40Cr13 steel, also known as 4Cr13, is a Martensitic Stainless Steel. It is recognized for its exceptional hardness and wear resistance. Compliant with GB1220-92 and GBT1220-2007 standards, it contains 0.4% carbon and 12-14% chromium.
This steel is employed extensively in high-load, high-wear resistance, and corrosive applications. Additionally, it is ideal for plastic mold creation.
This article will examine 40Cr13’s chemical composition, mechanical and physical properties, and equivalent grades. It will also highlight its diverse industrial applications.
Overview
In the context of Cr13 steel, 4Cr13 and 40Cr13 are essentially the same material, named differently based on the respective GB1220-92 and GBT1220-2007 national standards. They are both martensitic stainless steels that exhibit similar characteristics, notably in their heat treatment, corrosion resistance, machinability, weldability, and surface finish.
The heat treatment process of these steels involves hardening and tempering to achieve desirable properties. Hardening enhances the strength and wear resistance, while tempering reduces brittleness, ensuring a good balance between hardness and toughness.
4Cr13 and 40Cr13 demonstrate exceptional corrosion resistance, primarily due to their high chromium content. The chromium forms a passive layer on the surface, protecting the underlying material from oxidation and corrosive substances.
The machinability of these steels is moderate, making them suitable for a variety of machining processes. However, their hard nature requires the use of appropriate cutting tools to prevent premature wear.
Their weldability is fair, with preheating and post-weld heat treatment typically required to prevent cracking. Lastly, these steels can achieve a high-quality surface finish through polishing, enhancing their aesthetic appeal and corrosion resistance.
4Cr13 ( 40Cr13) Overview
4Cr13 steel (New name: 40Cr13) is a martensitic type stainless steel, which has higher hardness than 3Cr13 steel after quenching.
4Cr13 reference standard: GB/T 1220 & GB/T 20878
40Cr13 reference standard: GB/T 3280
Equivalent Materials
Equivalent materials to 4Cr13 and 40Cr13 include X39Cr13 (1.4031) as per the European EN 10088-3 standard. These materials share similar heat treatment processes, including annealing, quenching, and tempering, to achieve desired mechanical properties.
The corrosion resistance of these materials is adequate due to their high chromium content, making them suitable for use in environments prone to corrosive agents.
In terms of machinability, 4Cr13 and 40Cr13 are comparable to X39Cr13, although specific tooling and cutting speeds may vary based on the alloy’s specific composition.
The weldability of these materials is generally good, with pre- and post-weld heat treatment often recommended to prevent cracking and maintain strength.
Comparing these alloys to other stainless steel grades, they offer a balanced blend of hardness and toughness, which is not always found in high-carbon stainless steels.
It is important to note that material selection should always be based on the specific demands of the application, considering factors such as mechanical stress, operating temperature, and exposure to corrosive substances.
Understanding the properties of 4Cr13, 40Cr13, and X39Cr13 can help inform appropriate material selection in various industrial applications.
Characteristics
High hardness and wear resistance are key characteristics of both 4Cr13 and 40Cr13, making them suitable for applications such as cutting tools, nozzles, and valve seats. These materials undergo a series of processes, including heat treatment, to enhance their properties and performance.
- Heat Treatment: This process, critical for achieving the desired hardness and strength, involves heating and cooling under controlled conditions. It significantly improves the wear resistance of these alloys.
- Corrosion Resistance: The high chromium content in these alloys offers excellent corrosion resistance, enhancing their durability and lifespan in various environments.
- Machinability: Both 4Cr13 and 40Cr13 display good machinability, making them easy to shape and work with using various tools.
- Weldability: Although these alloys can be welded, the process must be managed carefully to avoid formation of undesirable microstructures that can compromise the material’s properties.
Comparing these alloys with other stainless steels, 4Cr13 and 40Cr13 offer a superior combination of hardness, wear resistance, and corrosion resistance. However, their weldability and machinability are comparable to other stainless steel grades. This balance of properties makes them versatile, well-suited to a range of demanding applications.
Uses
Both 4Cr13 and 40Cr13 materials find extensive use in various industries due to their exceptional hardness, wear resistance, and corrosion resistance properties. These stainless steels are frequently subjected to heat treatment processes, such as quenching and tempering, which significantly enhance their mechanical properties. The performance of 4Cr13/40Cr13, in terms of hardness and corrosion resistance, is commendable when compared with other stainless steels, making them a preferred choice in many applications.
One standout application is in the automotive industry. Here, these materials are instrumental in the manufacturing of crucial components like valve seats and nozzles. Their superior wear resistance properties lead to a longer tool life, reducing the frequency at which these components need to be replaced.
The corrosion resistance of 4Cr13 and 40Cr13 stainless steels is another significant advantage in automotive applications, where parts are often exposed to a variety of corrosive environments. Consequently, the use of these steels contributes to the longevity of automotive parts and reduces maintenance costs. Therefore, the adoption of 4Cr13 and 40Cr13 materials has a profound impact on the overall functionality and life expectancy of automotive tools and components.
Physical Properties
The physical properties of 4Cr13 and 40Cr13, including their density and hardness, play a critical role in their applicability across various industries. These materials possess a density of 7.75 g/cm3, indicating a robust structure that withstands external pressure. Moreover, their hardness, when quenched and tempered, exceeds 50 HRC, signaling excellent wear resistance.
- Heat Treatment: Both 4Cr13 and 40Cr13 undergo a heat treatment process to enhance their hardness and strength. It involves heating the materials to 1130-1150 °C, followed by a cooling phase.
- Corrosion Resistance: Containing about 13% chromium, these materials offer substantial corrosion resistance. This property makes them ideal for use in harsh environments with corrosive elements.
- Machinability: The machinability of these materials is commendable. They can be smoothly cut, shaped, and finished according to the application requirements.
- Weldability: Despite their high hardness, both 4Cr13 and 40Cr13 demonstrate excellent weldability. This attribute allows them to be conveniently joined with other components without compromising their physical properties.
The surface finish of these materials enhances their aesthetic appeal and resistance to external elements, making them a preferred option in various industries, including tool manufacturing, metalworking, and more.
| Code in GB/T 20878 | Unified numerical code | New Grade | Original Grade | Density /(g/cm3) 20 ℃ | Melting point ℃ | Specific heat capacity (kJ/Kg · K) | Thermal conductivity (W/m·K) | Coefficients of linear thermal expansion (10-6/K): | Electrical Resistivity (Ω·mm2/m) 20 ℃ | Longitudinal modulus of elasticity (kN/mm2) 20 ℃ | ||
| 100 ℃ | 500 ℃ | 0～100 ℃ | 0 ～ 500 ℃ | |||||||||
| 104 | S42040 | 40Cr13 | 4Cr13 | 7.75 | 0.46 | 28.1 | 28.90 | 10.50 | 12.00 | 0.590 | 215 | |
Mechanical Properties
Mechanical properties of 4Cr13 and 40Cr13 include a HRC hardness of over 50 when quenched and tempered, indicating a high level of resilience and durability. This is achieved through a heat treatment process, which involves heating the steel to a high temperature before cooling it rapidly. This process alters the microstructure of the steel, enhancing its hardness and impact resistance.
Hardness testing reveals that both 4Cr13 and 40Cr13 steel grades have superior hardness, which is a measure of a material’s resistance to permanent deformation. This characteristic makes these materials suitable for applications where durability and wear resistance are paramount, including cutting tools, nozzles, and valve seats.
In addition, both 4Cr13 and 40Cr13 exhibit excellent corrosion resistance. Their chromium content, which is approximately 13%, allows the formation of a thin, protective oxide layer on the surface. This layer shields the steel from various corrosive environments, prolonging its service life.
Moreover, wear resistance, another noteworthy mechanical property, is evident in these steel grades. This attribute, linked to their hardness and enhanced by their heat treatment, provides the ability to withstand friction and wear, making these materials reliable for high-stress applications.
| Code in GB/T 20878 | Unified numerical code | New Grade | Original Grade | Mechanical property of test piece through quench tempering | Hardness of annealed steel bars | ||||||
| Proof strength, non-proportional extension Rp0.2/(N/mm2) | Tensile strength Rm/(N/mm2) | Stretching rate after breaking A/% | Section shrinkage rate Zb/% | Impact absorbing energy Aku2d/J | HBW | HRC | HBW | ||||
| No less than | No more than | ||||||||||
| 104 | S42040 | 40Cr13 | 4Cr13 | – | – | – | – | – | 50 | 235 | |
Chemical Composition
Analyzing the chemical makeup of 4Cr13 and 40Cr13 reveals a composition primarily consisting of carbon and chromium elements, which significantly influence the material’s hardness and corrosion resistance. These elements, along with silicon, manganese, and others, contribute to the overall properties of these metals.
Post heat treatment, 4Cr13 and 40Cr13 exhibit increased hardness and strength. The high chromium content enhances their corrosion resistance, making them ideal for applications in harsh environments. Their machinability is commendable, allowing for smooth operations during manufacturing processes. However, the high carbon and chromium content can impact the weldability of these materials, necessitating appropriate precautions during welding procedures.
For a comparative analysis, we present a table outlining the composition and properties of 4Cr13, 40Cr13, and another popular stainless steel type:
| Code in GB/T 20878 | Unified numerical code | New Grade | Original Grade | Chemical compositions (mass fraction) % | ||||||||||
| C | Si | Mn | P | S | Ni | Cr | Mo | Cu | N | Other elements | ||||
| 104 | S42040 | 40Cr13 | 4Cr13 | 0.36~0.45 | 0.6 | 0.8 | 0.04 | 0.03 | (0.60) | 12.00 ~ 14.00 | – | – | – | – |
Despite similarities, 4Cr13 and 40Cr13’s hardness significantly surpasses 316L stainless steel, attesting to their superior performance in wear-resistance applications.
Redstone Manufacturing does not guarantee the accuracy of the information contained within the above table. Some metrics have been rounded, converted, or estimated. Consult a qualified engineer to confirm the accuracy of the information contained on this webpage.