Metal Archives - Page 6 of 6

What is the Tempering Process?

Steel is a term we consider synonymous with strength. Having a steely glare, being tough as steel: both expressions used to describe someone who is hard, strong, and determined.

So then, it may surprise you to learn that untempered steel can be nearly as fragile as glass! Without the tempering process, any steel produced will be extremely hard but also quite brittle. If it remains this way, it would be too prone to breakage to use in most applications.

Tempering is a method of heat treatment used to increase the resilience of iron-based alloys such as steel. After an initial heat treatment has been done to boost the steel’s hardness, tempering then reduces some of that hardness to help improve its strength. The end result is a steel which is less brittle, with increased ductility and abrasion resistance.

The tempering process begins after the steel has gone through an initial hardening treatment. With hardening, steel is brought to very high temperatures just short of melting, and quenched to cool it as quickly as possible. This quenching essentially locks the steel’s crystal structure and creates a very hard material. Tempering is then done immediately afterwards; if left to sit after quenching, the risk of cracking within the material will increase. To temper the steel, it involves reheating it once again to a high temperature and cooling, but in a less extreme or abrupt way than with hardening. Once exposed to the desired temperature, the steady heat application helps to relieve any internal stresses within the steel. Finally, the metal is removed and allowed to cool naturally in still air. So perhaps the best way to imagine tempering is as though you were baking a cake: you’ll have the best result if you are careful to set the right temperature, length of time, and gradual cooling.

Adjusting the peak temperature for tempering allows you the opportunity to create a product for a specific need. There are 3 temperature range categories when tempering steel:

Low temperature: this tempering will somewhat reduce the metal’s brittleness, while retaining its hardness. Steel produced this way is often used for case hardening components and cold work tools.

Medium temperature: the heat used in this range will produce a more elastic product. This means it’s now a more machinable and formable metal, which can be shaped and worked without losing the original shape. This steel is often used to manufacture knives.

High temperature: the higher the temperature used during the tempering process, the greater toughness that is given to the steel. This combination of resiliency and toughness makes it a good choice when producing structural steel and machine components.

Overall, it’s a rule that any hardened steel must be tempered. And without tempering, your stainless steel and other alloys won’t have the high level of ductility and weldability that we’ve come to expect from high quality materials.

What is Metal Aging?

Aging [verb]: the process of growing older. While that definition does apply, in the metals industry “aging” is specific jargon referring to treatments which speed up that process. But why would you choose to age your new metal products? It helps if you remember not to view aging as a negative. In fact, much like wine, the properties of a metal alloy often improve with age.

As metal ages, its base material physically transforms. The interaction of the metal’s atoms with the oxygen in its environment – whether surrounded by air or water – will begin change its surface texture and color. This starts with a basic oxide layer being formed. The oxide then becomes a hydroxide, and the hydroxide layer continues to interact with the atmosphere.

So why is this exposure to the elements considered a desirable result, unlike rust? That’s because iron oxide, or rust, is much more fragile and ultimately destructive when compared to a hydroxide. Exposed iron develops rust which flakes off and forms again, and will continue this cycle until it deteriorates the metal below. Meanwhile, a hydroxide layer actually creates a more stable surface composition. This hydroxide effectively creates an outer shell, which shields the metal below from any further interaction to its environment. The aging process of the metal comes to a near halt, with the hydroxide layer giving it both greater strength and longevity.

In general, there are two types of metal aging:

Natural aging: just as the name suggests, this is letting the metal age with time, in its natural environment. The strengthening benefits of aging will be more gradual but still effective.

Artificial aging: this refers to any method used to artificially accelerate the aging process. This is usually done through heat treatment of the metal alloys.

Both types do carry a risk of over-aging. This happens when the aging process pushes the metal past the point of strengthening into stressing and deteriorating it. As you might expect, this is more likely to occur with artificial aging: either because the metal has already undergone the aging process, or the heat applied is too intense or prolonged. However, when properly carried out, metal aging is a great benefit to the finished product.

Decoding Steel by its Numbers

Like any other field of expertise, the steel industry has its own jargon – one that may be confusing upon first encounter. Why are they assigned four-digit codes? What’s the difference between Alloy 4130 and 4140?

Steel is sorted into four main categories as set by the AISI (American Iron and Steel Institute):

Carbon steel
Alloy steel
Stainless steel
Tool steel

Being steel, these contain the same two basic elements of iron and carbon. Determining their category depends on the percentage of carbon and other alloys added to the iron, which changes the properties of the finished metal.

Within each category, steel can then be classified according to type. This usually includes several of the descriptive factors below:

Composition: the main categories of carbon, alloy, stainless, and tool steel.
Microstructure: these are the subcategories of composition. For instance, stainless steel can be classed as ferritic, austenitic, martensitic, and duplex steels.
Method of production: two methods account for almost all modern steel production, known as EAF (electric air furnace), and BOS (basic oxygen steelmaking).
Form/Shape: also known as primary forming, creating shapes such as plate or bars.
Method of finish: this is referred to as secondary forming, the techniques which give the final product its properties and finish. This can include processes such as hot and cold rolling, tempering, or galvanizing.
Physical strength: using ASTM (American Society for Testing and Materials) standards, the designation typically includes a letter prefix and assigned number.

There are two primary numbering systems used to classify metals, so steel descriptions typically will include both. Along with AISI, the numbering system set by SAE (Society of Automotive Engineers) is most used in the metals industry. For the most part, SAE has adapted their system to align with the classifications set by AISI, so that specifications are standardized for steel.

So with this information, consumers have the ability to recognize the category and classification of a steel item. In the four digit code system, the first number will determine the type:

Starting with 1: Carbon steel

2: Nickel steel

3: Nickel-chromium steel

4: Molybdenum steel

5: Chromium steel

6: Chromium-vanadium steel

7: Tungsten-chromium steel

8: Nickel-chromium-molybdenum steel

9: Silicon-manganese steel and other SAE grades

The following numbers then give additional detail to the specific type of steel. In most cases, the second digit indicates the percentage of alloying element. The last two digits are the percentage of carbon concentration within the steel.

So using the example of 4130 vs 4140 steel: both start with a 4, so they are molybdenum steels – with the concentration of molybdenum being 1%. The difference between the two is that 4130 has a carbon percentage of roughly 0.30%, while 4140 contains 0.40 percent carbon. Because of its lower carbon percentage, 4130 would be more easily machined and weldable than 4140. However, the higher degree of carbon in 4140 alloy gives it greater hardness and strength than 4130. Armed with this knowledge, this may better help you choose the right type of steel for your needs.

Uniform Metal Corrosion and Prevention

Corrosion is the deterioration of a metal due to an electrochemical reaction between the atoms on the metal’s surface and its surrounding environment. Most commonly, corrosion refers to oxidation: the process where a metal reacts to the oxygen in air or water. The most familiar example of corrosion is iron oxide (rust), but other metals can corrode in similar ways. Given sufficient time and exposure, corrosion will have a significant negative impact on the metal’s appearance, strength, and durability. If left unchecked, corrosion will eventually lead to the weakening or total disintegration of the metal parts. The World Corrosion Organization (WCO) estimates the annual cost of corrosion to be up to $2.5 trillion dollars – and that up to 25% of that damage is entirely preventable.

General Attack Corrosion, also known as Uniform Attack Corrosion, is characterized as the reaction occurring over the exposed surface area of a metal object or structure. This is the most common type of corrosion, leading to the greatest overall destruction of metal by tonnage. However, from a technical standpoint, it is also considered to be the ‘safest’ form of corrosion to encounter. The damage which occurs with general attack corrosion, being fairly uniform and predictable in its progress, means it is the easiest to diagnose and prevent.

How to Prevent Uniform Metal Corrosion

1. Selecting the Right Metal: The four basic types of metals referred to as “corrosion-proof”

Stainless Steel: This alloy contains iron, which easily oxidizes to form rust, and chromium, an element even more reactive to corrosion than iron itself. However, when chromium is added to steel, the corrosion which results then forms a protective layer on the surface of the metal. In contrast, corrosion which occurs on uncoated carbon steel will repeat continuously as the rust forms, wears off, and forms again. Eventually the rusting will lead to the metal’s disintegration. Iron oxide layer on stainless steel will resist further corrosion. This means the layer actually prevents oxygen from reaching the steel underneath. Corrosion-resistant in stainless steel can be further boosted by the addition of other elements in the alloy such as nickel and molybdenum.

Aluminum: Since aluminum alloys contain almost no iron, they are free from rust. The corrosion with this metal is similar to chromium in stainless steel; after the initial corrosion occurs, it creates a surface layer that protects the metal from any further damage. This film of aluminum oxide can be unsightly with dark marks or streaking, but as long as it remains, it will shield the underlying metal.

Brass, Bronze, and Copper: Like aluminum alloy, these metals contain little to no iron. They do react with oxygen – most noticeably with copper, which oxidizes to a distinctive green patina. The oxidized layer helps protect the copper from further corrosion. The other two metals combine copper with other metals, which makes them naturally corrosion-proof: copper and zinc to produce brass, and copper and tin for bronze.

Galvanized Steel: This is carbon steel that is galvanized, or coated, with a thin layer of zinc. Like chromium and copper, zinc is highly reactive to oxygen and will quickly begin to oxidize. This layer of zinc oxide prevents any further corrosion on the galvanized coating. Even more importantly, it acts as a barrier preventing oxygen from reaching the steel. Eventually, the zinc will wear off which will make the carbon steel vulnerable to rust, so this type of metal is not entirely corrosion-proof. However, it will take much longer to rust than untreated carbon steel.

2. Protective Coatings

In addition to galvanized steel, other coatings can be applied as a barrier between the environment and the metal. Painting is one of the most cost-effective ways of preventing corrosion. Powder-coating is another popular option. This involves applying a dry powder to the metal and then heating it to fuse it in an even, smooth film. Both methods work by creating a uniform physical barrier between oxygen and the metal.

3. Monitoring the Environment

Simply put, corrosion is the reaction of the metal with its surrounding environment. So whether the environmental factor is air, water, stresses placed upon the metal itself, or all of the above, regular maintenance and monitoring goes a long way towards preventing or lessening the impact of corrosion. Crevice corrosion, for example, is commonly found in areas where metals overlap each other. This means the metal parts are exposed to varying oxygen concentrations, leading to uneven wear and deterioration. Proper maintenance such as eliminating crevices when found, or ensuring complete drainage in vessels, can help to prevent this corrosion. In harsher environments, replacing parts and fastenings with higher alloys can help preserve the metal’s functionality.

All metals will corrode eventually, but the process does not necessarily need to be a destructive one. By anticipating how and where an item will be used, the choice of metal and its maintenance can prevent corrosion from becoming a serious problem. Corrosion prevention not only helps save equipment and money, but it will also help keep metals safer for the people who use them.

Stainless Steel Kitchen Remodel

Property and home improvement shows are more popular than ever – and according to those experts, a kitchen remodel is one of the most effective ways to maximize your budget for home renovation. Stainless steel’s durability and stylishness make it a great construction material and design element in a kitchen. Whether used to equip a sleek industrial space, adding modern touches to classic or mid-century design, or used for cookware and utensils, consider the benefits of using stainless steel to update your surroundings.

5 Reasons to Use Stainless in Your Kitchen

Durability: Stainless steel is the standard in the restaurant industry for good reason; it’s strong, rust-free, and resists heat damage! Grade 304, the most commonly available type of stainless steel, will hold up to the daily wear of food preparation and cleaning because it is a non-reactive metal. This makes it incredibly versatile for everything from appliances and cutlery to pots and pans. Metals like copper or aluminum will react to acidic ingredients such as vinegar, discoloring its shiny finish and adding unpleasant flavors to your food. Countertops made of stainless steel can hold up to heat, liquids, and cleansers without negative effects – the same treatment which can crack or stain granite surface
Low Maintenance: The addition of chromium to produce stainless steel makes it very resistant to oxidation, which can rust and wear down other materials. Whether it’s exposed to water in a kitchen sink, high temperatures in a barbeque grill, or the cold of a freezer, stainless steel requires little maintenance to keep it looking its best. Stainless steel cabinets will not warp, making them ideal for high humidity or outdoor cooking areas.
Style and Versatility: Despite what you may think, stainless steel is not simply for those who like minimalist or industrial design! It coordinates well with any color or décor and makes for easy matching between your appliances, fixtures, and pots and pans. Cabinets or countertops with a high shine finish can help brighten a dim kitchen area. Appliances made of brushed-finish stainless steel give an elegant glow. Blended with natural materials such as wood and stone, stainless steel helps to give a timeless yet modern look to your kitchen.
Hygiene: Stainless steel is a non-porous material. This means its surface doesn’t allow air or liquid to pass through, which prevents the growth of bacteria within the steel. So kitchen surfaces and implements can be easily and thoroughly cleaned. Stainless steel makes an ideal choice for kitchen sinks and backsplashes since it can hold up remarkably well to regular use, water, and household cleansers.
Eco-Friendly Material: Nontoxic, long-lasting, and recyclable: stainless steel makes an environmentally-friendly choice of material for your kitchen and home. When treated with care, the durability of stainless steel means your appliances, décor, and cookware will last for many years, preventing excess waste and landfills. The easy cleanup for stainless steel – just soap and water – helps to cut down on the use of chemicals. As consumer demand increases for sustainable choices, consider the advantages of building and outfitting your kitchen with stainless steel. Its long life makes it a good choice for your finances, and for the good of our communities.

FastMetals is your online supplier for Stainless Steel Sheet. Talk to us about what you are planning for your home improvement, we do custom cutting to fit your specific needs.

Aluminum Tread Plate

What is Tread Plate?

Rolled aluminum tread plate is made of an alloy, where elements such as copper or silicon are added to aluminum to increase its strength and corrosion resistance. The two of the most common grades of aluminum alloy include:

Alloy 3003: The most widely used of all aluminum alloys. Manganese gives the alloy up to 20% more strength over pure aluminum, while still allowing for good workability. While not as strong as 6061, aluminum 3003 tread plate’s shiny reflective finish makes it both functional and decorative.

Alloy 6061: 6000-series aluminum is mixed with magnesium and silicon, giving the metal a high degree of strength. This, along with its corrosion resistance and weldability, is why 6061 is often referred to as structural aluminum. Aluminum 6006 tread plate comes in a mill finish, which means its surface is untreated with little to no shine.

Uses of Aluminum Tread Plate

Tread plate, Diamond plate, Checker plate. No matter what the name, it all refers to the same product: metal sheet or plate with a regular pattern of raised diamond marks. When looking to keep workers safe on the job, aluminum tread plate is a durable, high-quality option to help reduce slips and falls. So why choose aluminum tread plate over other materials? It has numerous benefits including:

Slip resistance: The raised pattern provides traction even under tough weather conditions that can find surfaces covered in water or mud. For this reason, tread plate is typically used on stairs, ramps, loading docks and other industrial areas.
Corrosion resistance: Unlike iron oxidization, aluminum oxidization stops at the surface. Iron rust can be easily worn or flaked off, exposing fresh metal which rusts and leads to further deterioration. Aluminum oxidation, on the other hand, will not progress beyond the outside layer unless the oxide is removed. This makes well-suited to wear and tear, including exposure to corrosive elements like seawater.
Hygiene: Tread plate is easy to wash down, and the corrosion resistance of aluminum alloy means it can hold up to regular use of strong cleaning agents. This makes it ideal for areas needing regular heavy-duty sanitation, such as food processing plants, kitchens and walk-in freezers, and ambulances.
Protection: The design of tread plate gives impact and surface protection, coupled with the strength of solid metal. When used for corner guards and door plates, aluminum tread plate will help prevent unsightly marks or damage in high-traffic areas.
Decorative: Aluminum tread plate is often used for its decorative quality. Vehicle trim, shop walls, and furniture can be made of tread plate, most often in a bright polished finish. The high shine combines both form and function, with the shiny surface also helping with ease of cleaning.

FastMetals is your one stop spot to get tread plate. Starting at .063 thickeness up to .375, FastMetals.com has you covered. In size selection as small as 1 foot by 1 foot, all the way to 4 feet by 8 feet. Need something really specific? No problem – just submit a fast quote for a custom cut.

Hot Rolled vs Cold Rolled, So much to know

Is one a better choice for your project?

What type of rolled steel would make the better choice for your project? It’s important to understand the fundamental differences between hot and cold rolled steel in order to select the best one for your needs.

Rolling is a metalworking process where the metal is passed through one or more pairs of rolls, which reduces thickness and makes the material uniform throughout the roll. Imagine the steel as if rolling dough through a pasta-maker, flattening and thinning it out until you have an even, smooth product. The two types of rolling are hot and cold, which is determined by the metal’s temperature during processing. Hot rolling occurs when the metal is heated above its recrystallization temperature. Cold rolling is when the metal is processed while below the recrystallization point.

Hot Rolled Steel

Hot rolling involves rolling the steel at a temperature point above its recrystallization temperature, typically around or above 1700 degrees F. This means the steel can be shaped and formed easily, including producing much larger sizes. Since the manufacturing can be done without pauses or delays in the process, this means hot rolled steel is typically cheaper than cold rolled steel.

Because of the high processing temperature, the hot rolled steel will have a rougher, scaly finish and will also shrink slightly as it cools. This means the finished product can vary in its size and shape dimensions, and at a lower price point than the same item produced through cold rolling. Hot rolled steel is best suited for uses like welding, railroad tracks or construction, where precise shapes and tolerances may not be required.

Cold Rolled Steel

Cold rolled steel is manufactured below its recrystallization temperature. Essentially, it’s hot rolled steel with additional processing in cold reduction mills. Because it is typically produced around room temperature, the process allows for closer dimensional tolerances and a wider range of surface finishes for the steel.

‘Cold rolled’ is often mistakenly used to describe all steel products, but it refers specifically to the rolling of flat rolled sheet and coil products. For other steel shapes produced below the recrystallization temperature, the accurate terminology is “cold finishing”. For instance, a cold finished steel bar is produced by cold drawing (pulling) the metal, then turning, grinding and polishing. This produces a much more precise end product with four advantages:

Increased yield and tensile strength
Fewer surface imperfections due to the turning process
Grinding gives closer size accuracy and precise shapes
Polishing improves the surface finish

The exception is cold rolled sheet versus hot rolled sheet. For this particular product, the cold rolled steel has a low carbon content and is typically annealed (heat treatment to increase ductility). This means cold rolled sheet will be softer than hot rolled sheet.

Overall, cold rolled and cold finished steel is superior to hot rolled steel in finish, straightness and tolerance, and comes at a higher price point. It would be the recommended choice when visual appeal is a priority for your project. Typical uses include building materials for sheds and garages, metal furniture, and home appliances.

Buy Hot Rolled or Cold Rolled Steel

Here at FastMetals we offer a range of Hot Rolled and Cold Rolled steel products – we offer great quality product, reasonable pricing and fast shipping – shop online at FastMetals.com or call us toll free at (833) 327-8685.