Ever wondered why engineers choose one steel grade over another when building machines, vehicles or industrial tools?
The answer is steel is not one material – it’s many different types of steel, each with its own strengths, weaknesses and applications.
One way to understand these differences is through BHN steel ratings (Brinell Hardness Number) which measures how resistant a grade is to wear and pressure.
The most common grades are 1018 steel known for its ductility and machinability and 4140 steel known for its toughness and strength.
ProleanTech works with both 1018 and 4140 steel in CNC machining, sheet metal, and other on-demand manufacturing services. Their team helps you choose the right material for your project so you get the best balance of performance and cost.
In this guide we’ll compare 1018 vs 4140 steel, breaking down composition, hardness and best applications.
Steel gets made when iron mixes with carbon. This easy mix makes many steel types when carbon amounts change.
Carbon amounts pick what steel type you get. Other things like chromium and molybdenum and nickel get added too. These make steel either soft and easy to bend or hard and strong and tough.
This way helps engineers pick the right stuff for jobs. 1018 steel is mild carbon steel grade that works easy. 4140 steel is medium-carbon steel with chromium and molybdenum that makes it work different and do different jobs.
1018 steel is a low carbon steel. It is also called as mild steel. The number "1018" comes from its carbon content. It has about 0.18% carbon.
This steel has low carbon levels. This makes the steel soft and easy to shape. You can weld it without problems. It gives a clean and smooth surface when you cut it.
1018 steel is not as strong as alloy steels. But it costs less money. People use it for common parts. These parts include fasteners, shafts and brackets.
4140 steel is a strong alloy with chromium and molybdenum in it. These elements make it stronger and tougher than 1018 steel.
It has about 0.40% carbon which makes it a medium carbon steel. This combination of carbon and alloying elements makes 4140 harder, more durable and more wear resistant.
Because of these features it is used in heavy machines, car parts and tools that need high strength.
This combination gives 4140 steel a special balance of hardness, toughness and wear resistance.
The density of 1018 steel is about 7.87 g/cm³. This is similar to most carbon steels.
This steel is soft by nature. Do not use it for high performance tasks. Do not use it for heavy duty work. Use it for projects where shaping matters most. Use it when welding is important. Use it too when low cost is important.
In short: 1018 steel is the right choice when you need cheap steel. Pick it when you need steel that is easy to machine. Pick it when you need steel that is easy to weld. Do not pick it if you need the strongest steel.
4140 is popular because it gives both strength and hardness and is flexible enough to take stress. Here are some uses:
To make the difference clear, here’s a chart of steel grades comparison:
From this comparison, it’s clear that 1018 is chosen for cost and ease of machining, while 4140 is preferred when strength and durability matter most.
Each steel type has good points and bad points.
Some steels cost less money and are easy to cut. Other steels are strong and last long.
Here are the main good points and bad points of 1018 steel and 4140 steel. This helps you pick the right steel for your job.
Steel grades are not just defined by their properties but also by how they perform in real world industries. 1018 and 4140 steel have their own roles in manufacturing but serve very different purposes. Let’s see how each is used across industries.
1018 or 4140 steel? It depends on what you need for your project. If you want low cost, easy to machine, and easy to weld then 1018 steel is the way to go. It’s good for parts that don’t carry heavy loads but need smooth finishes and precise machining.
On the other hand if your project needs high strength, toughness and wear resistance then 4140 steel is the better choice. It’s used in industries like aerospace, oil & gas and automotive where durability is key.
ProleanTech will help you to choose the right steel for your needs. Whether it’s the easy machinability of 1018 or the strong performance of 4140, their CNC machining services will get you accurate and reliable results every time.
1018 vs 4140 Steel FAQs
Q1: What is steel material?
Steel is an alloy of iron and carbon with varying amounts of carbon and other alloying elements like chromium, molybdenum or nickel.
Q2: Is 4140 stronger than 1018?
Yes. 4140 is much stronger and harder than 1018.
Q3: What are the disadvantages of 4140 steel?
It’s more expensive, requires special welding and has lower corrosion resistance than stainless steel.
Q4: What is 1018 steel used for?
1018 is used for fasteners, brackets, shafts and parts that require welding and forming.
Q5: How to tell 4140 from 1018?
Testing hardness and strength is the easiest way. 4140 is much stronger and harder, 1018 is softer and easier to machine.
Q6: What is 1018 steel equivalent to?
Equivalent to European C15 or EN32B mild steel.
Q7: Is 4140 hot rolled or cold rolled?
It can be both. Hot rolled is better for forming, cold drawn 4140 is better for strength and surface finish.
Q8: Can 1018 be welded?
Yes, it welds without special precautions.
Q9: Is 4140 good for knives?
Yes, due to its toughness and hardness after heat treatment, but not corrosion resistant.
Q10: Is 4140 ductile or brittle?
It’s ductile in annealed state but becomes less ductile if over hardened.
