Hot Billet Chain

The Hot Billet Chain (also designated as a specialized Hot Billet Conveying Chain or Heavy Duty Roller Chain for Hot Bars) is a high-integrity, robust mechanical transmission component engineered specifically for continuous steel rolling mills and thermal processing lines. Operating as a critical element within the Billet Cooling Bed Chain network, this Conveyor Chain is designed to withstand extreme thermal radiation up to 900°C from newly rolled steel bars and billets, ensuring smooth, synchronized transverse and longitudinal material transfer under heavy mechanical loads.

 

 

1. Working Principles

The operational mechanics of this Conveyor Chain for Steel Mill applications rely on precision power transmission and load distribution across heavy-duty tracks:

 

Synchronized Mechanical Drive & Power Transmission:

Driven by high-torque sprockets (e.g., pitch diameter Ø326.6 mm with 8 teeth, per famous industry brand Danieli engineering standards), the chain converts rotational motion into linear motion, moving heavy billets across cooling beds at controlled speeds (~0.7 m/s).

 

Thermal Radiation Management & Load Support:

The chain links and rollers support massive distributed loads while maintaining structural integrity under continuous ambient temperatures up to 300°C on the chain body and in direct contact with ~900°C hot bars.

 

Friction Reduction via Precision Rollers:

Equipped with precision-machined internal sleeves and external rollers, the assembly minimizes sliding friction against guide tracks, ensuring smooth cycling (120 cycles/hour) without jamming or uneven wear.

 

2. Core Parameters & Mechanical Performance Indicators

Manufactured in strict accordance with OEM design customers' drawing files and verified by rigorous quality inspections, the technical attributes are outlined below:

 

No.	Technical Attribute	Specification / Value	Performance Standard
1	Chain Pitch	125 mm	Precision CNC Machined
2	Breaking Load	440 kN	High Tensile Strength
3	Chain Plate Hardness	HRC 45 – 50	Wear & Fatigue Resistant
4	Pin Shaft Hardness	HRC 32 – 38	High Shear Strength / Toughness
5	Sleeve Hardness	HRC 38 – 42	Surface Hardened & Ground
6	Roller Hardness	HRC 45 – 50	Impact & Abrasion Resistant
7	Max Operating Temperature	300°C (Chain Body) / ~900°C (Billet Contact)	Thermal Stability
8	Working Cycle Speed	120 Cycles / Hour (~0.7 m/s)	High Duty Cycle Endurance
9	Total Length & Link Count	8,750 mm / 6,250 mm (N50 / N70 Links)	Customizable OEM Match
10	Material Grade	40Cr Alloy Steel (Forged & Heat Treated)	Metallurgical Certification

 

3. Material Composition (40Cr Alloy Steel)

To guarantee exceptional mechanical strength, wear resistance, and thermal fatigue life, all Roller Chain Spare Parts are forged from premium 40Cr alloy steel. Chemical composition verification from quality inspection reports confirms strict adherence to metallurgical standards:

 

Element	Tested Composition (%)	Standard Requirement (%)	Status
Carbon (C)	0.38%	0.37 – 0.40%	Pass
Silicon (Si)	0.20%	0.17 – 0.37%	Pass
Manganese (Mn)	0.91%	0.80 – 1.10%	Pass
Phosphorus (P)	0.024%	≤ 0.035%	Pass
Sulfur (S)	0.002%	≤ 0.035%	Pass
Chromium (Cr)	0.63%	0.50 – 0.80%	Pass
Nickel (Ni)	0.09%	≤ 0.03% (Trace)	Pass

 

4. Common Operational Issues & Professional Solutions

Issue 1: Thermal Fatigue & Surface Cracking on Outer Links due to extreme radiation.

 

Solution: Employ vacuum quenching and high-temperature tempering processes on 40Cr steel, establishing controlled surface hardness (HRC 45–50) while preserving core toughness to absorb shock loads.

 

Issue 2: Accelerated Pin and Bushing Wear from scale buildup and dry friction.

 

Solution: Implement induction hardening on pin shafts (HRC 32–38) and sleeves (HRC 38–42), combined with automated high-temperature synthetic lubrication intervals to purge mill scale.

 

Issue 3: Chain Elongation (Pitch Stretching) under heavy periodic shock loads.

 

Solution: Utilize precision pitch control (125±0.1 mm tolerance) during assembly and execute pre-stretching testing prior to delivery to eliminate initial settling stretch.

 

5. Brand Compatibility & Mainstream Industrial Applications

Designed as direct, high-performance drop-in replacements for OEM systems originating from major metallurgical plant builders such as Danieli, SMS Demag, and Siemens VAI, this hot billet chain serves three core industrial applications:

 

Billet Cooling Beds: Safely transferring hot steel billets (~900°C) away from rolling stands to ambient cooling zones.

 

Walking Beam & Walking Hearth Furnaces: Facilitating precise, step-by-step transfer of heavy slabs and bars inside thermal reheating lines.

 

Hot Bar Transfer Lines: Operating heavy-duty roller tables and transfer chains where shock absorption and high tensile breaking loads (440 kN) are mandatory.

 

6. Manufacturing Process & Critical Quality Control Points

The production of our industrial chain lines follows strict manufacturing protocols with rigorous checkpoints:

 

Step 1: Precision Forging & Electro-Slag Remelting (ESR) Inspection: Raw 40Cr steel bars undergo ultrasonic testing (UT) to eliminate internal inclusions and micro-voids before hot forging.

 

Step 2: CNC Machining & Tolerance Control: Pin bores, bushings, and link profiles are machined on high-precision CNC centers to maintain strict geometric tolerances (e.g., pin diameter Ø25 mm, width tolerances within ±0.1 mm).

 

Step 3: Controlled Heat Treatment & Hardness Verification: Components undergo specialized thermal treatment followed by multi-point Rockwell hardness testing across chain plates, pins, and rollers to ensure wear profile compliance.

 

7. Quality Assurance & Certification Standards

100% Dimensional & Metallurgical Inspection: Every production batch is delivered with a comprehensive Material Testing Report certifying chemical composition, tensile strength, and hardness gradients.

 

Traceability & Permanent Marking: Each link assembly is laser-engraved with part numbers and production batches for complete manufacturing accountability.

 

Rigorous Factory Acceptance Testing (FAT): Pre-shipment verification includes assembly smoothness checks, pitch accuracy measurement, and protective anti-corrosion packaging (oil coating, plastic wrapping, and secure steel strapping).

 

 

8. FAQ

Q1: Can this Hot Billet Conveying Chain directly replace original Danieli spare parts without altering track dimensions?

 

A1: Yes. Our chains are engineered strictly in accordance with original equipment dimensions (e.g., 125 mm pitch, Ø80 mm rollers, and exact pin centers), ensuring seamless drop-in replacement without requiring modifications to existing sprockets or guide tracks.

 

Q2: What is the expected service life of the Billet Cooling Bed Chain under continuous 24/7 heavy steel mill operation?

 

A2: Under recommended high-temperature lubrication protocols and proper tension maintenance, our 40Cr induction-hardened chains typically achieve an extended operational lifespan of 18 to 36 months, significantly reducing mill downtime.

 

Q3: How are the chains packaged and protected against marine corrosion during international export shipping?

 

A3: All chains are treated with high-grade anti-rust industrial oil, wrapped tightly in heavy-duty plastic sheeting and bubble film, and securely bundled on robust steel-reinforced wooden pallets suitable for bulk or container shipping.

 

Q4: What technical details must we provide when ordering custom or non-standard Conveyor Chain lengths?

 

A4: To ensure exact compatibility, please provide your OEM drawing number (e.g., Danieli, SMS part number, etc), total chain length, link count (e.g., N50 or N70), pitch size, and operating temperature range. 

 

9. Get in Touch for Your Custom Mill Solutions

Ready to upgrade your steel mill's conveying efficiency? Contact our technical sales engineering team today at Hongkong Ting Xuan Industrial Co., Ltd. for competitive pricing, customized drawings, and rapid-response quotations on all heavy-duty rolling mill spare parts. We welcome global inquiries and OEM partnership discussions!

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