{"id":6316,"date":"2024-12-03T01:33:58","date_gmt":"2024-12-03T09:33:58","guid":{"rendered":"https:\/\/richconn.com\/?p=6316"},"modified":"2024-12-03T01:44:48","modified_gmt":"2024-12-03T09:44:48","slug":"1018-vs-4140-steel","status":"publish","type":"post","link":"https:\/\/richconn.com\/1018-vs-4140-steel\/","title":{"rendered":"1018 vs 4140 Steel: What Are The Similarities and Differences","gt_translate_keys":[{"key":"rendered","format":"text"}]},"content":{"rendered":"\n

Looking for carbon steel but confused between 1018 and 4018 steel? We are here to help you out!<\/p>\n\n\n\n

For high-strength and heavy-duty applications, 4140 steel is more suitable than 1018. However, if your main concern is machinability and welding, go for 1018 steel. <\/strong><\/p>\n\n\n\n

Want to learn more? Go through the below similarities and dissimilarities to pick the best steel between 1018 and 4140:<\/p>\n\n\n\n

What is 1018 Steel?<\/h2>\n\n\n\n
\"steel<\/figure>\n\n\n\n

1018 steel or AISI 1018 is low-carbon mild steel. If we define the numbers, \u201810\u2019 <\/strong>stands for 10xx series of carbon steels as categorized by AISI (American Iron and Steel Institute). The last 2 digit, \u201818\u2019<\/strong>, defines its carbon content as 0.18% (approx).  <\/p>\n\n\n\n

1018 steel is not so hard, which makes it an excellent metal for machining and welding. You can shape it into a complex structure, and it is highly suitable for general application. Besides, they have excellent weldability and mechanical properties.<\/p>\n\n\n\n

What Is 4140 Steel?<\/h2>\n\n\n\n

4140 has more carbon content than 1018 steel. This increases the robustness and strength of the steel. The first two digits, \u201841\u2019<\/strong>, define the steel as under the AISI 41xx series, and the later two digits, \u201840\u2019<\/strong>, indicate its carbon content of  0.40% (approx). <\/p>\n\n\n\n

Due to increased carbon content, you can use 4140 steel for heavy-duty applications. Besides carbon, it also contains chromium, molybdenum, magnesium, etc. The presence of these alloying elements hardens and boosts the strength of 4140 steel.<\/p>\n\n\n\n

Comparison Chart: 1018 vs 4140 Steel (Overview)<\/h2>\n\n\n\n
Property<\/strong><\/th>1018 steel<\/strong><\/th>4140 steel<\/strong><\/th><\/tr><\/thead>
Type<\/strong><\/td>Low-carbon steel<\/td>Low-alloy steel<\/td><\/tr>
Main Alloying Elements<\/strong><\/td>Manganese<\/td>Chromium, Molybdenum, Manganese<\/td><\/tr>
Strength<\/strong><\/td>Moderate<\/td>High<\/td><\/tr>
Hardness<\/strong><\/td>Moderate<\/td>High<\/td><\/tr>
Ductility<\/strong><\/td>High (excellent for cold-forming)<\/td>Moderate<\/td><\/tr>
Heat Treatment Ability<\/strong><\/td>Limited<\/td>Excellent<\/td><\/tr>
Machinability<\/strong><\/td>Excellent<\/td>Good after annealing<\/td><\/tr>
Weldability<\/strong><\/td>High<\/td>Moderate<\/td><\/tr>
Corrosion Resistance<\/strong><\/td>Low<\/td>Low (slightly higher than 1018 steel)<\/td><\/tr>
Cost<\/strong><\/td>Lower<\/td>Higher<\/td><\/tr>
Application<\/strong><\/td>General applications, like- precision parts, fasteners, and frames<\/td>Heavy-duty applications, like- shafts, gears, and high-stress components.<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

1018 vs. 4140 Steel: In-depth Comparison<\/h2>\n\n\n\n
\"1018<\/figure>\n\n\n\n

Composition and Alloying Elements<\/h3>\n\n\n\n

Both 1018 and 4140 steel have the majority of iron (Fe) in their chemical composition. Comparing the alloying elements, 4140 contains more alloying elements than 1018. Besides, 4140 steel has greater carbon content than 1018 steel. <\/p>\n\n\n\n

Additionally, the presence of additional elements like chromium, silicon, and molybdenum makes 4140 more robust and corrosion-resistant. In contrast, 1018 steel lacks these alloying elements.<\/p>\n\n\n\n

Alloying Element<\/th>Symbol<\/th>1018 steel<\/th>4140 steel<\/th><\/tr><\/thead>
Carbon<\/strong><\/td>C<\/td>0.15% – 0.20%<\/td>0.380% – 0.430%<\/td><\/tr>
Phosphorous<\/strong><\/td>P<\/td>0.04% (max)<\/td>0.035%<\/td><\/tr>
Manganese<\/strong><\/td>Mn<\/td>0.60% – 0.90%<\/td>0.75% – 1.0%<\/td><\/tr>
Sulfur<\/strong><\/td>S<\/td>0.05% (max)<\/td>0.040%<\/td><\/tr>
Chromium<\/strong><\/td>Cr<\/td>–<\/td>0.80% – 1.10%<\/td><\/tr>
Iron<\/strong><\/td>Fe<\/td>Balance<\/td>Balance<\/td><\/tr>
Silicon<\/strong><\/td>Si<\/td>–<\/td>0.15% – 0.30%<\/td><\/tr>
Molybdenum<\/strong><\/td>Mo<\/td>–<\/td>0.15% – 0.25%<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Mechanical Properties<\/h3>\n\n\n\n

Compared to 1018 steel, 4140 steel has a tensile strength that is roughly 1.49 times higher. If you need a robust solution, 4140 steel is more suitable. Besides, due to higher elongation at break, you can shape and bend 4140 steel with greater flexibility.<\/p>\n\n\n\n

Features<\/strong><\/th>1018 steel<\/strong><\/th>4140 steel<\/strong><\/th><\/tr><\/thead>
Poisson\u2019s ratio<\/strong><\/td>0.29<\/td>0.27-0.30<\/td><\/tr>
Tensile strength<\/strong><\/td>440 MPa<\/td>655 MPa<\/td><\/tr>
Elongation at break (in 50 mm)<\/strong><\/td>15%<\/td>25.70%<\/td><\/tr>
Yield strength<\/strong><\/td>370 MPa<\/td>415 MPa<\/td><\/tr>
Modulus of elasticity<\/strong><\/td>205 GPa<\/td>190-210 GPa<\/td><\/tr>
Shear modulus<\/strong><\/td>80 GPa<\/td>80 GPa<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Thermal Properties<\/h3>\n\n\n\n

The thermal properties of 1018 and 4140 steel are quite similar. They share the same melting properties. However, there are differences in their thermal conductivity. 1018 steel has a thermal conductivity of 51.9 W\/mK, which is much higher than 42.6 W\/mK of 4140 steel. <\/p>\n\n\n\n

This makes 1018 more suitable for applications where efficient heat dissipation and minimal thermal expansion are needed. In contrast, 4140 steel is great for applications that deal with heat treatment to increase strength.<\/p>\n\n\n\n

Thermal & Electrical Features<\/strong><\/th>1018 steel<\/strong><\/th>4140 steel<\/strong><\/th><\/tr><\/thead>
Thermal Expansion Coefficient<\/strong><\/td>12 \u00b5m\/m-K<\/td>12.2 \u00b5m\/m\u00b0C<\/td><\/tr>
Thermal Conductivity<\/strong><\/td>51.9 W\/mK<\/td>42.6 W\/mK<\/td><\/tr>
Melting Onset (Solidus)<\/strong><\/td>1420\u00b0C<\/td>1420\u00b0C<\/td><\/tr>
Melting Completion (Liquidus)<\/strong><\/td>1460\u00b0C<\/td>1460\u00b0C<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Electrical Characteristics<\/h3>\n\n\n\n

1018 steel has lower electrical resistance than 4140 steel. That is, electricity flow in 1018 is smoother in 1018 as it faces less hindrance. Thus, it has better electrical conductivity than 4140 steel. So, if your application deals with electrical conduction, choose 1018 steel.<\/p>\n\n\n\n

Characteristics<\/strong><\/th>1018 steel<\/strong><\/th>4140 steel<\/strong><\/th><\/tr><\/thead>
Electrical Resistivity<\/strong><\/td>1.590\u00d710^{-7} ohm-m<\/td>2.200\u00d710^{-7}ohm-m<\/td><\/tr>
Electrical Conductivity (% IACS)<\/strong><\/td>10.84% IACS<\/td>7.84% IACS<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Machinability and Weldability<\/h3>\n\n\n\n

The machinability of the steel is related to its carbon content. As 1018 has a lower carbon content than 4140 steel, it\u2019s soft and easy to work with. This feature makes 1018 more machinable than 4140 steel. You can shape its complex structure and also weld it with ease. <\/p>\n\n\n\n

In contrast, welding and machining is challenging with 4140 steel. You need to go through a preheating procedure before welding, which increases manufacturing costs.<\/p>\n\n\n\n

Hardness<\/h3>\n\n\n\n

4140 steel exceeds 1018 Steel in all types of hardness tests. The Brinell hardness test shows that 4140 steel has a hardness value of 197 kgf\/mm\u00b2. In comparison, 1018 steel is softer, with a hardness of only 126 kgf\/mm\u00b2. Thus, you can see the difference is huge. So, considering robustness and hardness, 4140 steel wins the race.<\/p>\n\n\n\n

Hardness Test<\/strong><\/th>1018 steel<\/strong><\/th>4140 steel<\/strong><\/th><\/tr><\/thead>
Brinell Hardness (BHN)<\/strong><\/td>126 kgf\/mm\u00b2<\/td>197 kgf\/mm\u00b2<\/td><\/tr>
Knoop Hardness (KHN)<\/strong><\/td>145 kgf\/mm\u00b2<\/td>219 kgf\/mm\u00b2<\/td><\/tr>
Rockwell B Hardness (HRB)<\/strong><\/td>71 HRB<\/td>92 HRB<\/td><\/tr>
Vickers Hardness (VHN)<\/strong><\/td>131 kgf\/mm\u00b2<\/td>207 kgf\/mm\u00b2<\/td><\/tr><\/tbody><\/table><\/figure>\n\n\n\n

Corrosion Resistance<\/h3>\n\n\n\n

1018 steel has poor resistance against corrosion. So, it’s not quite suitable for applications that consciously deal with moisture. In contrast, a 0.80% – 1.10% chromium content in 4140 contributes to providing corrosion resistance. The addition of molybdenum also extends its anti-rust resistance features. <\/p>\n\n\n\n

However, compared to stainless steel, the corrosion resistance of 4140 steel is nothing significant. It requires plating, coating, and other measures to stay protected in an excessively rust-prone environment.<\/p>\n\n\n\n

Application<\/h3>\n\n\n\n
\"Parts<\/figure>\n\n\n\n

The application of the steel depends on its physical and mechanical properties. Due to the softer and lower strength of 1018 steel, it is mostly used for general applications. For example:<\/p>\n\n\n\n