patrick

I got one from yupu222 yesterday. Also looks like a scam.

Frosty- The mokume I forge is all bonded by Mike Sakmar, who is using the methods described in the book "Mokume Gane in the small Shop" by Steve Midgett. A digital copy of that book is available free on Mr. Midgett's website. There are several methods used in the book. The method used for the billets I work with is to clean the pieces to be bonded in a strong acid, rinse in a solvent like acetone, then layer up the billet. From the point of cleaning onward the pieces are handled with gloves to avoid getting any finger print oils or other contamination on them. Once the stack is complete, it is wrapped in stainless heat treat foil. It is has been many years since I've visited the shop where this happens and I don't have pictures of this part of process, hence the reference to the book above. If I remember correctly, I think a small amount of charcoal may be added to the foil package to serve as an oxygen consumer, but I don't recall for sure. Once the billets are wrapped in stainless foil, they are clamped between flat steel plates with bolts at the corners. They are put into electric kilns and heated to the desired temperature for a time commensurate with the size of the billet, but usually an hour or two. Bonding temps are picked based on the alloys used, but will be a little bit below the melting temp of the alloy with the lowest melting temp in the billet. After the bonding cycle is done, the billets are removed, clamped in a vise and the bolts removed. The foil wrap is ground or machined away leaving the billet sides smooth. That is what I get. (picture below). My forging is done almost exclusively with flat dies, and all under my 300 # Bradley. Sizes I make are dictated by my customer, (Mike Sakmar) who owns the material and pays me to covert it to his desired sizes. Common sizes are 0.230x01.675 flat (twist before flattening) and a variety of octagon sizes. Occasionally there will be some larger flat cross sections like 5/8 x 2 1/2. Most material is twisted to generate the pattern. When some other pattern like raindrop or ladder is desired, I forge to a specified flat bar size, send the metal back to Mike who machines in the desired pattern with a ball end mill, then it is sent back to me for forging to final thickness. I've been doing this work for probably 16 years or more and most of that time the twisting has been done by hand. A few years back I did add a twisting machine to the shop, which is simply a very old (line shaft driven) pipe threader modified to take the flattened end of an octagon in the "chuck end" of the machine. Mike does sell his material to anyone, though many of his customers are from the knife making and fidget spinner community. You can google him to find his website. Because these are copper alloys, there is no need for a hammer as big as mine, it's just what I have. I will say though that I much prefer a hammer to a press. Presses are much slower than hammers and though they'd work fine for the initial break down of the billets, they pull heat out of the work too fast for effective forging of the thin flat bar and plate often make and they are just too slow for drawing out small cross sections. The 0.230 x 1.375 flat size I usually forge to 3/4" octagon before twisting, but I do that using die bites that are about 1/2" long. That is a LOT of strokes and most presses a just not that fast. Most of the success or failure associated with forging mokume is not in the tooling but in how you USE the tooling. As mentioned, almost everything I'm doing is with flat dies, but how big a die bite you take and how hard you hit the metal changes as the job progresses and if you don't do that right you will end up splitting the billets apart. Describing that detail is pretty hard in text, but the approach is not that different from what you'd used when forging very slaggy wrought iron.

You can cut and rebond mokume billets without flux. In fact flux generally is not used. The cut and rebond technique is not common but I did do some "graph paper" pattern mokume a few years ago and it did work. There was lots of material loss with that approach because of all the cuts, but a feather patter would not be too bad in that regard. I think it would actually look pretty cool once you worked out the right layer count and thickness.

I have forged thousands of pounds of mokume in the last 15 years, usually starting with blocks much bigger than what you are working on. the key to successful mokume is keeping the surfaces clean prior to bonding. If you do that, then run a bonding cycle that is effective, meaning long enough and hot enough for the materials in your billet, you should have very good success. As you work the billet, take time to grind out layer separations and cracks. When twisting, I always forge to an octagon first, then twist, then forge to final size and shape. This minimizes the risk of getting corners that tear apart or form laps during later forging. I don't do much cold work. You can do a little bit, but brass and nickel silver (which are common elements in the billets I'm forging) do work harden fairly quickly so if you were going to do much cold work you'd need to anneal frequently.

I have not read the referenced article but based on the assessments you've provided it doesn't sound that good. There is evidence for the use of steel going back to the times referenced though. There is a two volume set by V.F. Buchwald that discusses the ancient use of iron and steel in Europe and traces the historical development of that technology. In those books, he details the use of steel found in fasteners used to too join the stone blocks that were used to build the Parthenon. He also points out that Homer gives a description of quench hardening. Homer's works are not quite as old as 900 BC, but the setting (The Trojan War) is roughly 1250 BC. In the book of Proverbs, Solomon writes that "iron sharpens iron" which I take to mean a file sharpening something else. It could be a different technique, but if he was referring to a file then you have another piece of literary evidence from about 900 BC pointing to a knowledge of quench hardening steel.

Hi DaniH-You've raised an interesting question and I may be able to help a little bit. In the US, stainless grades, especially those that are austenitic, are mostly made starting with scrap stainless steel that has a composition close to that desired in the final product. Because the starting material is already loaded with chrome and nickel, special techniques are used to remove what little carbon is in the melt charge. It will be MUCH less that what is in your pig iron. The methods used are either Argon Oxygen Decarburization (AOD) or Vacuum Oxygen Decarburization (VOD). Both methods are used because they substantially limit the amount of chrome that is lost to oxidation. If the conventional methods of removing carbon by blowing oxygen into the liquid metal under normal atmospheric conditions are used, a great deal of chromium is lost and that is very expensive. If you are starting with conventional pig iron you will not have much chromium in it, but it will be high in carbon. You could used an oxygen blow to get rid of the carbon, but getting the chromium into that melt gets to be a challenge. Adding pure chromium to liquid pure iron is pretty hard because the melting temp of the chromium is a good bit higher than the iron. In conventional steel making this problem is solved by adding something called ferro chrome to the bath. That is a very high chromium, iron carbon alloy. For steels other than the austenitic stainless grades, this method works well because the carbon in the ferro chrome is not so high as to cause a problem. Lots of steel has carbon over 0.10%, in fact quite a bit more. But to successfully make austenitic stainless (316L) you have to get the carbon down below 0.08%. It is getting that low carbon without loosing a substantial portion of the chromium that is so hard. You can do it, you just loose a lot of chrome and that makes for a very expensive heat of steel. This difficulty in getting rid of carbon is one of the reasons that the martensitic stainless grades, which do have some carbon, were the first to made commercially. It took a bit longer to develop the technology to get rid the carbon. In your original question you asked if you could add something to a 70Kg melt to get rid of the carbon without blowing in oxygen. The answer is YES! Historically, mill scale, forge scale or other sources of iron oxide where added to furnaces for the purpose of reducing carbon. This was done as part of the puddling process used to make wrought iron and was also used in the open hearth steel making process, which has some similarities to the puddling process. this will not help you get the chromium and nickel into the iron, but it will help you get the carbon out. Here in the west we no longer add mill scale to the pig iron as part of steel making because so much of our steel is make by remelting scrap via electric arc melting. In that process it is more cost effective and faster to just blow oxygen into the liquid steel, but for your situation this may be a workable solution to your carbon issue. Good luck.

Hey Guys- I know I'm a bit late to this conversation but I thought I'd add a little bit. The spark test actually was used for differentiation of more than just carbon until fairly recent times. I have a copy of the spark testing training manual that was used at Inland steel and it very clearly shows and discusses how to distinguish the spark characteristics of elements like molybdenum and chromium. The training required to get that good was extensive. The manual was given to me by a former salesman who represented the successor to Inland Steel. I asked why that technique was still in use since laboratory methods that are much better have been in place for a long time. He said the method was used with a hand grinder by inspectors checking bundles of bars as the left the mill. The goal was to quickly hit the ends of the bars in the bundle and confirm different steel grades had not been mixed in the bundle. Up until fairly recent times there was no other method fast enough to keep up with production in a steel mill setting. Within the last 10 years or so portable X-ray analysis tools have replaced the spark testing method for this application. Interestingly, the most common laboratory method, optical emission spectroscopy, is really just an advanced version of the spark test. In this method an electric arc is struck between a steel sample and a tungsten electrode in an environment flooded with argon. Special optics and software analysis the colors in the light and determine the percentages of each of the elements present in the steel. The use of the traditional spark testing technique to sort steel by carbon content is one of the earliest tests. By 1916 this was a well established test and is discussed, with illustrations, in the book Heat Treatment of Tool Steel by Harry Brearly. The image shared by the original poster does not have a lot of spark features shown. I agree that pictures zoomed out with more of the spark showing, especially the burst if there is one, would be helpful. Assuming there actually are no bursts then I'd guess this to be something like a high speed steel rather than 01, but I don't think there is enough info to say for sure.

I'm an active member of ASTM and user of their specificaitons. Not only do they have specifications by application, such as the music wire , bearings and rail road applications but within a given standard their are often several, sometimes many, different grades. For example, Specification A350 has several different grades with substantially different compositions. We work with A350 LF2 and LF6. Those names have no connection to the composition, they are just generic labels so you have to look up the spec to see what the compositions are for each of those materials.

All- i have an anvil in need of repair. Before people jump on me about need for the repair or my abilities to execute this kind of welding, please know I've done this on numerous occasions in the past and I'm well aware of when and when not to do this kind of work. In this case, the anvil in question is definitely in need of repair. My go-to rod for hard facing has been a Hobart product-Hardalloy 58, which was recommended by them years ago specifically for this application. However, I can no longer find this rod. It is a self hardening rod that does not crack or cross check provided the layers thickness is limited to 2 passes. It appears to be similar to tool steel grade H-12. I have found similar products by Weld Mold and Core-Met. I have also seen many people refer to Robb Gunther's method using Stoody 2110/1105. The 2110 product is described as work hardening grade that, after work hardening, will have the hardness i'm looking for. However, my experience with other work hardening alloys has been that they really need a lot of pounding to bring the hardness up. I'd rather not have to do a bunch of cold work to the weld deposit to get it to harden. I'm curious what experience this group has had with the Gunther method or even using 2110 by itself. Thanks in advance.

I'm not of the rules regarding public posting of specific vendors. If you send me a PM I can put you in touch with sources for mokume blocks, bars etc.

Your questions about hardness and heat treatment of these dies are addressed in some other threads. But seeing the pics you've shared I have real concerns about cracking in the corner of the dovetail during quenching. I had that happen to similar dies I made from 4340. I suggest you use a ball end mill of at least 1/2 diameter to create a bigger radius in that corner. If you can go bigger, like 5/8 or 3/4, I'd do that. these dies are designed for load bearing on the bottom of the die, not the shoulders, so if you have to take a little off that shoulder to improve the corner radius it will not hurt die performance.

15N20 etc are not specific designations by one company but are the designations used in many of the European countries. 17CrNiMo6 is another example, but there are hundreds, just like in the SAE system. Many times there are equivalents from one system to another and sometimes not. Each system make sense in its own way, but they are all different. Japan has a different system as does China. There is also something called the Unified Number System. In that system, most of the familar SAE designations are prefixed by the letter G and given a couple of extra digits at the end. For example, 1095 is G1095x. In this system Tool steels all start with T, stainless with S, copper with C, titanium and other refractory metals with R. Each system has strengths and weaknesses. I like the SAE system because that is what I learned first and am most familiar with, but I"m sure someone from Europe would say the same about their system.

Generally speaking it is going to be tough to get 4340 up to HRC 60. The maximum as-quenched hardness of any steel is a function of the carbon content (barring the very highly allowed cutlery and high speed steel types). It typically takes about 0.57% carbon to hit HRC 60. More carbon above that value will not give you higher hardness, but it does give increased wear resistance which is why cutlery grades have carbon close too or sometimes exceeding 1% carbon. For steels in the 0.405 carbon ranges, max hardness is going to be in the mid 50s HRC. Usually, the parts will be tempered, so working hardness will be somewhat, or maybe a lot, less than this. Flame hardening is a technique using a torch to locally heat the surface. Typically a quench nozzle or spray follows close behind the torch tip. The goal is to create a hardened surface layer while keeping the interior of the part at a lower hardness for better toughness. For the power hammer dies that were discussed in another thread, I would suggest a through hardened part rather than a surface hardened one. With the use of special coatings or other treatments such as carburizing and nitriding, it is possible to achieve surface hardness of HRC 60 or above, but I can't think of an application in the blacksmith shop that would benefit from this. This type of hardness is used for gears and bearings in high wear applications or shafting subjected to a lot of sliding wear. In the blacksmith shop, the hardest tools usually will be power hammer dies, anvil faces and hand hammer faces. These should all be made with hardness closer to the low 50 HRC range to reduce the chances of brittle failure.

45-50 HRC is a good hardness for a power hammer die and 4340 is fine material for that application. Your original post in this thread does have some errors though. Normalizing is done at temperatures in the 1600-1700 f range. Those you gave were for high temperature tempering. they will not have the same effect as the higher temperature range. When it comes to heat treatment, especially of critical tools like power hammer dies, control of the heat treat process really is extremely important to getting the outcome you need. Uniformity of temperature during heating, sufficient volume of quench fluid etc all must be considered. Here are the recommended temperatures for your project: 1. Normalize at 1600 F. Air Cool. 2. Austenitize at 1550 F. Oil Quench. 3. Temper in the range of 600-700 F for a final hardness of 45-50 HRC You will want a minimum of 10 gallons of oil. you will need to agitate the part vigorously during the quench. Paying a commercial heat treater to process these dies to your specification will be much cheaper than buying a furnace with the proper controller needed to properly heat treat these dies. of course, if you have other projects planned for that kind of furnace, you could justify the cost that way.

I'll give you the metallurgy perspective: All the grades will perform equally well. They will all get hard enough for a hand hammer. The choice really comes down to what you can get and what resources you have for heat treatment. If you are buying new steel, 4330 will be the most expensive. 1045 will probably be the cheapest. 1045 is probably the lest likely to crack in hammer-section sizes and should be water quenched. They will all respond about the same to tempering. I'd suggest 450-475 F for 30 minutes per inch of maximum thickness. For a typical 2-3 pound hammer 1-2 hours should be fine. I would be sure to temper as soon as you are done with the quench. I would avoid stamping a makers mark in if you are going to heat the entire hammer to the critical temperature and quench. If you are able to heat just the faces (both at the same time) and quench then you could stamp in a region that will not be above critical. I have seen cracks originate in these kinds of stamps after quenching on numerous occasions.