304 Vs. 430 Stainless Steel
The debate over 304 vs. 430 stainless steel is widespread. Some argue that one is superior, while others prefer the latter. In reality, no material is best for every application—this is something we want to share after years of working in the industry and producing parts. The ideal choice depends on your specific needs, budget, and environment.
If you’re unsure which grade of stainless steel suits your project best and interested in exploring CNC machining services in China and worldwide, ProleanTech is here to help. As experts in precision manufacturing, we provide CNC machining services to 30+ countries for both small and large production needs.
Below, we’ll also provide a detailed comparison of both steel types, highlighting the conditions in which each performs best to help you choose the correct stainless steel.
A Quick Overview: 304 vs 430 Stainless Steel
Below is a comprehensive comparison table outlining 304 vs 430 stainless steel, highlighting their key differences to help you make an informed choice:
| Factor | 304 Stainless Steel | 430 Stainless Steel |
| Type | Austenitic | Ferritic |
| Main composite difference | 18-20% Cr, and 8-10.5% Ni | 16-18% Cr, and <0.75% Ni |
| Corrosion resistance | 304 is high corrosion resistance | Moderate corrosion resistance |
| Heat resistance | Up to 800°C | Up to 815°C |
| Magnetic | Non-magnetic | Fully-magnetic |
| Machinability | Harder to machine | Easier to machine |
| Cost | Expensive | Cost-effective |
What Is 304 Stainless Steel?
Stainless Steel Sheet
304 stainless steel is classified under the AISI (American Iron and Steel Institute) and ASTM (American Society for Testing and Materials) standards. The composite was developed by W. H. Hatfield at Firth Brown in 1924. It is an austenitic stainless steel containing 18% chromium and 8% nickel, earning it the nickname “18-8 stainless steel.”
304 stainless steel material properties also include carbon, but that’s in a small amount (typically ≤0.08%). In addition to carbon, its properties are influenced by elements like manganese, silicon, and phosphorus, which contribute to its corrosion resistance, durability, and machinability.
Here’s a table that can help you understand the key composition and properties of 304 grade stainless steel:
| Chromium (Cr) | Nickel (Ni) | Carbon (C) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulfur (S) |
| 18-20% | 8-10.5% | ≤0.08% | ≤2% | ≤1% | ≤0.045% | ≤0.03% |
What Is 430 Stainless Steel?
Stacks of stainless steel sheet
430 stainless steel, like 304, is also a SAE (Society of Automotive Engineers) steel grade. However, unlike 304, it is a ferritic stainless steel, meaning it contains low nickel content (≤0.75%) and is primarily composed of 16-18% chromium.
430 stainless steel composition offers good corrosion resistance. It is also magnetic and has excellent resistance properties to oxidation and heat. Below, you can read about its detailed composition and properties.
| Chromium (Cr) | Nickel (Ni) | Carbon (C) | Manganese (Mn) | Silicon (Si) | Phosphorus (P) | Sulfur (S) |
| 16-18% | ≤0.75% | ≤0.12% | ≤1.00% | ≤1% | ≤0.040% | ≤0.30% |
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Difference Between 304 vs 430 Stainless Steel
Stainless Steel 430 vs. 304 Comparison
Now you must think of which is the best choice between 304 vs 430 stainless steel for machining and what the difference is. Don’t worry; our guide to stainless steel machining will help you make the right decision. Here’s an overview of the main factors:
1. Corrosion Resistance
Corrosion Resistance
One of the most important factors to consider when manufacturing stainless steel parts is corrosion resistance. It’s the ability to withstand damage caused by environmental factors.
This ability comes from chromium (a chemical element with the symbol Cr) and nickel (Ni). Chromium forms a thin, protective oxide layer on the surface, which prevents oxidation and enhances durability. On the other hand, Nickel improves corrosion resistance by strengthening the stability of the oxide layer.
In 304 stainless steel, the combination of elements like chromium and nickel is higher, with 18-20% chromium and 8-10.5% nickel. This makes 304 stainless steel highly resistant to rust, oxidation, and chemical exposure, even in harsh industrial environments.
2. Strength and Durability
Strength and durability are also crucial when selecting stainless steel for machining applications. In the industries, they are determined by calculating the tensile strength and elongation.
Tensile strength refers to the maximum amount of stress a material can withstand before breaking. Elongation measures the percentage of stretch from the steel’s original length before it fractures.
Interestingly, both values are higher in the 304 stainless steel. The tensile strength is around 515-620 MPa, and elongation is 40%. This means 304 stainless steel can endure significant stress and deformation without cracking, which makes it ideal for high-stress applications.
However, that doesn’t mean you can’t use 430 stainless steel in machining applications. While it has lower ductility and tensile strength, it is still a viable option for many industries.
3. Heat Resistance
Heat Resistance
The next significant difference between 304 vs 403 stainless steel is heat resistance and the role of tolerances in CNC manufacturing. 304 stainless steel performs well across a broad temperature range, from cryogenic levels (-200°C) to approximately 800°C.
If we compare the heat resistance capability of 304 stainless steel to 430 stainless steel, the latter excels in high-temperature applications. 430 stainless steel resists scaling up to 815°C (1500°F), primarily due to its ferritic structure and protective chromium oxide layer.
4. 430 vs 304 Stainless Steel Cost
430 stainless steel costs less than 304 stainless steel. The reason behind the higher value of 304 stainless steel lies in its high percentage of nickel, which is 8% to 10.5%. As stated, higher nickel content enhances corrosion resistance, durability, and overall performance.
The reasons cited are the main factors that make 304 stainless steel a preferred choice for industries such as healthcare, aerospace, and automotive.
You can get your custom quote by contacting our team today. ProleanTech experts are also ready to assist individuals who want to Explore CNC Machining & Its Advantages, and the best stainless steel option for your specific application.
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What Type of Stainless Steel is Easier to Machine?
Stainless steel CNC machining
Besides the cost, 430 stainless steel also stands out for its better machinability. Not just this one, but the entire 400 series of stainless steel (specifically 430 ss) is considered easier to machine than the 300 series.
The reason is rooted in their metallurgical structures and how they behave during cutting. Their ferritic structure—16-18% chromium, ≤0.75% nickel—produces short, brittle chips that ease cutting and reduce tool wear, making them the best options for manufacturing parts.
Head-to-Head: Which Wins for Your Industry?
304 vs 430 Stainless Steel Comparison
To be very honest, there’s no straightforward answer, 304 vs 430 stainless steel, because we don’t have a one-size-fits-all approach. Choosing between these two stainless steel comes down to your priority, the part you want, and its requirements.
If you’re looking for stainless steel that’s corrosion-resistant and excellent in terms of durability, strength, and heat resistance, then 304 stainless steel is the superior choice. 304 ss corrosion resistance properties make it a preferred choice for machining worldwide.
However, if low cost is your priority, 430 stainless steel isn’t a bad choice either. It provides a balance between affordability and performance for CNC machining. Contact us now for more details about which one best suits your industry and our Stainless Steel Sheet Metal: Process & Applications.
Prolean Tech CNC Machining Service!
Contact our team if you want to explore CNC machining and its advantages with stainless steel. We’ve been providing high-precision machining solutions with fast turnaround times, expert design support, and global delivery to (30+ countries).
The ProleanTech team will provide all the information you need about sheet metal fabrication services, CNC machining services, and 304 vs. 430 stainless steel, ensuring you get the best solutions for your manufacturing requirements.
Frequently Asked Questions (FAQs)
What’s the density of 304 ss?
The density of 304 ss (stainless steel) is 7,930 kg/m³ or 7.93 g/cm 3 (0.286 lb/in³).
Is 430 stainless steel shiny?
Yes, it is! It’s often polished to achieve a bright and reflective finish.
What is the life expectancy of 304 stainless steel?
The life expectancy of 304 stainless steel is between 20 and 50 years.
What are the weaknesses of 304 stainless steel?
One of the negative characteristics of 304 stainless steel is its cost and its difficulty in machining compared to 430 stainless steel. These factors are the primary reason experts prefer 430 stainless steel.
Is 430 stainless steel magnetic?
430 stainless steel is a ferritic stainless steel, which is fully magnetic.
Is 430 stainless steel food grade?
Yes, 430 stainless steel is a food-grade stainless steel.
Does 304 stainless steel rust?
Stainless steel can’t rust; it’s just a myth. In reality, it can rust but it’s highly resistant to corrosion as compared to others.
What makes stainless steel not rust?
Stainless steel has chromium and nickel, which provide excellent protection against oxidation and rust.
What is the best grade of stainless steel?
Many grades of stainless steel are widely used worldwide and considered the best, such as 304, 420, 416, and 316.
Is food-grade stainless steel magnetic?
No, most food-grade stainless steel products are non-magnetic, but there’s always an exception, and some food-grade stainless steel can be magnetic.
Is 430 or 304 stainless steel better?
There’s no definitive answer because the best choice depends on your requirements, budget, and intended use. 304 stainless steel might be the best option for superior corrosion resistance and durability. 430 is the best if you’re looking for a budget-friendly, durable option.
Will 430 stainless steel rust outside?
Yes! Despite being corrosion resistant, 430 stainless steel can rust outside in a harsh environment.
Is 403 stainless better than 304?
The better option is always the one that suits your requirements. If you want a cost-effective material with high durability, then yes, 430 is the best choice compared to 304 stainless steel. The latter is suitable for industries that require highly corrosion-resistant material.
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