Product Name
Round Steel for Mechanical Parts (Precision & Engineering Round Bar)
Introduction
Round steel for mechanical parts are solid cylindrical bars supplied in a range of materials, diameters and supply conditions specifically intended as blanks or semifinished stock for shafts, pins, journals, axles, rollers, bushings and machined components. They are produced to deliver consistent geometry, controlled metallurgy, tight tolerances and surface quality so downstream machining, heat-treatment and assembly are efficient and predictable.
Typical Materials & Grades
Carbon steels: C15, C45 / 1045 (general-purpose, easy to machine or heat-treat).
Alloy steels: 4140 / 42CrMo, 4340 (higher strength, quench & temperable).
Tool & bearing steels: 52100, AISI H-series (wear- and fatigue-resistant applications).
Stainless: 303 (free-machining), 304/304L, 316/316L, 17-4PH (corrosion resistance / precipitation-hardening).
Special alloys: nickel alloys, duplex stainless, or custom chemistries on request.
Supply Conditions & Finishes
Hot-rolled (as-rolled): economical for larger diameters, standard surface finish.
Cold-drawn / cold-rolled bright: tighter diametral tolerances, better surface finish and improved mechanical properties.
Precision ground / turned & ground: for bearing journals, sealing surfaces and tight OD tolerances.
Quenched & tempered / normalized / annealed / case-hardened / induction-hardened: provided per part requirements.
Surface protection: pickled & oiled, VCI wrapped, black-oxide, phosphate, or coated for corrosion protection.
Typical Sizes & Tolerances
Diameter range (typical): Ø3 mm → Ø800 mm (custom larger by forging/machining).
Lengths: cut-to-length (1–12 m typical), standard mill lengths 3 / 6 / 12 m; single-piece length limited by transport/handling.
Tolerances (typical):
Hot-rolled: ±0.3 → ±2.0 mm depending on diameter.
Cold-drawn bright: ±0.02 → ±0.2 mm.
Precision ground: down to ±0.005 → ±0.02 mm.
Straightness: typical ≤ 0.5 – 2.0 mm/m (tighter for precision shafts). Specify class for critical parts.
Mechanical Properties (guidance - grade & heat treatment dependent)
Carbon steels (C45 normalized): yield ~300–400 MPa, tensile ~600–800 MPa.
4140 quenched & tempered: yield ~700+ MPa, tensile ~900–1200 MPa (varies with temper).
Stainless 304 (cold-drawn): tensile ~520–750 MPa (strain-hardened).
Exact properties will be supplied by MTC per selected grade and heat-treatment.
Weight Calculation (quick)
Mass per metre (kg/m) ≈ 0.0061654 × (diameter in mm)²
Examples:
Ø10 mm → ≈ 0.62 kg/m
Ø25 mm → ≈ 3.85 kg/m
Ø50 mm → ≈ 15.41 kg/m
Ø100 mm → ≈ 61.65 kg/m
Key Features & Advantages
Dimensional accuracy & surface quality - reduces machining allowance and cycle time.
Material & thermal flexibility - available in grades and supply conditions to meet strength, wear and corrosion needs.
Good machinability - options for free-machining grades or annealed supply for heavy cutting.
Improved fatigue & toughness - forging/cold-drawing and controlled heat-treatment routes available for critical rotating parts.
Traceability & certification - MTC and test reports per order.
Typical Applications
Shafts, spindles, axles and pins.
Bearing journals, rollers and cam shafts.
Gear blanks, couplings and hubs.
Fastener blanks, studs and dowel pins.
Machine-tool components, hydraulic pistons and valve stems.
Quality Assurance & Testing
Mill Test Certificate (MTC): chemical and mechanical results with heat number traceability.
Dimensional inspection: OD, straightness and length reports; roundness and runout checks for precision ground bars.
Mechanical testing: tensile, yield, hardness and Charpy impact tests as required.
NDT options: ultrasonic (UT), magnetic particle (MT) or dye-penetrant (PT) for critical parts.
Metallography: grain flow or microstructure checks for forged/critical components on request.
Value-Added Services
Cut-to-length, end chamfering & facing.
Precision turning / grinding / centerless grinding to final journal tolerances.
Keyways, splines, threads, holes and drilling prior to shipment.
Heat-treatment cycles (quenched & tempered, case hardening, nitriding, induction hardening).
Balancing, straightening and shot-peening for rotating components.
Kitting & labeling for production-line delivery.
Packaging & Delivery
Bundled on timber skids with polymer spacers; individual crating for precision/ground bars.
Protection: VCI paper/oil, plastic end caps for ground ends.
Handling: lifting lugs or cradles provided for heavy single pieces.
Lead time: stock/standard grades 1–6 weeks; forged, heat-treated or precision-ground orders 4–12+ weeks depending on size and quantity.
Ordering Information - What We Need
Please provide:
Diameter × length × quantity (or a size list).
Material grade and required supply condition (hot-rolled / cold-drawn / ground / heat-treated).
Tolerance class and straightness requirement.
Surface finish / protection and any machining features (keyways, threads, splines).
Required tests/certificates (MTC, tensile, hardness, NDT) and delivery schedule.
Application notes (rotating shaft, bearing journal, forging blank) so we can recommend best grade and processing.
If you like, send your diameter/quantity list and intended use for each size - I'll produce a size-to-weight table, recommend grades and supply conditions for shafts vs bearing journals, and estimate machining allowances.
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