Stamped steel vs. cast steel – what is the best option for your manufacturing needs? The answer always depends on a number of factors such as the part’s application, a manufacturer’s budget, production run size and deadline, part tolerance, finish, and any other specific needs a manufacturer may have.
Steel stamping and steel casting are starkly different metal fabrication processes. With stamping, steel is fed into a machine and then pressed and shaped into a specific part. For steel casting, steel is heated in a furnace and poured into a mold where it cools and is then removed.
Each type of steel has specific strengths and weaknesses, many of which come from their processes. Steel cast parts can be intricate and complex without sacrificing tolerance, and the stamped steel method can create a large volume of simple parts in an affordable way. Understanding the advantages and drawbacks of each method and considering all options could mean the difference between reliable parts or deformed parts that quickly need replacing.
Regardless of the process, nearly every industry that requires metal parts and components utilizes one of these methods, from agriculture to defense. This article discusses the processes, benefits, and drawbacks of stamped steel vs. cast steel.
Stamped Steel Process
When deciding between using stamped steel vs. cast steel method for manufacturing parts, it is important to first consider the fabrication process. Metal stamping involves feeding sheet metal into a press where a tool and die are used to rapidly shape the desired part or component.
While the term ‘stamping’ is used to describe this type of metal fabrication, the metal can be formed using a variety of processes.
- Stamping: Also known as pressing, this process feeds sheet metal into a press where a tool and die form it into a metal part.
- Drawing: This is the stamping portion of the fabrication process that creates the primary shape of a workpiece. Two types of drawing are shallow and deep. Although it is similar to stamping, drawing is used to create parts that are deeper than stamping can achieve.
- Bending: As its name suggests, the steel part is placed against a die, and a ram pushes into the metal, creating the desired bend.
- Embossing: This process uses male and female roller dies to create raised or sunken designs in sheet metal without any change in overall thickness.
- Notching: This method is a shearing process that uses a punch press to remove portions of a workpiece.
- Punching: For this process, a special punch press is used to create holes in stamped steel sheets.
- Blanking: Usually, the first step in the fabrication process, blanking cuts larger sections of coiled or sheet steel into smaller pieces.
- Piercing: This allows for the formation of holes, slots, or other types of cutouts in metal parts.
- Lancing: A distinct process that simultaneously bends and cuts sheet metal to create tabs or vents in a workpiece.
- Pinch Trimming: This is a unique fabrication method where the vertical walls of a part are cut by pinching the metal between two tool die sections.
The above processes are not mutually exclusive, and it is common for stamped steel to go through multiple stamping steps before the desired part is finished. This flexibility in production makes stamped steel vs. cast steel a more desirable option in certain industries.
Stamped Steel Applications
Using stamped steel vs. cast steel is a popular choice among several industries. Stamped metal parts remain an essential building block of countless manufacturers. These parts can be found in electronics, vehicles, appliances, medical supplies, and even airplanes.
The stamped steel fabrication process allows for the production of the most intricate components to massive industrial housings.
Here are a few industries that use stamped steel in their daily activities.
- Aerospace requires strict adherence to quality and precision. Part production is meticulously documented with the ability to make adjustments in real-time without sacrificing cost.
- Fluid Power industry uses powerful hydraulic and pneumatic systems that require complex fittings to remain operational. Metal parts such as valve sealing components, brackets, and mounting flanges are stamped and used under high pressures and harsh environments.
- Medical industry requires both longevity and precision because its equipment has a direct impact on people’s health. Metal stamping allows for accurate engineering and control over critical components.
- Oil & Gas depend on safety, quality control, and efficient parts to function. Stamping in this industry is used to create internal sealing components, washers, brackets, and handles that can withstand all of the hazards that come with this industry.
Does Stamped Steel Rust?
Oxidation is a nightmarish word across nearly every industry that requires metal parts and components to function. Stamped steel is prized for its longevity and durability, but it needs some help to make it go the distance.
Often, alloys are added to steel, and different finishing methods are used to make steel rust-resistant.
So, does stamped steel rust?
The answer is, ‘it depends.’
Rust resistance depends on the percentage of alloying elements to the steel. Alloys such as chromium and nickel can help improve corrosion and rust resistance making it nearly rustproof.
Cast Steel Process
Important differences in stamped steel vs. cast steel parts come from how a part is produced. Steel casting has been around for centuries, which is a testament to its value. Steel cast parts are used for robust machines and must withstand heavy loads, shocks, and continual use.
During manufacturing, molten metal is poured into a pre-made mold. The metal is then allowed to cool, and the part can be removed and finished depending on a manufacturer’s specifications.
There are two popular methods for casting steel, investment casting, and sand casting.
Investment Cast Steel
Investment casting is also known as lost-wax casting and is prized for its ability to produce highly detailed parts. This method works with both non-ferrous and ferrous metals such as alloy steel.
Patterns for the finished part are assembled within a mold from a tree making it easy to manufacture multiple parts within a single run.
Steel investment casting can produce parts weighing over 1000 pounds; however, it is more common to cast lighter parts using this method.
Sand Cast Steel
Metals with high melting points have limited options for cast parts. Sand casting utilizes non-reusable sand molds, which is a flexible and cost-effective option to produce steel cast parts.
A pattern for a single or multiple parts is set into a sand mold. Like other casting methods, liquid metal is then poured into the mold and given time to cool. The part is then broken out of the mold, and the sand can be reused to create a new mold in subsequent castings.
Sand casting can produce parts weighing only a few ounces to several tons and in a variety of shapes.
Each steel casting method lends itself toward specific industries.
Cast Steel Applications
- Turbine Engine manufacturers are governed by strict standards and tight tolerances. Fuel system components, various cases, hardware, and support systems are produced through investment casting.
- Defense sector requires parts that can withstand high temperatures, variable climates, and have substantial durability. Cast steel is used in weapons, propeller, valve, and launch components.
- Mining requires wear and heat-resistant parts to maintain operations. Grate components, brushings, and feeder rolls all depend on cast parts.
- Railway industry utilized cast steel for wheels, rail braces, wheel hubs, assemblies, and a number of other products. Parts of this size and strength can be easily achieved through casting.
Cast Steel and Brittleness
It is common for manufacturers to ask about steel and brittleness. A material is considered brittle if it breaks without significant plastic deformation and little elastic deformation.
Depending on their alloy composition, steel can become brittle at lower temperatures making it unsuitable for certain applications.
Cast steel is excellent at withstanding sudden impact without deforming or breaking, making it a great option for parts that must stand up to high-stress forces. Steel has an ideal combination of ductility and strength, making it the champion of structural and mechanical applications.
Stamped Steel vs. Cast Steel Strengths
- Steel stamp dies are affordable and typically last the lifetime of the part.
- Even with multiple stamping processes, it is faster than steel casting.
- Lower cost per unit.
- High level of automation translates to lower labor costs.
- More affordable than casting when manufacturing simple parts.
- Greater design freedom with more detailed and intricate designs.
- Better tolerance control with steel cast parts.
- Excellent surface finishes.
- Ability to create blind holes in parts.
- Reusable sand for molds is cost-effective.
Stamped Steel vs. Cast Steel Weaknesses
- Extra labor cost and machining when multiple steps (i.e., Cutting, bending, and welding).
- Less tolerance control.
- Greater part complexity increases cost and requires more components in the stamping process.
- Less flexibility in the shape and thickness of a metal part.
- Unused scrap metal is considered waste and adds extra cost.
- Long pre-production time to create tool and dies.
- Must remake mold for every run using sand and investment casting.
- High viscosity of molten steel requires additional inspections and observation during the metal cooling process.
- Higher cost of dies to make patterns – must be able to withstand high temperatures.
- Steel is susceptible to porosity and oxidation – a challenge of cold chamber casting.
Why is Lubricant Used in Metal Stamping?
Stamped steel is a popular fabrication method because of its relatively high speed of manufacturing. During the process, a die continually forms metal sheets into a specified shape. All of that movement creates friction, which also generates a massive amount of heat.
Friction and heat are detrimental to maintaining the integrity of both the tool and die surface as well as the metal sheet.
Friction causes excessive wear and scratches to the tool and die surface. In the long run, this increases cost in two ways:
- Added lead time to replace the parts (time the machine is not running because part needs to be replaced).
- The cost of replacing the part (labor to produce the tool and die and install the part).
Friction can also create surface scratches on metal sheets undergoing the fabrication process. Surfaces need to easily glide around each other, or they will also create excessive heat. This can alter the shape of the finished part and cause extra wear on the tool and die surface.
This is where lubrication comes in.
Lubrication helps both the tool and die surface as well as the sheet metal form around each other. It also helps prevent wrinkles, rips, and tears in the stamped steel.
Choosing stamped steel vs. cast steel can be a difficult decision. Overall, it perfectly combines strength and ductility, which makes it the perfect metal choice across countless industries. The process is ultimately up to two primary factors: part application and budget.
While stamping is ideal for simple parts and large production runs, cast steel parts are prized for their complexity and tolerances. Both methods, however, have longer pre-production times because of tooling, die making, and automation required.
If you need help with finding the right manufacturing partner contact our team.