Recently, I joined a group called Material Advantage, which is an organization at Illinois Institute of Technology. They focus on using science in order to have fun with projects that they participate in. One of these projects is making a blade from scratch. Before I joined, they already made the purchase of the steel sheets. These sheets were then cut into smaller sheets. They will be stacked and pressed to form an ignot.
On the first day of work with them, the first step was done. The sheets were cut and the remainder of the sheets was used in order to cut samples from them. These samples were cut at different side, such as the top, and the two different side faces. These were later put into a press along with some copper power in order to form a sample. Two different high carbon steels were used.
This process of putting these steels into a sample allowed us to later see what process was used to make the sheet. For example, we could find that the sample was hot rolled in a certain direction base on the grain pattern found in the micro structure of the steel.
I was first given the task to polish these samples in order for us to be able to see what is below the surface. This was mainly to get rid of scratches on the surface as well as any unwelcome foreign particulates. An Alumina mixture was used to polish the larger scratches of the material. Later on, a more fine mixture of a different substance was used in order to get the smaller scratches out.
Once this was done, we took pictures of the micro structure before and after we etched the material with some acid.
These images are just a few pictures before we etched. We saw small cracks and defects. However, the material usually looked nice and uniform as shown below.
After etching, we were able to get a closer look at what happened to the material.
The grains are more visible and allow us to determine how we will press our ingot.
08/01/2016
Initially, we used some mild steel and other carbon steel that we found around the shop to practice the process of making laminated steel. The steel was then layered and welded at one end. The steel was then placed into a furnace to reach forging temperature. After reaching the proper temperature, the billet was placed through a hydraulic roller to provide a reduction of thickness very quickly and easily. The metal is shown before and after, having a small bend outward due to layers sliding when being rolled.
As shown above, one layer went far outside the outline of the ingot. The ingot itself is also heavily oxidized due to long exposure at high heat. This was actually the nicer ingot that was made. the one shown below is what was usually made. The reason is because we practiced folding it over to create more layer in the ingot.
A much large piece was attempted as well. The thought behind it was that a larger piece's layers would have a harder time sliding out since there is more contact area for friction. However, we were not expecting the roller to not be able to have enough power to take the larger piece through. The piece was first heated up in an electric furnace, then placed through the roller for reduction. Since we could not pass the piece at the required reduction for welding to occur, we tried using a smaller reduction. The result was a delaminated, oxidized, and ruined piece of steel.
We also tried to create lamination by using a hammer. This was to see if this task is feasible by hand. A small anvil and chain was used to hold the ingot and create welds. However, this proved to be quite tiresome and problematic. The piece would crack as we did not have the experience of striking with the right force. If the force was too small, there would be deformation but no welding. Likewise, if the force was too great, the piece would actually crack and delaminate.
The pictures of the metals shown above are also shown after quenching (for heat treatment). That is why the sides appear to be cracked (due to thermal stresses). We kept trying later on, but we made sure to do more research on bladesmithing so we do not ruin more expensive steels.
12/01/2016
After a year of practicing this new process, we were able to get some proper laminated steel ingots. These were composed of a combination of high nickel steel, S30V steel, and 1095 steel. Some of the ingots had brushed faces while others did not. This simply means the surfaces was scrubbed of oxides and particulates prior to welding with a small wire brush. These metals were chosen because the thermal coefficients were similar, and would allow for low thermal stresses. The process consisted of layering these metals, and tying them together with some metal wire. Once this was done, this layered bar would be placed into a thin stainless steel tube.
One end of the tube was hammered flat and folded over. The folded over portion was then welded with an oxyacetylene torch to make an airtight seal.The pipe was flattened in a vice where the bar was to be so that the rectangular bar would fit properly. A rubber stop with a pipe going through it was placed into one end of a pipe. This was used to fill the now airtight tube with Argon gas so that the metal would not oxidize when in the furnace. After a few cycles of filling and evacuation of Argon, the end was folded over and welded so that the argon would not escape.
After being rolled through, the ingots inside the sealed stainless tube, or "burrito," the burrito looked very flat. There were multiple passes to get our ingot to the desired thickness. Previously, after tediously removing the stainless tube, we had some very nice looking ingots, but they were not layered yet.
This is was were inside the flatter burritos. We heat treated by placing the metals into salt (just solid salt crystals). The images before and after oxidation removal were shown. We even shaped our longer ingots into a blade like figure.
The next step is to create the handle such that the center of mass is at the base of the blade (where the hand ends). We are using brass since the blade is very long, and we need a lot of mass to displace this.
Along the way, we also did check for the hardness of our materials through a Vickers test. Since this is a material similar to a composite, the hardness changed as we progressed along the layers. This was to keep a record of important quantities, along with dimensions, surface appearance, etc.
02-01-17
A handle was added and the blade was cleaned up a bit. Still not sharpened as we still have to present at the TMS conference in San Diego during the week of February 26th.
This blade is meant to be similar to the type used to open champagne bottles. We tried, but our skills are not worthy.
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