Most know that it is important to identify from the beginning the material from which a part will be run. But what is the best material to use for your project? Below we explore the differences between aluminum, stainless steel, and carbon steel materials.
The dash (-) refers to hardness. For example, –H32 means the customer is asking for Aluminum at ¼ hard. Below are some of the more common choices we see at Estes.
Description: This is the most common aluminum requested at Estes. This is the highest strength alloy of the more common non heat-treatable grades of aluminum. Fatigue strength is higher than most aluminum alloys. In addition this grade has particularly good resistance to marine atmosphere and salt water corrosion. It has excellent workability. It may be drawn or formed into intricate shapes and its slightly greater strength in the annealed condition minimizes tearing that occurs in 1100 and 3003. It works very well on a laser.
Applications: Used in a wide variety of applications from aircraft components to home appliances, marine and transportation industry parts, heavy duty cooking utensils and equipment for bulk processing of food.
Description: This is the most widely used of all aluminum alloys. It is essentially commercially pure aluminum with the addition of manganese which increases the strength some 20% over the 1100 grade. Thus, it has all the excellent characteristics of 1100 with higher strength. It has excellent corrosion resistance and workability. It may be deep drawn or spun, welded or brazed. It is non heat treatable. While some lasers do not cut 3003, Estes can do so using its fiber laser.
Applications: cooking utensils, decorative trim, awnings, siding, storage tanks, chemical equipment.
6061-T4 and 6061-T6
Description: 6061 is the least expensive and most versatile of the heat-treatable aluminum alloys. It has most of the good qualities of aluminum. It offers a range of good mechanical properties and good corrosion resistance. It can be fabricated by most of the commonly used techniques. In the annealed condition it has good workability. In the T4 condition fairly severe forming operations may be accomplished. The full T6 properties may be obtained by artificial aging. It is welded by all methods and can be furnace brazed. The T4 is soft and the T6 is hard making it harder to form. The T6 is so hard that it is impossible to form sharp edges. You will have large radii (almost 8x the material thickness).
Applications: This grade is used for a wide variety of products and applications from truck bodies and frames to screw machine parts and structural components. 6061 is used where appearance and better corrosion resistance with good strength are required.
Stainless steel is best run on laser because it is one of the harder materials. There are two primary series of stainless steel used by Estes. Estes uses the 300 series and the 400 series.
The 300 series is the most commonly used stainless steel by Estes. It contains very little carbon. The 300 series cannot be heat-treated, and is non-magnetic. It has a very high scrap value.
The 400 series has a higher carbon content than the 300 series. It is magnetic making it slightly more prone to rust. If the 400 series is welded, there is a chance of carbon precipitation to cause a problem of rust on the stainless steel.
There is also a wide range of finishes available. The most common to Estes are:
Description: The 2B finish is a standard mill finish. It is gray and uniform looking with no texture at all.
Description: The #3 and #4 are brushed finishes that are more expensive. Often, service centers will provide the same product for both finish numbers. To protect the brushed finish, the material is supplied with vinyl protection that adheres to the surface. The vinyl is typically peeled by the end user when the product is in the field.
One thing to note about Carbon Steel is that it ALWAYS starts as Hot Rolled. When it is rolled into sheets it can either remain hot rolled or change to cold rolled. Cold rolled means that the steel is rolled to its final dimensions below the recrystallization temperatures.
Cold Rolled Steel
When carbon steel is cold rolled, it tends to become a bit more brittle than when it is hot rolled. The extra brittleness is of little consequence to most fabricating processes, though hemming operations could be affected. Cold rolled steel can be laser cut or punched.
Hot Rolled Steel
Hot rolled steel is a better forming steel that is usually cheaper than cold rolled steel. It is not as clean as cold rolled and has a black residue. Hot rolled steel can be laser cut or punched.
Hot Rolled Pickled and Oiled Steel
The Pickled and Oiled option is the same as hot rolled steel, with the one difference being that the steel runs through a bath of pickle liquor that contains strong acids. The bath helps to clean the material and prevent rust. Hot rolled pickled and oiled carbon steel can be laser cut or punched.
Coated Steel Products
Coated steel products reduce the possibility of corrosion.
Aluminized, Galvanized, and Galvannealed are all offered as coated steel products. Laser cutting galvanized can leave a drossy edge, as the coating is melted during the cutting process and then rehardens on the bottom edge of the material. All three materials form the same, but it is best not to paint the Galvanized.