20-40 mm B2 Forged Steel Grinding Balls for Copper Ore Secondary & Fine Grinding

Product Description

20-40mm B2 Forged Steel Grinding Balls for Copper Ore Secondary & Fine Grinding
UpdateAugust 14th, 2026

Small-Diameter Grinding Media for Secondary Ball Mills and Regrind Circuits

JUNDA B2 forged steel grinding balls in 20-40 mm diameters are designed for copper ore secondary grinding, fine grinding, and selected regrind applications.

Available in 20, 25, 30 and 40 mm diameters, JUNDA B2 grinding balls can be selected according to mill type, feed size, target P80, ore characteristics and grinding circuit configuration.

Why Use 20-40 mm Grinding Balls for Copper Ore?

As copper ore progresses from primary size reduction to secondary and fine grinding, the required grinding media size typically becomes smaller. Smaller grinding balls provide a larger number of grinding media per unit mass and can increase the number of grinding contacts in appropriate fine-grinding circuits.

JUNDA 20-40 mm B2 forged grinding balls are designed for these applications, where the objective is to achieve efficient size reduction and mineral liberation rather than high-energy primary grinding.

More Grinding Contacts

Smaller balls provide a larger number of individual grinding media within the same grinding charge, supporting more frequent grinding contacts.

Fine Particle Size Reduction

20-40 mm media can be considered when the grinding circuit requires a finer product size than the preceding primary grinding stage.

Controlled Wear

B2 hardness is designed to provide a balance between wear resistance and mechanical integrity.

Flexible Size Selection

20, 25, 30 and 40 mm sizes allow the grinding media to be matched to different feed sizes and target P80 requirements.

B2 Steel Chemical Composition
Element	C	Si	Mn	Cr	P	S
Typical Range	0.75-0.85%	0.17-0.35%	0.70-0.90%	0.40-0.60%	≤0.035%	≤0.035%

 Technical Specifications

Material	Diameter	Surface Hardness	Core / Volume Hardness	Typical Application	Impact Toughness	Breakage Rate
B2	20 mm	63-66 HRC	63-66 HRC	Fine Grinding / Regrind	≥12 J/cm²	<1%
	25 mm	63-66 HRC	63-66 HRC	Fine Grinding
	30 mm	63-66 HRC	63-66 HRC	Secondary Grinding
	40 mm	62-66 HRC	62-66 HRC	Secondary Grinding
Note: These are general selection guidelines. The optimum ball size should be determined according to feed size, target P80, ore hardness, mill diameter, mill speed, ball charge and circuit configuration. Test results depend on ball size, test method and operating conditions. Actual performance should be evaluated according to the applicable test standard or customer operating data.

Key Factors for Selecting Grinding Balls for Copper Ore

Factor

Why It Matters

Feed Size

Determines the required impact and grinding action

Target P80

Finer targets may require smaller grinding media

Ore Hardness

Influences wear rate and grinding energy

Mill Diameter

Affects impact intensity

Mill Speed

Influences ball trajectory and grinding action

Ball Charge

Affects grinding media interactions

Ore Mineralogy

Influences abrasion and liberation behavior

Current Media Size Distribution

Helps optimize the replacement or top-up strategy

Typical Target P80 Ranges

Grinding Stage	Typical P80 Range*
Secondary Grinding	75-150 μm
Fine Grinding / Regrind	38-75 μm
Typical reference ranges only. Actual P80 depends on ore characteristics, mill configuration, classification efficiency and operating conditions.

Applications in Copper Ore Grinding

Secondary Ball Mill Grinding

20-40 mm B2 grinding balls can be used in secondary ball mills to further reduce particle size after primary grinding.

Fine Grinding

Smaller grinding media can be selected when the circuit requires finer particle size reduction and improved mineral liberation.

Regrind Circuits

20-30 mm grinding balls can be considered for regrind applications where fine particle size and mineral liberation are required.

Packaging Type	Ball Size	Net Weight
Container Bag (Net weight: 1,000 kg for all sizes)	20-30 mm	930-1,000 kg
	40-60 mm	900-930 kg
	70-90 mm	830-880 kg
	100 mm and above	830-850 kg
	Steel Drum - 60 x 90 cm, 15-20 kg, 0.25 CBM

Bag: 73 x 60 cm, 1.5 kg, 0.252 CBM | Pallet (single): 60 x 60 x 9 cm, 4-6 kg | Pallet (double): 120 x 60 x 10 cm, 12-14 kg

Company Profile

Certifications

FAQ

Q1: What is the advantage of your company?
A: JUNDA has more than 20+ years of experience in grinding media manufacturing, with established production and quality-control systems for forged and cast grinding balls.
Q2. In which countries are your products sold?
A:Our products are exported to customers in the Americas, Africa, Asia, Australia, and other international markets, including Mexico, Canada, Brazil, Tanzania, and Ghana.
Q3: Are you trading company or manufacturer?
A: We are a manufacturer with our own production facilities for forged steel grinding balls and other grinding media.
Q4: How long is your delivery time?
A:Typically, our delivery time is 10-15 days, depending on order quantity and production schedule.
Q5: Do you provide samples? Is it free or extra?
A:Yes. We can provide samples at no charge, while the customer is responsible for the freight cost.
Q6: What are your terms of payment?
A:We normally accept T/T: 30% deposit and 70% upon receipt of the copy of the B/L. L/C at sight is also available upon agreement.
Q7: What standards and quality controls do you use for B2 forged steel grinding balls?
A: We control raw material composition, forging, heat treatment, hardness, dimensional accuracy, and other key parameters according to the applicable product specifications. Material certificates and inspection reports can be provided upon request.
Q8: What is the hardness index of Junda Steel Balls and how is the uniformity ofhardness guaranteed?
A:For this 20-40 mm B2 product, the typical surface and core/volume hardness is 62-66 HRC, depending on ball size and applicable specifications.
Q9: Can the size specifications and tolerances of the steel balls meet the overseasrequirements?

A: Junda can produce full specifications of wear-resistant steel balls ranging from 20 mm to 40 mm. The dimensional tolerance is controlled within ±0.3 mm to ±1 mm, and the sphericity/ellipticity is 0.2 mm. The fully automatic production lineensures precise dimensions, making them suitable for various imported grindingmills.