440C STAINLESS STEEL | 1.4125 | SUS440C Supplier for Bulk Orders
1.4125 / SUS440C Round Bar & Plate | MOQ 5 Tons | Export Mill Length 2–5.5m
440C stainless steel is a high-carbon, high-chromium martensitic stainless steel. It belongs to the 400 series of stainless steels, which are generally magnetic. In the medical field, 440C steel is widely used for manufacturing surgical knives and other medical instruments. It is also used in industry to manufacture corrosion-resistant plastic and rubber molds.
440C Stainless Steel Supply Overview
| Calificación | 440C STAINLESS STEEL | 1.4125 | SUS440C |
| Condiciones de entrega | Totalmente recocido (estado blando para el mecanizado) |
| Formularios disponibles | Barra redonda / Barra plana / Placa / Bloque forjado |
| Capacidad de producción mensual | Aproximadamente 1000 toneladas métricas |
| Cantidad de exportación recomendada | Contenedor completo de 20GP (~26 toneladas) |
| Cantidad mínima de pedido | 5 toneladas |
| Plazo de entrega (con existencias de lingotes) | Aproximadamente 20 días |
| Plazo de entrega (fundición reciente) | 30–45 días |
| Plazo de entrega (Grado ESR) | Aproximadamente 60 días |
| Inspección | Equipo interno de pruebas ultrasónicas + Inspección por terceros disponible |
| Documentación | MTC (EN 10204 3.1) + Informe UT |
Why Global Distributors Source 440C from Aobo Steel
- Suministro mensual continuo de alrededor de 1000 toneladas
- Cantidad mínima de pedido (MOQ) a partir de 5 toneladas para pedidos al por mayor.
- Longitudes de barras y placas optimizadas para contenedores
- Se admiten tamaños mixtos para la carga de exportación.
- Entrega recocida para mecanizado posterior
- Abastecimiento estable a través de socios de cadena de suministro integrados
- Inspección UT disponible para SEP 1921-82 D/d o E/e
- Trazabilidad del MTC y del lote con cada envío
- Seguimiento del número de lote para el control de pedidos
- Opciones de superficie negra, torneada y pulida
- Embalaje a granel para exportación marítima
- Ruta de conversión clara a la página dedicada al suministro a granel.
Producción estable para un suministro a granel a largo plazo
- Ciclos de producción continuos para la reposición de inventario.
- El proceso ESR (refundición por electroescoria) está disponible bajo petición.
- Suministro estable de aleaciones para reducir el riesgo de interrupción del suministro.
- Trazabilidad completa del lote vinculada al número de colada original.
Available 440C Stainless Steel Forms
Control de calidad para pedidos al por mayor
Cada lote de acero para herramientas suministrado por Aobo Steel se verifica antes del envío para garantizar la precisión del grado, la integridad interna y la trazabilidad de los pedidos a granel.
- Composición química verificada mediante un espectrómetro.
- Pruebas ultrasónicas disponibles (SEP 1921-82)
- Entregado en estado recocido esferoidizado
- Certificado de prueba de fábrica (EN 10204 3.1) con número de colada
- Inspección dimensional y superficial antes del envío.
Embalaje para exportación y carga de contenedores
- Embalaje profesional apto para exportación marítima
- Carga de 20GP optimizada hasta ~26 toneladas
- Se admiten grados y tamaños mixtos.
- Protección anticorrosión para largos tránsitos marítimos
Para envíos internacionales, se recomienda encarecidamente la carga de contenedores completos para garantizar la rentabilidad y una tramitación aduanera más ágil.
1. Applications
- Herramientas de corte
- Bearings
- Plastic Mold Materials
- Valve Parts
- Gears, Shafts, Cams
- Surgical and Dental Instruments
- Springs
- Medical Applications
- Wear-Resistant Applications
- Automotive Industry
- Hardware
2. 440C Stainless Steel Composition
| Carbon (C) | Cromo (Cr) | Manganeso (Mn) | Silicon (Si) | Molibdeno (Mo) | Phosphorus (P) | Sulfur (S) |
| 0.95 – 1.20 | 16.0 – 18.0 | 1.00 max | 1.00 max | 0.75 max | 0.040 max | 0.030 max |
3. 440C Stainless Steel Properties
3.1 Mechanical Properties
| Condition/Type | Tensile Strength (ksi/MPa) | Yield Strength (0.2% Offset) (ksi/MPa) | Elongation in 2″ / 50mm (%) |
|---|---|---|---|
| Annealed | 110 ksi (758 MPa) (Min 110 ksi / 758 MPa for bar) | 65 ksi (448 MPa) (Min 65 ksi / 448 MPa for bar) | 14% (Min 14% for bar) |
| Heat Treated / Hardened | 285 ksi (1965 MPa) | 275 ksi (1896 MPa) | 2% |
| Cold Finished Bar | Minimum 125 ksi (862 MPa) | Minimum 100 ksi (689 MPa) | Minimum 7% |
| Annealed Wire | Minimum 140 ksi (965 MPa) | – | Minimum 13% |
| Cold Heading Wire | Typical 110 ksi (760 MPa) | – | – |
| Lightly Drafted Wire | Typical 120 ksi (830 MPa) | – | – |
| MIM (Metal Injection Molded) 440C | 876 MPa (after heat treatment) | – | – |
3.2 Physical & Thermal Properties
| Propiedad | Value |
|---|---|
| Toughness (Heat Treated) | 5 ft-lb |
| Módulo de elasticidad | 29 x 10^6 psi (Approx. 200 GPa) |
| Specific Heat (32-212°F) | 0.11 Btu/lb·°F |
| Density | Approx. 0.29 lb/in^3 (8.02 g/cm^3) |
| Thermal Conductivity (20°C) | 29.3 W/(m·K) |
| Coefficient of Linear Thermal Expansion | Approx. 10.5 x 10^-6 K^-1 (Over ranges: 20-100°C, 20-200°C, 20-300°C, 20-500°C) |
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4. Heat treatment
The heat treating of 440C stainless steel, like other martensitic stainless steels, typically involves austenitizing, temple, and tempering. The process aims to transform the steel into a martensitic microstructure, which is then tempered to optimize its balance of hardness, strength, ductility, and corrosion resistance.
4.1 Austenitizing(hardening)
The austenitizing temperature is 925 to 1065 °C (1700 to 1950 °F). We recommend 1038°C (1900°F) because we believe it provides the best hardness and corrosion resistance. Additionally, we suggest preheating the material to 650°C (1200°F) before this step to minimize distortion, warping, or cracking from high thermal gradients during rapid heating or quenching. Soaking time should be sufficient to ensure carbides dissolve into the austenite, which can be slower than in plain carbon steels due to the presence of chromium.
4.2 Quenching
Following austenitizing, 440C steel is typically quenched in air or oil. Oil quenching at temperatures such as 1038°C (1900°F) or 1040°C (1900°F) is a common choice. After quenching, the steel transforms into martensite, a hard yet brittle structure.
4.3 Tempering
The step following quenching is tempering, which aims to reduce hardness, enhance toughness and ductility, and relieve internal stress.
The tempering temperature is 392°F to 662°F (200°C to 350°C). Different tempering temperatures result in varying hardness levels, as follows:
| Temperatura (°C) | Temperature (°F) | Dureza (HRC) |
| 150 | 300 | 60 |
| 315 | 600 | 57 |
| 425 | 800 | 58 |
| 480 | 900 | 57 |
| 540 | 1000 | 55 |
It should be noted that tempering 440C stainless steel and similar high-carbon martensitic stainless steels in the range of 427 °C to 566 °C (800 °F to 1050 °F) will result in temper brittleness and reduced impact strength and corrosion resistance.
If tempering outside the aforementioned temperature range is necessary to enhance toughness, we recommend a tempering temperature of 593°C (1100°F) or higher. Tempering at this temperature improves impact strength and corrosion resistance but sacrifices some hardness.
4.4 Special Considerations in 440C Steel Heat Treatment
- Preheating: Before the main hardening(austenitizing) process, we suggest preheating 440C stainless steel to approximately 650°C (1200°F). This helps to ensure a more uniform temperature distribution and minimize thermal shock during the subsequent austenitizing stage.
- Slow Cooling After Forging: For high-carbon steels such as 440C, we recommend slow cooling after forging, or intermittent cooling, which involves cooling to 150-250°C, reheating to approximately 650°C, and then final cooling. This helps prevent cracking and the formation of grain boundary carbides.
- Managing Retained Austenite: As-quenched 440C steel can sometimes contain a significant amount of retained austenite (potentially 20-30% by volume). If not addressed, this retained austenite can transform spontaneously over time, leading to dimensional changes and an increased risk of cracking. Performing a subzero cold treatment after quenching can effectively transform this retained austenite into untempered martensite. This cold treatment must be followed by at least one standard tempering cycle to temper the newly formed martensite and relieve internal stresses.
- Post-Weld Heat Treatment (PWHT): For welded 440C components, PWHT is almost always necessary. This treatment serves to temper the martensite formed in the weld and heat-affected zone and to relieve residual stresses. The PWHT temperature range for 440C is 480°C to 750°C (895°F to 1380°F).
5. Equivalent Grades
- DIN EN (Europe): 1.4125 (X105CrMo17)
- JIS (Japan): SUS440C
- ISO: X105CrMo17
- GB (China): 9Cr18Mo or 95Cr18