Alloy Steel

 

The correct product route depends on the final part, section size and inspection plan. A bar specification should not be used as a blanket substitute for a forging or pressure-component specification. We review the requested form before confirming the manufacturing route.

Product form	Typical purchasing details	Typical downstream use
Alloy steel round bar	Diameter, length, tolerance, straightness, surface and heat-treatment condition	Pins, axles, shafts, fasteners and machined parts
Forged bar and shaft	Finished envelope, forging allowance, step geometry, heat treatment, test location and UT class	Drive shafts, rotor shafts, rolls and heavy-duty spindles
Gear blank and disc	Outside diameter, bore, thickness, machining allowance, hardness requirement and NDT	Gears, couplings, flanges and transmission parts
Ring forging	Outside diameter, inside diameter, height, contour, heat treatment and inspection plan	Bearing rings, slewing components, pressure and power equipment
Plate and block	Thickness, width, length, flatness, surface condition and through-thickness inspection if required	Bases, dies, structural components and machined blocks
Rough-machined component	Controlled drawing, datum system, machining allowance, critical dimensions and final inspection	Near-net shafts, sleeves, hubs and custom mechanical parts

 

 

 Use the grade families below as a sourcing map, not as a substitution chart. Final selection must be confirmed by the purchaser or design authority using the applicable standard, service temperature, load, section size, heat treatment and acceptance criteria.

Grade family	Grades available for review	Common selection purpose
Case-hardening Ni-Cr-Mo and Mn-Cr-Ni-Mo steels	15CrNi4Mo, 15CrNiMoA, 16MnCr2NiMoV, 18CrMnNi2MoA, 20MnCr1Ni1Mo, 23CrNi3MoA, 24CrNi4Mo	Hard, wear-resistant carburized case with a tougher core for gears, pinions and transmission shafts
Quenched and tempered high-strength steels	30CrNi4MoA, 30CrMnSiA, 30CrMnSiNi2A, 38CrA, 38CrSi, 40SiMnCrNi2MoV, 45CrNiMo1V, 45CrNiMoV	High core strength, fatigue resistance and toughness for shafts, pins, heavy gears and loaded mechanical parts
Project and ultra-high-strength grades	22Si2MnCrNi2MoA, 25CrMnSiNi2MoA, 25Si2MnCrNi2MoVA, 15MnNi4MoA	Drawing-controlled components that require a project specification, confirmed heat treatment and section-specific properties
Heat-resistant Cr-Mo-V and rotor forging steels	1Cr11Ni2W2MoV, 2Cr12MoVA, 2Cr12NiMo1W1V, 20Cr1Mo1VTiB, 20Cr1Mo1VNbTiB, 21CrMoVA, 25Cr2Mo1VA, 25Cr2MoVA	Turbine, rotor, shaft and elevated-temperature components where creep, tempering stability and cleanliness requirements are defined by the engineering specification

Availability of a grade in a particular form or size is confirmed at quotation. Project grades and enterprise specifications require the purchaser's complete chemical, mechanical, heat-treatment and test requirements.

 

 

 The grade name alone does not define the order. The purchase specification must match the product form and the properties required after heat treatment. Use the revision stated in the purchase order.

Standard	Procurement role	Important limitation
GB/T 3077	Alloy structural steel grades and technical delivery requirements	Confirm the exact grade designation, revision, form and heat-treatment condition
ASTM A29/A29M	Common requirements used by referenced carbon and alloy steel bar specifications	It is a general requirements standard, not a complete grade purchase specification by itself
ASTM A322	Hot-wrought alloy steel bars in standard grades	Properties and delivery requirements still depend on the order and referenced requirements
ASTM A434/A434M	Hot-wrought or cold-finished quenched and tempered alloy steel bars	Specify strength class, size, condition and required tests
ASTM A668/A668M	Carbon and alloy steel forgings for general industrial use	Select the applicable class, heat treatment and mechanical requirements
ASTM A470/A470M	Vacuum-treated carbon and alloy steel forgings for turbine rotors and shafts	Use only when the component and ordered class fall within its scope
ISO 683-2	Alloy steels for quenching and tempering	Mechanical requirements apply to defined product forms, conditions and size ranges
ISO 683-3	Case-hardening steels supplied as specified semi-finished, bar, rod, flat-product and forging forms	Define surface condition and heat-treatment condition in the order
EN 10083-3 and EN 10084	European quenched-and-tempered alloy steels and case-hardening steels	Use the exact grade and current contractual standard; do not rely on an approximate cross-reference
EN 10204	Inspection document types including 3.1 and 3.2	Document type must be agreed before production; 3.2 requires the specified independent validation route

 

Start with the component's required performance after manufacturing. Alloy content improves hardenability or service behavior, but the final result also depends on section size, steelmaking route, forging reduction, heat treatment, test location and machining history.

 

Decision	Case-hardening steel	Quenched and tempered steel	Heat-resistant forging steel
Primary goal	Wear-resistant surface with a tough core	High strength and toughness through the working section	Stable properties under specified elevated-temperature service
Typical process	Carburize or carbonitride, quench and temper as specified	Austenitize, quench and temper to a defined property range	Grade-specific melting, forging and heat treatment under the governing specification
Key RFQ inputs	Effective case depth, surface hardness, core properties, distortion allowance and final geometry	Section size, tensile and yield targets, hardness range, impact temperature and test location	Design temperature, time-dependent properties, component standard, heat treatment, cleanliness and NDT acceptance
Selection risk	A direct grade swap can change case response, core hardenability and distortion	Properties quoted for small bars may not apply to a large forging	Do not substitute a structural or pipe grade without engineering approval

 

1. Service load and failure mode. State whether the part is governed by contact wear, bending fatigue, impact, torsion, creep or a combination.

2. Operating temperature and environment. Include the continuous and upset temperatures, corrosion exposure and any hydrogen-related requirement.

3. Finished section size. Hardenability and cooling rate change with diameter and wall or section thickness.

4. Required condition. Specify annealed, normalized, quenched and tempered, carburized or another defined condition.

5. Mechanical properties and test location. State the required tensile, yield, elongation, hardness and Charpy values together with the sampling location and orientation.

6. Internal quality. Define cleanliness, macrostructure, grain size, decarburization and ultrasonic acceptance when they affect performance.

7. Manufacturing route. Provide machining allowance, welding plan, distortion limits and any special melting, degassing or remelting requirement.

 

An equivalent-grade table can be a useful search aid, but it is not approval to substitute. Two grades may have similar chemistry and still differ in hardenability, residual-element limits, cleanliness, heat-treatment condition, section-size limits or guaranteed properties. For a cross-standard request, send the original specification and the properties that must be met. We will identify a candidate route for purchaser approval.

 

Size capability changes with grade, heat-treatment condition, inspection level and order quantity. For that reason, this page does not publish one artificial size range for bars, pipes, plates and forgings. Send the dimensions below and we will confirm a viable mill or forging route.

Form	Dimensions to specify	Additional controls
Round bar	Diameter, length and quantity	Diameter tolerance, straightness, end condition, surface and decarburization limit
Forged bar or shaft	Maximum and minimum section, step diameters, overall length and finished envelope	Forging allowance, forging ratio if specified, grain-flow requirement, test location and UT class
Gear blank or disc	Outside diameter, bore, thickness and machining stock	Heat-treatment condition, hardness, flatness, runout and NDT
Ring	Outside diameter, inside diameter, height and contour	Rolled or open-die route, machining stock, grain flow and inspection zone
Plate or block	Thickness, width, length and weight	Flatness, surface, edge condition, through-thickness testing and cutting method
Machined blank	Controlled drawing and revision	Datums, critical tolerances, roughness, heat treatment, inspection report and marking

 

 

• Surface condition options may include black, shot-blasted, descaled, peeled, turned, ground or rough-machined, depending on product form.

• Delivery conditions may include as rolled, as forged, soft annealed, normalized, normalized and tempered, quenched and tempered or stress relieved.

• Cutting and machining options may include sawing, peeling, turning, facing, center drilling, boring and drawing-based rough machining.

• Final availability, tolerances and machining allowances are confirmed on the quotation and drawing review.

Heat treatment is part of the material specification, not an optional label. The schedule must account for grade, section size, furnace loading, quench severity, target properties and distortion risk. When properties are required after a customer's final heat treatment, the quotation should state whether tests apply to the supplied condition, a reference heat treatment or the finished component.

Process	Purchasing purpose	What to define
Soft annealing	Improve machinability or prepare for subsequent hardening	Hardness range, spheroidization if relevant and surface/decarburization limits
Normalizing and tempering	Refine structure and obtain a controlled condition for selected grades	Cycle, final hardness or mechanical properties and test location
Quenching and tempering	Develop section strength and toughness	Target strength, hardness, impact temperature, section size and sampling position
Carburizing and final hardening	Create a hard case around a tougher core	Effective case depth, case and core hardness, grinding allowance and distortion control
Stress relieving	Reduce residual stress after rough machining or fabrication	Temperature limit, hold requirement and whether properties must be reverified

 

Provide adequate machining stock for scale removal, decarburization, heat-treatment distortion and final inspection. For long shafts or asymmetric blanks, agree the machining sequence and whether stress relief is required between rough and finish machining.

Weldability must be assessed by grade, carbon equivalent, section thickness, hydrogen control and restraint. High-strength and air-hardening grades may require controlled preheat, low-hydrogen consumables, interpass limits and post-weld heat treatment. The fabricator should use an approved welding procedure rather than a generic statement that alloy steel is easy to weld.

 

A useful inspection requirement names the test method, sampling location, frequency and acceptance level. A statement such as UT tested is incomplete unless the purchase order also identifies the applicable standard, scan coverage, reference sensitivity and reject criteria.

Inspection item	Buyer purpose	Order details to state
Heat and product chemistry	Confirm grade and residual-element limits	Governing grade standard, product-analysis requirement and any tighter project limits
Material identification	Maintain traceability from heat to finished piece	Heat number, piece marking, transfer method and packing-label requirements
Tensile testing	Verify yield strength, tensile strength and elongation	Condition, specimen location, orientation, test temperature and acceptance values
Hardness testing	Control machinability, heat treatment or final part performance	Scale, location, frequency and acceptable range
Charpy impact testing	Verify notch toughness at the design temperature	Test temperature, specimen orientation, location, size and absorbed-energy requirement
Ultrasonic testing	Detect internal discontinuities in bars and forgings	Applicable practice such as ASTM A388/A388M where relevant, coverage and acceptance class
Surface NDT by MT or PT	Detect surface-breaking discontinuities	Method, examination zone, timing and acceptance criteria
Metallurgical testing	Check grain size, decarburization, macrostructure, inclusion rating or microstructure	Test method, sampling location and limits
Dimensional inspection	Verify purchase dimensions and machining allowance	Drawing revision, tolerance standard, critical characteristics and report format

 Portable X-ray fluorescence can identify many alloying elements but does not directly verify carbon content. Where carbon is decisive for grade confirmation, require a suitable spectrometric or laboratory chemical method in addition to alloy PMI.

 

• Mill test certificate with heat chemistry and the ordered mechanical test results

• EN 10204 3.1 inspection certificate when specified

• EN 10204 3.2 documentation when agreed with the required independent validation route

• Heat-treatment chart or report when included in the order

• NDT report with method, standard, acceptance level and examined locations

• Dimensional inspection report for drawing-based forgings or machined blanks

• Third-party witness or inspection by an agreed agency when arranged before production

Industry or component	Typical material route	Critical RFQ information
Gears and pinions	Case-hardening alloy steel or through-hardened Q&T steel	Contact stress, tooth size, case depth, core properties, distortion and grinding allowance
Transmission and drive shafts	Q&T Ni-Cr-Mo or multi-alloy high-strength steel	Finished diameter, torque, fatigue requirement, impact temperature, straightness and UT
Heavy machinery and mining parts	Q&T bar, forging, disc or block	Load spectrum, wear mode, section size, repair welding and field temperature
Turbine and power components	Project-specific heat-resistant rotor or shaft forging steel	Component standard, design temperature, creep or rupture basis, cleanliness, heat treatment and NDT
Aerospace and defense components	Purchaser-controlled special grade and process route	Approved specification, qualified source requirements, traceability and inspection plan
Oil gas and pressure equipment	Product-standard-specific bar or forging route	Pressure code, sour-service or hydrogen requirements, impact temperature and third-party inspection

 

Packing is selected for product mass, surface condition, machining status and transport route. Bars may be bundled with protected ends and durable heat-number tags. Machined blanks may require anti-rust oil or VCI protection, separators, moisture barriers and cases or steel frames that prevent metal-to-metal damage. Heavy forgings require agreed lifting points, center-of-gravity marking and secure blocking for container or break-bulk shipment.

The final packing list should identify the purchase order, item number, grade, heat number, piece count, net weight and gross weight. Marking and preservation requirements must be included in the RFQ when the goods will enter long storage, sea transport or a controlled production line.

 

Dongmeng Group supports alloy steel purchases that require more than a grade and diameter. Our role is to translate the drawing and purchase specification into a supply route that covers material form, heat treatment, machining allowance, inspection documents, packing and shipment.

• One inquiry can cover round bar, forged bar, shafts, gear blanks, rings, plates and rough-machined parts.

• Grade review distinguishes a useful cross-reference from a contractually approved equivalent.

• Processing can be coordinated around the ordered condition, including cutting, peeling, turning, heat treatment and rough machining when available.

• Inspection planning links each requested test to a method, acceptance level, report and traceable heat number.

• Export packing is matched to product geometry, surface protection and destination handling requirements.

Material approval remains with the purchaser or design authority. We confirm supply feasibility against the final purchase order before production.

What information is required for an alloy steel quotation？

Send the grade and standard, product form, dimensions, quantity, delivery condition, mechanical properties, inspection requirements, machining scope, packing and destination. Include a controlled drawing for forgings or machined blanks.

Can you supply an international equivalent to a Chinese alloy steel grade？

We can review candidate grades, but similar designations are not automatically interchangeable. The purchaser must approve the substitute after comparing chemistry, hardenability, delivery condition, section-size limits, mechanical properties and test requirements.

What is the difference between case-hardening steel and quenched and tempered steel？

Case-hardening steel is selected when a hard, wear-resistant surface and tougher core are required. Q&T steel is selected for strength and toughness through the working section. The final choice depends on the component design and heat-treatment route.

Which product forms can be supplied？

Common inquiry forms include round bar, forged bar, shafts, stepped shafts, gear blanks, discs, rings, plates, blocks and rough-machined components. Feasible sizes and quantities are confirmed by grade and condition.

Can alloy steel be supplied heat treated？

Yes, orders may specify annealed, normalized, normalized and tempered, quenched and tempered, stress-relieved or another grade-appropriate condition. The required properties, test location and heat-treatment responsibility must be stated before quotation.

How should I specify ultrasonic testing for a forging？

State the applicable test practice, scan coverage, reference method, acceptance class, examination stage and report requirement. ASTM A388/A388M may be used for suitable steel forgings, but the component specification or drawing may require different criteria.

What inspection certificates are available？

EN 10204 3.1 is available when included in the order. EN 10204 3.2 or third-party inspection can be arranged when the validation route, hold points and document responsibility are agreed before production.

Can you provide cutting and rough machining？

Saw cutting, peeling, turning, facing, drilling, boring and rough machining can be quoted according to the product and drawing. State the final envelope, machining allowance, datum references and critical dimensions.

Is alloy steel easy to weld？

Weldability varies by grade, carbon equivalent, strength level and section thickness. Many high-strength grades need controlled preheat, low-hydrogen practice, interpass control and sometimes post-weld heat treatment. Use a qualified welding procedure for the specific material and joint.

How do section size and test location affect mechanical properties？

Large sections cool more slowly during heat treatment, so the center may not reach the same hardness and toughness as the surface or a small test bar. Specify the actual section and the required specimen location and orientation.

What affects the price and lead time？

The main drivers are grade, product form, section size, heat-treatment route, order weight, machining allowance, special melting requirements, NDT acceptance, testing frequency, inspection documents and packing. Lead time is confirmed after the complete specification is reviewed.

How are alloy steel bars and forgings packed for export？

Packing may include bundles, end protection, anti-rust oil, VCI material, separators, cases or steel frames. Heavy pieces require secure blocking and clear lifting and traceability marks. The final method is agreed for the product and transport route.

For an accurate quotation, include the following information

• Grade designation and governing standard with revision

• Product form and complete dimensions

• Delivery and heat-treatment condition

• Required mechanical properties with test location and temperature

• Surface condition, tolerance and machining allowance

• NDT method, coverage and acceptance criteria

• Quantity, piece weight or total order weight

• Inspection document and third-party requirements

• Packing method, destination port and required delivery date

• Drawing, end use and any purchaser specification

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Xi'an Dongmeng Group Co., Ltd. is one of the leading alloy steel manufacturers and suppliers in China. We warmly welcome you to buy or wholesale cheap alloy steel in stock here from our factory. All customized products are with high quality and competitive price. For free sample, contact us now.