patrick

There are a few mis-conceptions or misundertandings in this post that I'd like to clear up. 1. "Burning" Steel in general means that you have begun to get localized or grain boundary melting without melting the entire part. Both oxidation and carbon depletion of the surface (decarburization) happen at much lower temperature than melting and so they are NOT considered burning in the same way that over heating to a sparkling white heat is. Certainly both oxidation and decarburization are happening during burning and as temperatures increase the rate of these reactions also increases, but burning is separate and distinct phenomenon. 2. Buildings, like cans, can be made to topple over. What is required is careful positioning of the explosives and a removal of a portion of the structure on the side in which the building is to fall. It's just like cutting down a tree. Notch one side, then cut from the back. I'm not sure what this has to do with crystal structures though. 3. Iron and steel are always crystalline unless except when you have a liquid or a metallic glass. Carbon does not make steel "crystalize" . What it does do is allow you to transform from austenite to martensite given sufficiently rapid cooling. Both austentite and martensite are crystals, just different kinds of crystals. Carbon in the microstructure will form carbides which do pin dislocations (see below) so you do find that the rate of work hardening will be greater as the carbon content increases. 4. Grain size does affect yield strength in metals of the same crystal structure and smaller grains do result in higher yield strength. The reason for this is not because small grains provide fewer stress concentrators. It's because grain boundaries provided a barrier to dislocation movement. Since iron and steel are crystalline, the atomic arrangement is by definition organized and repeating within the crystal. When a load or stress is applied to the crystal, that atomic arrangement is disrupted, much like what happens if you have a wrinkle in a rug or bed sheet. That wrinkle moves through the crystal unimpeded until it hits a grain boundary (or something trapped within the grain like a carbide). A dislocation of the crystal is a minute amount of plastic deformation on the atomic level. These dislocations build up at grain boundaries. The more grain boundaries there are (or carbides), the more dislocations can be stopped within, or at the edge, of an individual grain before measurable yield strength of the bulk product has occurred. Once you have plastic deformation, the yield strength has been exceeded, but dislocations continue to be formed and pinned, resulting in a continuing increase in hardness. This is what we commonly call work hardening. Hardness is increasing WITHOUT a change in phase. 5. If you put a load on a piece of metal and it deforms and stays deformed you have exceeded its yield strength. If you put a load on a part and it deforms but springs back to its original size and shape you have not exceeded the yield strength. Instead you are using the metal in its elastic region. That's what springs do. Through a combination of microstructure (crystal type, size etc) and form they can be loaded and unloaded over and over again. This type of loading is called fatigue loading, that is there is cyclic deformation that does NOT exceed the yield strength. This particular application is significantly benifitted by having a small grain size.

Dendrites form during solidification and they are NOT square. A dendrite grows from a nucleation site and develops primary, secondary and tertiary arms. If you look at it with the aid of an SEM you will see that It actually looks a little bit like a fern or evergreen, which is where the word dendrite comes from. While it is true that the iron crystal lattice is cubic, that is on the atomic level. At larger scales, the arrangements are not cubic unless forced that way by deformation. As I noted in my earlier post, we forge square because that is the most efficient method and that has to do with constrained and unconstrained surfaces, not atomic structures. At the macro scale, iron has no particular tendancey to form cubes. It takes on the shape of the contain in which it solidifies and after that it takes on whatever shape it is forced into, whether square, round or some intricate configuration. That ability to be formed in some many ways into so many things is one of the reasons iron based alloys are so widely used.

The crystal structure of iron has nothing to do with why you taper in a square form. You'd use the same process with any other metal, regardless of crystal structure. The reason for tapering a square is because it is the most efficient method. if you are forging a square, you fully contact the work on two sides (hammer and anvil) with each blow, leaving the two perpendicular sides unconstrained. If you tried to taper a round you'd have to deliver considerably more blows per unit of length since you have to work your way evenly around the circumference. For example, for forge an octagon requires 4 blows, while a square only requires 2. A sixteen sided shaper would require 8 blows and so on.

Not a Bradley. The anvil on a Bradley has 3 flat sides blending into a half round on the side that mates with the hammer. Also, Bradleys use a double wedge system on the dies, not the single wedge system on the anvil in question. Most likely this was a Nazel or Chambursburg, though I'm sure there are other options to choose from.

Keep in mind too that the very heavy work that would damage a thin heeled anvil was usually done on big anvils with proportionally more material in the heel area. From my observations, I think that most broken heels and horns are not due to the presence of the hardy hole location, but rather to faulty welding of anvils constructed by the build up method. I replaced heel on a 180# anvil that was almost completely broken off when I got it. Only the face plate was holding it together and even that was partially cracked. I've seen other examples of faulty welds too. It certainly is possible to break off the heel of a solid steel anvil such as a the later haybudden and trentons, but that still takes an awful big hammer and big swing.

Being magnetic or non magnetic is NOT a function of grain alignment. It is function phase-austentite is non magnetic while ferrite is magnetic. The difference between austenite and ferrite has to do with the relative position of carbon and iron atoms in the crystallographic matrix. Those change with temperature in a plane carbon steel. The 300 series stainless steels are alloyed with nickel which alloys austenite to be stable to cryogenic temperatures which is why those alloys are non-magnetic even at room temperature.

Anything and everything. I can cut 1/2 square cold. Much beyond that just takes too much power. H13 can get pretty hard, as I note above up into the lower 50s HRC. The edge geometry is not a flat grind but more of an apple seed/convex grind to add strength.

Though the large fisher noted above was an exposition piece, I've seen enough period anvils in excess of 500 lbs to conclude that there was in fact an industrial market for these large anvils at one point in time. It seems that most of them were made in Europe rather than the USA and I assume that is for a few reasons: 1. Heavy manufacturing has been going on much longer in this part of the world than the US. 2. Countries with a strong manufacturing culture based on hand labor (such as England) seem to have maintained that hand work approach much longer than was done here in the US. As examples, chain, barrels and knife blades were all made by hand in England up into the 1970s, while in the states, these activities had been done by mechanized methods for decades. Another example of this approach is that the book "A Blacksmith's Manual Illustrated", one of the all time best books on open die hammer work, was first published in 1930 and again in1944, 1949,1960, 1970, and 1978. Many examples of the work in this book are can actually be made much more efficiently by fabricating and machining, rather than from forging from 1 piece. This book was first written and published in England with a focus on railroad related forgings, but you can see from the publication dates that up into the 1970s there was a market in England for this information.

I currently have 2 anvils, a nearly 400 # peter wright and a 1050# pound double horn I made myself. I'd have to agree that in general, I can do most of what I do on anvils smaller than both of these, and the drive to have extra large anvils was driven by envy. However, I will point out that I've never had my anvils anchored to any kind of stump set in the ground or other permanent installation. I found that when working on the horn or side of the PW I could make that anvil walk across the floor. That doesn't happen with the big anvil, yet I can still move it if I need to.

I chose to heat treat the cut of hardy because it will see the most severe use of any tool made from H13 in my shop because I use that tool as both a hot cut and a cold cut. With the right combination of tool geometry and hardness you can do that. If I chose not to heat treat the tool and just use it in the as-forged condition, I would limit its use to hot metal only due do the relatively brittle nature of the as forged material. I make punches for as well as hacks for use under my power hammer from as-forged H13 and they work great, but I'd never use them on cold material the way I do with the anvil hardy.

This is kind of big topic as are most of those related to metallurgy. Let's first draw a distinction between steels used for tools and steels designated as tool steel by industry. For example, 4130 is often used for tools by some blacksmiths and it is very effective, but by industrial standards it is NOT a tool steel. Next, we need to break down the industrial tool steels into catagories since there are so many. It is unfortunate that the industrial designations are not uniform in their approach. Some are based on quench media generally used, some based on primary alloying elements and some based on intended service. The challenging thing is that many cross over more than one category. Those which are relatively low in alloy content have lower austentizing temperatures and also lower tempering temperature. Included in this group are the W, O, and L series tool steels. All of the remaining types are going be fairly high in alloy content, high in austentizing temperature and tempering temperature and will be air hardening in the section size used by blacksmiths. H13 specifically is alloyed to maintain its hardness at high temperature. To accomplish this, the alloying elements must be dissolved in the austenite during the austenitizing process. Because these alloying elements form complex iron/carbon/alloy compounds, the tempers and TIMES needed to dissolve them are much high than what is need for steels which only form iron carbides. These complex carbides and their dissolution temperature is what requires the use of austenitizing temps of 1850 F or more. If the entire tool is heated to forging temperature during forging, then you absolutely will get a fully hardened tool. If you start with annealed material and only heat one end, you can successfully maintain a soft striking end. Because of the high temperatures (1000 F or more) and very slow cooling rates needed to anneal this grade, it is very difficult to soften one end once you have the entire tool hard. You can however do a couple of things to get around this. 1. Grind the striking end with a generous radius. 2. Use a soft faced hammer. 3. Temper the entire tool to the hardness you want. Keep in mind that H13 will not get as hard as other grades-only to the low 50s HRC. This is not much different from an anvil face. If you don't need the maximum hardness but can live with something in the upper 40s HRC then temper the tool to get that hardness. For H13 that is going to be well in excess of 1000 F as Thomas mentioned.This has the advantage of adding a bit of toughness, but it also means you can get the working end of the tool that much hotter in service before it begins to be affected. If you have access to a furnace that can do this, I'd recommend this approach. 4. Depending on the tool geometry, you may be able to make a sleeve of soft steel to fit over the striking end. Any time you can get access to proper heat treating resources, you should take the time to use them and make your high alloy tool steels uniform in hardness (assuming they were completely heated to forging temp) since this gives you the most control of the final out come and tool performance. Differential forging and heat treat of high alloy tool steels can work, but it is not very controllable or predictable so you do assume more risk when using this approach. This is because the temperatures involved are so high that they cannot be easily judged by color in the same way that you can "run" colors from about 300F-550 F on a shiny piece of steel. With H13 you are dealing with tempering temps that are 1000-1200 F, depending on the hardness you need. That range is pretty tough to judge by eye. All that being said, when I use H13 it is often in the as-forged condition with no further heat treatment. Exceptions to this are my cut off hardy and if I ever get around to it, a set of power hammer dies. These tools I would absolutely have heat treated under controlled conditions.

It looks to me like that crack is coming from the key way in the top of the tool. This is a common way for cracks to start since key ways often have a sharp corner between the bottom and side. My bet is that the crack is the result of quenching the entire tool. Differential tempering could have been the trigger for the crack form, but had you only quenched the working end it likely would have worked out.

Thomas-Are you sure you getting all the medicine you need? Posting all that sunny weather for us Wisconsin folk is just mean. Why is that sunny in Wisconsin means -20 and sunny in New Mexico is a balmy 76? If we have much more of this weather I'll have to spend my days hanging out by the 3000 ton press watching them break down 30,000 blocks of steel basking it is artificial tropical glow.

300 lb Bradley Guided Helve is the working hammer. I have a 500 lb of the same type sitting in the yard waiting for the funds to do the installation.

The kind of work this shop did is still being done in the US but now with more modern equipment. Take a look a the Scot Forge website. We make parts for all kinds of things. Yesterday and Monday we were forging submarine components. Then its on to gears for the big mining shovels and axels for the massive dump trucks used in the tar sands operation. Forgings for oil wells, off shore oil rigs, even the wheels on the Mars rover were made as forgings by Scot Forge. Though I absolutely sympathize with the loss of equipment associated with scrapping out a shop like this, you can be sure that industrial forging is by no means dead or even dying. If anything, the industry is expanding. What has changed in the industry is the need to create some of the very intricate forgings that used to be a part of railroad and other specialized shops. With modern welding, cutting and machining techniques and the relatively low cost of steel as compared to 150 years ago it has become more cost effective to produce a fairly simple forging and machine in those intricate features or weld on extensions rather than create them by splitting and drawing out the stock.

I spent several days in a power hammer class using a big blue 110. It did perform well and worked as it was designed. Where we ran into trouble was with die width when making spring swages. The dies we had were pretty narrow and the stock for the swage spread beyond the width of the die. Dean Curfman, who was running the Big Blue operation back then, stopped by one night after class and he made the same comments Josh did (see earlier post). The hammer was not designed to replace an industrial style hammer so it is really unfair to compare them with a Nazel, Chambursburg, or large mechanical hammer. However, within their design limits they work very well. This is best illustrated in the video Free Form Forging featuring Uri Hofi. If you can, watch this video before committing to the hammer. If your needs are more along the industrial style of work with a large amount of tooling then I'd suggest an Iron Kiss, large mechanical or self contained unit. Patrick

I use a product called Alligator belt lacing which is available from Mcmaster and can be installed very easily with just a hammer. I do have a local shop that can install the type of lacing you have posted, but I have found the Alligator style to be just as effective.

I'm sure I'm missing something basic, but I can't figure out how to post pics. Anybody give me a hint?

You have a ton of work ahead of you to restore this hammer. It looks like all the specialty pivot bolts and there mating inserts are gone and that is why there are repairs to the shell around the crank. With the pin set up shown there is insufficient flexibility in the system. You MUST get those parts replaced. I have purchase 2 Bradleys, a 300 and 500, both with all their parts except the helve for the 300. I never paid more than scrap. In fact, I ran the 500 before I bought and the motor was included in the deal. The 300 needed a complete rebuild which I did. I photographed all the parts can post anything you wish to see. Here are images of the spherical end bolts. Note that these are bearing surfaces and they are hard. After running the hammer several years, I did break one and made a replacement from a grade 8 bolt and that is working fine. The problem you will have is that the threads in the holes that accept these bolts are likely severally damaged due to the use of pins. I would highly recommend that you not invest in this machine but save your money for something that is more restorable. Another thing that seems to be missing is the upper half of the husk which clamps the beam in place. You could fabricate one from heavy plate, but you will likely need a very large mill or big radial drill to properly locate the hole that must match with the holes in the lower half. There are several large bolts which lock these two pieces together. Again, this hammer is just not worth putting money into. You'll have several thousand dollars tied up in it an for that you can go get a rebuilt 100 lb LG. In fact, you could probably buy two bigger hammers for what it will cost you to rebuild this one. Patrick

I regularly forge billets 2x2x6 and 2.5x2.5x6. These are all made by the compression plate technique described by Steve Midgett in his book "Mokume Gane". The billets I forge are either copper/nickel silver combos or copper/red brass/nickel silver. Layer thickness can be the same or varying depending on the pattern desired. When I was first learning to forge these materials I used a copper bar as my gage. The copper could be forged just a little hotter than the mokume billet. I have never had any trouble with dissimilar flow rates of the various materials, but I have had some trouble with over heating as my forge tends to develop hot spots. If you are forging round our octagons you can also get layers shearing apart when you forge in the corners. Patrick

Grain direction is NOT changed by heat treatment. It is a function of the hot (or sometimes cold) deformation processes used prior to heat treatment. Heat treatment changes properties like hardness and ductility, but the grain direction is not changed. This means that properties are generally NOT the same in all directions, regardless of heat treatment. If you perform a tensile test on a plate you will find that there is greater ductility when the test specimen is cut parrellel to the direction that had the greatest deformation than when you perform the same test at 90 degrees to this deformation direction. This is true whether the plate is in the as rolled condition, normalized, quenched and tempered etc. The actual values measured change with these heat treatments, but the fact that the values are different depending on the specimens orientation relative to deformation does not.

Steel does indeed have a grain direction though you normally can't see it without a microscope. It does however make a significant difference in mechanical properties so it is a real cosideration in engineering and component design. I've been dealing with this on a daily basis for the last 10 years in my role as a plant metallugist for Scot Forge. The term "grain" is a direct reference to wood because, until recent times iron and steel were so dirty that when broken they actually looked almost exactly like wood. We don't see thaft today at the macro level but the condition still exists and the term grain flow is common in steel making and forging. Patrick

John- In the forging industry a reduction in area of 3:1 from cast ingot to final forged shape is usually the minimum reduction required to consider a product "wrought". That is probably a good rule of thumb for developing a distinct grain flow as well.

In answer to Andrew's proposed the experiment, the results will be that tensile and yield strengths will be about the same in both directions but the impact strength, elongation and reduction of area will all be less in the transverse direction than in the direction parrellel to the grain flow. The exception to this is that very clean steels, typically those which have very low sulfur contents or those which have been remelted can have uniform properties in all orientations. Note that it is NOT normal for slag to exist as an inclusion element in properly made steel. What is there are oxides such as aluminum and silicon oxides and usually manganese sulfides. I will point out that by adding small amounts of calcium, the manganese sulfides are made spheroidal and they stay way during hot working. This is another way to get uniformity of properties in all directions.

Grain flow or direction in metal alloys is not a function of heat treatment but of mechanical deformation. What heat treating will do for you is change individual grain size and shape so you can go from columnar grains to equiaxed grains but the grains will still have a direction that is imparted by the mechanical deformation. The experiment you have described is similar to the jominy end quench test which consists of heating a 1" round 4" long specimen to predetermined temperature and water quenching one end with a constant, predetermined flow of water. Hardness is measured at 1/16" intervals from the quench end to the mid-length of the specimen. This test is used to compare the hardenability of one grade or heat of steel to another. You end up with a hardness gradient, but there is no change in grain flow because of this heat treatment. For a detailed description of the Jominy end quench test see ASTM specification A255. As a side note, grain flow is not "undone" by overheating since, in today's steels the term "grain flow" has to do primarily with the orientation of micro inclusions such as oxides and sulfides. Overheating does not change the orientation of these particles even though the individual crystals of iron are change as I noted above. That is to say, if I have a closed die forged wrench and I heat it to forging temperatures without forging it, the grain flow is the same before and after that process. The grain size and microstructure (martensite, austenite, pearlite etc.) will not be the same before and after.