1. Pain Points in Grinding Rod Production

In mining ball-mill operations, grinding rods suffer from high impact, severe abrasion, and repeated contact stress. Many manufacturers face common failures:

• High hardness, but poor wear resistance

• Inconsistent structure, leading to bending or breakage

• Uneven hardening depth / “black skin” after quenching

• Large quality variations between batches

• Short service life and unstable performance in the mill

The root cause: unstable heat-treatment processes and insufficient temperature control.

2. Principle: Induction Heating + Quenching + Tempering

To achieve both hardness and toughness, grinding rods must be properly quenched and tempered.

① Fast & Uniform Heating (Induction Heating)

• Medium-frequency induction rapidly heats rods to the austenitizing range

• Strong penetration depth ensures uniform temperature

• No overheating or insufficient core temperature

② Controlled Quenching (Multi-zone Spray System)

• Adjustable flow & pressure in multiple zones

• Ensures uniform hardening depth around the circumference

• Minimizes distortion or bending

③ Secondary Tempering (Stabilizing the Structure)

• Converts brittle martensite to tempered martensite

• Improves core toughness

• Enhances impact resistance and long-term durability

The result is a hard surface, tough core, and excellent impact performance.

3. Yuantuo Solution: Complete Grinding Rod Heat-Treatment Line

With 20+ years of experience in induction heating systems, Yuantuo provides a full set of solutions:

✓ Induction Heating System (Quenching Section)

• Power range: 400 kW – 2000 kW

• Customized coil structure for strong penetration & uniform heating

• Infrared thermometers + PLC closed-loop control

✓ Multi-Zone Spray Quenching System

• Independent regulation of flow, pressure, and angle

• Higher uniformity in hardness and case-depth

• Reduced deformation or bending

✓ Induction Tempering Furnace

• Continuous online tempering

• Accurate temperature control for stable microstructure

✓ Conveying & Control System

• 304 stainless-steel water-cooled rollers

• Independent VFD drives on each roller

• IPC/PLC control, real-time parameter monitoring

• Recipe memory for fast size changeover

Supported Rod Range

Performance improvement for customers:
✔ Wear resistance ↑ 2–3 times
✔ Breakage rate ↓ significantly
✔ Stable hardness and case-depth
✔ Longer service life in ball mills

4. Case Study: Grinding Rod Producer (42CrMo, Ø50–90 mm)

Project Specs

• Rod diameter: Ø50–90 mm

• Material: 42CrMo

• Capacity: 2–3 tons per hour

• Configuration: One quenching line + One tempering line

Results

• Hardness: HRC 55 ±1

• Case-depth: 5–8 mm, highly uniform

• Service life increased by 2.2 times in the mill

• Repair/return rate reduced by ≈70%

Client feedback:
“Rod performance is stable, wear rate lower, and breakage almost eliminated.”

5. Looking for a Grinding Rod Heat-Treatment Line?

Yuantuo has delivered reliable induction Q&T lines to mining suppliers worldwide.

👉 Share your rod diameter and production capacity, and we will prepare a complete technical solution and quotation.