- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Engineered 4130 round bar / 4130 steel bar for high-strength, fatigue-resistant parts in aerospace, motorsports, oil & gas, and general machinery.
Wide size coverage (Ø8–800 mm; length 2–12 m) in hot-rolled or cold-drawn states, with cut-to-length service.
Cross-standard equivalence across AISI/ASTM/EN/DIN/JIS/GB/BS for global sourcing and qualification.
Value-added processing: precision sawing, bending, chamfering, hole-punching, welding prep, marking, and tailored packaging.
Ideal for buyers seeking dependable 4130 round bar suppliers with consistent documentation and heat-level traceability.
| Quantity: | |
|---|---|
PRODUCT DESCRIPTION
When stock meets spindle, you feel it: a steady, metallic ring, chips curling cleanly, and a satin-smooth surface that makes inspection almost anticlimactic. That’s what well-made AISI 4130 delivers. The chromium-molybdenum matrix offers deep hardenability for strength through the section, while chromium keeps scale and abrasion in check. After quench-and-temper, you get strength on demand without brittle surprises; in the annealed or normalized state, machinists enjoy predictable tool life and easy finishing around HB ≤229. Welders value a forgiving arc with proper preheat and controlled interpass. The net effect is simple: fewer variables on your floor, more first-pass yield, and parts—pins, shafts, valve bodies, chassis nodes—that do the quiet work, shift after shift.
Supply Scope (Standard Program)
Diameter: 8–800 mm
Length: 2–12 m (cut-to-length available)
Shape & Process: Round / Flat; Hot-Rolled / Cold-Drawn
Standards: AISI, ASTM, EN, DIN, JIS, GB, BS
Grade Equivalents: 25CrMo, 25CrMo4, SCM430, 1.7218, 1.7214, 25CD4, 30XM, 2225
Services: Bending, Welding Prep, Uncoiling, Cutting, Punching, Chamfering, Marking
Typical Chemical Composition (wt. %)
| C | Si | Mn | Cr | Mo | S (max) | P (max) | Ni (max) | Cu (max) |
|---|---|---|---|---|---|---|---|---|
| 0.28–0.33 | 0.15–0.35 | 0.40–0.60 | 0.80–1.10 | 0.15–0.25 | 0.040 | 0.035 | 0.030 | 0.030 |
Typical Mechanical Benchmarks (condition-dependent)
Tensile Strength: ≈ 930 MPa
Yield Strength: ≈ 785 MPa
Elongation: ≥ 12 % Reduction of Area: ≥ 50 %
Hardness: ≤ HB 229
Heat-Treatment Reference: Austenitize ~880 °C (oil/water quench), Temper ~540 °CNote: Actual values depend on section size, prior process history, and final temper. We certify per PO.
Why this matters to youA clear parameter envelope shortens PPAP and buyer qualification, aligns internal routings (saw → rough → HT → finish), and de-risks cross-plant transfers. We maintain heat-level traceability and 3.1 certification to keep audits tidy.
How it reduces your total cost of ownership
Strength on demand — Q\&T response allows multiple strength classes without re-drawing the part.
Dimensional confidence — Cold-drawn bars bring tighter size/roundness; you remove less stock and scrap less.
Process-friendly — Good weldability with proper preheat and stable machinability around HB ≤ 229 supports takt time.
Thermal stability — Maintains properties at moderate elevated temperatures, extending service windows.
Cross-standard mapping — Equivalents (25CrMo4/SCM430/1.7218) simplify multi-region qualification and VMI.
Ready-to-use services — On-spec cutting, chamfering, and marking reduce internal WIP touches.
Outcome you can expect
Fewer set-ups and reworks
Faster first-article approvals
Lower unit cost at stable quality levels
We align to major international bar standards and can tailor inspection to project or industry norms. Documentation packs are structured for regulated environments and export compliance.
Coverage & Documentation
Standards: AISI / ASTM / EN / DIN / JIS / GB / BS
Certificates: EN 10204 3.1 heat analysis + mechanicals; optional third-party witnessing
NDT Options: UT, MPI, and surface integrity reports on request
Export documents: COO, packing lists, and compliant MSDS as needed
4130 is versatile across annealed, normalized, and Q\&T states. Choose the condition to fit your machining plan and final property target.
Condition-to-Use Quick Guide
| Supply Condition | Typical Use Case | Buyer Benefit |
|---|---|---|
| Annealed | Rough machining, deep drilling, forming | Soft cutting, consistent chip control |
| Normalized | Pre-HT machining, balanced ductility | Stable microstructure, good weld response |
| Quench & Temper | Final strength & toughness | High strength with reliable impact margin |
| Stress-Relieved | Tight-tolerance finishing | Dimensional stability in thin-wall sections |
Post-weld tempering recommended to recover toughness. Preheat/interpass control scales with chemistry and section size.
We cover both small machining blanks and large feedstock. Cold-drawn programs deliver tighter dimensional bands and improved surface, which directly lowers your machining allowance.
Options
Diameters: 8–800 mm; specials on request
Lengths: 2–12 m; optimized cut-to-length to reduce remnant waste
Tolerances: Commercial bars to ±1% typical on made-to-order; tighter per cold-drawn standards
Straightness & Roundness: Project-specific callouts supported; inspection reports available
4130 is known for good weldability with appropriate preheat and hydrogen control; machinability is stable at sub-HB 229 hardness.
Best-Practice Pointers
Welding: Preheat matched to section & chemistry; control interpass; temper after welding
Machining: Coated carbide, positive rake, reliable flood coolant; finish-temper before bore finishing
Distortion Management: Stress-relief before tight finishing; balanced stock removal
Surface Integrity: Verify Ra/Rz by operation; protect bearing fits with caps and VCI
The alloy’s specific strength and fatigue resistance make it the bar of choice for load-bearing components where predictable heat-treat response and weldability matter.
Typical Parts
Aerospace: pins, struts, engine mounts, actuator rods
Motorsports: chassis nodes, control arms, steering shafts
Oil & Gas: forged valve/pump bodies, tool joints
General Machinery: gears, couplings, shafts, hydraulic hardware
We integrate first-step processing so your machines start closer to net.
Available Services
Precision sawing, bundle-cut, chamfering, deburring
Bending, hole-punching, and welding preparation
Peel/turn, bright draw, and polishing options
Heat-treat coordination (normalize, Q\&T, stress relief)
Marking & barcode labeling aligned to your ERP
From mill black to bright-drawn, surface condition is tuned to your finishing plan. Packaging protects both surface quality and identification.
Choices
Surfaces: Black, peeled/turned, bright-drawn, polished
Ends: Square-cut or chamfered; protective caps optional
Protection: VCI oiling, seaworthy bundling, palletization to spec
Identification: Heat/lot tags, barcode labels, custom stencils
We balance inventory and made-to-order programs to meet project gates without over-committing your working capital.
Commercial Terms
MOQ: From 1 ton on standard sizes
Lead Time: 7–21 days for custom diameters/lengths (capacity-dependent)
Incoterms: EXW / FOB / CFR / CIF
Programs: Forecast-based VMI, consolidated shipments, inspection prior to dispatch
Audit-ready documentation streamlines PPAP/FAI and simplifies non-conformance analysis.
What You Receive
3.1 MTC with chemistry & mechanicals at heat/lot level
Optional UT/MPI & dimensional inspection reports
COC, packing list, and labeled bundles with heat numbers
Retention of records per contract for lifecycle traceability
You’re procuring throughput and confidence, not just metal. Our quality discipline and process integration reduce your internal handling and stabilize downstream yields.
Value to Your Operation
Consistency: Tight chemistry & cleanliness discipline for predictable HT and machining
Speed: In-house first-step processing cuts lead times and WIP
Scalability: From prototypes to series production without re-qualification
Support: Engineering assistance on condition selection, welding, and finishing windows
Below are the practical questions procurement and manufacturing teams raise before sign-off. If your print includes legacy callouts, share it—we’ll map the exact route and inspection scope.
Q1. Can you match aerospace-style callouts or legacy drawings?
Yes. Provide the specification and drawing; we’ll quote condition, NDT scope, and cert package accordingly.
Q2. What preheat is recommended for welding 4130?
Preheat scales with section size and chemistry. We’ll recommend a range and interpass control; post-weld tempering is advisable to recover toughness.
Q3. How tight can you hold diameter on cold-drawn bars?
Commercial tight bands are standard. For critical fits, we align to the project tolerance and supply inspection data.
Q4. Can you supply near-net lengths and chamfered ends to reduce waste?
Yes—precision cut-to-length and end-conditioning reduce set-up time and scrap on your line.
Q5. What about documentation?
Each shipment carries 3.1 MTC with heat/lot traceability; optional UT/MPI and third-party witnessing can be added.
Q6. Typical lead time for non-stock sizes?
Generally 1–3 weeks depending on diameter, condition, and load. We confirm at PO with a capacity-backed plan.
Zhongjing Steel Group (Guangdong) Co.,Ltd. specializes in the production of cold-rolled/hot-rolled coils, carbon steel pipes, bars, and PPGI materials. It is a modern enterprise integrating carbon steel production, processing, and trade. It is a Chinese iron and steel enterprise group.
