SUS 440C Stainless Steel Round Bar Supplier | S44004 1.4125 High Hardness Rod

Overview

SUS 440C (UNS S44004 / DIN 1.4125) is a high-carbon martensitic stainless steel known for achieving the highest hardness of all stainless steels — 58-60 HRC after quenching and tempering — combined with good corrosion resistance and excellent wear resistance. As a leading SUS 440C round bar supplier, Vertex Alloy provides diameters from 3 mm to 300 mm in annealed, quenched & tempered, peeled, ground and polished conditions, compliant with ASTM A276, AMS 5630 and JIS G4303, with EN 10204 3.1 mill test certificates. 440C round bars are the first choice for ball and roller bearings, premium knife blades, surgical instruments, valve seats and balls, pump shafts and plastic mold inserts. Free-machining 440F and cross-rolled forged bars available on request. Contact us for the latest price list and stock sizes.

Description (English)

SUS 440C (UNS S44004, DIN 1.4125) is a high-carbon martensitic stainless steel that achieves the highest hardness of any stainless steel — up to 60 HRC after quenching and tempering — combined with good corrosion resistance in fresh water and mild media. Vertex Alloy supplies 440C round bars from 3 to 300 mm diameter in annealed, quenched & tempered, peeled, ground and polished conditions to ASTM A276 and AMS 5630, with EN 10204 3.1 certificates. Typical applications include ball and roller bearings, premium knife blades, surgical and dental instruments, valve seats and balls, pump shafts and plastic mold inserts. Free-machining 440F and low-carbon alternatives available on request.

Applications

SUS 440C Stainless Steel Round Bar Supplier | S44004 1.4125 High Hardness Rod is supplied for demanding applications such as Bearings, Cutlery, Medical, Valves, Molds, Aerospace, Marine, and Textile. These application areas rely on a carefully specified metal product that can be selected by grade, form, dimensions, and service requirements rather than by a generic material description. The listed applications provide practical context for engineers and purchasing teams reviewing this product: they indicate where corrosion resistance, strength, fabrication performance, or dimensional consistency may matter. Final suitability depends on the operating environment, design code, temperature, media, joining method, and applicable inspection requirements. Buyers can use the application information together with the grade and property data below to request a technically appropriate specification, finish, tolerance, and quantity from Vertex Alloy.

Key Mechanical & Physical Properties

SUS 440C Stainless Steel Round Bar Supplier | S44004 1.4125 High Hardness Rod is described using the available technical records rather than an assumed specification. The supplied data includes mechanical data including key c88120d971db, type mech_item, property Tensile Strength (Annealed), value ≥ 758 MPa, mechanical data including key c69a6214d972, type mech_item, property Yield Strength (Annealed), value ≥ 448 MPa, mechanical data including key ac9f639cfa26, type mech_item, property Elongation (Annealed), value ≥ 14 %, mechanical data including key 968a5d86f9b2, type mech_item, property Hardness (Annealed), value ≤ 255 HB, mechanical data including key 14a049d88f31, type mech_item, property Hardness (Quenched & Tempered), value ≥ 58 HRC, mechanical data including key 272ba24e882f, type mech_item, property Max Working Hardness, value 60 HRC, mechanical data including key 498b0623773e, type mech_item, property Impact Energy (Annealed), value ≥ 16 J, physical data including key 7aef5a7d7f86, type phys_item, property Density, value 7.74 g/cm³, physical data including key 07fe3d4ad526, type phys_item, property Melting Point, value 1370 – 1480 °C, physical data including key 4695269f80e7, type phys_item, property Specific Heat Capacity, value 460 J/(kg·K), physical data including key 555f5f32068c, type phys_item, property Thermal Conductivity, value 24.2 W/(m·K), physical data including key d91944af1073, type phys_item, property Electrical Resistivity, value 0.60 μΩ·m, physical data including key 6d6f0e67636f, type phys_item, property Elastic Modulus, value 200 GPa, physical data including key e467d74c7580, type phys_item, property Thermal Expansion (20–100 °C), value 10.2 × 10⁻⁶ /K, physical data including key 8ba97061a9be, type phys_item, property Magnetic, value Yes, composition data including key b216bfda291b, type composition_item, element C, value 0.95 – 1.20, composition data including key f60fd070e85d, type composition_item, element Si, value ≤ 1.00, composition data including key 3ecc1a072016, type composition_item, element Mn, value ≤ 1.00, composition data including key ff3b1d1fe59b, type composition_item, element P, value ≤ 0.040, composition data including key 597e6d5d0c60, type composition_item, element S, value ≤ 0.030, composition data including key b11494ce4546, type composition_item, element Cr, value 16.00 – 18.00, composition data including key b8a212b8799d, type composition_item, element Mo, value ≤ 0.75, composition data including key 0dea650e02d0, type composition_item, element Ni, value ≤ 0.60, and composition data including key ae76ada31423, type composition_item, element Fe, value Balance. Keeping these values visible helps a technical buyer compare the product with a drawing, purchase specification, or applicable standard before requesting a quotation. Mechanical values can guide early checks for strength and forming requirements, while physical values and composition details help with material identification, process planning, and service-environment review. Values should be confirmed against the latest mill certificate, heat or lot documentation, product condition, test method, and governing standard before production use. Vertex Alloy can review the required performance range and clarify which supplied values apply to the requested size and delivery condition.

Available Sizes & Forms

SUS 440C Stainless Steel Round Bar Supplier | S44004 1.4125 High Hardness Rod is listed in bar form with size information including Dia.3 – 300 mm, L1000 – 6000 mm, and Available on request. The size range is intended to help buyers screen availability and prepare an enquiry; it is not a substitute for a confirmed production schedule or tolerance agreement. When requesting this product, include thickness or diameter, width or length, cut-to-size needs, edge condition, surface finish, straightness, tolerance, quantity, and preferred packing. Dimensions may vary with grade, processing route, minimum order quantity, and mill capacity. Sharing the complete requirement allows Vertex Alloy to check whether the requested size can be supplied directly, cut from stock, or produced to order. The final commercial confirmation should state the agreed form, dimensions, tolerances, condition, inspection documents, and delivery terms.

Grade Compliance

SUS 440C Stainless Steel Round Bar Supplier | S44004 1.4125 High Hardness Rod carries the recorded grade references JIS SUS 440C, ASTM / AISI 440C / S44004, DIN / EN 1.4125 / X105CrMo17, GB 9Cr18Mo / 102Cr17Mo, and ISO X105CrMo17. These references give engineering and procurement teams a starting point for checking material identity, equivalent designations, and documentation requirements. A grade reference should always be read together with its applicable standard, product form, dimensional range, delivery condition, heat treatment, testing requirements, and revision level. Equivalent designations are not automatically interchangeable in every service, so the governing project specification remains controlling. Before order placement, confirm the required standard and certificate format, including chemical, mechanical, visual, dimensional, and any special testing requirements. Vertex Alloy can help compare the requested designation with the available product record and identify details that need confirmation from the producing mill.

Size Range

• Dia.3 – 300 mm
• L1000 – 6000 mm
• Available on request

Grade Specification

Chemical Composition

Mechanical Properties

Physical Properties

Applications

• Bearings
• Cutlery
• Medical
• Valves
• Molds
• Aerospace
• Marine
• Textile