Table of content
Quick Answer
Carbon steel has different tensile strengths depending on its carbon content. But the approximate range is between 400 MPa and 1200 MPa (58000-174000 psi).
Carbon steel is divided into three types: low carbon steel, medium carbon steel, and high carbon steel. Low carbon steel has good ductility and weldability. High carbon steel has high strength and hardness. The main difference in performance is the difference in carbon content. Of course, regardless of the type of carbon steel, appropriate heat treatment can improve its strength.
Introduction
There are various types of carbon steel, and different properties are suitable for different applications. Therefore, it has a wide range of applications, from daily necessities to industrial equipment, pipeline equipment, and bridges and buildings.
Why is carbon steel so popular, and what are the differences between it and other metals? This article will provide a detailed introduction, including but not limited to mechanical strength, applications, performance, etc.
What Determines the Strength of Carbon Steel?
The strength of carbon steel is mainly determined by the following aspects:
Carbon content
- The carbon content is a major factor determining its strength.
- The higher the carbon content, the higher its strength and hardness.
- The higher the carbon content, the lower the ductility and weldability.
- The carbon content is usually between 0.05% and 2.0%.
Heat treatment
- Heat treatment includes annealing, quenching, and tempering. All three processes can alter the internal structure of steel.
- Annealing: Softens steel and increases its formability.
- Quenching: Improve strength and hardness.
- Tempering: Restoring its toughness after quenching.
Microstructure
- The interior of steel is divided into ferrite, pearlite, and martensite. These three structures determine the mechanical properties of steel.
- Ferrite: mainly determines the flexibility and ductility (in low carbon steel).
- Pearlite: a stronger mixture composed of ferrite and cementite
- Martensite: high strength and hardness, but relatively brittle (in high carbon steel)
- These three factors together determine the strength and durability of carbon steel.
Types of Carbon Steel and Their Strength
There are three types of carbon steel: low carbon steel, medium carbon steel, and high carbon steel. The following are the carbon content and mechanical properties of three types of carbon steel.
| Type | Carbon % | Tensile Strength (MPa) | Yield Strength (MPa) | Hardness (HB) | Characteristics |
|---|---|---|---|---|---|
| Low Carbon Steel (Mild Steel) | 0.05–0.30% | 400–550 | 250 | 120–160 | Soft, ductile, easily welded |
| Medium Carbon Steel | 0.30–0.60% | 600–900 | 400–600 | 150–220 | Balanced strength and toughness |
| High Carbon Steel | 0.60–1.00% | 900–1,200 | 700–900 | 200–300 | Very hard, strong, but brittle |
Low-Carbon Steel
Has good ductility and weldability. Also commonly known as “soft steel”, it is often used in products that do not require high strength and hardness, such as car bodies and some structural components.
Medium carbon steel
It has both high strength and hardness, as well as good ductility and weldability. It is commonly used in some mechanical parts, bearings, and other relatively precise zero advantages and disadvantages.
High carbon steel
The strength and hardness are highest in carbon steel. Therefore, it is often used in products that require high sharpness, such as cutting tools, cutting tools, etc.
Tensile and Yield Strength of Carbon Steel
Tensile strength and yield strength are two important factors for understanding the mechanical properties of carbon steel.
- Tensile strength: refers to the maximum stress that a material can withstand before fracture.
- Yield strength: refers to the point at which permanent deformation occurs under stress.
| Grade | Type | Yield Strength (MPa) | Tensile Strength (MPa) | Applications |
|---|---|---|---|---|
| AISI 1018 | Low-carbon | 370 | 440 | Construction, bolts, frames |
| AISI 1045 | Medium-carbon | 530 | 620 | Gears, shafts, axles |
| AISI 1080 | High-carbon | 850 | 1,200 | Springs, blades, tools |
| AISI 1095 | High-carbon | 900 | 1,250 | Knives, cutting edges |
It can be seen that the higher the carbon content, the higher the strength and hardness, and the corresponding ductility and weldability are lower.
How Strong Is Carbon Steel Compared to Other Metals?
The strength comparison between carbon steel and other metals is as follows:
| Metal | Tensile Strength (MPa) | Weight (Density g/cm³) | Key Traits |
|---|---|---|---|
| Carbon Steel | 400–1,200 | 7.8 | High strength, low cost |
| Stainless Steel | 500–1,000 | 7.9 | Strong, corrosion-resistant |
| Aluminum | 150–400 | 2.7 | Lightweight, low strength |
| Titanium | 900–1,200 | 4.5 | Strong, lightweight, expensive |
By understanding these, we can not only have a certain understanding of the strength of carbon steel, but also have a better understanding of the strength of other metals.
Is Carbon Steel Hard to Break?
Uncertain, whether it is prone to fracture depends on which type of carbon steel.
Low carbon steel is not easy to break due to its softness and good ductility.
High carbon steel is prone to fracture due to its high strength and hardness, but poor ductility.
Example:
AISI 1080 and 1095 carbon steel are prone to fracture, but they have high strength and are therefore commonly used in cutting tools and cutters.
AISI 1018 and 1020 carbon steel are not easily broken due to their good flexibility and ductility.
Advantages and Disadvantages of Carbon Steel Strength
Advantages:
- When requesting high-strength materials, the price is lower than stainless steel.
- For products with hardness requirements, high carbon steel is suitable for cutting tools after heat treatment.
- For products that require high load-bearing and high stress, carbon steel has a good surface.
- For products that require frequent processing and shaping, carbon steel can adjust its strength through heat treatment.
Disadvantages:
- Easy to corrode, prone to rust and corrosion in some humid environments.
- Carbon steel is not suitable for products that require both strength and ductility.
- High strength carbon steel has poor welding forming.
- It is heavier than aluminum, titanium, and other materials.
Applications of Carbon Steel Based on Strength
| Type | Strength Range | Typical Uses |
|---|---|---|
| Low-Carbon Steel | 400–550 MPa | Pipes, structural frames, automotive panels |
| Medium-Carbon Steel | 600–900 MPa | Machinery parts, axles, couplings |
| High-Carbon Steel | 900–1,200 MPa | Knives, tools, springs, high-tension wires |
There are still some differences in the application of carbon steel with different properties. Only the general applications of carbon steel are listed below:
- Construction field: steel bars, bridge structures.
- Automotive field: automotive chassis, gears, etc.
- Industrial fields: machinery, pipelines, cutting tools, etc.
- Home furnishings: kitchenware, furniture stands, etc.
Of course, the specific purpose needs to be selected based on performance.
Summary
Carbon steel is widely used, with different mechanical properties such as high strength, high hardness, high ductility, and high weldability. Choose different performance based on different applications.
Carbon steel is also divided into three types: high carbon steel, medium carbon steel, and low carbon steel. These three types of performance are also different.
- High carbon steel: high strength and hardness, but relatively brittle.
- Medium carbon steel: It has a certain strength and hardness, as well as a certain degree of ductility.
- Low carbon steel: excellent flexibility, ductility, and weldability.
The tensile strength of the three types of carbon steel ranges approximately from 400 to 1200 MPa. The yield strength is between 250 and 900 MPa. But the specific model and numerical value.
I hope these contents will help you understand the strength, hardness, and ductility of carbon steel, so that you can make better choices.
