Properties and characteristics that affect formability

Each metals has its own blend of physical, chemical, and surface properties and characteristics. Knowing about the major work metals (not tool steels), their properties, grades, and characteristics helps to achieve the best results in stamping and forming best results. Baking a cake requires the right amount of the right ingredients, added at the right time, and baked at the optimal time and temperature. Sheet metal production is not that different. Literally hundreds of different "flavors" of metals are available, each with its own blend of physical, chemical, and surface properties and characteristics.

Strengthening Metals

Pure elements are relatively soft and malleable. When you move a carpet, it takes a lot of force to pull the carpet from one end. However, if you first create a little wave or ripple and propagate that through the carpet, it becomes much easier to move. Metal forming on the atomic scale is not that different.

Atomically, a pure metal can be pictured like a 3-D network of racked billiard balls all the same size. To make a steel alloy, for example, some of the iron billiard balls would need to be replaced with ones made of manganese (Mn), silicon (Si), phosphorus (P), titanium (Ti), and so forth, which are similar but not identical in size to the iron balls. Furthermore, even though all the balls touch, small gaps exist between them, called interstices. Small stuff can fit in between, like cue chalk. This is where small elements like carbon and nitrogen fit. The disruption in the pure iron atomic lattice caused by these alloying additions is responsible for what is known as solid solution hardening. When some alloys are heat-treated, these small elements combine with larger ones and precipitate out of the matrix, creating more obstacles to metal flow, resulting in higher strength associated with precipitation hardening. An example of this is titanium carbide precipitates in steel. Work hardening, also known as strain hardening, occurs when many dislocations accumulate. (Remove one ball. Now the balls themselves can change spots. Of course, this changing of spots is harder if many pieces of cue chalk are in the gaps-the balls don't roll as easily. It'll take more force to move them. And that is what higher strength is all about.)

Ultralow Carbon Steels

Steel is, by minimal definition, an alloy of iron and up to 2 percent carbon (if it is more than 2 percent, the alloy is cast iron). Carbon is small enough to fit into the interstices of a primarily iron matrix, making it an "interstitial element" in steel. If the steel alloy has an ultralow carbon level (typically less than 50 parts per million), most of these gaps will not be occupied and, as such, can be called interstitial-free (IF) steel. These primarily ferric (iron), very formable IF steels are extra-deep-drawing steel (EDDS). Achieving this low carbon level does not occur using conventional steel processing. Instead, the molten steel must be put under a vacuum that decarburizes it by removing carbon monoxide, as well as other gases like hydrogen and nitrogen. This process is called vacuum degassing, and it is done in the production of vacuum degassed interstitial-free steels (VD-IF).

Mild and Higher-strength Steels

Mild steel (also known as drawing steel) contains about 0.04 percent carbon and 0.25 percent manganese, along with several other elements in much smaller quantities. Even with all the alloying, these low-carbon steels are still about 99.5 percent iron. Increasing the alloying typically leads to an increase in strength, a decrease in formability, and more challenging weldability (higher carbon equivalent). High-strength steels (carbon-manganese); conventional high-strength, low-alloy steels (HSLA); and advanced high-strength steels (AHSS) such as dual-phase (DP) and transformation-induced plasticity (TRIP) steels have different balances of strength, formability, and weldability based on their different chemistries and processing at the steel mill.

The AISI/SAE name for carbon and low-alloy steels is a four-digit number: The first digit indicates the primary alloying element; the second digit reflects the type and amount of the other alloying elements; and the last two digits indicate the carbon content, in hundredths of a percent by weight .

An entire spectrum of properties is available, varying with alloying addition, heat treatment, and mechanical processing. However, the composition variations can be illustrated by bending two seemingly identical paper clips back and forth a few times. Although they both have the same composition, one has less formability than the other. With this in mind, you might consider adding mechanical property limits to your material order. The tighter range of properties may reduce your scrap.


	Metallurgy Electrodes Metallurgical Properties Properties of Metals Steel and Technology Precious metals Alloys

	Steel and Technology
	Properties and characteristics that affect formability Each metals has its own blend of physical, chemical, and surface properties and characteristics. Knowing about the major work metals (not tool steels), their properties, grades, and characteristics helps to achieve the best results in stamping and forming best results. Baking a cake requires the right amount of the right ingredients, added at the right time, and baked at the optimal time and temperature. Sheet metal production is not that different. Literally hundreds of different "flavors" of metals are available, each with its own blend of physical, chemical, and surface properties and characteristics. Strengthening Metals Pure elements are relatively soft and malleable. When you move a carpet, it takes a lot of force to pull the carpet from one end. However, if you first create a little wave or ripple and propagate that through the carpet, it becomes much easier to move. Metal forming on the atomic scale is not that different. Atomically, a pure metal can be pictured like a 3-D network of racked billiard balls all the same size. To make a steel alloy, for example, some of the iron billiard balls would need to be replaced with ones made of manganese (Mn), silicon (Si), phosphorus (P), titanium (Ti), and so forth, which are similar but not identical in size to the iron balls. Furthermore, even though all the balls touch, small gaps exist between them, called interstices. Small stuff can fit in between, like cue chalk. This is where small elements like carbon and nitrogen fit. The disruption in the pure iron atomic lattice caused by these alloying additions is responsible for what is known as solid solution hardening. When some alloys are heat-treated, these small elements combine with larger ones and precipitate out of the matrix, creating more obstacles to metal flow, resulting in higher strength associated with precipitation hardening. An example of this is titanium carbide precipitates in steel. Work hardening, also known as strain hardening, occurs when many dislocations accumulate. (Remove one ball. Now the balls themselves can change spots. Of course, this changing of spots is harder if many pieces of cue chalk are in the gaps-the balls don't roll as easily. It'll take more force to move them. And that is what higher strength is all about.) Ultralow Carbon Steels Steel is, by minimal definition, an alloy of iron and up to 2 percent carbon (if it is more than 2 percent, the alloy is cast iron). Carbon is small enough to fit into the interstices of a primarily iron matrix, making it an "interstitial element" in steel. If the steel alloy has an ultralow carbon level (typically less than 50 parts per million), most of these gaps will not be occupied and, as such, can be called interstitial-free (IF) steel. These primarily ferric (iron), very formable IF steels are extra-deep-drawing steel (EDDS). Achieving this low carbon level does not occur using conventional steel processing. Instead, the molten steel must be put under a vacuum that decarburizes it by removing carbon monoxide, as well as other gases like hydrogen and nitrogen. This process is called vacuum degassing, and it is done in the production of vacuum degassed interstitial-free steels (VD-IF). Mild and Higher-strength Steels Mild steel (also known as drawing steel) contains about 0.04 percent carbon and 0.25 percent manganese, along with several other elements in much smaller quantities. Even with all the alloying, these low-carbon steels are still about 99.5 percent iron. Increasing the alloying typically leads to an increase in strength, a decrease in formability, and more challenging weldability (higher carbon equivalent). High-strength steels (carbon-manganese); conventional high-strength, low-alloy steels (HSLA); and advanced high-strength steels (AHSS) such as dual-phase (DP) and transformation-induced plasticity (TRIP) steels have different balances of strength, formability, and weldability based on their different chemistries and processing at the steel mill. The AISI/SAE name for carbon and low-alloy steels is a four-digit number: The first digit indicates the primary alloying element; the second digit reflects the type and amount of the other alloying elements; and the last two digits indicate the carbon content, in hundredths of a percent by weight . An entire spectrum of properties is available, varying with alloying addition, heat treatment, and mechanical processing. However, the composition variations can be illustrated by bending two seemingly identical paper clips back and forth a few times. Although they both have the same composition, one has less formability than the other. With this in mind, you might consider adding mechanical property limits to your material order. The tighter range of properties may reduce your scrap.


	Metallurgy Electrodes Metallurgical Properties Properties of Metals Steel and Technology Precious metals Alloys