permanent distortion.
I go 300 - 400 degrees on a preheat via crayon also and like the Lincoln 211 "innershield" wire myself if outside repairing something. Still use 7018, and 8018 also on truck frames when called for and the repair is small. Although the suitcase feeder is handy, it's still cumbersome to drag out the leads, feeder, install wire and mig gun, and set up for a small job so stick is still used as everything is together and on running gear. Been many years since welded on booms and such besides repairing dipper and crowd arms on TLB's which was done a lot. Also installed a lot of thumbs in years gone by. Many times I'd repair someone's installation and would groove or arc out the old and cracked welds and triple pass with any of the aforementioned fillers. Nothing has come back for failure I'm aware of.
We used to run a lot of gasless wire doing blade skins,bucket cutting edges. Lincoln NS3M 3/32".Hard to even find big wire like that now,its all 1/16" or 5/64" It was good outdoors as the wind wouldnt affect it. But it was nasty for smoke,white smoke .If the sun was shining into the shop you could see little strings floating in the smoke. I used to take the torch off the track cutter and clamp a wire feed gun to it ,worked awsome for buildup on shovel pads and long welds with 3/32" + Co2 wire. Id do the same thing with a welding positioner for doing Idlers and shovel track rollers .Just rigging a clamp for the gun with a cross feed screw to step the passes over. An old Lincoln handbook of welding led me to these ideas,we just never had access to the fancy Lincoln equipment . Sub Arc was a set up we never did try .
I've done the same thing with my track torch only for plasma cutting long straight, or curved lines via pattern. Don't do it enough to justify a table but a section of plywood laid out, or a small tube formed into the shape you need works very well for the tractor wheels to bear/slide against.
I bought a 5'X10' table years ago.Its 2 torches follows hand drawn patterns ,black ink on white background drawn full scale. Its a very handy tool around the shop when your inventing things. If i need big chunks or multiple peices i get my steel supplier to burn for me ,but they are always 2 weeks out .Special stuff i can do on my own when i need it .
We would preheat at least enough to drive the moisture out of the steel. On big stuff like plating stacker booms we would preheat and then throw a blanket on top and sit down on it for cold mornings. For ripper shanks we only used rod and preheat was a minimum 300 degrees. We kept inter-pass temps around 500 degrees one inch to the sides of where the cover passes would sit. We would post heat keeping temps above 300 for a couple of hours after the last pass and then cover the welded sections in blankets to cool at least overnight. I did that based on what the old timers who taught in the welding schools told us when I was there. There was never a procedure given for any of the noses and quarter shanks that we purchased. Bucket tooth shanks were different in that all that was ever done was preheat till the water was gone and start pouring the wire in. When all was finished we slapped on the teeth and put it to work. Broken booms, sticks and heel racks happened all the time on the loggers. Air out the cracks, grind everything smooth and pour the rod back in. Never removed a boom or stick for those repairs. The guys at the Komatsu dealer I worked at used the dual shield on all those and I admired their work. When they were done, it looked good. The Cat dealership guys were locked to whatever Cat said to do. It was always done nice but all the hoops that Cat engineering put down meant the repairs took far longer and were far more expensive than anyone else would have charged. Booms removed and cut apart at the cracks. New backing strips welded inside, extensive grinding done on inside and outside and all the welds done flat. There were many 308 and larger booms that were just scrapped and new booms provided. In the end user machines, there are a lot of cracked booms and sticks that were just arced out in place, welded up, ground smooth and fish plated to solve the problem.
NR211 MP Innershield is about the worst wire to use for high stress applications. It is a basic general purpose wire and not designed for dynamic loading. NR232 or 233 would be much better choices for Innershield. NR211 isn't even recommended for over 3/4" steel and that's with the largest wire size. Years ago when it was just NR211 it required something like 22 passes on 3/4" test plates to meet the required specs. If you can block the wind or work inside dual-shield flux-core is the best option if there's a significant amount of weld required. Smaller jobs stick is usually the easiest process.
I never had any problems with it, (NR211) myself but really wasn't putting things such as boxed sections back together that were snapped off; only welding back together after vee grooving out the cracks to ensure full penetration. Don't think I've ever welded anything broken near 3/4" in thickness.
The problem is the wire isn't designed for twisting and loads under a lot of stress.
I would agree. I did not do a lot of welding jobs offered as I've not been certified or really had any formal training of the craft. Just happened to know how to weld, (for the most part as self taught). I always look at "liability exposure" before engaging in most any activity where something or somebody could get hurt, or worse. Most everything I've worked with has been repair type affairs with the occasional add on or modification.
Welding is a great skill to have. Sometimes all someone needs to do is ask for some assistance in how to best tackle a repair and the best filler metal to use. I've seen a few self taught welders that I could have helped with 5 minutes of instruction but they were too stubborn to ask. It can be as simple as the right rod angle.
It's been a great skill to have and be able to work with. Guy across the street from us in the early 70's was an excellent welder out of his garage in the back yard and had a nice mobile setup for the times on his one ton Chevrolet truck. He actually gave me my first Hobart Bros. G-213 engine drive machine. I learned a lot by watching, keeping my eyes open, and mouth shut except for when I had a question. The question(s) was/were then answered in terms I could understand. In hindsight it wasn't too bad being 12-14 years old at the time. I still remember like it was yesterday the booming voice: "Get me a beer boy, I'm gonna learn you sumthun". Agent Orange was blamed for the cancer that took him away in 78. Few people in this life I've actually looked up to and he certainly was one. I still have the 68 Plymouth Barracuda given me he purchased new as a reward for surviving the time across the pond courtesy of Uncle Sam. Swore I'd never sell it and that word has been kept since 4/26/76 which is the day I got a driver's license.
Let's see some pics. of the car.
Rather poor images taken almost five years ago. I have the fully rebuilt original 340 engine and four speed transmission in the shop but not reinstalled. The car had almost 341,000 miles on it when I quite driving it almost daily in March, 1996 when my new Dodge truck came in which I still drive daily. Up till that time, only a water pump, alternator, master cylinder, and routine maintenance had been performed for it's operational life. I have NOS OEM fenders, doors, and DMD reproduction 1/4 panels which are stamped from the original OEM dies to replace the originals some day. Was dating my wife when the car was given to me and still have both. She is "Affair 1" and wouldn't let me have that number for the plate so had to settle for number two. The shop was called "Auto Affair" so where the name originated. Once kids educations were funded, the shop was closed yet retained.
That would be excellent to restore.
Dayum thats one heck of a car for sure ! Im just finishing up a big truck, class 8 Bison with cummins big cam.... restored from frame up. I try and post some pics soon. thanks for sharing... you need to get the ole Barracuda restored.