Hard and Soft Metals

The amount of appliances in our daily lives that come from metal fabrication is massive, including tools, electronic appliances, cars, phones, and so on. Metal fabrication is a massively complicated process that has many different variations, each of those suitable for a specific goal.

We would go to each and every one of them, but first, we have to explain the basics of metal fabrication as a whole – as well as a few words about different metals used in fabrication.

HARD AND SOFT METALS

Metals themselves can be separated into two large categories – hard metals and soft metals. Each category has a share of advantages and a number of issues.

HARD METALS

Hard metals are stainless steel, chrome, steel, Inconel, and titanium. Each of these can be created during the smelting process by adding a small percentage of other elements to the alloy. Adding molybdenum and chromium creates 4140 steel alloy, which is great for aircraft creation and similar use cases, while carbon and manganese create tough 1018 steel. Both of these metal types are easy to weld but are susceptible to rusting if there is no additional finishing on the metal piece.

A combination of nickel and chromium creates 300-series stainless steel which is rather tough when it comes to machining but also makes a great resource for food equipment, medical instruments, pressure vessels, and so on. It also cannot be hardened the way carbon steel does. Another metal variation is 17-4 PH, which is a rather tough material that adds copper, chromium, and nickel to the alloy, creating a material that is technically stainless steel but has the machineability of a superalloy, capable of achieving great results in both tensile strength and hardness when treated with heat. It is a good choice for nuclear and aerospace industries, as well as any other industry that requires high corrosion resistance and incredibly high material strength.

There are also materials suitable for only the most extreme circumstances, such as Inconel – a material that uses over 50% of nickel in its alloy, often used for jet engine combustion chambers, gas turbine blades, and nuclear reactors due to its excellent capabilities with a high range of operable temperatures. Another similar alloy is cobalt chrome – the one that uses cobalt in the alloy, creating a material with massive wear resistance and also, surprisingly enough, biocompatibility with humans. This last reason is why cobalt chrome is often used for knee/hip replacements, dental implants, arterial stents, etc.

The last, but not the least material on this list is titanium, which is twice as strong as mild steel while being half of its weight. It is created via aluminum and vanadium, generating a corrosion-resistant and strung material that is also biocompatible – making it suitable for bone screws, plates, pins, etc. This strength-to-weight ratio is one of the reasons why titanium is so appealing to high-performance vehicle manufacturers and the aerospace industry, as a whole.

SOFT METALS

A second large category of metals is dubbed “soft metals”, and for a reason. Most of these materials are far from being as strong as basic stainless steel – which also doesn’t make it less useful for specific circumstances. Some of the more common examples of soft metals are brass, aluminum, copper, and magnesium.

Aluminum as an element is extremely malleable and soft, which is why it is basically unusable for mechanical purposes. Luckily enough, it can be used to create an alloy when combined with zinc, copper, magnesium, or silicon (and then made stronger via heat treatment). This kind of material has its use cases in a wide variety of industries, from consumer products to airframes and automobiles.

6061 aluminum is combined with silicon and magnesium to create a corrosion-resistant material that is easy to weld, which is why it is used fairly frequently in all kinds of low-fatigue applications – automotive parts, hydraulic valve bodies, machinery, as well as automotive and marine parts. 7075 aluminum, on the other hand, is stronger and harder than 6061 aluminum, but also several times more expensive. It is created with copper, zinc, and magnesium, with use cases such as wig spars for Boeing aircraft, connecting rods in top fuel dragsters, and even details for a lot of American firearms.

Magnesium is one of the lightest examples of structural metals, which is why it is commonly found in chassis for laptops and smartphones, as well as in frames for power tools, seat frames and transmission cases for automobiles, etc. One of the more common alloys of magnesium is its combination with zinc and aluminum, creating a machineable metal that has excellent dampening capabilities and is easy to mold. It is fairly easy to manufacture, but somewhat more expensive than most of the aluminum variations.

Brass is one of the most versatile materials on this list, boasting extremely high resistance to both corrosion and weather effects. C260 cartridge brass is a good example here, a combination of zinc and copper that is the most “general-purpose” material for all brass-related alloys. It has a tensile strength of mild steel and can be turned into screws, rivets, and many other elements with a relatively simple modification to the original alloy.

Copper, on the other hand, is strikingly different from everything above, even though its biggest component is brass in the first place. It is one of the most electrically-conductive materials in history, one of the few materials that make all of the electricity in the world possible in the first place. It is difficult to weld, but easy to braze – an uncommon combination for metals in general. However, it’s not just about conducting electricity, either – copper is also used in glass-to-metal seals, in semiconductor manufacturing, and even in some specific locations as an antimicrobial surface.

Copper is an ingredient of several hundred different metal alloys, creating nickel-copper, tellurium copper, aluminum, gunmetal, bronze, steel alloys, and so much more.

THE DEFINITION OF METAL FABRICATION AND TYPES OF FABRICATED PRODUCTS

As a process, metal fabrication is all about creating various metal structures using different processes using both manual labor and automation. Facilities that specialize in one specific field of metal fabrication are often called fabrication shops, and the products of said facilities are also often called fabrication. It is also true that some other types of metalworking, such as forging, casting, and metal stamping, are not considered fabrication, even though they can be similar in shape.

The most common types of raw materials for metal fabrication are sectional metal, welding wire, plate metal, castings, flat metal, fittings, and more. At the same time, it’s not uncommon for fabrication shops to employ multiple different experts in various fields, like blacksmiths, welders, boilermakers, and ironworkers, among many others.

That’s not to say that the only people employed in fabrication shops are directly related to the process of metal fabrication – there are also managers, team assemblers, solderers, first-line supervisors, brazers, cutters, welders, etc.

As for the types of products that can be created with metal fabrication – it is possible to separate all of them into three segregated categories. Each category has its own variety of processes used in the process of metal fabrication, or it can be just a single process altogether. Here are three main categories of metal fabrication:

Structural. Mostly covers metal fabrication as a part of the building process, providing metal components to be used in various large-scale fabrication efforts, such as buildings, shops, skyscrapers, and so on.

Commercial. As the name suggests, this mostly covers the commercial products, designed to be used by customers directly, be it appliances, cars, or something else entirely.

Industrial. Specializes in creating products that are used as a part of other pieces of equipment – equipment that is used to generate consumer goods, for the most part. Some of the examples of industrial fabrication are ironworking machines and bandsaws, as well as many other ones.

TYPES OF METAL FABRICATION PROCESSES

Metal fabrication consists of many different processes that may or may not be involved in the project depending on what needs to be done, as well as the material type and some other dependencies. You can find many different metal fabrication process types in the list below:

Сutting

Bonding

Tooling

Folding

Extrusion

Punching

Stamping

Casting

Drawing

Forging

Machining

Shearing

Welding.

Now that we’re aware of what they’re called, it’s time to go over what each of those actually implies, starting with cutting.

CUTTING

While metal fabrication includes a lot of different processes, cutting is pretty much the most common one out there. The oldest example of a cutting process that can be replicated nowadays is sawing – but there are also many newer ones, using waterjets, lasers, and even plasma arcs to cut metal. The cutting methods can be drastically different, as well, including manual, power tools, computer-controlled cutting, and more.

There are also some cutting types that are extremely specific in the way the cut is performed. For example, there’s cutting with a die as the part that cuts off the necessary part of the material. This includes three general types of die cutting – the regular one, the rotary die cutting, and the flatbed die cutting.

While the regular die cutting process has been explained already – it’s using a die to cut metal, simple as that – two of the other examples are not as obvious.

For example, a rotary die employs a specific cylindrical die that spins around in one place to cut some specific parts of a material. There’s also a flatbed die – reserved specifically for tougher and thicker materials, this one uses a lot more force and flat surface than the other ones.

Of course, these are not the only options to cut metal, since laser cutting also exists – and it is often treated as the preferred way to cut metal. It is quick, precise and does not lead to the metal in question deforming in some way. However, it is at its best when working with sheet metal, and may struggle with thicker metal types – which is where plasma cutting comes in, being a quick alternative to laser cutting that is a bit cruder in how it leaves the cut metal pieces. However, it is sometimes the only option for some of the specific thick metal variations.