Within the stainless steel family, martensitic stainless steel, with its heat-treatable strengthening properties, holds a significant position in machinery manufacturing, hardware tools, and kitchen and bathroom equipment. 410 and 420 are two classic and widely used grades within this category. While both belong to the martensitic stainless steel category and share the core advantages of high strength and quenchability, subtle differences in key chemical compositions lead to significant variations in hardness, corrosion resistance, processing performance, and applicable scenarios.
A thorough understanding of the differences in characteristics between 410 and 420 stainless steel is crucial for accurately matching production needs and optimizing product performance and cost. This article will provide a detailed comparison from the perspectives of chemical composition, core properties, processing technology, and application scenarios, offering clear guidance for material selection and application practices in related fields.
Comparison of Chemical Composition
| Element | AISI 410 | AISI 420 | Differences |
| Carbon (C) | 0.08-0.15% | ≥0.15% | Key difference: Higher carbon content (420) is the basis for improved hardness and strength. |
| Chromium (Cr) | 11.5%-13.5% | 12.0%-14.0% | Similar, provides basic corrosion resistance. |
| Others | Si≤1.00% Mn≤1.00% P≤0.04% S≤0.03% | Si≤1.00% Mn≤1.00% P≤0.04% S≤0.03% | Basically the same |
The carbon content of 420 is significantly higher than that of 410, which allows 420 to achieve higher hardness and wear resistance through heat treatment (quenching + tempering), but at the same time reduces its toughness and weldability.
Key Performance Comparison
| Property | AISI 410 | AISI 420 |
| Corrosion resistance | Average | Average |
| Hardness | HRC 40-45 | HRC 50-55 |
| Toughness | Good | Poor |
| Weldability | Good | Poor |
| Wear resistance | Average | Excellent |
| Heat treatment | can be hardened by quenching, but its hardening capacity is limited. | strongly relies on heat treatment to achieve its high hardness properties. |
| Polishability | Average | Excellent |
| Machinability | Good | Average |
Heat Treatment Process Comparison
| Process | AISI 410 | AISI 420 | Difference Explanation |
| Quenching temperature | 950-1050°C | 980-1040°C | For 420 steel, the quenching temperature should be slightly higher to ensure full austenitization. |
| Tempering temperature | 650-750°C (high temperature) | 150-400°C (low temperature) | 410 uses high-temperature tempering to achieve a balance between strength and toughness. 420 uses low-temperature tempering to retain high hardness. |
| Typical processes | Quenching + high-temperature tempering → sorbite structure | Quenching + low-temperature tempering → tempered martensite structure | The difference in microstructure determines the final properties. |
Typical Application Scenarios Comparison
| AISI 410 | AISI 420 |
| General-purpose corrosion-resistant structural components: valves, pump parts, fasteners, shafts | High-hardness, wear-resistant parts: surgical instruments, scalpels, razor blades, cutting blades |
| Turbine blades, boiler components (medium-temperature environment) | Plastic molds (require polishing and moderate corrosion resistance) |
| Cutlery, low-load knives | Bearings, measuring tools |
| Offshore oil platform equipment (requiring certain corrosion resistance and strength) | High-end kitchenware (such as high-end dinner knives) |
| Core positioning: Balanced overall performance (strength, toughness, corrosion resistance) | Core positioning: Pursuing high hardness and wear resistance, with non-extreme requirements for corrosion resistance. |
Summary: “Twins” with their own strengths
Key Differences and Applicable Principles:
- 410 Steel: A “Balanced Performer,” with moderate carbon content, a balance between strength and toughness, good machinability and weldability, suitable for industrial structural components requiring comprehensive performance.
- 420 Steel: A “Hardness Specialist,” with a high-carbon formula, outstanding hardness after heat treatment, and excellent wear resistance, suitable for “hardcore” applications such as cutting tools and precision parts.
Selection Recommendations
- Application Priorities: Choose 420 for high hardness and wear resistance; choose 410 for toughness and machinability.
- Cost Priorities: 420 steel is generally more expensive than 410 steel, mainly due to its higher carbon content, stricter heat treatment requirements, and its market positioning as “cutting tool grade” steel. Therefore, 410 steel offers better cost-effectiveness in industrial structural applications, while 420 steel is more cost-effective in specialized fields such as cutting tools.
