Views: 0 Author: Site Editor Publish Time: 2026-05-25 Origin: Site
In our previous article, we discussed why the precision machinery industry is increasingly turning to martensitic stainless steel — higher hardness, better wear resistance, dimensional stability, and lower lifecycle costs.
However, when customers encounter grades such as 410, 420J1, 420J2, 4Cr13, 5Cr15MoV, and 6Cr13, many become even more confused:
Which one should I choose?
When speaking with engineers and purchasing managers from precision machining factories, tool manufacturers, and medical device companies, we frequently hear questions like:
What’s the difference between 410, 420J1, and 420J2?
Is 4Cr13 basically the same as 420J2?
Why is 5Cr15MoV more expensive?
Can 6Cr13 directly replace 440C?
Why do some high-hardness materials chip or crack easily?
Why can the service life of two “420J2” parts differ several times depending on the supplier?
Behind these questions lies a deeper realization:
For the precision machinery industry, what truly matters is not simply the grade name itself, but:
Whether it matches the actual working conditions (load, media, temperature)
Whether it suits the heat-treatment process (distortion, hardness uniformity)
Whether it performs consistently over long-term use (batch consistency, wear life)
Whether it fits the customer’s budget (material cost + processing cost + replacement cost)
This is why more customers are focusing on how to properly choose martensitic stainless steel, instead of simply asking for “the hardest” or “the cheapest” material.
The table below is based on our decade-plus experience serving the precision machinery industry.
It is not designed for academic precision — it is designed to help customers quickly identify the right direction within 30 seconds.
Material | Hardness | Wear Resistance | Corrosion Resistance | Toughness | Cost | Typical Applications |
★★ | ★★ | ★★☆ | ★★★★ | Low | Spacers, washers, solenoid cores, structural parts | |
★★★ | ★★★ | ★★☆ | ★★★★ | Low | Mini springs, elastic claws, impact-resistant wear parts | |
★★★★ | ★★★★ | ★★☆ | ★★★ | Medium-Low | Precision scrapers, food blades, mold ejector pins | |
★★★★ | ★★★★ | ★★★ | ★★★ | Medium | Surgical instruments, mold cores, sterilizable parts | |
★★★★★ | ★★★★★ | ★★★★ | ★★★★ | High | Medical blades, pump plungers, premium tools | |
★★★★★ | ★★★★★ | ★★☆ | ★★ | Medium | Ultra-hard shafts, ceramic cutting blades, economical 440C replacement |
Note: More stars indicate better performance.
Corrosion resistance benchmark: 304 = ★★★★, 316L = ★★★★★.
Martensitic stainless steels generally have lower corrosion resistance than austenitic grades, but Mo and V additions can significantly improve performance.
Many suppliers begin with carbon content and chromium percentages.
But customers care about one thing:
“Which material is right for my product?”
Below, we explain the selection logic based on common customer applications.
Typical Applications· Structural components · Spacers · Solenoid valve cores Core RequirementAffordable material with moderate hardness (HRC 38–45) and basic corrosion resistance. |  |
410 has the lowest carbon content among martensitic stainless steels (~0.1%), giving it:
· Better toughness
· Easier machining
· Lower cost
After heat treatment, it provides sufficient hardness for dry or oil-lubricated environments.
410 is not suitable for salt spray or acidic environments. If parts contact sweat or cleaning agents, upgrading to 4Cr13 is recommended.
Pre-hardened polished bars at HRC 35–40 for direct machining without additional heat treatment.
Typical Applications· Miniature springs · Elastic claws · Wear-resistant components under impact Core RequirementHRC 45–50 with better wear resistance than 410 while maintaining good toughness. |  |
420J1 can be considered an “enhanced 410.”
Compared with 420J2, it retains better toughness while offering higher hardness than 410.
It is ideal for components requiring elasticity or impact resistance.
For springs and elastic components, toughness is often more important than maximum hardness.
At around HRC 48, 420J1 still maintains good fatigue resistance, while 420J2 at the same hardness is more likely to crack.
Fine wire and thin strip materials in customizable pre-hardened conditions for direct spring forming or stamping.
 | Typical Applications· Precision scrapers · Food slicer blades · Plastic mold ejector pins · Textile machinery wear parts Core RequirementHRC 52–56 with good wear resistance and moderate toughness. |
420J2 is one of the most widely used martensitic stainless steels in industrial blade applications.
Its heat-treatment process is mature and widely available worldwide.
Why do some 420J2 parts show uneven hardness or grinding cracks?
· Carbide segregation
· Poor tempering process
We supply ESR (Electroslag Remelting) 420J2 with refined carbides and provide vacuum air quenching + cryogenic treatment.
Hardness uniformity can be controlled within ±1 HRC.
Typical Applications· Surgical instruments · Injection mold cores · Measuring tools Core RequirementHRC 50–54 with resistance to alcohol, disinfectants, and humid environments. |  |
Compared with 420J2, 4Cr13 offers:
· Better hardenability
· More stable corrosion resistance
· Better performance under repeated sterilization
“Is 4Cr13 the same as 420J2?”
Not exactly.
420J2 follows JIS standards, while 4Cr13 follows Chinese GB standards.
For medical applications, 4Cr13 is often preferred in the Chinese market.
Peeled and precision-forged bars with straightness ≤0.1 mm/m for direct automatic lathe processing.
 | Typical Applications· Premium industrial blades · Medical knives · Pharmaceutical pump plungers · Long-life precision parts Core RequirementHRC 56–60 with chloride corrosion resistance and good toughness. |
This grade contains:
· Mo (Molybdenum): improves pitting resistance and tempering stability
· V (Vanadium): refines grain structure and improves wear resistance
Is the 15–20% higher cost worth it?
If the part contacts saline solution, chemicals, or experiences impact loads — absolutely.
We helped a medical pump customer replace imported 440C with 5Cr15MoV, reducing material costs by 47% and scrap rates from 15% to 3%.
Cold-drawn precision-ground bars with h6 tolerance and Ra ≤ 0.2 μm surface finish.
Typical Applications· Disposable razor blades · Disposable medical surgical blades · Surgical blades Core RequirementHRC 58–62 with excellent edge retention and high wear resistance for precision blade applications. |  |
6Cr13 offers high hardness, stable heat treatment performance, and cost-effective cutting efficiency for razor and surgical blades.
Due to its high hardness, 6Cr13 is less suitable for impact-loaded or high-toughness applications.
We use ultra-fine grain control and low inclusion technology to improve consistency and reduce quenching crack risks.
Same “420J2,” completely different service life.
· Inclusion content
· Carbide segregation
· Material cleanliness
Every batch includes ASTM E45 inclusion ratings and grain size reports.
Different grades and section sizes require different quenching and tempering processes.
We provide customized heat-treatment process cards based on part size and furnace type.
If you need both HRC 55 and 100-hour salt spray resistance, martensitic stainless steel may not be enough.
For highly corrosive environments, consider austenitic or duplex stainless steel instead.
High-carbon martensitic grades can dramatically increase machining costs.
Free-machining versions such as 410F and 420F are available for improved efficiency.
We do not sell “universal materials.”
Instead, we simplify choices based on actual application needs.
We ask customers four questions:
1. What is the operating environment?
2. What type of stress or wear is involved?
3. What precision level is required?
4. Is material price or lifecycle cost more important?
Then we provide:
· 2–3 recommended grades with pros/cons comparison
· Heat-treatment recommendations
· Estimated hardness and distortion range
· Suitable material forms
Starting from just 10 kg for process validation.
If you are selecting materials for:
· Industrial blades
· Precision mechanical components
· High-hardness wear-resistant parts
· Medical devices
· Springs or elastic components
feel free to provide:
· Application details
· Hardness requirements
· Corrosion exposure conditions
· Machining methods
Even a simple drawing or description is enough.
We will help match the most suitable martensitic stainless steel solution and provide a customized:
“Material Selection & Process Recommendation Report.”
