Product Overview
Industrial-grade alloy steel square bars supplied in hot-rolled, forged, or cold-drawn conditions. Engineered for high-load mechanical components, structural frameworks, and heavy-machinery parts requiring high tensile strength, wear resistance, and impact toughness after heat treatment. Supported by in-house 2000T heavy forging lines and continuous production capacity to fulfill bulk industrial supply contracts.
Technical Specifications
|
Parameter |
Specification Details |
|
Available Grades |
AISI/SAE 4140, 4340, 8620, 5140, 6150; 42CrMo4, 34CrNiMo6, 16MnCr5 |
|
Size Range |
Hot Rolled: 16 mm - 250 mm; Forged: Up to 600 mm |
|
Delivery Condition |
Hot Rolled (HR), Annealed (A), Quenched & Tempered (Q+T), Peeled / Turned |
|
Length |
3 m - 6 m standard, or custom cut-to-length |
|
Dimensional Tolerance |
ASTM A29 / A29M, EN 10059, DIN 174 |
|
Surface Finish |
Black, Grit Blasted, Peeled, Ground (Tolerance to h9/h11) |
|
Testing Standards |
ASTM, DIN, EN, JIS, ISO 9001, IATF 16949 |
Product Advantages
Controlled Hardenability:
Strict chemical composition limits per ladle analysis ensure predictable response during client quenching and tempering processes.
Internal Soundness:
Vacuum degassing and refining processes minimize non-metallic inclusions, reducing risk during deep-hole drilling or heavy milling.
Dimensional Stability:
Straightness controlled within 2 mm/m max deviation, minimizing vibration and runout during high-speed CNC machining.
Traceability:
Heat numbers hard-stamped on bars and mapped directly to EN 10204 3.1 Mill Test Certificates.
Applications
Power Transmission: Heavy-duty drive shafts, rotor shafts, high-torque industrial gears for wind energy and heavy machinery.
Oil & Gas Field Equipment: High-pressure mud pump shafts, drill collars, and critical downhole valve stems.
Tooling & Die: Mold bases, bolster plates, and heavy-duty structural clamping fixtures.
Automotive & Commercial Vehicle: Axle beams, steering knuckles, and high-stress suspension components.
Customization & Processing
Controlled atmosphere furnace lines for annealing, normalizing, and through-hardening (Q+T) up to 300 HBW hardness targets.
High-speed automatic band saws providing square ends with burr-free tolerances (± 0.5 mm).
Centerless grinding and peeling lines removing decarburized surface layers down to micro-inch surface roughness targets (Ra <= 1.6 um).
Quality Control & Inspection
Spectrometry: Direct-reading OES spectrometers verify carbon, chromium, molybdenum, and nickel percentages prior to release.
Non-Destructive Testing (NDT): 100% ultrasonic testing (UT) per ASTM A388 or SEP 1921 for internal defect detection.
Mechanical Testing: Tensile testing, Charpy V-notch impact testing at sub-zero temperatures, and Brinell/Rockwell hardness testing performed on every heat lot.
Packaging & Shipping
Bundle Packaging:
Secured with high-strength steel strapping and wrapped in woven moisture-resistant polyethylene sheeting.
Corrosion Protection:
VCI (Volatile Corrosion Inhibitor) paper interleaving or anti-rust oil coating applied for ocean freight.
Marking:
Weatherproof metal tags indicating steel grade, heat number, dimensions, piece count, and net/gross weight.
FAQ
Q: What is the difference between rolled and forged alloy steel square bars for machining?
A: Rolled bars are suitable for standard structural and medium-duty mechanical parts within stock sizes. Forged bars undergo heavy mechanical working via internal forging equipment which refines the grain structure throughout larger cross-sections, making them necessary for heavy-duty shafts and high-stress components requiring uniform transverse impact strength.
Q: Can you supply material with specific hardness ranges for direct CNC machining?
A: Yes. Bars can be delivered in the Quenched and Tempered (Q+T) condition pre-machined or pre-heat-treated to specific hardness brackets (e.g., 28-32 HRC) to balance machinability and final part strength.
Q: Are Mill Test Certificates (MTC) provided with every shipment?
A: Yes. Every order ships with an EN 10204 3.1 Mill Test Certificate detailing exact chemical composition, ladle analysis, heat treatment parameters, and mechanical test results matching the heat number on the bars.
Q: What is your standard minimum order quantity (MOQ) for custom sizes or grades?
A: MOQ depends on rolling or forging schedules. For standard stock grades (e.g., 4140), small trial orders or cut pieces are available. For custom mill rollings, MOQ typically starts at 3 metric tons per size/grade.
Q: How do you prevent rusting during international container transport?
A: Bars are coated with a neutral rust-preventative oil and bundled with VCI vapor-phase corrosion inhibitors inside seaworthy packaging to withstand maritime humidity during transit.
Q: What NDT inspection reports can be provided upon request?
A: Third-party inspection reports (SGS, TÜV, BV) along with internal Ultrasonic Testing (UT) logs and Magnetic Particle Inspection (MPI) results can be included per purchase order terms.
Request a Quote
Submit your required steel grade, dimensions, delivery condition, and target volume to receive a commercial proposal and material data sheet within 24 hours.
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