Annealed Alloy Steel Bars - High-Strength Heat-Treated Steel Rods for Industrial Use

Shandong Kuaima Steel Co., Ltd.

Verified Custom manufacturer 7yrs

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Technical Specifications of Annealed Alloy Steel Bars

Property	Parameter	Description
Product Name	Annealed Alloy Steel Bars	Heat-treated alloy steel bars with improved ductility
Material Grade	AISI 4140 / AISI 4340 / EN 42CrMo4 / JIS SCM440	International grade equivalents for alloy steel
Standard Compliance	ASTM A29, ASTM A322, EN 10083-3, JIS G4053	Meets major international standards
Manufacturing Process	Hot rolled + Annealing	Heat treatment for stress relief and improved machinability
Carbon (C)	0.38-0.43%	Carbon content for strength and hardness
Chromium (Cr)	0.80-1.10%	Enhances hardenability and wear resistance
Molybdenum (Mo)	0.15-0.25%	Improves toughness and tensile strength
Manganese (Mn)	0.75-1.00%	Improves hardenability and strength
Silicon (Si)	0.15-0.35%	Deoxidizer and strengthener
Tensile Strength	≥655 MPa (annealed condition)	Minimum tensile strength after annealing
Yield Strength	≥415 MPa	Minimum yield strength in annealed state
Elongation	≥22%	Ductility in 50mm gauge length
Hardness	≤217 HBW (annealed)	Brinell hardness in annealed condition
Diameter Range	10mm - 300mm	Available bar diameter options
Length	3m - 12m or custom	Standard and custom lengths available
Surface Finish	Black, Peeled, Polished, Ground	Multiple surface treatment options
Application	Gears, shafts, fasteners, automotive components	Typical application in machinery and automotive
Certification	EN 10204 3.1, ISO 9001, ASTM certification	Quality certifications provided
Packaging	Bundled with steel straps, wooden case for export	Standard export packaging
MOQ	5 tons	Minimum order quantity

Annealed Alloy Steel Bars - High-Strength Heat-Treated Steel Rods for Industrial Use

Annealed alloy steel bars represent a critical category of heat-treated steel products engineered to deliver optimal mechanical properties for demanding industrial applications. Through controlled annealing processes, these bars achieve superior machinability, enhanced ductility, and uniform grain structure, making them the preferred choice for manufacturers requiring precision-machined components in automotive, aerospace, and heavy machinery sectors. Our mill-direct supply ensures consistent quality conforming to ASTM A29/A29M and SAE J1268 specifications.

What is Annealed Alloy Steel Bars?

Annealed alloy steel bars are heat-treated steel rods that undergo a controlled cooling process to refine their microstructure, reducing internal stresses while improving machinability and dimensional stability. The annealing treatment typically involves heating the alloy steel to 790-870°C followed by furnace cooling at rates of 10-25°C per hour, resulting in a ferritic-pearlitic structure with hardness values ranging from 170-220 HB depending on alloy composition.

Annealed alloy steel bars supplier

Annealed Alloy Steel Bars Technical Specifications

Our annealed alloy steel bars comply with ASTM A322 Standard Practice for Steel Bars, with chemical composition tolerances per ASTM A29/A29M-20. Typical grades include 4140 (0.38-0.43% C, 0.80-1.10% Cr, 0.15-0.25% Mo), 4340 (0.38-0.43% C, 1.65-2.00% Ni, 0.70-0.90% Cr), and 8620 (0.18-0.23% C, 0.40-0.70% Ni, 0.40-0.60% Cr). Tensile strength ranges from 655-850 MPa with elongation values of 18-25% in 50mm gauge length per ISO 6892-1 testing protocols.

Why Choose Our Annealed Alloy Steel Bars

We maintain ISO 9001:2015 certified production facilities equipped with continuous annealing furnaces ensuring temperature uniformity within ±5°C across the entire heating zone. Our bars undergo 100% ultrasonic testing per ASTM A388 to guarantee internal soundness, with surface finish meeting Ra 3.2μm standards. Material test certificates per EN 10204 Type 3.1 accompany every shipment, documenting full traceability from heat number to mechanical properties verification.

Frequently Asked Questions

What is the minimum order quantity (MOQ)?

Our standard MOQ is 5 metric tons per grade and size combination. For prototype requirements or specialized diameters, we accommodate orders as low as 1 metric ton with adjusted lead times. Mixed-grade containers are available for orders exceeding 10 tons to optimize logistics costs.

Do you provide material test certificates?

Yes, we supply EN 10204 Type 3.1 certificates as standard, issued by our accredited in-house laboratory holding ISO/IEC 17025 accreditation. Certificates include chemical analysis via optical emission spectrometry, tensile testing results per ASTM E8, hardness measurements, and grain size determination according to ASTM E112. Third-party inspection by SGS, TÜV, or Bureau Veritas can be arranged upon request.

Annealed alloy steel bars manufacturer

What is the typical delivery time?

For stock sizes in 4140 and 8620 grades (diameters 25-150mm), delivery occurs within 15-20 working days FOB Shanghai. Custom annealing cycles for non-standard grades require 35-45 days from order confirmation. Expedited processing is available with 10-day delivery for surcharges of 15-20% on orders below 10 tons.

Can you cut to custom sizes?

Our precision sawing capabilities handle lengths from 500mm to 6000mm with tolerances of +0/-3mm per ASTM A29 requirements. Saw-cut surfaces achieve roughness values below Ra 12.5μm. For applications requiring tighter tolerances, we offer CNC turning services providing diameter tolerances of h9 and straightness within 0.5mm/meter per DIN 1013 standards.

Get a Competitive Quote for Annealed Alloy Steel Bars

Request your customized quotation today by submitting your specifications including grade, dimensions, quantity, and delivery requirements. Our technical sales team responds within 8 business hours with mill-direct pricing, material availability confirmation, and tailored logistics solutions. Volume buyers benefit from quarterly contract pricing with locked rates and priority production scheduling.

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Ratings & Reviews

5.0

Very satisfied

Based on 8 reviews for verified purchases

Supplier service

5.0

On-time shipment

5.0

Supplier service

5.0

John Anderson

United States

verified purchases

2025-09-07

Perfect Annealed Bars for Aerospace Tooling
Sourced 4 tons of 4340 annealed bars (diameter 120mm) for aerospace fixture manufacturing. Compared quotes from 5 suppliers - this supplier offered best combination of quality certification and lead time. Material exceeded expectations: yield strength 530 MPa, Charpy impact 85J at room temperature. Grain size uniformity ASTM 6-7 throughout cross-section confirmed by our metallurgical lab. CNC machining performance excellent with tool life 15% better than previous supplier. Full traceability to original mill heat with batch sampling records included.

William Taylor

Australia

verified purchases

2025-09-25

Acceptable Quality with Initial Documentation Delay
Ordered 5 tons of 4140 bars (diameter 55mm, length 4000mm) for marine propeller shaft blanks. Material quality acceptable - hardness 195 HB, tensile strength 698 MPa met minimum requirements. Initial shipment missing EN 10204 certificates, but supplier sent complete documentation within 48 hours after our request. Bars required additional straightening (0.8mm/meter vs specified 0.5mm/meter). Supplier offered 5% discount on next order as compensation. Product usable after minor rework. Communication improved significantly after initial issues.

Carlos Silva

Brazil

verified purchases

2025-10-14

Solid Quality 8620 Bars for Gear Manufacturing
Bought 7 tons of 8620 annealed bars (diameter 65mm) for carburizing applications. Material certificates showed nickel at 0.52%, chromium at 0.48% - good for our heat treatment process. Decarburization depth less than 0.15mm met our specifications. Price competitive compared to four other Asian suppliers we evaluated. One batch had slight surface scratches (within ASTM A29 tolerance) but didn't affect machining. Overall good value for production runs requiring subsequent case hardening.

Ahmed Al-Hassan

UAE

verified purchases

2025-11-02

Premium Annealed Bars for Oil Field Equipment
Ordered 15 tons of mixed grades (4140 and 4340) for oilfield drilling equipment. Bars arrived with detailed heat treatment charts showing annealing temperature profiles - heated to 845°C, furnace cooled at 15°C/hour. Microstructure analysis confirmed uniform ferritic-pearlitic structure. All bars passed our third-party SGS inspection for NACE MR0175 compliance requirements. Packaging was excellent with rust prevention and clear heat number marking. Delivery to Jebel Ali port completed in 19 days as promised.

Robert Brown

United Kingdom

verified purchases

2025-11-20

Reliable 4140 Bars for Hydraulic Cylinder Production
Third repeat order - 10 tons of 4140 annealed bars in mixed diameters (40mm, 60mm, 80mm). Consistent quality across all three orders over past 8 months. Chemical composition variance less than 0.02% between heats. Annealing uniformity excellent with hardness spread only 8 HB across 6-meter lengths. Cut-to-length service at 2500mm with +0/-2mm tolerance saved us significant processing time. ISO 9001 certification and traceability documentation always complete. Recommended for high-volume hydraulic component manufacturers.

Hans Mueller

Germany

verified purchases

2025-12-08

Good Quality Bars with Competitive Pricing
Purchased 6 tons of 4340 annealed bars (diameter 80mm) for heavy machinery crankshafts. Material quality met our DIN 1.6582 equivalent specifications. Tensile strength at 745 MPa, elongation 21% in 50mm gauge. Pricing was 8% lower than European suppliers we compared. Minor delay of 3 days beyond quoted 35-day lead time due to customs documentation, but supplier proactively communicated. Straightness within 0.4mm/meter exceeded DIN 1013 requirements. Would order again for cost-sensitive projects.

James Wilson

United Kingdom

verified purchases

2025-12-23

Outstanding Service and Technical Support
Needed urgent 12-ton shipment of 8620 annealed bars (diameter 100mm, length 3000mm) for gear manufacturing project. Sales team responded within 6 hours with detailed technical data sheets and mill test certificates from previous batches. They arranged expedited processing and delivered in 11 days instead of standard 20 days. Surface finish measured Ra 2.8μm, better than our Ra 3.2μm requirement. This is our fourth order this year. Their technical knowledge of case-hardening steels is exceptional.

Michael Chen

Singapore

verified purchases

2026-01-07

Excellent 4140 Annealed Bars for Automotive Components
Ordered 8 tons of 4140 annealed bars (diameters 50mm and 75mm) for automotive transmission shafts. Material certificates confirmed carbon at 0.41%, chromium at 0.95%, molybdenum at 0.20% - all within ASTM A29 specs. Hardness tested at 187 HB, perfect for our CNC machining requirements. Grain size ASTM 7-8 provided excellent machinability. Ultrasonic testing reports showed zero internal defects. Delivered FOB Shanghai in 18 days with full EN 10204 Type 3.1 documentation.