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The Difference Between 304J1 Stainless Steel And 304 Stainless Steel

Oct 29, 2024

304 stainless steel and 304J1 stainless steel both belong to the 304 series of austenitic stainless steel, but there are significant differences in performance and application between the two. 304 stainless steel is widely used in many fields such as industrial manufacturing, food processing, and kitchen utensils, and has excellent corrosion resistance and mechanical properties. 304J1 stainless steel adds a higher copper content to 304. This improvement brings better ductility, making it suitable for more complex cold working and forming needs. Here are their differences:

304j1 ss plate.jpg

1.Basic Overview Of 304 Stainless Steel And 304J1 Stainless Steel

304 stainless steel is the most common austenitic stainless steel. Because of its good corrosion resistance, mechanical properties and processing properties, it is widely used in construction, industrial manufacturing, food equipment, household appliances and other fields. Its composition contains about 18% chromium and 8-10.5% nickel, which makes it exhibit excellent corrosion resistance in acid and alkali environments.

304J1 stainless steel is an improved stainless steel made based on 304 by adding 1-2% copper element. This increase in copper content significantly improves the ductility of 304J1, making it suitable for processing needs with high formability such as deep drawing and deep drawing, and also gives it certain antibacterial properties. Therefore, 304J1 is widely used in stainless steel products that require complex shapes such as kitchen utensils, sinks, deep-drawn molded parts, and household appliances.

2. Chemical Composition:

The main components of 304J1 stainless steel and 304 stainless steel are iron, chromium and nickel, but 1-2% copper content is added to 304J1 to improve its ductility. The specific ingredients are compared as follows:

Grade

C

Mn

Si

P

S

Cr

Ni

Cu

304

0.08 max

2.00 max

1.00 max

0.045 max

0.03 max

18.00 – 20.00

8.0-10.5

-

304J1

0.08 max

3.00 max

1.70 max

0.045 max

0.03 max

18.00 – 20.00

6.00 – 9.00

1.00 – 3.00

Due to the introduction of copper, the composition of 304J1 is more suitable for deep drawing processing and cold forming processing, but some corrosion resistance is sacrificed to a certain extent. The presence of copper changes the crystal structure of the material, making 304J1 more flexible during deep drawing and drawing, making it suitable for making parts with complex shapes.

3. Mechanical Properties:

304 stainless steel has high tensile strength and high hardness; 314J1 stainless steel plate has improved ductility due to the addition of copper.

Grade

Ys (Mpa)

Ts (Mpa)

El (%)

Hv

304J1

≥ 155

≥ 450

≥ 40

≤ 200

304

≥205

≥515

≥ 40

≤210

304J1 has more advantages in flexibility and formability, while 304 performs better in strength and hardness.

4. Corrosion Resistance:

In terms of corrosion resistance, 304 stainless steel performs well in most environments, especially in humid, acidic and alkaline environments. Its corrosion resistance comes from the high content of chromium and nickel. These two elements can form a dense oxide film on the surface of the steel, thereby preventing the intrusion of external corrosion factors.

In comparison, 304J1 has slightly lower corrosion resistance than 304 due to its copper content. Especially when used in an acidic environment, the copper element may cause accelerated corrosion. Therefore, 304J1 is generally suitable for use in neutral or weakly acidic environments and is not recommended for use under strongly acidic or alkaline conditions. In addition, the presence of copper may increase the antibacterial properties of the material, which may provide additional protection in certain environments.

5. Hardness And Ductility:

The addition of copper makes the ductility of 304J1 significantly higher than that of 304. Specifically:

▪Hardness: 304 has high hardness and wear resistance, and is suitable for structural parts with high hardness requirements.

▪Ductility: The ductility of 304J1 is significantly better than that of 304, and it is suitable for occasions requiring high formability such as deep drawing, stamping and cold working. This feature makes 304J1 more suitable for the production of complex structural components.

For parts that require repeated forming and deep drawing processing, such as sinks, kitchen utensils, and decorative parts with complex shapes, 304J1 is a more ideal choice.

6.Processability And Forming:

The addition of copper significantly improves the formability of 304J1, making it more suitable for cold working processes than 304.

▪Cold working performance: 304J1 has better cold working performance, especially when deep drawing and cold pressing are required. 304J1 can effectively reduce the risk of workpiece cracking due to its higher flexibility and better formability.

▪Stamping and deep drawing: 304J1 performs better than 304 and is more suitable for multiple stampings or complex forming processes. In such applications, 304 may be prone to cracking due to its higher hardness.

Overall, the advantages of 304J1 in formability and processability make it better adaptable in cold working production.

7.Weldability And Heat Treatment Properties:

In terms of welding performance, both 304 and 304J1 stainless steel show good weldability and are suitable for a variety of welding methods. However, the cooling rate of the weld needs to be controlled after welding to avoid the occurrence of hot cracks.

▪Welding performance: Both are suitable for common welding methods such as manual arc welding and tungsten arc welding. However, when welding 304J1, due to the high copper content, excessive cooling should be avoided after welding, and appropriate post-weld heat treatment is recommended to eliminate internal stress.

▪Heat treatment properties: Neither stainless steel can be hardened by heat treatment, hardening can only be achieved by cold working. The hardness of 304 and 304J1 can be increased after cold working, but cold working will reduce the toughness, so the processing technology needs to be reasonably selected according to the application requirements.

8.Comparison Of Specific Application Scenarios

304 and 304J1 stainless steel differ in specific applications due to differences in composition and performance. The following are several common application scenarios:

▪Food processing and medical equipment: 304 stainless steel has better corrosion resistance and is suitable for use in food processing equipment, tableware, medical equipment and other occasions that need to be kept clean.

▪Deep-drawn formed parts: 304J1 has better formability and is suitable for sinks, kitchen appliances, decorative components and other parts requiring complex shapes.

▪Architectural decoration and household appliances: 304 is often used in architectural decoration that requires high strength and corrosion resistance, while 304J1 is suitable for household kitchen appliances due to its good ductility.

Therefore, 304 is more suitable for environments with higher corrosive environments and higher hardness requirements, while 304J1 is more suitable for environments with complex forming and deep drawing requirements.

9.Cost And Sustainability

Due to the higher copper content, the cost of 304J1 is usually slightly higher than that of 304. However, in actual production, the ductility and formability advantages of 304J1 can reduce material waste, thereby reducing processing costs. At the same time, 304J1 can reduce material fatigue loss when manufacturing workpieces that require repeated stretching.

In terms of sustainability, both 304 and 304J1 are stainless steels with good recycling properties, so they perform well in terms of green environmental protection and sustainable manufacturing.

10.How To Choose The Right Stainless Steel?

In actual applications, it is recommended to select appropriate materials based on specific usage environment and performance requirements. If you are pursuing a balance between high corrosion resistance and mechanical strength, 304 is the ideal choice; if you pay more attention to formability and the manufacturing of complex shapes, 304J1 will be more suitable. By combining the cost of the material with the application requirements, the appropriate steel type can be selected more efficiently to achieve the best cost performance and performance.

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