فولاذ مقاوم للصدأ 420 | 1.2083 | 2Cr13

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1. What is 420 stainless steel?

420 stainless steel is a martensitic stainless steel and is also the most commonly used martensitic stainless steel. It has similar corrosion resistance to 410 stainless steel, but with higher strength and hardness. It is also widely known as “cutlery stainless steel.”

2. What are the key properties of 420 stainless steel?

It has a hardness of 52-55 HRC (or Rockwell C55 when hardened and stress relieved), a density of 0.280 lbs/in³ (7.74 g/cm³), and a tensile strength of 275,000 psi (230 ksi or 1586 MPa when hardened and stress relieved). It is magnetic in both annealed and hardened conditions. Additionally, it possesses good machining properties, is hardenable, polishable, and conditionally acid resistant.

3. What is the chemical composition of 420 stainless steel?

Its chemical makeup typically includes Carbon (C) at 0.15 – 0.36% (or 0.15% minimum, extending up to 0.5% in some variations), Chromium (Cr) at 12 – 14%, and a maximum of 1.0% each for Silicon (Si) and Manganese (Mn). Phosphorus (P) is typically 0.04% Max and Sulphur (S) is 0.03% Max.

4. Does 420 stainless steel rust?

420 stainless steel has excellent corrosion resistance. It can resist corrosion from the atmosphere, fresh water, steam, gasoline, alcohol, blood, sweat, grease, and food.

5. Is 420 stainless steel magnetic?

Yes, 420 stainless steel is attracted to a magnet and is magnetic in both its annealed and hardened states.

6. What is the hardness of 420 stainless steel?

The hardness of 420 stainless steel ranges from 52 to 55 HRC.

7. What are the equivalent international standards for 420 stainless steel?

420 stainless steel has several equivalent international standards, including AISI 420, BS970 420S37, 420S45, DIN 1.4021, 1.4025, 1.4034, AFNOR Z30C13, Z40C14، و JIS SUS 4200JI, 420J2. It is also covered by ASTM A 176 and AMS 5506 specifications, and its UNS number is S42000.

8. What are the typical uses for 420 stainless steel?

Typical uses include bearing manufacture, valve parts, hose connectors & fittings. It is also widely used for cutlery, surgical and dental instruments, scissors, tapes, and straight edges. It is considered ideal for applications that demand both good corrosion resistance and high hardness.

9. Is 420 stainless steel suitable for knives?

Yes, 420 stainless steel, particularly the 420HC (High Carbon) variant with proper heat treatment, is considered suitable and can be an excellent steel for knives. While some generic 420 might be considered outdated for general-use knives due to its softness and poorer edge retention, 420HC is known for being tough, stainless, easy to sharpen, and having respectable edge retention. Companies like Buck Knives have achieved solid performance with 420HC through specialized heat treatments. Learn more about this article please read Is 420 stainless steel good for knives?

10. Is 420 stainless steel considered “budget” or “low-quality” for knives?

While often referred to as a “budget” steel because it is an older alloy, 420 stainless steel is not necessarily low-quality. Its performance heavily relies on the heat treatment it receives; with proper heat treatment (especially for 420HC), it can be a solid, usable, and even underrated performer for real-world use. It offers good corrosion resistance, toughness, and ease of sharpening, making it a viable option for everyday carry (EDC) knives.

11. Is 420 stainless steel suitable for swords?

No, 420 stainless steel is generally not recommended for functional swords and is often found in “wall hangers” (decorative swords). The carbon content of 420 can be fairly low, making the blade softer. Functional swords are typically made from carbon steel because it is cheaper, easier to forge, and easier to heat treat for the required performance. Stainless steel swords are broadly viewed as too brittle and prone to chipping or shattering for practical use.

12. Can 420 stainless steel be used with aluminum?

There are conflicting views on the compatibility of stainless steel (including 420) with aluminum, particularly in exterior or wet environments, due to the risk of galvanic corrosion. Some sources indicate that stainless steel can be worse than galvanized steel when in contact with aluminum, leading to severe aluminum corrosion in marine or wet conditions. Conversely, other sources suggest stainless steel bolts might be used to avoid galvanic reactions, or that reactions are minimal in mild conditions due to aluminum’s protective oxide layer. To mitigate potential galvanic corrosion, it is widely recommended to use isolation washers made of plastic or rubber between the two metals to minimize direct contact.

13. How does heat treatment affect 420 stainless steel’s performance?

Heat treatment is crucial for enhancing the performance characteristics of 420 stainless steel. Its maximum corrosion resistance is achieved only when the steel is fully hardened or hardened and stress-relieved; it is generally never used in the annealed condition for optimal corrosion resistance. Proper heat treatment can significantly improve properties such as hardness and edge retention, especially for variants 420HC. When 420 is soft (annealed), it is flexible; when hardened, it becomes quite hard.

14. How is 420 stainless steel heat-treated?

Common heat treatment processes for 420 stainless steel include:

• Annealing (for maximum softness): Heat uniformly to 1500 – 1650°F (816 – 899°C) and cool slowly in the furnace.
• Process Annealing: الحرارة إلى 1350 – 1450°F (732 – 788°C), then air cool.
• التصلب: Preheat, then heat to 1800 – 1950°F (982 – 1066°C), soak at the temperature, and then air cool or quench in warm oil.
• تخفيف التوتر: Heat at 300 – 800°F (149 – 427°C) for 1 to 3 hours, then cool in air or quench in oil or water.

15. Is 420 stainless steel weldable?

Martensitic stainless steel series, including type 420, has limited weldability. If welding is required, it is recommended to preheat to 550°F (260°C). It is also recommended to perform heat treatment after welding.

16. Is 420 stainless steel formable?

Yes, if 420 stainless steel is annealed for maximum softness, it can be moderately drawn and formed.

17. What are the temperature limitations for 420 stainless steel?

420 stainless steel is not typically used at temperatures exceeding 800°F (427°C). This is because higher temperatures lead to rapid softening and a loss of its corrosion resistance.

18. What is the difference between 420 and 420HC stainless steel, particularly regarding carbon content?

The key difference lies in their carbon content, which significantly impacts their performance. Generic 420 (and 420J) typically has a lower carbon content, around 0.15%. In contrast, 420HC (High Carbon) has a notably higher carbon content, usually around 0.46%. This higher carbon content, especially when combined with specialized heat treatment, provides 420HC with improved hardness, better edge retention, and more robust performance for applications like knives. The variation in carbon content among different 420 grades explains why sources may report different carbon percentages for “420” steel.

19. How does 420 stainless steel compare to 440 stainless steel?

Both 420 and 440 are generally considered decent and usable “budget” stainless steels. 420 (specifically 420HC) is described as very tough with respectable edge retention. 440 (particularly 440C) can achieve higher hardness (58 HRC or above) and typically offers better edge retention, though it may not be as tough as 420. 440C is also a corrosion-resistant martensitic chromium steel with high wear resistance. The specific grade and heat treatment are important for comparing their actual performance.

20. How does 420 stainless steel’s corrosion resistance compare to 316 stainless steel?

While 420 stainless steel offers good corrosion resistance compared to other cutlery steels, its corrosion resistance is inferior to 316 stainless steel. SAE 316 and 316L (often called “marine grade”) are chromium, nickel, molybdenum alloys known for their superior strength and corrosion resistance, and are considered biocompatible when produced to specific standards.

21. Is 420 a good stainless steel?

420 steel is indeed a good stainless steel, offering a satisfactory level of corrosion resistance for a wide range of applications, particularly when properly heat-treated. Its combination of corrosion resistance with achievable high hardness and wear resistance makes it a versatile material, notably for cutlery and certain tooling applications.