Acier inoxydable, martensitique
420 Stainless Steel (S42000) Bar
Une barre d'usinage martensitique dont l'usinabilité est améliorée par l'ajout de soufre.
As with most other free-machining stainless steels the improvement in machinability is achieved by addition of sulphur which forms manganese sulphide inclusions; this sulphur addition also lowers the corrosion resistance, weldability and formability to below that of its non-free machining equivalent Grade 410.
420 stainless steel is a high-carbon martensitic stainless steel known for its high hardness, good wear resistance, and moderate corrosion resistance. It is commonly used in applications that require cutting edges, wear resistance, and the ability to be hardened.
Martensitic stainless steels are optimised for high hardness, and other properties are to some degree compromised. Fabrication must be by methods that allow for poor weldability and usually also allow for a final harden and temper heat treatment. Corrosion resistance is lower than the common austenitic grades, and their useful operating temperature range is limited by their loss of ductility at sub-zero temperatures and loss of strength by over-tempering at elevated temperatures.
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420 Stainless Steel Related Specifications
| Système / Standard | Pays / Région | Grade / Désignation |
| AISI | ÉTATS-UNIS | 420 |
| Nations Unies | International | S42000 |
| FR / Numéro de dossier. | Europe | 1.4021 |
| Nom EN | Europe | X20Cr13 |
| ASTM A276 | ÉTATS-UNIS | Type 420 (bars, shapes) |
| ASTM A314 | ÉTATS-UNIS | Type 420 (forged/rolled bars) |
| ASTM A743 | ÉTATS-UNIS | CA-40 (cast 420-type) |
| RU | Chine | 2Cr13 |
| ISJ | Japon | SUS420J1 / SUS420J2 |
| BS | Royaume-Uni | 420S37 / 420S45 |
Propriétés
Composition chimique
1.4021 Steel
EN 10088-3
| Élément chimique | % Présent |
| Carbone (C) | 0.16 - 0.25 |
| Chrome (Cr) | 12.00 - 14.00 |
| Manganèse (Mn) | 0.00 - 1.50 |
| Silicium (Si) | 0.00 - 1.00 |
| Phosphore (P) | 0.00 - 0.04 |
| Soufre (S) | 0.00 - 0.03 |
| Fer (Fe) | Équilibre |
Propriétés mécaniques
Bar Up to 160mm Dia / Thickness
EN 10088-3
| Propriété mécanique | Valeur |
| Limite d'élasticité conventionnelle | 500 - 600 MPa |
| La résistance à la traction | 700 - 950 MPa |
| Allongement A | 12 - 13 % |
Propriétés physiques générales
| Propriété physique | Valeur |
| Densité | 7.75 g/cm³ |
| Dilatation thermique | 10.3 x 10-6/K |
| Module d'élasticité | 200 GPa |
| Conductivité thermique | 24.9 W/m.K |
| Résistivité électrique | 0.55 x 10-6 Ω .m |
Applications of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son excellent hardness, good wear resistance, and moderate corrosion resistance. Il est largement utilisé dans les applications nécessitant cutting performance, precision, and durability.
1. Cutting Tools and Blades
Knives, scissors, and surgical instruments
Razors and trimming tools
Industrial cutting and shaping tools
2. Mechanical and Industrial Components
Gears, shafts, and bushings
Bearings and valve components
Dies, molds, and wear-resistant parts
3. Automotive and Aerospace Applications
High-strength fasteners and pins
Springs and precision components
Components requiring wear resistance under stress
4. Household and Decorative Applications
Kitchen knives and utensils
Tools and hardware exposed to moderate wear and moisture
Decorative fittings requiring moderate corrosion resistance
Résumé
420 stainless steel combines high hardness, good wear resistance, and moderate corrosion resistance, ce qui le rend idéal pour cutting tools, precision mechanical components, industrial parts, and household items. It is particularly suitable for applications requiring sharp edges, durability, and dimensional stability.
Characteristics of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son high hardness, excellent wear resistance, and moderate corrosion resistance. Il est largement utilisé dans les applications nécessitant cutting performance, durability, and dimensional stability.
1. Composition chimique
Carbone : 0.15–0.40% – provides high hardness and wear resistance
Chrome 12–14% – gives corrosion resistance and hardenability
Minor elements such as manganese, silicon, and nickel enhance mechanical properties
2. Hardness and Mechanical Properties
Peut être trempé à 50–55 HRC après traitement thermique
Excellent tensile strength and wear resistance
Moderate ductilité et ténacité, designed primarily for hard, wear-resistant applications
3. Résistance à la corrosion
Résistance modérée à oxydation et environnements légèrement corrosifs
Better than carbon steels but lower than austenitic stainless steels (e.g., 304, 316)
Convient à kitchen tools, industrial components, and precision parts exposed to mild moisture or chemical exposure
4. Machinability and Fabrication
Machinable état recuit
Peut être polished to a bright finish for aesthetic or functional applications
Welding is possible but may reduce hardness in the heat-affected zone; post-weld heat treatment is recommended
5. Applications
Knives, scissors, and cutting tools
Gears, shafts, bearings, and wear-resistant mechanical components
Springs, dies, molds, and precision engineering parts
Kitchen utensils and decorative hardware
Résumé
420 stainless steel is characterized by high hardness, excellent wear resistance, and moderate corrosion resistance. Sa combinaison de propriétés en fait un choix idéal pour cutting tools, precision mechanical components, industrial parts, and household items requis durability and dimensional stability.
Informations supplémentaires
Fabrication
Fabrication of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son good hardness, wear resistance, and moderate corrosion resistance. Fabrication requires careful handling due to its high carbon content and potential for hardening during processing.
1. Formation
Travail à chaud :
Best performed in the état recuit.
Température typique de travail à chaud : 900–1050°C (1650–1920°F).
Avoid overheating to prevent grain growth and loss of toughness.
Travail à froid :
Possible in the état recuit.
Cold deformation increases strength through écrouissage, but excessive deformation can cause cracking.
Suitable for bending, stamping, and rolling thin sections.
2. Usinage
Machining is easier in the annealed condition.
Hardened 420 is difficile à usiner, requiring carbide tooling and proper cooling.
Use cutting fluids to reduce heat and maintain tool life.
3. Soudure
Welding is limited due to high carbon content.
Preheating and post-weld stress relief are recommended to prevent cracking.
Utiliser matériaux de remplissage homologués ou à faible émission de carbone for better corrosion resistance and strength.
4. Traitement thermique
Annealing is used before fabrication to soften the steel for forming or machining.
Hardening followed by tempering is applied after fabrication to achieve desired hardness and wear resistance.
5. Traitement de surface
Polishing or passivation can improve corrosion resistance and appearance.
Surface finishing is particularly important for cutlery, surgical instruments, and precision components.
6. Applications bénéficiant de la fabrication
Cutlery and knives
Surgical instruments and medical tools
Industrial tooling and valve components
Precision mechanical parts requiring wear resistance
Résumé
420 stainless steel fabrication is typically performed in the état recuit to allow hot or cold forming, machining, and limited welding. Post-fabrication traitement thermique et finition de surface assurer l'optimal hardness, wear resistance, and moderate corrosion resistance, making 420 ideal for cutting tools, surgical instruments, and precision mechanical components.
Soudabilité
Weldability of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son good hardness, wear resistance, and moderate corrosion resistance. Welding this steel requires care due to its high carbon content and tendency to harden, which can lead to cracking if not properly managed.
1. Considérations Générales
High carbon content increases the risk of cracking during welding.
Preferred welding in the annealed or soft condition to reduce brittleness.
Preheating and post-weld heat treatment are recommended to minimize residual stresses and prevent martensitic hardening.
2. Préchauffage
Preheat to 150–250°C (300–480°F) before welding.
Helps reduce thermal stress and the risk of cracking dans la zone affectée par la chaleur (ZAC).
3. Méthodes de soudage
TIG (GTAW) and MIG (GMAW) are commonly used for precision welds.
Soudage à l'électrode enrobée (SMAW) is possible but requires skilled control.
Utiliser électrodes à bas hydrogène pour réduire le risque de fissures.
4. Matériaux de remplissage
Utiliser matching 420 filler metal for best corrosion resistance and mechanical properties.
Lower carbon or martensitic stainless fillers can be used to reduce cracking risk.
5. Traitement thermique après soudage
Stress relief or tempering after welding is critical to restore toughness.
Avoid quenching immediately after welding unless specifically required.
Typical post-weld tempering: 150–250°C (300–480°F) for 1–2 hours.
6. Limites
Soudure dans le hardened condition is not recommended.
Not suitable for applications requiring high corrosion resistance in welded joints without proper post-weld treatment.
Careful control of heat input is necessary to prevent distortion and cracking.
7. Applications
Welded components in cutlery and knives (annealed condition)
Light-duty industrial components
Mechanical parts requiring moderate corrosion resistance after welding
Résumé
420 stainless steel is weldable with caution, preferably in the état recuit. Approprié preheating, controlled welding, low-hydrogen filler, and post-weld tempering are essential to prevent cracking and ensure good mechanical properties. While weldability is limited compared to austenitic stainless steels, it can be effectively welded for cutlery, tools, and moderate-duty mechanical applications.
Usinabilité
Machinability of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son good hardness, wear resistance, and moderate corrosion resistance. Its machinability depends heavily on its traitement thermique, with the annealed state being much easier to machine than the hardened state.
1. Caractéristiques générales
État recuit :
Machinable with standard high-speed steel (HSS) or carbide tools.
Fournit bonne finition de surface et le contrôle dimensionnel.
Hardened condition:
Machining is difficult due to high hardness (up to ~50 HRC).
Exige carbide tooling, slow cutting speeds, et ample coolant.
Strain hardening: High-carbon content may cause work hardening during machining.
2. Paramètres de coupe recommandés
Vitesse de coupe Lower speeds compared to mild steels to prevent tool wear.
Vitesse d'avance : Moderate, to balance surface finish and tool life.
Profondeur de coupe : Shallow cuts in hardened material to avoid excessive tool stress.
Liquide de refroidissement : Use water-soluble oil or cutting fluid to reduce heat and friction.
3. Outillage
Hardened 420: Best machined with carbide or ceramic tools.
Annealed 420: Can be machined with high-speed steel (HSS) tools.
Filetage et taraudage : Use slow speeds and sharp tooling to prevent galling.
4. Advantages
Achieves bonne finition de surface in the annealed condition.
Allows precise machining of complex shapes before hardening.
Hardened 420 retains shape and wear resistance after final machining and polishing.
5. Limites
High carbon content reduces machinability in hardened condition.
Excessive heat during machining may cause tool wear or surface discoloration.
Exige un examen attentif cooling and cutting control in hardened condition.
6. Applications Benefiting from Machining
Cutlery and knives
Surgical instruments
Precision components such as valve parts and industrial tools
Résumé
420 stainless steel is moderately machinable in the annealed condition et difficult to machine when hardened. Approprié tool selection, cutting speeds, feed rates, and coolant use sont essentiels à réaliser accurate dimensions, good surface finish, and tool longevity, ce qui le rend idéal pour cutlery, surgical instruments, and precision industrial components.
Résistance à la corrosion
Corrosion Resistance of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son good hardness and wear resistance. Sa résistance à la corrosion est modéré, higher than ordinary carbon steels but lower than austenitic stainless steels such as 304 or 316.
1. General Corrosion Properties
Fournit moderate resistance to atmospheric corrosion and mild oxidizing environments.
Sous susceptible de pitting and rusting in chloride-rich or marine environments.
Polished surfaces improve corrosion resistance by reducing surface roughness.
2. Facteurs affectant la résistance à la corrosion
Carbon content: Higher carbon improves hardness but slightly reduces corrosion resistance.
Finition de surface : Smooth, polished, or passivated surfaces significantly improve resistance.
Traitement thermique : Hardened 420 may be more prone to corrosion due to microstructural changes.
Environnement Best suited for dry or mildly corrosive environments; avoid prolonged exposure to saltwater or acidic conditions.
3. Amélioration de la résistance à la corrosion
Polissage : Reduces surface roughness, minimizing sites for corrosion initiation.
Passivation : Treatment with nitric or citric acid forms a protective oxide layer.
Proper maintenance: Regular cleaning prevents accumulation of corrosive agents.
4. Applications bénéficiant de la résistance à la corrosion
Cutlery, knives, and surgical instruments in low-corrosion environments
Industrial tools and precision components exposed to mild conditions
Valve components and fittings in non-marine environments
5. Limites
Ne convient pas pour environnements marins ou hautement acides sans revêtements protecteurs.
Prolonged exposure to moisture can lead to rust and pitting.
Welding without proper care may reduce corrosion resistance in the heat-affected zone.
Résumé
420 stainless steel offers résistance modérée à la corrosion, approprié pour cutlery, surgical instruments, and industrial tools in mild environments. Its corrosion resistance can be enhanced through polishing, passivation, and careful maintenance, mais c'est not recommended for prolonged exposure to aggressive or marine environments.
Travail à froid
Cold Working of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son good hardness, wear resistance, and moderate corrosion resistance. Cold working is a key process for shaping and strengthening this steel, but it must be performed with care due to its high carbon content and work-hardening tendency.
1. Caractéristiques générales
Le travail à froid augmente résistance et dureté through écrouissage.
Excessive cold working can lead to cracking, especially in hardened or heat-treated conditions.
Convient à bending, rolling, stamping, and drawing in the annealed state.
2. Pratiques recommandées
Perform cold working in the état recuit to reduce brittleness.
Utiliser déformation progressive rather than aggressive forming to prevent fractures.
Lubrification during forming helps reduce surface defects and tool wear.
Intermédiaire recuit may be necessary for extensive deformation to restore ductility.
3. Effets du travail à froid
Increased hardness and strength proportional to the amount of deformation.
Ductilité réduite as work hardening progresses.
Enhanced surface finish and dimensional precision in certain forming processes.
4. Applications bénéficiant de l'emboutissage par déformation à froid
Cutlery and knives (pre-hardening shaping)
Surgical instruments
Springs and small mechanical components
Precision tools and industrial fittings
5. Limites
Hardened or overworked 420 is difficult to form and prone to cracking.
Exige un examen attentif contrôle de la température and potential recuit intermédiaire for large deformations.
Cold working alone cannot achieve final maximum hardness—post-working traitement thermique is usually required.
Résumé
Cold working of 420 stainless steel is most effective in the annealed condition, allowing shaping through bending, rolling, stamping, and drawing. It increases strength and hardness but reduces ductility, so careful control of deformation and intermediate annealing is essential. After cold working, traitement thermique is typically applied to achieve final hardness and wear resistance, making it ideal for cutlery, surgical instruments, springs, and precision mechanical components.
Traitement thermique
Heat Treatment of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son high hardness, wear resistance, and moderate corrosion resistance. Heat treatment is essential to achieve optimal hardness, strength, and dimensional stability.
1. Recuit
Objet : Ramollit l'acier pour le formage, l'usinage ou le travail à froid.
Traitement :
Chauffer à 800–900°C (1470–1650°F).
Hold at temperature to allow uniform microstructure.
Slow cooling in the furnace or in still air.
Résultat : Steel becomes soft, ductile, and machinable.
2. Hardening (Quenching)
Objet : Increases hardness and wear resistance.
Traitement :
Chauffer à 980–1050°C (1800–1920°F) until fully austenitized.
Quench in air, oil, or water depending on section size.
Résultat : Martensitic structure is formed, producing high hardness (~50 HRC).
3. Tempering
Objet : Relieves stresses and improves toughness while maintaining hardness.
Traitement :
Heat quenched steel to 150–250°C (300–480°F).
Hold for 1–2 hours, then air cool.
Effet Reduces brittleness, enhances wear resistance, and stabilizes the martensitic structure.
4. Effets du Traitement Thermique
Annealed 420: Souple, ductile, apte au façonnage et à l'usinage.
Hardened 420: High hardness and wear resistance, suitable for cutting tools and knives.
Tempered 420: Balanced hardness and toughness, less prone to cracking during service.
5. Applications of Heat-Treated 420 Stainless Steel
Cutlery and knives
Surgical instruments
Outils industriels et composants de précision
Wear-resistant parts
6. Limites
Excessive tempering may reduce hardness and wear resistance.
Overheating during quenching can cause distortion or cracking.
Heat-treated 420 should be handled carefully to maintain dimensional accuracy.
Résumé
The heat treatment of 420 stainless steel involves annealing, hardening, and tempering to achieve the desired combination of hardness, wear resistance, and toughness. Proper control of temperatures and times is critical, making it suitable for cutlery, surgical instruments, industrial tools, and precision wear-resistant components.
Résistance à la chaleur
Heat Resistance of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son high hardness, wear resistance, and moderate corrosion resistance. Sa résistance à la chaleur est limited compared to austenitic stainless steels such as 304 or 316.
1. Propriétés générales
Peut résister intermittent exposure to temperatures up to 315°C (600°F) without significant loss of mechanical properties.
Continuous exposure to high temperatures may lead to oxidation, scaling, and loss of hardness.
Retains moderate mechanical strength at moderately elevated temperatures but is not suitable for high-temperature service.
2. Effets des hautes températures
Perte de dureté Martensitic structure may soften if exposed to high heat.
Oxydation et calamine Occurs at elevated temperatures, particularly in air or oxidizing atmospheres.
Dimensional changes: Extended exposure to heat can cause minor distortion.
3. Considérations pratiques
Meilleur utilisé dans ambient to moderately elevated temperatures.
Déconseillé pour continuous service above 315°C (600°F).
Peut être heat treated to optimize hardness and wear resistance, but high service temperatures will reduce hardness over time.
4. Applications
Cutlery and knives (not exposed to extreme heat)
Surgical instruments and tools
Industrial tooling where high wear resistance is more critical than heat resistance
5. Summary
420 stainless steel has limited heat resistance, approprié pour moderate-temperature applications. C'est idéal pour cutting tools, knives, surgical instruments, and industrial components where hardness, wear resistance, and corrosion resistance are important, but it is not recommended for high-temperature or continuous heat applications.
Travail à chaud
Hot Working of 420 Stainless Steel
420 stainless steel est un high-carbon martensitic stainless steel connu pour son high hardness, wear resistance, and moderate corrosion resistance. Hot working is an important process to shape the steel before it is hardened, as it improves ductility and reduces the risk of cracking.
1. Lignes directrices générales
Hot working should be performed in the état recuit to prevent cracking.
Température typique de travail à chaud : 900–1050°C (1650–1920°F).
Avoid overheating, which can cause croissance du grain, reducing toughness.
2. Procédés courants de travail à chaud
Laminage à chaud : Used to form sheets, plates, and bars.
Forgeage à chaud : Shapes parts such as blades, tools, and industrial components.
Extrusion à chaud : Produces complex profiles and precision components.
3. Avantages du travail à chaud
Réduit force et dureté temporairement, allowing easier forming.
Minimise le risque de cracking or brittleness.
Promouvoir homogeneous microstructure throughout the workpiece.
4. Considérations post-usinage à chaud
Recuit May be necessary after hot working to relieve stresses.
Machining: Typically easier after hot working in the annealed condition.
Traitement thermique : Hardening and tempering applied afterward to achieve final hardness and wear resistance.
5. Limites
High-carbon content limits hot working compared to lower-carbon martensitic steels.
Exige careful temperature control to avoid surface oxidation or scaling.
Not suitable for shaping in the état de trempe complète.
6. Applications bénéficiant du travail à chaud
Industrial knives and blades
Surgical instruments
Wear-resistant tooling and components
Precision mechanical parts before final hardening
Résumé
Hot working of 420 stainless steel is performed in the état recuit at temperatures of 900–1050°C (1650–1920°F). It allows shaping through rolling, forging, or extrusion, reduces brittleness, and produces a homogeneous microstructure. After hot working, annealing, machining, and final heat treatment sont appliqués pour atteindre le résultat souhaité hardness, wear resistance, and mechanical properties for applications such as cutlery, surgical instruments, and industrial tools.
