JB/T 7018-2015 is the dedicated industry standard for crane rail selection, laying, installation, and acceptance inspection, covering the design and construction of rail systems for all types of rail-mounted lifting equipment. Selecting the appropriate rail type and following the standard's requirements for installation and maintenance are essential to ensuring safe crane operation and maximizing rail service life.

Rail Types and Selection Criteria

JB/T 7018-2015 classifies crane rails into two main categories: railway rails (P-type) — P38, P43, P50, and P60 (the number indicates weight per meter in kg/m), made from U71Mn or U75V steel, with a narrower base suited for lighter wheel loads. Crane-specific rails (QU-type) — QU70, QU80, QU100, and QU120 (the number indicates rail head width in mm), made from U71Mn or U76CrRE steel, featuring a wider and thicker head and a heavier web, designed for cranes with higher wheel loads.

Rail selection guidelines: for wheel loads below 200 kN, P43 or P50 rails are suitable; for wheel loads between 200 and 350 kN, QU70 or QU80 rails should be used; for wheel loads above 350 kN, QU100 or QU120 rails are required. Standard rail lengths are 12.5 m and 25 m. U71Mn rails offer a tensile strength of ≥880 MPa and a rail head hardness of HB260–300; U75V rails provide a tensile strength of ≥980 MPa and a hardness of HB280–340, delivering superior wear resistance for heavy-duty crane service.

Rail Laying and Installation Requirements

Rail foundation — rails must be laid on a concrete rail foundation (or steel beams) with a concrete strength grade of at least C30, and the foundation width should be no less than three times the rail base width. After installation, the elevation deviation of the rail head surface must be within ±5 mm along the full length of a single rail, and the height difference between two rails at the same cross-section must not exceed 5 mm (for spans under 30 m) or 7 mm (for spans of 30–50 m).

Track gauge deviation must be within ±3 mm (measured every 5 m), with a cumulative deviation of no more than ±10 mm over the full rail length. Rail joint gaps: 2–4 mm for normal-temperature installation; 1–2 mm in summer; 4–6 mm in winter. Vertical misalignment and lateral offset at rail joints must both be ≤1 mm. Rails are secured using rail clamps (one clamp point every 500–600 mm), with an elastic pad (rubber or plastic) placed between the clamp and the rail.

Rail Joints and Accessories

Fishplates — rail joints are connected using fishplates (4-hole or 6-hole), with a material grade of at least Q345B (≈S355J2). Connection bolts must be high-strength bolts of Grade 8.8. Rail clamps are available in welded and bolted types. Under normal wheel loads, clamp plate spacing should be ≤600 mm; under heavy wheel loads, ≤500 mm.

Track tie rods — for spans of 20 m or more, track tie rods must be installed (one every 5–8 m), with a rod diameter of at least 20 mm. Rail earthing resistance must be ≤4 Ω. For rail runs exceeding 100 m in length, expansion joints must be provided (with a 50–100 mm gap connected by an expansion joint assembly) to accommodate thermal expansion and contraction of the rail.

Rail Inspection and Maintenance

Installation acceptance — after laying is complete, a full-line inspection is carried out, covering track gauge (measured every 5 m), elevation (measured every 2 m), straightness (using the string-line method), joint gaps, and joint height differences. A thorough examination is required every three months: check for loose clamp plates, crushed elastic pads, and waviness wear (grind down if wave depth exceeds 1 mm).

Rail replacement criteria: replace the rail when vertical head wear exceeds 15% of the original height; replace when side wear exceeds 10% of the rail head width; replace immediately if any cracks are found. It is recommended to perform a visual inspection monthly, a precision measurement quarterly, and a comprehensive evaluation annually.

Kelude Heavy Industry: Overhead & Gantry Crane Solutions

Kelude Heavy Industry specializes in the design, engineering, and manufacturing of heavy-duty overhead cranes, gantry cranes, and electric hoists. Our product range covers a wide spectrum of applications, from general manufacturing and warehousing to demanding steel mill, power plant, and port operations. With a focus on safety, reliability, and performance, we deliver tailored material handling solutions that enhance productivity and operational efficiency.

Frequently Asked Questions (FAQ)

Q: What is the typical lead time for a standard overhead crane?
A: Lead times vary depending on the crane's specifications and complexity. For standard single-girder cranes, lead time is typically 4-6 weeks. Double-girder cranes and custom designs may require 8-12 weeks. We provide a confirmed delivery schedule upon order confirmation.

Q: Do you provide installation services?
A: Yes, we offer professional installation services by our trained technicians or through our certified local partners. Installation time depends on the crane size and site conditions. We also provide detailed installation manuals and videos for self-installation if preferred.

Q: What safety certifications do your cranes comply with?
A: Our cranes are designed and manufactured in accordance with international standards, including ISO 4301 (crane classification), ISO 12480 (safe use), and IEC 60204-32 (electrical equipment). We can also provide documentation to support compliance with local regulations and third-party inspections.

Q: Can you customize a crane to fit an existing building?
A: Absolutely. We frequently adapt our crane designs to fit existing structures, considering factors such as column spacing, available headroom, and runway beam capacity. Our engineering team will conduct a site assessment or review your drawings to provide a tailored solution.

Q: What is your warranty policy?
A: We offer a standard warranty of 12 months from the date of commissioning, covering defects in materials and workmanship. Extended warranty options are available upon request. Our warranty includes free replacement of faulty parts and technical support.

Q: How do I choose between a wire rope hoist and a chain hoist?
A: Wire rope hoists are generally preferred for higher capacities, higher lifting speeds, and longer hook travel. Chain hoists are more compact and cost-effective for lighter loads and lower duty cycles. Our sales engineers can help you select the most suitable type based on your specific application.

Q: Do you supply spare parts for cranes not manufactured by you?
A: In some cases, yes. We can supply compatible spare parts for various crane brands, including motors, brakes, control systems, and wire ropes. Please provide the original part number or specifications for a compatibility check.

Q: What are the payment terms?
A: Our standard payment terms are 30% advance payment by T/T, with the balance due before shipment. For large projects, we can negotiate milestone payments based on project progress. We also accept L/C for certain orders.

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