Project Description
30Cr13 / AISI 420 Stainless Steel Seamless Tube
30Cr13 (also designated as 3Cr13, AISI 420, UNS S42000, SUS420J2, X30Cr13, 1.4028, and 30X13) is a martensitic stainless steel that delivers a compelling combination of high hardness, excellent wear resistance, and moderate corrosion resistance. With a carbon content of 0.26–0.35% and chromium at 12.0–14.0%, this grade can be heat-treated to achieve hardness levels up to 52 HRC — making it the hardest of the commonly used 13% chromium martensitic stainless steels. When supplied as a seamless tube, 30Cr13 offers exceptional dimensional precision and uniform mechanical properties across the wall section, characteristics that are critical for high-stress mechanical components operating in mildly corrosive environments.
Compared to its lower-carbon counterparts 12Cr13 (AISI 410) and 20Cr13 (AISI 420J1), 30Cr13 offers substantially higher strength, greater hardenability, and superior wear resistance — though with somewhat reduced corrosion resistance in dilute nitric acid and weak organic acids at room temperature. At Fushun Steel Tube, we manufacture 30Cr13 seamless tubes through both hot-rolled and cold-drawn/cold-rolled processes, supported by our integrated steelmaking capabilities including EAF + LF + VD, with optional ESR for demanding cleanliness requirements. Contact us for a free quote with your size and specification requirements.
Applications of 30Cr13 / 420 Stainless Steel Tubes
The combination of high hardness after heat treatment and adequate corrosion resistance makes 30Cr13 seamless tubes the material of choice for demanding mechanical components. Typical applications at the end-product level include:
- Shafts and spindles in pumps, compressors, and rotating equipment operating below 400 °C
- Valve stems, valve seats, and trim components for industrial valves in mildly corrosive service
- Bearing sleeves and bushings requiring high wear resistance and dimensional stability
- Pump plungers and piston rods in hydraulic and process fluid systems
- Plastic injection mold components including ejector sleeves and core pins
- Cutting tool bodies and knife blades operating below 300 °C where toughness is not the primary requirement
- Spring components and snap rings requiring high elastic properties
- Fasteners — bolts, studs, and nuts for high-strength applications up to 400 °C
- Precision mechanical tubing for instruments, meters, and electrical equipment
- Guide columns and wear sleeves in general engineering and automation machinery
Our 30Cr13 tubes are also available as round bars and forgings in matching grades, providing a complete material solution for integrated assemblies. Tell us your specifications and we will recommend the optimal product form for your application.
Specifications and Standards
30Cr13 and its international equivalents are covered by multiple national and international standards. The table below lists the most relevant standards for seamless stainless steel tube products in this grade.
| Standard System | Standard | Grade Designation | Product Form |
|---|---|---|---|
| ASTM (USA) | ASTM A511 | 420 (UNS S42000) | Seamless stainless steel mechanical tubing |
| ASTM (USA) | ASTM A276/A276M | 420 (UNS S42000) | Stainless steel bars and shapes (reference for chemistry & properties) |
| EN (Europe) | EN 10297-1 | X30Cr13 (1.4028) | Seamless circular steel tubes for mechanical and general engineering |
| EN (Europe) | EN 10088-3 | X30Cr13 (1.4028) | Stainless steels for general purposes — technical delivery conditions for semi-finished products, bars, rods, wire, sections, and bright products |
| JIS (Japan) | JIS G3446 | SUS420J2 | Stainless steel tubes for machine and structural purposes |
| JIS (Japan) | JIS G4303 | SUS420J2 | Stainless steel bars (reference standard) |
| GB (China) | GB/T 14975 | 30Cr13 (S42030) | Stainless steel seamless tubes for structural purposes |
| GB (China) | GB/T 20878 | 30Cr13 / S42030 / 3Cr13 | Stainless and heat-resisting steels — designation and chemical composition |
| GOST (Russia) | GOST 5632 | 30X13 (30Kh13) | High-alloy steels and corrosion-resistant, heat-resistant, and heat-treated alloys — grades |
| DIN (Germany) | DIN 2391-1 / DIN 2391-2 | X30Cr13 | Seamless precision steel tubes — dimensions and technical delivery conditions |
| ISO | ISO 683-17 | X30Cr13 | Heat-treated steels, alloy steels, and free-cutting steels — ball and roller bearing steels |
Within the Fushun Steel Tube product portfolio, 30Cr13 seamless tubes are also compatible with our broader range of stainless steel tubes and can be supplied as cold-drawn precision tubes or cold-rolled precision tubes when tight tolerances and superior surface finish are required.
Available Sizes and Delivery
Seamless Hot-Rolled Tubes
- Outside Diameter (OD): 32 mm – 530 mm (1.26 in – 20.87 in)
- Wall Thickness (WT): 2.5 mm – 50 mm (0.098 in – 1.97 in)
- Length: 5,800 mm – 12,000 mm, cut-to-length available
Cold-Drawn / Cold-Rolled Precision Tubes
- Outside Diameter (OD): 6 mm – 219 mm (0.24 in – 8.62 in)
- Wall Thickness (WT): 0.5 mm – 20 mm (0.020 in – 0.79 in)
- Length: Up to 12,000 mm in straight lengths; cut-to-length or coiled available for small diameters
Delivery Information
- Ready stock (common grades and sizes):
- Shipment within approximately 7 days from order confirmation.
- Custom and non-standard dimensions:
- Minimum order quantity of 2–3 tons; delivery in approximately 25–35 days depending on the complexity of the manufacturing route.
- Small trial orders:
- Accepted for special grades and development projects. Contact our technical sales team with your requirements.
- Volume orders:
- Negotiable pricing and delivery schedules. We welcome long-term supply agreements with scheduled releases.
Request a sample or ask for a delivery estimate based on your specific dimensions and quantity.
Chemical Composition
The chemical composition of 30Cr13 and its international equivalents is specified slightly differently across national standards. The table below provides the compositional ranges under each standard system. Note the key differences: the Chinese GB standard specifies a maximum nickel limit of 0.60%, while the ASTM A240 standard for flat products allows up to 0.75% nickel and separately limits molybdenum to 0.50%. The European EN standard permits a higher maximum manganese of 1.50% and recommends controlled sulfur for improved machinability.
| Standard | Grade | C | Si | Mn | P | S | Cr | Ni | Mo |
|---|---|---|---|---|---|---|---|---|---|
| GB/T 20878 | 30Cr13 / 3Cr13 | 0.26–0.35 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.0–14.0 | ≤ 0.60 | — |
| ASTM A276 | 420 | ≥ 0.15 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.0–14.0 | — | — |
| ASTM A240 | 420 | ≥ 0.15 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.0–14.0 | ≤ 0.75 | ≤ 0.50 |
| EN 10088-3 | X30Cr13 / 1.4028 | 0.26–0.35 | ≤ 1.00 | ≤ 1.50 | ≤ 0.040 | ≤ 0.015* | 12.0–14.0 | — | — |
| JIS G4303 | SUS420J2 | 0.26–0.40 | ≤ 1.00 | ≤ 1.00 | ≤ 0.040 | ≤ 0.030 | 12.0–14.0 | ≤ 0.60 | — |
| GOST 5632 | 30X13 | 0.26–0.35 | ≤ 0.80 | ≤ 0.80 | ≤ 0.030 | ≤ 0.025 | 12.0–14.0 | — | — |
* For machinability, a controlled sulfur content of 0.015% to 0.030% is recommended and permitted under EN 10088-3. The lower base sulfur limit shown is the default for general applications.
Manufacturing Process
Fushun Steel Tube produces 30Cr13 seamless tubes through a fully integrated manufacturing route that begins in our own steelmaking facility. The molten steel is produced via an EAF — LF — VD sequence, ensuring precise chemistry control, low gas content, and excellent cleanliness. For applications demanding the highest levels of micro-cleanliness — such as bearing sleeves and high-speed rotating components — we offer ESR and VIM+VAR upgrade routes that significantly reduce inclusion content and improve homogeneity.
The cast billets or ingots are then processed into seamless tubes using hot-rolling (piercing + elongation + sizing/reducing) for standard dimensions, or cold-drawing and cold-rolling for precision tubes with tighter tolerances and improved surface quality. Post-forming heat treatment — annealing for machinability and formability, or hardening and tempering for maximum mechanical properties — is carried out in computer-controlled furnaces to ensure batch-to-batch consistency. For honed tube requirements, we offer internal surface finishing to Ra 0.2–0.4 μm. Our forging equipment is also available for customers who require thick-wall tube blanks or tubular forgings in 30Cr13.
Mechanical Properties
The mechanical properties of 30Cr13 / AISI 420 stainless steel are highly tunable through heat treatment. In the annealed condition, the material is relatively soft and easily machinable. After hardening and tempering, it achieves its maximum strength and hardness. The tables below summarize mechanical property values under different conditions.
| Condition | Tensile Strength, max | Yield Strength (0.2%), max | Elongation, min | Reduction of Area, min | Hardness, max |
|---|---|---|---|---|---|
| Annealed (bar) | 655 MPa (95 ksi) | 345 MPa (50 ksi) | 25% | 55% | 195 HBW |
| Annealed & cold drawn | 760 MPa (110 ksi) | 690 MPa (100 ksi) | 14% | 40% | 228 HBW |
| Heat Treatment | Tensile Strength | Yield Strength (0.2%) | Elongation, min | Reduction of Area, min | Hardness |
|---|---|---|---|---|---|
| Quenched 1038 °C, tempered 316 °C | ≤ 1724 MPa (250 ksi) | ≤ 1482 MPa (215 ksi) | 8% | 25% | ≥ 52 HRC |
| Quenched, tempered 205–370 °C | 1550–1930 MPa (225–280 ksi) | — | — | — | 48–56 HRC |
Note: Actual mechanical properties will vary depending on section size, specific heat treatment parameters, and the governing standard. Fushun Steel Tube tailors heat treatment to each order’s mechanical property requirements. Contact our technical team to discuss your specific strength and hardness targets.
Heat Treatment
30Cr13 / AISI 420 is a heat-treatable martensitic stainless steel, and proper thermal processing is essential to achieving the desired balance of hardness, strength, and ductility. The table below summarizes the standard heat treatment procedures.
| Process | Temperature | Holding / Cooling | Typical Result |
|---|---|---|---|
| Subcritical Annealing | 675–760 °C (1245–1400 °F) | Air cool | Hardness 94–97 HRB |
| Full Annealing | 830–885 °C (1525–1625 °F) | Furnace cool to 790 °C, then 15–25 °C/h to 595 °C, air cool | Hardness 86–95 HRB |
| Isothermal Annealing | 830–885 °C, hold 2 h at 705 °C (1300 °F) | Air cool | Hardness ~95 HRB |
| Austenitizing (Hardening) | 980–1065 °C (1800–1950 °F) | Quench in oil or air (oil required for sections > 6.4 mm) | As-quenched martensite, ~60 HRC |
| Tempering | 205–370 °C (400–700 °F) | Air cool | 48–56 HRC; tensile 1550–1930 MPa |
| Stress Relieving | ~650 °C (1200 °F) | Slow cool | Residual stress reduction |
Key processing considerations: preheating to 760–790 °C is recommended before austenitizing to reduce thermal shock. For heavy sections, a two-stage preheat (540 °C then 790 °C) is advised. Cold treatment at –75 ± 10 °C immediately after quenching minimizes retained austenite and maximizes hardness. Hydrogen embrittlement is a recognized risk after hardening; stress relieving should be performed promptly if tempering is delayed. At Fushun Steel Tube, all heat treatment cycles are executed in computer-controlled furnaces with full cycle recording to ensure repeatable results.
Surface Finish and Tolerances
Fushun Steel Tube offers a range of surface finishes for 30Cr13 seamless tubes, matched to application requirements:
- Hot-rolled and pickled: Dark, matte surface with Ra 3.2–6.3 μm. Standard finish for general engineering and structural applications. Scale-free after acid pickling and passivation.
- Cold-drawn: Smooth, bright surface with Ra 0.8–1.6 μm. Achieved through cold reduction after annealing. Suitable for most mechanical applications.
- Cold-rolled: Fine, bright finish with Ra 0.4–1.6 μm. Tighter dimensional control than cold-drawn for high-precision components.
- Honed (internal): Ra 0.2–0.4 μm on the bore. Ideal for hydraulic cylinders, pump barrels, and bearing surfaces requiring low friction and tight clearance.
- Polished (external): Ra ≤ 0.2 μm upon request. Available for aesthetic or functional requirements in specialized applications.
Dimensional tolerances follow the applicable standards: hot-rolled tubes are typically supplied with OD tolerance of ±0.75% and WT tolerance of ±12.5%; cold-drawn precision tubes achieve OD tolerance down to ±0.08 mm and WT tolerance of ±10%. Tighter tolerances are available upon request for critical applications.
Quality Assurance and Testing
Every 30Cr13 seamless tube order at Fushun Steel Tube follows a comprehensive quality control workflow, from raw material to finished product shipment:
- Raw material inspection: Chemical composition verification via optical emission spectrometry (OES) on each heat. Raw material certificates are verified against order requirements before production release.
- In-process checks: Dimensional monitoring during hot rolling or cold drawing; surface quality inspection after each deformation stage; process parameter recording for heat treatment cycles.
- Finished product testing:
- Chemical analysis (re-verification), tensile testing at room temperature, and hardness testing (Rockwell, Brinell, or Vickers as specified)
- Hydrostatic pressure testing or eddy current testing for leak tightness and integrity verification
- Ultrasonic testing for internal flaw detection in critical-service tubes
- Dimensional inspection — OD, WT, length, straightness, ovality, and end squareness
- Surface quality — visual inspection at minimum 300 lux illumination; dye penetrant or magnetic particle testing available for detection of surface discontinuities
- Metallographic examination — microstructure, grain size, and inclusion rating per ASTM E45 or equivalent
- Intergranular corrosion testing (ASTM A262 or equivalent) upon request
- Certification: EN 10204 3.1 inspection certificates are standard for all orders. EN 10204 3.2 certificates with third-party or customer-witnessed inspection are available upon request.
Our ISO 9001 certified quality management system ensures full traceability from the steelmaking heat number through every production step to the final shipping documents.
Packing and Shipping
Packaging of 30Cr13 seamless tubes is tailored to the product type and shipping method to ensure damage-free delivery:
- Hot-rolled tubes: Bundled with steel straps in hexagonal or square bundles, wrapped in water-resistant polyethylene fabric or tarpaulin. End caps are fitted on threaded or beveled ends.
- Cold-drawn and cold-rolled precision tubes: Individually wrapped or packed in protective sleeves within reinforced wooden crates. Internal bores are coated with anti-corrosion oil; ends are plugged to prevent contamination.
- Honed tubes: Packed in dedicated protective wooden crates with internal separators to prevent bore surface contact damage. VCI (volatile corrosion inhibitor) paper is used inside the bore and on external surfaces.
- Shipping: We ship globally via sea freight (containerized or break-bulk for large-diameter tubes), air freight for urgent orders, rail to Central Asia and Europe, and truck for regional deliveries. Standard shipping marks include heat number, grade, size, specification, and bundle number for full traceability.
Frequently Asked Questions
What is the difference between 30Cr13 and 304 stainless steel tubes?
30Cr13 is a martensitic stainless steel that can be hardened by heat treatment to 48–56 HRC, whereas 304 is an austenitic stainless steel that cannot be hardened by heat treatment. 30Cr13 offers far higher strength and wear resistance but has lower corrosion resistance than 304. Choose 30Cr13 when hardness and wear resistance are the priorities; choose 304 when corrosion resistance in aggressive environments is paramount. For general-purpose stainless steel applications, explore our full range of stainless steel tubes.
Do you supply 30Cr13 tubes in the hardened and tempered condition?
Yes. We can deliver 30Cr13 / AISI 420 seamless tubes in either the annealed condition (ready for machining and subsequent heat treatment by the customer) or the hardened-and-tempered condition (with specified hardness and strength targets). For hardness-critical components such as valve stems and pump plungers, we recommend ordering in the hardened-and-tempered condition to ensure dimensional stability after our in-house heat treatment.
What is the maximum hardness achievable in a 30Cr13 seamless tube?
After proper austenitizing at 980–1065 °C, oil quenching, and low-temperature tempering at 205–370 °C, 30Cr13 can achieve hardness values of 48–56 HRC. Under optimized conditions (lower tempering temperature), hardness up to 52–54 HRC is attainable, with corresponding tensile strength of up to 1724 MPa. However, higher hardness values come with reduced toughness, so the optimal tempering temperature depends on the balance of properties your application requires.
Can you machine 30Cr13 tubes to custom configurations?
Yes. Through our precision processing capabilities, we can perform CNC machining, turning, threading, drilling, and end-preparation on 30Cr13 seamless tubes to meet your finished-component specifications. We also offer cut-to-length services with deburred and chamfered ends. For complex machined tube assemblies, our cold-drawn precision tubes provide an excellent starting point with minimal stock removal requirements.
Is there a minimum order quantity for 30Cr13 / 420 stainless steel tubes?
For standard sizes held in ready stock, there is no minimum order quantity — we ship from a single tube upward. For custom and non-standard dimensions, the minimum order quantity is 2–3 tons. We also welcome small trial orders for special grades and new application development. Volume orders benefit from negotiable pricing and scheduled delivery programs. Contact us to discuss your specific requirements.