Some Properties of Steel

Drop Forged, Forged, Cast, and Machined:

What makes one pair of pliers better than another? How the steel is manufactured is one factor. Drop-forged steel has essentially been hammered by a machine to form its final shape. This process stretches and aligns the grain for strength, whereas cast steel does not have this characteristic. Casting and drop forging are common mass-production processes. Here is a good resource on the subject:

The differencees between cast and forged metal.

Handmade tools created by blacksmiths are forged with heat and a hammer. These tools have the same quality as drop-forging, but are not mass produced. In fact, drop-forging is the production version of smithing.

Another method of manufacture is to machine the tool from a blank piece of steel. This process is labor intensive, and also does not impart grain realignment or stretching that occurs in drop forging. If a machined tool is made from extruded steel, then it may have various strengths imparted in the raw metal that were present in the extrusion process. However, these strengths are linear, rather than convoluted.

Heat Treated Steel

Tools made from steel can be made to take on different characteristics through selective heating and cooling. Not all alloys of steel have equal levels of these traits. Good tools are heat treated so that they are both tough and hard. A tool that is "case hardened" is tough on the inside and hard on the outside, making it resist denting and deformation while at the same time resist cracking. Inexpensive tools that are not properly heat treated can either snap in half under force, or bend. I have experienced both of these traits when using cheap tools.

Here is a list of properties that metals can acquire through the application of heat treatments. Tools that are too soft will deform. Tools that are too hard will shatter.

• Toughness - the ability to resist cracking.
• Hardness - the ability to resist abrasion.
• Malleability (malleable) - the ability to be reshaped by compressive force, such as by a hammer.
• Ductility (ductile) - the ability to be reshaped by tensile force, such as stretching.
• Brittleness - when steel is brittle, it will shatter or crack under enough strain with little deformation.

Temper -

• Dead Soft - the softest a metal can become when at room temperature.
• Full Hard - springy, and as stiff as the metal can become.
• Half Hard - balance between dead soft and full hard.

Properties of rolled raw metal profiles -

• Cold Rolled - means the steel was formed into its current state, such as a bar, wire, or channel, while it was cold. This imparts work hardening to the object, making it more rigid and difficut to work.
• Hot Rolled - means that the metal was glowing hot as it was formed into its current state, making it more easy to work, but also less rigid.

Steel Types

Steel is a blend of iron and carbon. Iron by itself is very soft. The addition of carbon makes the compound able to be hardened. Other additives can make steel much stronger for tools. These additives make them alloys of steel.

• Chrome Vanadium - is an alloy of steel that contains carbon, manganese, silicon, chromium, and vanadium. It is stronger than carbon steel, and is used for making long-lasting tools.
• Chromoly - is an alloy of steel that contains carbon, chromium and molybdenum. This makes it stronger than carbon steel. Like Chrome Vanadium, it makes excellent tools.
• Carbon Steel - the introduction of carbon into steel allows it to be hardened, but it lessens its ability to be worked. As more carbon is introduced, the steel will become more brittle, but also harder.
• Mild Steel - low carbon steel that is easy to work but extremely difficult to harden.