I blacksmith as a hobby and I've done a lot of research on blacksmithing, machining, heat treating, and the creation of steel. I decided to share my knowledge on blacksmithing here so that those who wish to include blacksmithing in their game would have idea of what really goes on and adapt that to their game if they desire.
This is part one in which the process is described as it actually occurs in real life and the technical aspects of it. Part two will beign to go into possible ways to make the game world reflect reality.
The basics
A blacksmith needs 5 things to do their work. They need a forge to heat their metal, an anvil (which can be any suitably hard object) to hit the metal against, a hammer to hit the metal with, tongs to hold the metal (if it is small), and of course metal to forge. These are the basic things you need to do ANY blacksmith work. There are things you will need for specialized tasks, but you will need these for anything you do.
The Forge
The forge is where the metal is heated. It can take many forms. They are usually grouped according to their fuel type. There is solid fuel types which use coal or charcoal as their fuel, gas forge which use flammable gas such as propane as fuel, and then there are electric forges which use eletricity to heat metal.
A solid fuel forge burns coal or charcoal to make it. In order to make it burn hotter, air is forced into it through means of some sort of blower. There are many types of blowers such as a bellows, which is used by your medieval blacksmiths (they are still used today actually). Then you have a crank blower, which is a centrifugal fan that is cranked by hand. It involves gears to get the fan spinning fast enough to push large volumes of air. Then you have electric blowers which replace human power with electric motors.
The more air you blow in, the hotter and faster the coal or charcoal burns.
A gas forge burns gas to make heat. They come in two varieties, forced air or venturi. A forced air gas forge uses a blower to force air into the forge to be burned with the propane. They use a lot less fuel and can get very hot. However they require something to force push air, which usually means an eletric blower.
A venturi burner forge uses the Venturi effect to do its work. These use more fuel and are harder to get to extremely high temperatures, but they don't require a blower and thus can run without electricity.
The electric forges can use heating elements, or more commonly magnetic induction heating.
Heating elements are usually employed in heat treating ovens.
The Anvil
The anvil is what the smith places the piece on to forge it. It is a second hammer because of Newton's Laws of motion. You hit the piece, which causes it to hit the anvil, and the anvil hits back. There are many types and styles of anvils. Typically, the heavier an anvil the better. It is sturdier and allows you to hit the piece harder without causing unintended movement in your anvil. There are different materials used in anvil construction.
Cast iron anvils are worthless for any serious forging. They are far too brittle and soft. These are often referred to as ASO's (anvil shaped objects).
A good anvil is going to have a nice hard face. The face is the top part where the work piece is placed to be forged. The rest of it is typically a wrought iron or a regular low carbon steel.
The Hammer
The hammer is the primary shaping tool of the blacksmith. A hammer can be classified by two attributes, it's weight and it's peen. The peen is the shape of the business end. For example, a ball peen hammer is called a ball peen hammer because the business end, the peen, is rounded like a ball. A cross peen hammer, the typical blacksmith hammer, as a peen on it that goes across. The peen determines what is going to happen when you hit the work piece. The peen is going to be negatively imprinted on the piece when struck.
A cross peen is used for the process of drawing out. Drawing out is making the work piece longer in one dimension. This causes it to shrink in either both or one of the other dimensions. The volume of the piece is always constant.
A cross peen is used because you can create dimples perpendicular to the dimension you wish to increase. This creates a wavy structure. You then take the flat face of the hammer and hit the raised portions of the wave. This causes the metal to be forced out and stretched.
Other forging methods with the hammer are things like upsetting and beveling. There are a lot of things you can do. Upsetting involved taking something like a rod, heating one end of the rod, placing it on that end on the anvil and then hitting the opposite end as though you were trying to drive the rod into the anvil like it were a nail. This will cause the heated end to bulge outward parallel to the plane it is hit against.
Beveling, most often used in forging blades, is when you angle the blade along the anvil and forge an angle into the blade.
The Tongs
The tongs are what the smith uses to hold the work piece. There are HUNDREDS of tongs. A tong for smithing is very different than a pair of pliers. A smithing tong is designed to hold a specific thickness of metal. When close all the way, the gripping end of the tongs will be open very close to their intended metal thickness. There are bolt tongs, wolf jaw tongs, box tongs, round tongs, and many other types of tongs. They are each intended to hold a different shape and size of metal.
The Material
The material of a blacksmith is typically steel. Steel is a very large category of metals. The basis of steel is iron and carbon. The carbon forms a crystalline structure with the iron and increases its strength. Other alloys can be included to produce other desired properties. Elements like chromium, nickel, silicon, molybdenum, vanadium, tungsten and many others. Each imparts a different set of properties in a different amount. For example, stainless steel is iron, carbon, and large amounts of chromium and nickel. There are many other possibilities.
The properties of the final steel depend on the elements and the amounts of those elements it is alloyed with. Increasing the level of carbon makes the steel stronger and harder. However, putting too much carbon in the steel will have the opposite effect and make it weaker and softer.
The alloy chosen depends largely on the use of the piece they are making. If they are making something ornamental, then a low carbon steel would be used because it is cheaper and easier to work. A gun barrel is typically made out of 4140 alloy, which is .4% carbon and has chromium and molybdenum. This particular allow is well suited to handling extreme pressures and shock. However, it would make a poor choice for a blade because the carbon content is too low to make it hard. W1 is a common alloy used for blades, but it would be a poor choice for a gun barrel because it cannot deal with the pressures and shock involved in firing a gun.
Additional Reading
http://en.wikipedia.org/wiki/Alloy_steel
https://en.wikipedia.org/wiki/Tool_steel
http://en.wikipedia.org/wiki/Stainless_steel
http://en.wikipedia.org/wiki/Spring_steel
http://en.wikipedia.org/wiki/Steel
From Billet To Final Product
There are many steps involved in bringing a billet, a blank bar of metal, to the final product. How many depends on the desired product. For this journal entry, I will use the quintessential fantasy object, the sword.
The process of forging a sword from billet is many fold. There is the forging process, in which the billet is brought to rough shape of the sword. Then, there is the grinding process in which the roughly forged shape is ground to the exact shape, with a little extra in key areas. Next comes heat treating. The blade is then ground to final shape. At this point, the hilt, handle, and pommel are made (or earlier, but the next steps will need these objects). The last stage is fit and finish in which all the details of the sword are completed such as polishing, acid etching, engraving, and assembling the four parts together into one solid object.
Selecting the Alloy
The alloy chosen for a sword is typically a steel with a medium-high to high carbon content. Allows used include things like 1070, 1085, W1, O1, 1095, 5160, and 9260. Each of these have a different composition of alloying elements. The 10XX series are pure carbon and iron. The last two digits designate how much carbon there is , in hundredths of a percent. 1070 is .7% carbon (70 hundredths), 1085 is .85% carbon, and 1095 is .95% carbon. W1 and O1 are tool steels. W1 is usually .95% carbon and includes a few points of vanadium. O1 is .9% carbon, 1% Manganese, .5% chromium, and .5% tungsten. 5160 and 9260 are spring steels (these are the alloys that are used in car leaf springs and coil springs). 5160 is .6% carbon, .8% chromium, .87% manganese, .22% silicon, .03% phosphorus, and .04% sulfur. There are HUNDREDS if not THOUSANDS of alloys.
These alloys are chosen because they can be made hard so they hold an edge, and they can be made tough so they do not break. The exact alloy chosen is personal preference of the smith, the user, or both.
There also exists different ways to make the final material. There is mono alloy, in which the blade is made up of a single alloy.
The second two involve a process called forge welding. This is the process of heating two pieces of metal to very high temperatures and putting them in a plastic, almost liquid state, and then pressing the two pieces together. This will cause the two pieces to fuse together into one.
The first of these is a san mai construction in which one alloy is sandwiched between two pieces of another alloy. The inner alloy is a hard alloy while the outer alloys are softer but tougher alloys.
The final type is pattern welded or damascus. Two or more alloys are brought together and they are arranged in an alternating stacking. They are then forge welded together, drawn out, folded over and forge welded together. This is repeated several times, depending on the effect desired. This is usually done for artistic purposes. Any actual benefit is largely debate and I have not read of any scientific studies to prove it is better or not.
Forging
Forging can be hot or cold. Most is done hot because it is easier. Cold forging can be done by large machines or on soft metals like copper. I will talk about hot forging.
Hot forging involved heating the metal and then while it is hot, hitting it with the hammer, bending the metal, twisting the metal, or otherwise manipulating its shape in some way while hot.
Different alloys have different ranges in which it can be forged. If the metal is made too hot, you can literally burn the steel. You will know you've done this if you pull the metal out and it is sparking. This the iron and carbon in the steel combining chemically with oxygen (mostly carbon). This is a bad thing.
If the metal is too cold, it will not be easily forged. If it is JUST too cold, you can actually cause stress build up and cracking. Forging the metal while it is within this forging temperature range is crucial. Forging at inappropriate temperatures can cause internal stresses and set you up for failure down the road, if not for the smith then for the user of their item.
A blade typically tarts off as a billet, a block of steel. It could also be a rod or a flat piece. It all depends on how the smith receives it. The smith will then heat the metal and forge it into shape.
A sword actually has a lot of shape put into it. There is a distal taper. This is the blade getting thinner as you go down it's length. This is crucial for allowing the sword to bend when force is applied on the flat sides.
There are bevels, which taper the thickness from side to side. These are rough forged into the sword. Some sword will have a fuller groove, which is the groove that runs across the middle of the sword. This can be forged or cut into the blade.
The forging process involves great care. It needs to be done in as few heats as possible (a heat is putting the blade into the forge to heat it up) because each time it is heated, it loses a tiny bit of carbon (very tiny). The more heats applied, the less carbon there will be in the end. The loss might be tiny, but if enough heats are applied it can add up.
Side Note
Often, a heat treating step called normalizing is performed after forging. Heat treating is discussed later but keep this in mind. Annealing could also be done. It comes down to personal preference of the smith.
Grinding to Shape
Once the blade is forged to a rough shape, it is ground and filed to get something very close to the exact dimensions required. In some dimensions extra is left over. The most typical area is the edge thickness. This is usually left thicker than desired because of the step to follow. A typical thickness is around that of a nickel coin.
Heat Treating
Heat treating is the MOST critical step. It can make or literally break the work. There are four heat treating processes: annealing, normalizing, quenching, and tempering.
Annealing
Annealing is heating the metal past critical and then cooling it very slowly. Most blacksmiths will bury the heated metal in vermiculite and let it sit for a day. It will often come out still very hot. Annealing in a controlled professional environment will cool it in the furnace at Xdegress per time. The purpose of annealing is to take the metal to it's maximum softness and to remove built up stresses in the metal. Stresses come from working the metal, such as forging and machining. The metal grain has a kind flow about it and annealing allows the metal to reform this flow and make the material as a whole much stronger.
Normalizing
Normalizing is the same as annealing, but it is cooled faster. Instead of cooling it inside of an insulation, you just allow it to cool in the air. This makes the metal softer and removes stresses, but to a lesser degree than normalizing. It is done when the stresses built up are not severe and maximum softness is not necessary. It is much faster than annealing.
Quenching
Quenching is heating the metal past critical, and then rapidly cooling the metal. This is probably the most difficult heat treating process because it creates TREMENDOUS stress in the metal because of the thermal shock. The more alloyed elements, specifically carbon, the slower it must be cooled. There are three quenching mediums: water, oil, and air (yeah air), in order of speed. Quenching something too fast will cause it to break from the thermal shock. Quenching forms martensite, which is the crystaline structure that makes steel hard. However, right after quenching, the blade is INCREDIBLE brittle. You could take a sword freshly quench and break it very easily by trying to bend it.
Tempering
Once you quench something, you must temper it. Tempering reduces the hardness in exchange for toughness, the ability to resist breaking. Tempering is heating the metal to a specific temperature and holding it there allowing the metal to soak. Typically the time is for an hour, and typically at least 2 soaks are done. The higher the temperature, the tougher and softer it will make the metal. Typically, before modern metalurgical science, blacksmiths would heat the metal until it turned blue and then they would heat it no further. The temperature you temper at depends on what you want the final product's properties to be. A sword would typically be tempered at a higher temperature because it needs to be able to deal with being bent versus a knife which would be tempered at a lower temperature because the change of it being bent is much lower.
Cryotreating
This one was left out of the original publishing because I forgot about it at the time. This was originally discovered, from what I've read, by NASA when they were studying the effect of extreme cold on materials. One thing they discovered was the effects it had on steel.
Steel, after being quenched, has parts in it that are still in the process of being transformed into martensite, the hard crystalline structure formed by quenching. It is a slow process, but being subjected to near -300 degree temperatures accelerates the transformation. The amount of new martensite formed varies from alloy to alloy. It also precipitates the creation of eta carbides. This increases the capable hardness of the steel and can greatly increase the wear resistance of the steel.
After cryotreating, the metal will need to be tempered again because of the newly formed martensite increasing the brittleness.
Heat treating the sword
The first step in heat treating a sword is normalizing. Often this is done right after forging before the grinding and filing stage. This is to relieve stresses built up in the metal from the forging process. Typically it is done three times in a row, just to be sure, each time going less above critical. Might not make any real difference. In the world of blacksmithing it's as much art as science.
After this comes the MOST critical and sensitive step. Errors made in forging, such as forging too cold or getting the metal too hot, will come out here.
There are different methods to quenching. There is just a straight up quench in which the entire blade is heated and quenched uniformly.
There is a differential hardening quench, in which the blade is coated with a clay material. The idea is to lightly coat the edge, if at all, but coat the spine of the blade. It is then heated to a uniform temperature and quenched. The idea is to get the edge hard, but to only make the spine semi hard. This is to attempt to make the blade both hard where it matter and tough where it matters and try to get the best of both worlds.
There is also something called an interrupt quench. The blade is heated and quenched like normal, but the blade is removed before being fully cooled, typically in the area of 450 degrees F. It then cools in air to about 150 degrees and tempered. This would be done when there is worry about bringing it to lower temperatures quickly could cause it to crack from stress. It is also done as part of the 'voodoo magic' of blacksmithing (there is a lot of 'voodoo magic' in blacksmithing. This is stuff that someone will swear up and down has this or that effect but they have no real proof of it). As it turns out, the interrupt quench actually does serve the purpose of counteracting the stresses involved in quenching. Some people do it without realizing this, they do it because they believe the voodoo magic.
The exact methods of quench all depend on the material involved and the desired results.
After it is quenched it is immediately tempered. The exact temperature of tempering depends on the intended use and the alloy involved.
Fit and finish
Fit and finish is the last stage. The hilt, handle and pommel are made. The blade is ground and filed down to the exact dimensions desired. Any artistic details are created.
Artistic details would be things like polishing, acid etching, engraving, and other finishes such as black oxide finishes or bluing.
The hole in the handle through which the pommel is made is formed often by a process called 'burning in'. The handle is predrilled to get as close to the tang shape without going over. The tang is then heated to a high temperature and the handle is thrust upon the heated metal. This causes the moisture in the wood to flash boil and the wood becomes very very malleable for a short period of time. It is repeated until the handle has a perfect fit around the tang (or the wood is ruined).
The hilt, handle and pommel are added to the the sword. They created a sandwich. All three parts have a hole for the tang of the sword to go through. The hilt goes on first, followed by the handle, and finally the pommel. The remainder of the tang, typically made thin and round, is cut off so a little is left and that little bit is hammered down to form a rivet and hold the sandwich together. The scabbard or sheath is also made at this point. A scabbard is a hard case and a sheath is a soft flexible case.
Blacksmithing in the Medieval Times
If you've never tried to make a sword, it is no easy process, especially if you do it without the benefit of modern science and mechanical advantages. The sword in this example would have had a group working on it, especially in a production environment. Each person would be doing a different part. Some parts might not even be done in the same place, aka the work was outsourced to someone else.
The steel needed to be made, which was an involved process on its own.
Conclusion
That is the process of smithing a sword. The process for other smithing is pretty similar, the differences are in the shape of the object and the intended use of the object. A full guide would be WAY to big for this. I highly encourage you to explore the matter on your own. One source I HIGHLY recommend is http://forums.dfoggknives.com/ Some of the best blade smiths in the entire world are on those forums. There are some BEAUTIFUL works of art there. You can learn a lot just from reading and they are more than happy to answer questions as long as you don't act like an idiot (they react the same to people there as we do to people here that come and post things like "OMG I HAVE TOTALLY AWESOME GAME FOR YOU TO MAKE FOR ME FOR FREEEE!!!!111ONE!")
How you apply what I've presented here is entirely up to you. At least now you have a good idea of what actually goes on when something is made through blacksmithing.
Journal Entry Update Log
18 Apr 2013: First Written
19 Apr 2013: Addendum on Cryotreatment Added In Heat Treatment area
Really great. Thank you kindly for taking the time to share.