Hot-Rolled Round Bar
Natural black mill surface for machining and further heat-treatment operations.
Global Steel Supply & Processing
GB/T 3077-2015 · Grade 42CrMo · Steel Code A30422
Source Cr-Mo alloy steel bar for shafts, forgings and heavy mechanical components. Share your diameter, length, delivery condition, quantity and destination port to receive factory pricing.
Explore 42CrMo specifications ↓Supply decisions begin with your grade, bar diameter, delivery state, inspection requirements and purchased tonnage.
| Product | 42CrMo Alloy Steel Bar |
| Material grade | 42CrMo / A30422 |
| Material standard | GB/T 3077-2015 — Alloy Structure Steels |
| Hot-rolled bar dimensions | GB/T 702 as agreed in the order; dimensions and tolerance edition confirmed in the contract |
| Steel family | Chromium-molybdenum low-alloy structural steel |
| Product forms | Solid round bars; square/flat forms subject to actual availability |
| Supply conditions | Hot-rolled, annealed, or quenched & tempered, according to quotation |
| Diameter and length | Requested sizes confirmed with current stock and production arrangements |
| Surface condition | Black hot-rolled, turned or peeled finish, as ordered |
| Certificates | Heat analysis, mechanical properties, hardness, dimensions and MTC as agreed |
| Commercial information | Bar sizes, quantity, destination port, Incoterms and target delivery date |
Compare the bar appearance and ordered condition for your machining or fabrication requirements.
Natural black mill surface for machining and further heat-treatment operations.
Surface and finished diameter requirements can be included with your purchase schedule.
Verify cut faces, round geometry and handling condition for your delivered bars.
Review the Cr-Mo alloy elements and request the actual heat analysis for your incoming material checks.
| Element | Mass Fraction |
|---|---|
| Carbon (C) | 0.38–0.45% |
| Silicon (Si) | 0.17–0.37% |
| Manganese (Mn) | 0.50–0.80% |
| Chromium (Cr) | 0.90–1.20% |
| Molybdenum (Mo) | 0.15–0.25% |
| Phosphorus (P) | ≤ 0.030% |
| Sulfur (S) | ≤ 0.030% |
| Residual Nickel (Ni) | ≤ 0.30% |
| Residual Copper (Cu) | ≤ 0.30% |
Limits refer to standard-quality 42CrMo under GB/T 3077-2015; A/E quality designations have their own residual and impurity requirements. Confirm the exact grade designation and mill test results for your order.
Send your material drawing and any special chemistry requirements with the RFQ. Your heat analysis and grade identification can be checked against the ordered standard.
Review the standard example for a 25 mm test specimen after specified quench-and-temper treatment. Set final limits against your supplied bar diameter and required condition.
| Property | Reference Requirement |
|---|---|
| Tensile strength (Rm) | ≥ 1080 MPa |
| Yield strength (ReL) | ≥ 930 MPa |
| Elongation after fracture | ≥ 12% |
| Reduction of area | ≥ 45% |
| Impact absorbed energy | ≥ 63 J (KU2, U-notch reference) |
| Standard test specimen | 25 mm size under the specified reference heat treatment |
These values reflect the GB/T 3077-2015 reference heat-treatment test sample. Applicable test procedures and size-based adjustments are governed by the supply standard and your agreed inspection terms.
| Condition | Procurement Consideration |
|---|---|
| Hot-rolled | Specify as-rolled condition and subsequent heat treatment, if planned. |
| Annealed / high-temperature tempered | Brinell hardness reference ≤ 229 HBW in the applicable delivery condition. |
| Quenched & tempered | Confirm required strength, hardness, diameter and test location for the order. |
Mechanical test acceptance may change with cross-section size. State the diameter, condition and required testing location for thick-section bars.
Choose the intended machining and heat-treatment route and confirm the delivery condition before production.
Bar stock for downstream machining or a separately specified heat-treatment process.
Material prepared for machining programs requiring a defined hardness range.
Purchased by diameter, strength target and inspection requirements, as agreed with the supplying mill.
Attach your target hardness/strength and inspection requirements to the same RFQ.
Compare procurement specifications across the GB and SAE systems and confirm acceptance to the exact requested material standard.
Cr-Mo alloy steel for shafts, gears, and heat-treated engineering components.
View product details ↗Cr-Mo alloy grade commonly specified for mechanical shafts and machined components.
View product details ↗Ni-Cr-Mo alloy steel commonly selected for demanding large-section machine components.
View product details ↗Compare full chemistry ranges, heat-treatment conditions, strength and inspection requirements using the specified standard for each grade.
Get alloy bar stock for structural and mechanical components defined by your engineering drawings and heat-treatment requirements.
Bar stock for machined transmission and mechanical drive shafts.
Forged or machined blanks for gearmaking and industrial power trains.
Steel bar for heavy-duty hydraulic equipment components.
Components produced to defined strength, toughness and machining requirements.
Structural fastener stock where the specified grade and heat treatment are suitable.
Machined alloy components for industrial equipment assemblies.
Share the drawing, target diameter, total volume and acceptance requirements.
Use genuine production scale, regular steel inventory and specification-led sourcing when comparing suppliers.
Our business produces 8 million metric tons of steel annually across multiple product categories.
Manufacturing ↗Regular combined steel inventory reaches 1 million metric tons; the 42CrMo stock position is confirmed for your diameter and condition.
Steel Inventory ↗Order by GB/T 3077 grade, heat-treatment state, dimension tolerance and documented acceptance criteria.
Quality Control ↗Plan bar length, bundle weight, packing preferences, trade terms and destination port together with the quotation.
Alloy Steel Bar ↗Estimate the nominal weight of your solid round bars from diameter, length and piece count before requesting a freight quote.
Theoretical weight based on solid cylindrical steel and a nominal density of 7,850 kg/m³. Actual invoice and shipment weight follow the contracted measurement terms.
Send a complete size list so your quotation can reflect the grade, machining route and intended delivery state.
Discuss project and recurring bar requirements with a steel supplier operating at 8 million metric tons of annual steel output across the full product range. Your exact 42CrMo size and condition are checked against available stock and production routes.
Send your round bar diameter, length, quantity and delivery state. We will confirm 42CrMo availability, production coordination and commercial delivery terms for the specific order.
Include the required grade, heat analysis, mechanical properties and inspection certificate with your RFQ. Your quotation will confirm the test scope for the specified diameter and heat-treatment condition.
Attach your cut-length list or machining drawing. Include diameter tolerance, edge finish and any required end preparation so the available processing scope can be checked for your order.
Confirm bar length, unit/bundle weight, packaging and port details with your order. We can include loading and document arrangements in the factory quotation.
Use the correct grade and heat-treatment requirements from your drawings; each linked bar grade has its own material specification.
GB/T 3077-2015 covers 42CrMo alloy structural steel. Include the standard edition, ordered quality grade and bar dimensions in your RFQ.
42CrMo uses chromium at 0.90–1.20% and molybdenum at 0.15–0.25%, with 0.38–0.45% carbon in its reference chemistry.
Send your machining route and required hardness, strength or impact results. The quotation will confirm the offered as-rolled, annealed or Q&T condition.
You can compare chemistry and mechanical requirements using both specifications. Select the final grade according to your drawing, contract standard and engineering acceptance criteria.
Provide diameter, length, quantity, test documents, packaging requirements and destination port. You can attach a cutting or machining drawing to the form.
Send your required grade, dimensions, quantity and destination. Our team will review the inquiry.