Metal forging is an age-old process that has been used to shape and strengthen metal items for centuries. This technique creates items of superior strength and ensures precise detail. Metal forging requires extreme heat, typically from a furnace or torch, to succeed.
Once the appropriate temperature has been achieved, it takes precise timing and a skilled craftsman to shape the heated metal into its desired form.
The process also requires hammers or presses, which further weaken the original material until it becomes malleable enough for the smith to manipulate it into its intended shape.
What kinds of materials can be used for forging?
Many people may don’t know what raw materials are used in forging. In fact, the modern forging process incorporates a wide variety of raw steel, including stainless steel, alloy steel, micro-alloy steel, titanium, tool steel, carbon steel, etc.
These different raw materials have different features and advantages. In this blog, we shall introduce them.
Stainless Steel
Stainless steel is a significant player in the forging process due to its solid and rugged qualities. It can withstand temperature changes and external conditions much better than other metals like copper or aluminum, making it ideal for items that need to last long-term.
Stainless steel is also resistant to corrosion, meaning it won’t rust away over time and can handle being exposed to multiple elements. All of these factors make stainless steel the perfect choice when it comes to forging items that need to be strong, durable, and reliable.
Normally speaking, there are two series of carbon steel: Stainless Steel 300 Series and Stainless Steel 400 Series.
Stainless Steel 300 Series
| Feature | |
| Grade 302 | Grade 302 is a very strong and tough material that is not magnetic. It can be made harder by using cold working processes. |
| Grade 303 | Grade 303 can resist being corroded in mildly corrosive atmospheres better than other grades, but not as well as Grade 304. |
| Grade 304 | Grade 304 is a good material because it is strong and does not corrode easily. |
| Grade 304-L | Grade 304-L is a variation of Grade 304 that has a lower carbon content. This grade is more ductile and resistant to corrosion than Grade 302. |
| Grade 309 | Grade 309 is more resistant to corrosion and stronger than Grade 304. |
| Grade 310 | Grade 310 is a type of stainless steel that is good at resisting oxidation, or rusting. |
| Grade 316 | Grade 316 is a type of stainless steel that contains molybdenum. This makes it more resistant to corrosion than Grade 304. |
| Grade 316-L | Grade 316-L is not sensitive and offers high stress,creep and tensile strength. |
| Grade 317 | Grade 317 is a good option because it is strong and does not corrode easily. It can be hardened through cold working processes but doesn’t have reaction to heat treating. |
| Grade 321 | Grade 321 is similar to Grade 304, but it has five times as much titanium. |
| Grade 330 | Grade 330 is good because it doesn’t rust or get damaged easily by hot temperatures. It is also strong. |
Stainless Steel 400 Series
| Grade 403 | Grade 403 stainless steel is a type of chromium steel that offers good resistance to corrosion, heat, and scaling at high temperatures. |
| Grade 405 | Grade 405 is not recommended to be forged below 1500°F (816°C).Then increase the temperature to a range between 1900°F (1038°C) and 2050°F (1120°C). |
| Grade 410 | Grade 410 is a type of stainless steel that contains 11.5% chromium. This material is always magnetic and has good resistance to rusting (which can be improved with processes such as quenching, polishing, and tempering) and heat. |
| Grade 414 | Grade 414 is a type of welding filler metal that is commonly used. |
| Grade 416 | Grade 416 is a type of stainless steel that is easy to machine. It is resistant to fresh water, acids, dry air, and alkalis. However, it is not as resistant to corrosion as other austenitic grades. |
| Grade 418 | Grade 418 is a martensitic type of steel that is very hard and strong. It also does a good job of resisting corrosion. |
| Grade 422 | Grade 422 is a good alternative to Grade 403. It is stronger and can resist oxidation and scaling at higher temperatures, up to 1400°F (760°C). |
| Grade 431 | Grade 431 is a type of steel that can be heat-treated. It is tough, strong, and resistant to corrosion. This grade is heated to between 2100°F (1150°C) and 2200°F (1205°C) and then forged. |
| Grade 440-A | Grade 440-A is a high carbon martensitic stainless steel that is strong and resistant to corrosion. |
| Grade 440-C | Grade 440-C is a type of steel that is mostly used for bearings. It is strong and can resist corrosion well. |
Alloy Steel
Alloy steel is a strong and durable material thanks to its iron and carbon components with added nickel, chromium, molybdenum, and manganese alloys. This composition grants it an edge over traditional pure iron, which is much more prone to damage from wear and abrasion.
In the forging process to make high-performance tools and machines, the custom alloys can add strength and toughness to the steel and increase resistance to shock loading. Thus, many companies are now turning towards alloy steel for its improved corrosion resilience and risk reductions.
Carbon Steel
.Carbon steel is commonly used to make parts that require durability and strength in order to function correctly. Examples include hand tools, knives, and springs. Its increased carbon content compared to regular steel makes it a material of choice when strength and performance are important.
The great thing about carbon steel is that it meets these needs without expensive alloys like tungsten, chromium, cobalt, titanium, and nickel. Some alloys might be necessary depending on the needed properties of the part, but usually, an economical solution can be reached using only carbon steel.
The hardening power of the carbon gives this type of steel a wide range of uses and is often favored for parts that do not require temperatures higher than standard operating tolerance levels.
Titanium
Titanium has become a preferred option for applications that require high strength. Its strength and heat resistance properties make it an excellent match for working with other metals that are melted at lower temperatures.
Although titanium can withstand incredible amounts of force and temperature, the downside is that it melts at a higher temperature than many other materials used in forging.
By combining titanium with other metals, items forged from weaker materials like iron and steel are given a much-needed boost in strength and durability. It also increases the hardness of softer metals such as copper, making it an ideal material in forging processes.
Aluminum and its alloy
Aluminum alloys have been prized over the years for their strong resistance to corrosion, making them an ideal choice for various applications. Open die forging is emerging as one of the most high-quality methods of aluminum forging available.
Compared to casting, it offers superior internal integrity and results in maximum impact strength due to denser grain structures, which also eliminates potential internal voids. These qualities make aluminum open die forging an essential process in many industries.
Also, we have written a blog about aluminum forging. You can click and make a reference to it.
What is the strongest forging material?
The most robust forging material is typically thought to be tungsten. This is due to its jaw-droppingly high tensile strength of 142,000 psi – nearly three times stronger than stainless steel’s already impressive tensile strength.
Yet, though it’s strong in terms of maximum pressure, tungsten is still a brittle material and tends to shatter when subjected to impacts or shocks. A better choice for specific forging applications is Titanium, with a tensile strength of 63,000 psi and superior impact resistance besides.
When weighed against other materials, Titanium proves to be an excellent choice for forging products that need both strength and shock resistance.
Which metal cannot be forged?
Some people may wonder if there is some material that can’t be forged. Actually, iron cannot be forged. Cast iron is a versatile and widely used metal known for its durability and affordability compared to other materials. Its popularity comes from the fact that it can be easily cast into intricate shapes and sizes, making it perfect for various applications like cookware or engine parts.
However, its toughness also makes it impossible to be forged in the same manner as other metals – hammers and anvils won’t do the trick here!
Casting is the usual way to deal with it. Molten iron is poured into molds of the desired shape to form products. Welding would not work with cast iron either, as its higher carbon content results in a brittle weld. Therefore, while it has excellent shape-making capabilities, cast iron cannot be forged.
Conclusion
Metal forging has been used for centuries by craftsmen and engineers to create objects of incredible strength and beauty.
From historically significant artifacts like swords, spears, and armor to modern innovations like bridges, aircraft components, and engines – metal forging has provided a dependable source of material that can perform under extreme pressure.
The process involves heating metals until they become malleable, then using precision tools to shape them into the desired form.
Different steel compositions are used depending on their intended use – low-alloy steels deliver general toughness while high-carbon or alloyed metals can be heat-treated to achieve superior strength and hardness.
As technology advances, so do the materials used in metal forging for specific industrial applications.