C103 Electrode Sampling
|Team Name||Niobium Extraction Squad|
|Duration||Summer 2018 - Fall 2018|
|Faculty Adviser||Matthew Swenson
The goal of the project is to improve the sampling process by which ATI (Allegheny Technologies – Albany, OR) uses to sample their Niobium Alloy, C103.
ATI is global provider of specialty alloys and components which include our alloy of interest, Niobium based C-103. C-103 is refractory alloy commonly used for aerospace applications due to its heat resistive properties. For quality control purposes, ATI samples each C103 ingot they forge multiple times so verification testing can be completed at their lab. The current process which accomplishes this task is via the use of an air hammer while it is held in a lathe. This practice often produces inconsistent samples that are either rejected by the lab or produce skewed results, and is not at all ergonomic.
The scope of this project, titled C103 Electrode Sampling, is to create a sampling mechanism to improve the current procedure on the C103 ingot and final C103 pole. The focus will be placed on changing the operator’s current sampling process to meet the lab’s wants/needs and improve efficiency for the operators. An improved and successful sampling mechanism/process will be faster and consistent as well as incur savings as a result of reduced yield loss.
- Produce CONSISTENT samples
- Reduce the time it takes the operators to take sample from the logs/electrodes
- Produce samples that have a relatively flat surface area, so that lab technicians can easily prep and test accurately
- Minimize the depth of tooling into the logs/electrodes when sampling
- Sample should provide 4 grams of turnings for the lab
- Reduce possibilities of contamination
- Be more ergonomic and efficient so that the operator experiences less strain when taking samples
- Sample should be at least ⅛” thick and at least ½” by ½”
As this is a class project, we have been cataloging things we have learned along the way.
- We have taken great strides in communication, learning how to set up conference calls, and effectively use email chains as a primary means of communication, both with fellow team members, and with other team memebers.
- So far, we have learned that C103 can be brittle, and react negatively with aluminium.
- Alloy Formation Process
- Client interview trip
- Final C103 is crumbly and brittle
- C103 cannot come into contact with aluminium
- Alloy forged incopper crucibles and undergo electromagnetic stirring
- Pole sampling done at top, 3/4 point, ½ point, 1/4 point, and bottom
- Relatively flat metal surface preferred for gas analysis
- Common dimple sampling technique not ideal for C103 alloy; technique cause fab to remove significant amount of material in preparing final product for shipping. Expensive alloy.
- Lab prefers to make their own millings/turnings
- Go/no go gauge idea was well received
- Hardened steel chisel was used
- C103 used for second stage rocket engine applications, ex. SpaceX and Apollo 11
- Niobium is the lightest of the refractory metals and makes it a good candidate for aerospace applications
- Sampling happens to make sure that they are correctly alloying the Niobium
There were several concepts we came up before arriving at our final concept.
|Idea||Description||Supporting Image 1||Supporting Image 2||Supporting Image 3|
|Ramset Design||The Ramset concept was based off of a construction tool called a ramset. A ramset is a nail gun loaded with a 0.22 caliber that shoots a nail to fasten objects, like sheet metal, to a concrete wall. The idea was to punch out samples from the ingots at a high velocity. With high velocity it would take milliseconds for the device to take a sample. When revised, the updated design has a bar mount to the initial sawhorse, and uses a simple lever design to simply increase the force and guide the existing chisel.|
|Hydraulic Strap||External structure to lathe that slides into place and latches two sides together over the top of the lathe to allow operator to operate air chisel with guidance assistance and pushing assistances on the air chisel.|
|Hydraulic Collar||This is collar/pinching mechanism that has curved teeth to bite out tangent to the poles. When revised, the updated design uses a hydraulic press to push a tooth on a guide to scrape out a piece slowly, but more consistently.|
|Pendulum Swing Blade||Blade/chisel moving in pendulum motion to minimize impact depth.|
As per the decision matrix, we decided to somehow attach a chisel to a hydraulic cylinder, and hold that onto the log to take a sample. We spent months developing this idea, and it went through many, many iterations before being finalized.
|Version 1.0||This was the base idea. The "Crown" would sit on the ingot at the divot, and a hydraulic chisel inside the crown would push a sample out. The log would be held on via a strap, and the spikes on the crown would insure the log would not rotate. This was scrapped due to the log rotating on the crown, as well as the crown being too heavy in general|
|Version 2.0 "The Crown of Hell"||This was the developed crown. Spikes were added to reduce rotation, and the unnecessary material was cut down, making this more light and effective. however, it fell short still in weight, and the spikes were ineffective.|
After several iterations of the design, we found a shape for the device that was balanced, relatively light, and had a great way to prevent rotation.
|Design Aspect||Description||Supporting Image|
|Device Support Plates||This was inspired by the earlier designs, and holds the cylinder onto the ingot. it is designed in such a way that no matter how it is placed on the ingot, it the cylinder will always contact it the same way. It is laser cut, and made of STX 700, a high strength steel.|
|Hydraulic Cylinder||This is the hydraulic cylinder we picked out, from Bailey Hydraulics. We were looking for a cylinder with a 2 inch bore and a pin-eye rod, and one that could deliver the forces we got in testing and from our math model. It is column rated for ~9000lbf, 3000psi, and is double acting. It is of welded construction, and should test just fine for a long life.|
|Cutaway of Main Apparatus||This is a better view of the main structure.|
|Hydraulic Power Unit||This is the power unit we picked out from ReHobot. We wanted to choose one that was mobile, as well as powered by air, something we already had access to in the ATI workshop where this design would be. Of the power units we looked at, this one was not only strong enough to power the cylinder we chose, but also had a hand operation system, an uncommon feature compared to a foot pedal system, which would have been far less mobile. It outputs a hydraulic pressure of 10,000 psi, and requires 97-145 psi in air, which the shop can provide with no modifications. The reservoir size is also sufficient for our hose needs, as well as the larger than normal attachments, providing ~0.5 Gallons of storage.|
|Chisel||This is a simple chisel made of high speed steel. It is designed with an scoop-like path for clean sample taking, has a fattened edge on the bottom to prevent clearance when coming off the log, and is easily reproducible by ATI for different sample sizes or simply when the chisel wears out.|
|Chisel Adapter||This is the device that will attach the chisel to the hydraulic cylinder. It has 3 pins that are press fit and attach 1 to the cylinder rod, and 2 to the chisel. It is machined from low-carbon steel (citation needed)|
|Straps||These are high strength straps purchased from SOMEPLACE (citation needed), and are designed for minimum stretch under load. They will prevent the device from rotating during sampling.|
|Strap Support Structure||This is a set of laser cut, press bent plates made out of High Strength Steel (citation needed). They are bolted to the existing stands for the ingots, and serve as an anchor point for the straps.|
|Cutaway of Support Structure|
As part of our validation, we received test materials of Niobium to verify the strength of our hydraulics. We used a force gauge on a hydraulic press to verify that our calculations are accurate. from that, we gathered a force of ~3-5 tons.
Free Body Diagram
|When we designed the plates, we drew up a free body diagram describing forces on the plates, to prepare a finite element analysis.|
Finite Element Analysis
|From those FBDs, we set up a finite element analysis in SolidWorks 2018, and validated our force calculations and material selection. with STX 700, the highest point of stress was only ~30% of yield, giving us an estimated factor of safety of 3.|
Design Validation Plan
|These are the design testing plans we formulated.|
Major: Mechanical Engineering
Major: Mechanical Engineering
Major: Mechanical Engineering
Major: Mechanical Engineering