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I Forge Iron

patrick

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Everything posted by patrick

  1. The original poster raised the question of doing a short quench and letting the residual heat in the piece effectively temper the part. I agree that this would not give quite the expected result, but such processes are actually quite widely used, especially with steels that have higher hardenabilty than 1095. The is a process, known as austempering, in which the steel is rapidly cooled to some temperature below the pearlite formation temperature but above the martensite formation temperature. For example 600 F. If you rapidly cool to 600 F, you will avoid forming pearlite. By holding at 600 F for an extended period and then cooling to room temperature, the structure formed is bainite. When formed at relatively low temperautre, bainite is quite hard, some times in excess of HRc 50, and can be so tough that no further tempering step is needed. A similar effect can be achieve by quenching in water or oil or polymer solutions for a fixed time to remove most of the heat from the part and then let the residual heat "hold" the part at the desired temperature above the martensite temperature until the part has naturally cooled to room temperature. These kinds of practices are use by at least one sword maker I know. Similar approaches used to be common place with commercial knive and sword makers. They would sometimes quench in molten lead. Today, various molten salts are used to achieve similar effects. In the example from the original poster, I think the bar is so small that these practices are not practical, but pulling a part out of a quench bath while it still has residual heat in it is a common practice in industrial heat treatment.
  2. Thanks for this info Glenn. Do you have a reference for where this data came from? I know the commercial quenchants typically have that in their tech sheets, but I don't think I've seen it for the cooking oils before.
  3. Those are very neat pictures. Cast iron and high carbon steel really are very different materials, Not only do you have different compositions in two sections of the anvils but you also have different structures since the base is cast and the top is made from rolled plate. My first "real" anvil was a 150# vulcan. I sold it to a friend so I could reinvest in a a decent and slightly large Peter Wright. I was not a bad anvil, but I have a preference for steel or wrought iron anvils myself. That is mostly because they are easier to repair if needed.
  4. Thank you for the updates Thom. that is slighlty more positive than what I'd heard earlier in the day. I did try to call Joanne, but it went to voice mail and the mail box was full. Please let them know we are thinking of and praying for them both. Patrick
  5. Sorry it has taken me a while to get back to this question. Historically sulfur was found in the iron ore and also in coal. The use of coal in the conversion of iron ore to iron has only been going on for a few hundred years or so. Prior to that it was done using charcoal which is free of sulfur, so in those older iron pieces the sulfur was coming along from the ore. This is a big reason why irons made in different areas had different characterisitcs and why iron from some areas, such as Sweden, were highly prized. When dealing with iron and steel made by converting iron ore to pig iron and then converting that to pure iron or steel, the points in the process where the metal is liquid are the times it is most likely and able to absorb sulfur from the fuel. When solid, as in the case of general forging, there will be much less pick up of sulfur by the iron or steel. As Thomas noted, most modern steel contain additions of manganeese to counteract the red shortness caused by sulfur, so it is extremely unlikely that you will find sulfur in the coal to be a problem. I'd be more concerned about just getting the work piece too hot and having it crumble due to overheating rather. I hope that helps.
  6. Thomas- You look really good. I'm very glad to see you back in the shop. Keep it up and happy New Year!
  7. Steve- I understand. An interesting thing about molybdenum is that because it has such a high melting temperature it can be used as a forging die material for situations in which you want the dies themselves to be heated to the same temperature as the work piece. This method is used for some areospace forgings made by the closed die method. However, molybdenum oxidizes extremely rapidly at these temperatures so these forging setups are done in a vacuum. Pigsticker- You can get steel and nickel hot enough to weld, which can actually be done at a temperature lower than the melting temperature, but that will only happen if the materials being joined are free of any oxide coating. Oxidation of metals happens very rapidly at forging temperatures so you have to find a method to prevent this if you want to have effective forge welding, no matter what metals are being used. Quite often some type of flux, usually borox based is used. In other cases the billet is sealed in a container or by some other method to keep oxygen out of the system. Burning steel is really the carbon in the steel reacting so rapidly with the oxygen in the environment that it combusts. When this happens there is often also melting of the steel. There really is no way to convert burned steel back to good steel but if burned material is just on the surface or on one end it can be cut or ground off and the remainder of the billet can still be used. Ideally you'd start welding just before sparking starts but if you get just a little bit of sparking you likely can steel proceed with good results. As far as identifying burned steel I suggest you get a scrap and burn it on purpose so you have an example to use for comparison. Filling a hole in a billet is not a simple task and I'm not sure how to advise you on that point.
  8. Beside the compression needed for working powder metal the other thing that is required is that powdered metal exposed to the atmosphere at high temperatures will oxides rapidly, even nickel, so you won't have benefit of metal powder but rather oxide contamination. This is one reason why powder is used in cans. The atmosphere in the can can be controlled to prevent this oxidation. Steve-Nickel melts at about 2650 F. Also, according to R. F. Tylecote on page 220 of Solid Phase Welding of Metals, pure nickel can be welded at room temperature but a deformation of 89% is required. He cites a paper by A. B. Sowter published in 1948 in Materials and Methods, vol 28 pg 60-63 for this infomation.
  9. I'll add a bit more to this topic as it is one that I have personal experience with. Pure iron melts at about 2800 F. Adding carbon to the iron to make steel lowers the melting point in the same way that adding salt to water lowers its melting point. When we make steel by modern methods, the carbon in the liquid steel is uniformly distributed. However, as that liquid steel is allowed to cool, the bits that solidify first reject some carbon into the remaining liquid. This happens over and over again resulting in a sold product which no longer has a uniform carbon content (at the microscope level) but instead has areas of higher and lower carbon. The lower carbon regions can be heated to higher temperatures than the high carbon areas before they start to melt. When the carbon content is about 2%, the melting temperature is reduced to about 2100 F. Now, there are all kinds of steel alloys with widely varying carbon content, so not every alloy will have such a wide range between the start and completion of melting. When we forge, we are always using a temperature which is lower than the lowest melting temperature region of the steel. Usually that limit is set a couple of hundred degrees below this temperature because the metal will get hotter as you forge it. When choosing a forging temperature, you have to build in this safety factor. In general, it is the carbon content that primarily drives the choice of forging temperature. Alloys with 1% of carbon are usually forged at a maximum temperature of 2100 F, while those with less than 0.5% of carbon are forged at about 2300 F. These are rules of thumb and not absolutes because alloying elements other than carbon will affect the melting temperature. It is important to know that some unexpected "alloying" elements will significantly influence and reduce the maximum forging temperature of steels. The first is sulfur. When sulfur is present, even in amount as little as 0.03%, (and probably less, but my personal experience was with a bar that had this sulfur content) the forging temperature is dramatically reduced making the steel (or iron) "hot short". In such cases the forging temperature may have to be limited to less than 2000 F or the bar will crack and break apart. This effect of sulfur occurs because iron and sulfur react to form iron sulfide (FeS) which collects at grain boundaries. FeS has a lower melting temp than iron. If forging is done at a temp where the FeS is liquid, it will melt and the grains of iron will fall apart. If there is iron oxide mixed with the FeS, the melting temperature of that combination of materials is reduced further, to less than 1800 F. Since the middle 1800s the element manganese has been added to steel to react with sulfur. This compound, Mangenese Sulfide (MnS) has a melting temperature higher than that of iron so even if all the sulfur is not removed from the steel, the steel with Mn is not hot short. This is why almost all modern steel contains some Mn. Typically the Mn to sulfur ratio must be at least 8:1 for successful prevention of FeS. Manganese has the benefit of also improving depth of hardening during quenching (hardenability) but is a very low cost alloying addition. So we get a two for one benefit with manganese. For industrial applications this is a great benefit. For some knife applications where you are trying to get a hamon using clay coatings on the blade this manganese can make that difficult because the depth of hardening is actually too much for this process. In more recent years there have been suppliers of steel to the knife making community who have special ordered low Mn content carbon steels for this application. If the steel is contaminated by copper, it too will make the steel hot short. This can happen if you forge copper or bronze, have some of that melt and get on the forge floor and then that copper comes in contact with steel later. There are some steel alloys that do contain copper and in low levels it can be a useful alloying element. Wootz is a quite different material from modern steels. Most of what we think of as wootz today was very high in carbon content. Historical examples show carbon ranging from 1.3-1.8%. Due to the way in which the ingots were allowed to cool and due to the presence of phosphorus and carbide forming elements such as vanadium or manganese, the separation of iron and carbon was exceptionally dramatic in this material. In at least one case that was investigated in 2018, the researcher found that the high carbon regions contained carbon at near 2% as well as phosphorus. This combination of elements resulted in a region with a composition and melting temperature similar to that of cast iron rather than steel. The result of this is that, in at least some cases, wootz ingots have structure that is alternating regions of high carbon steel and cast iron. In addition to this, the high carbon and other trace additions of carbide forming elements resulted in the formation of large carbides or collections of carbides. These also influence the forging characteristics of the wootz, contributing to the difficulty of forging this material in relation lower carbon steels of more homogenous structure.
  10. Thomas-So good to see you home and in good spirits. those are the first pics I've seen of your New Mexico shop. Looks like quite a step up from the one in Columbus.
  11. The problem you are having requires two things to correct: 1 You need to make sure you are pounding on a minimum of 3/4 inch of length as measure from the end that is being tapered and 2 you must have enough power to get deformation at the center of the cross section. Without both at the same time you will always get that fish mouth/pucker effect no matter if you are forging by hand, with a power hammer or with a press. Another way to say this is that your die bite must be at least 1/2 the cross section of the stock and you must have a pretty deeply penetrating blow ( I typically recommend a blow hard enough to penetrate 20% of the stock cross section. That is tough to do by hand hand with stock this big so an alternate approach is to cut or grind a taper, even a blunt taper, on the end before forging. This will put the center ahead of the surface and prevents the fish mouth effect.
  12. You are exactly right about the putter. I just realized that this set of pictures was supposed to go in the thread on mokume delamination, not this one. I had the wrong thread open when I uploaded the images. My appologies. Patrick Follow up to the question about bonding Ti to other metals: the answer is yes it can be done and is described in the book Mokume Gane by Ian Ferguson. However, Titanium is a very reacitive metal and will form new compounds with most of the metals you might try to bond it to, such as copper. These new compounds can make the interfaces between the layers very brittle and really limit the amount of deformation you can do after bonding. I have seen succussfull billets made of alternating titanium alloys such as CP grade 2 and Ti 6-4. After anodizing, these can really have a striking contrast. The big challenge with any titanium laminates is keep oxygen out of the system because it reacts so easily with titanium. Patrick
  13. Frosty- Here are some in process pictures of twisting a large batch and then a couple of photos of finished projects that were made from the blocks I forged. Other folks made those finished products.
  14. Frosty i provide a forging service for one of the mokume sellers who serves the knife market among other things so all my pics are just stacks of big billets in various stages of processing. The best pics of finished projects will be found on the website of william henry studios. Many of the billets i start with ate 2x2x6 or even bigger and they may weigh 10 to 12 pounds each so forging on the ends is not practical for me but could be helpful in other circumstances. I do all my work on flat dies with stop blocks. Im sure swages could be used. You'd have to work out the exact geometry to prevent forming laps. I wouldn't normally use square stock as input into a swage like that. Round would be better i think.
  15. Yes that is true but if you're using a billet of copper based alloys such as brass, copper and nickel silver, those differences are not so big as to be the primary source of the problem. I didn't mention it above but most of the lay separations I deal with are on the very end of the billet where no hammering ever happens. The ends usually bulge out for me and this bulging creates a tensile load on the layers at the end just as it does on the sides. The difference is that since the ends are never struck that tensile load just continues to act on those layers as you draw out the billet. I usually end up trimming a little bit off to clear those splits before i start forging to and octagon, which is my preferred shape for twisting. The biggest risk I see for layer seperation aside from interfaces which are not properly cleaned before bonding is the shearing action that happens when you do go from square to octagon. I minimize that by taking tiny little die bites and very shallow drafts. If I do that right, I usually don't have catastrophic failures. Patrick
  16. The reason that mokume splits when forging on edge is because you are creating a tensile load at the layer interface. They want to spread side to side. When striking with the layer horizontal you put that same interface in compression. As was already noted, you really need very clean surfaces before starting the bonding process and then when you do forge with the layers vertical you need to used a technique that minimized the side to side spread. Basically you need to deform only very short lengths at a time. I've been production forging mokume in batches upwards of 100#s at a time for about the last 12 years and I've managed to make it fail in most of the ways that can be done. Patrick
  17. The work bench in the dorm room story: While I was a student, the Welding Engineering department was given a brand new building. The old one, from the early 1900s, was going to be demolished and something new built in its place. A lot of things in that old building were not going to be taken to the new facility. At Thomas's urging, I'd made friends with the student workers and lab manager in the welding building and as they got ready to move I was told that anything left in the building marked with at "T" sticker was going to get tossed and was free to take. I started roaming the halls (both floors and the basement). I found 3 green wooden work benches, all with thick hard maple tops, 3 or 4 draws in the center and a large cubby on each side of center. I called Thomas to help move them as I had no vehicle at the time. We wrestled them down from the second floor and got them in his truck (a little white Toyota about the size of a Ford Ranger). I lived just off campus in a frat house so had a little bit more flexibilty with odd things in the room than I'd have been able to get away with in an on-camput dorm. As I recall, I was running late for a test by the time we got back to the frat house with that work bench. I recall taking in down a back set of exterior stairs to the lowest level of the building and making my room mate finish getting it into the room so I could get to the test. The room had been set up with alternating closet/desk tops down one wall; 3 closet spaces and two desks. The desks were just painted plywood screwed to cleats on the sides of the closet walls. I removed the plywood but found the desk was about 6 inches too long. I had to trim the top to fit, but I did. I still have that work bench. I did have an anvil in the room and a small soup can forge and a 4 or 5 inch post vise. I scrounged a lot of metal from that same building and that got stored under the bed. All this happened in my sophomore years and later. I didnt' have a lot of roommates. Only once did I have a housemate ask me to stop forging in the middle of the night, which I did. Most of the rest of the time those guys were either out partying or partying in the common room with music so loud I couldn't sleep anyway. I have lots of other great stories of how Thomas helped me. Once I moved away from Columbus and he to New Mexico we only saw each other at Quad State and then only those years that he and Joann would make the trip. We kept in touch through email and the forums and have kept tabs on each other's families. I am pleased that he has been able to meet my children and see them grow just as I remember his daughters as little girls when I would visit his house in Columbus. I'm glad to hear of some positive changes with respect to communication from the doctor and the possibility of some addition relief via the fluid removal.
  18. All- I have not been a frequent poster to IFI for a while, but some will remember me from my earlier posts about metallurgy and heat treatment and years ago I was very active on some of the forums that preceded IFI. I have known Thomas since the Spring of 1997 when he invited me to come inside his tent and pick up a hammer. He was my first teacher and mentor of blacksmithing and metalworking history and I learned those skills from him while learning metallurgy in college. As a college student with little funds, he introduced me to the fine art of dumpster diving, flea markets and getting the most out of limited budget and resources. He provided countless rides to events in the Columbus and Dayton Ohio areas. Without his generosity and encouragement I would not be where I am today. I had a very good chat with Thomas and his wife last night. Thomas is the same humorous, quirky and knowledgeable man I’ve always know. He was very alert and engaged during our entire conversation (probably 40 minutes). I have no updates on his prognosis. Both he and Joanne are very frustrated with the lack of communication on the part of the medical staff. At this point, friends and family who are able are coming to visit and both he and Joanne are looking forward to those visits in upcoming days. For those who do know Thomas personally, I do encourage you to call. I know they appreciate that support. Joanne has also mentioned the great blessing it has been to have the help of their local blacksmith community and students. It is good that they have friends and family close who can provided immediate physical assistance for them, but I am sure they need all the prayers and remote support they can get during this time. Patrick Nowak
  19. That is probably a region of decarbuization. That happens more rapidly in this grade than many more common blade steels. You can minimize it by packing the blade in carburizing compound during austenitizing. You can grind it off too. In theory you could recarburize the are that list carbon, but it is much simpler to prevent it from the beginning.
  20. In my haste to help out the original poster I included a link to an offsite buyer. My apologies for going out of bounds on that. My recent experiences with collectors and small anvils is different that what Thomas has shared. Just last weekend at Quad State in Ohio I saw several anvils in the 20-30# range with prices in the $800 range. I do know some collectors who will spend that much on an item if they want it bad enough. I think this craze of paying extreme amounts for small anvils is fairly recent, but it certainly is not new for collectors in general to be willing to spend huge sums on something rare. Art, coins, guns and other tools like specialty wood planes are all good examples.
  21. There are collectors who specialize in these small, rare anvils from well known makers and they will pay exceptionally high prices. If you want to sell it contact advertising link removed. To someone looking for a shop anvil it has much less value.
  22. patrick

    metallurgy

    Thomas, thanks for the good words. Please feel free to give them my email. I am looking for interns. Will you make it to quad state this weekend? We're heading there tomorrow.
  23. patrick

    metallurgy

    For you The Complete Modern Blacksmith by Alexander Weygers will be a good investment. He covers lots of ways to recycle old steel into tools and does so based in their prior use rather than knowing the specific steel grade. Practical Blacksmithing is another good reference. Almost everything you need can be made from low carbon/low alloy steel. The exception, and even here it is not an absolute necessity, is hammers. Other steels often offer significant advantages but require that deeper knowledge not only of alloying elements but also heat treatment if you are going to use them. Grade 1045 is perfectly fine for hammers, but others will work too. That one is cheap and easy to heat treat.
  24. The easiest way to see big crystals id to find a galvanized item: trash can, highway gaurd rail, ductwork for a central heating system etc. I've seen grains much larger than 1/4 inch on all these things. Not every galvanized item will show these big grains but many do. The other place you can often see grains without the need for a microscope is old brass door hardware. The are often castings with fairly large grains. Over time the action of people grabbing the door handles will have an etching effect making the grains visible. When i was in college one of the examples Dr. MOBLEY used was those turbine blades Frosty mentioned. He had a set of 3 that were all the same part. One was made with small equiaxed grains. The next best had larger directionally solidified grains and the 3rd was a single crystal.
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