SCM420 Carburizing Bearing Steel Capillary

SCM420 Carburizing Bearing Steel Capillary (Composition Spec) Product Information -:- For detailed product information, please contact sales. -: SCM420 Carburizing Bearing Steel Capillary (Composition Spec) Synonyms -:- For detailed product information, please contact sales. -:

SCM420 Carburizing Bearing Steel (Composition Spec) Product Information -:- For detailed product information, please contact sales. -: # **Product Technical Datasheet: SCM420 Carburizing Bearing Steel** ## **1. Product Overview** **SCM420** is a chromium‑molybdenum (Cr‑Mo) alloy steel, classified under the Japanese Industrial Standards (JIS) as a **carburizing (case‑hardening) steel**. It is specifically designed to achieve a high‑surface‑hardness, wear‑resistant case combined with a tough, ductile core through the carburizing heat treatment process. While not a dedicated bearing steel in the classical sense (like SAE 52100), SCM420 is extensively used for **bearings, gears, and transmission components** requiring exceptional surface durability and fatigue resistance under high contact stresses. The steel is supplied in the annealed or spheroidized condition to facilitate machining prior to heat treatment. ## **2. Governing International Standards** SCM420 is primarily defined by the **Japanese Industrial Standard JIS G 4105 – Chromium‑Molybdenum Steels**. Its closest international equivalents include: * **AISI / SAE:** 4120, 5120 (approximate equivalents with slight compositional variations) * **DIN / EN:** 1.7213 / 20CrMo5 (Europe) * **GB:** 20CrMo (China) * **ISO 683‑11:** Designated for case‑hardening steels. ## **3. Chemical Composition** The composition is optimized for deep‑hardenability and core strength after carburizing. Standard composition ranges (in weight %) are: * **Carbon (C):** 0.18 – 0.23% * **Silicon (Si):** 0.15 – 0.35% * **Manganese (Mn):** 0.60 – 0.85% * **Phosphorus (P):** ≤ 0.030% * **Sulfur (S):** ≤ 0.030% * **Chromium (Cr):** 0.90 – 1.20% * **Molybdenum (Mo):** 0.15 – 0.30% **Key Feature:** The strategic combination of **Chromium and Molybdenum** ensures sufficient hardenability for a deep, hardened case and a strong core, even in moderately sized components, while maintaining good machinability in the annealed state. ## **4. Typical Properties & Heat Treatment Response** ### **As‑Supplied Condition (Annealed):** * **Hardness:** 140 – 180 HBW * **Tensile Strength:** ~ 500 – 650 MPa * **Microstructure:** Ferrite + Pearlite (spheroidized for optimal machinability) ### **After Carburizing & Heat Treatment:** A typical process sequence involves: Carburizing → Quenching → Low‑Temperature Tempering. * **Case Properties:** * **Surface Hardness:** 58 – 63 HRC * **Effective Case Depth (ECD):** Variable, typically 0.5 – 1.5 mm (0.020” – 0.060”) at 550 HV. * **Microstructure:** High‑carbon martensite with retained austenite and fine carbides. * **Core Properties:** * **Hardness:** 30 – 45 HRC (depending on component size and quench severity) * **Microstructure:** Low‑carbon martensite or bainite, providing high strength and toughness. * **Core Tensile Strength:** 1000 – 1300 MPa (approx.) ### **Physical Properties:** * **Modulus of Elasticity:** 205 GPa * **Density:** 7.85 g/cm³ * **Coefficient of Thermal Expansion:** ~ 11.5 x 10⁻⁶/°C (20–100°C) ## **5. Key Characteristics & Engineering Advantages** * **Excellent Case Hardness & Wear Resistance:** The carburized case provides outstanding resistance to abrasive wear, pitting, and rolling contact fatigue. * **Strong & Tough Core:** The alloying elements ensure a high‑strength core that supports the hard case, resisting bending and impact loads. * **Good Hardenability:** The Cr‑Mo combination allows for effective case hardening of components with moderate cross‑sections, providing a good depth of hardening with oil quenching. * **Superior Fatigue Strength:** The compressive residual stresses in the carburized case significantly enhance bending and contact fatigue life. * **Good Machinability:** In the properly annealed or spheroidized condition, it offers good machinability for producing precise components before heat treatment. * **Cost‑Effective Performance:** Offers a favorable balance of performance and cost compared to higher‑alloy carburizing steels like SCM822 or SNCM420. ## **6. Typical Applications** SCM420 is widely used for high‑performance, case‑hardened mechanical components, particularly in automotive and industrial machinery: * **Bearings:** Needle roller bearing races, slewing rings, cam followers, and large‑sized rolling element bearings. * **Gears & Transmission:** Automotive transmission gears (gears, synchronizer hubs), differential pinions, industrial gearbox gears, and shafts. * **Automotive Components:** Crankshafts, camshafts, piston pins, and universal joint yokes. * **General Machinery:** Pins, bushings, couplings, and heavily loaded shafts requiring a wear‑resistant surface. * **Oil & Gas:** Components for downhole tools and valves requiring surface hardness. ## **7. Summary** **SCM420** is a versatile and reliable **chromium‑molybdenum carburizing steel** that delivers an optimal combination of a **super‑hard, wear‑resistant surface** and a **tough, load‑bearing core**. Its well‑balanced chemistry makes it a prime choice for manufacturing critical, fatigue‑resistant components like bearings and gears, especially where cost‑performance ratio is a key consideration. Its standardized specifications under JIS and equivalence to major international grades ensure its global availability and consistent quality for demanding engineering applications. -:- For detailed product information, please contact sales. -: SCM420 Carburizing Bearing Steel (Composition Spec) Specification Dimensions Size： Diameter 20-1000 mm Length <5864 mm Size:We can customized as required Standard： Per your request or drawing We can customized as required Properties（Theoretical） Chemical Composition -:- For detailed product information, please contact sales. -: SCM420 Carburizing Bearing Steel (Composition Spec) Properties -:- For detailed product information, please contact sales. -:

Applications of SCM420 Carburizing Bearing Steel Capillary (Composition Spec) -:- For detailed product information, please contact sales. -: Chemical Identifiers SCM420 Carburizing Bearing Steel Capillary (Composition Spec) -:- For detailed product information, please contact sales. -:

Packing of SCM420 Carburizing Bearing Steel Capillary (Composition Spec) -:- For detailed product information, please contact sales. -: Standard Packing: -:- For detailed product information, please contact sales. -: Typical bulk packaging includes palletized plastic 5 gallon/25 kg. pails, fiber and Steel Capillary drums to 1 ton super sacks in full container (FCL) or truck load (T/L) quantities. Research and sample quantities and hygroscopic, oxidizing or other air sensitive materials may be packaged under argon or vacuum. Solutions are packaged in polypropylene, plastic or glass jars up to palletized 2335 gallon liquid totes Special package is available on request. E FORUs’ is carefully handled to minimize damage during storage and transportation and to preserve the quality of our products in their original condition