A SAG mill runs a high ball charge at low speed, so grinding media must survive repeated high-energy impacts instead of pure abrasion. Grindium SAG balls are hot-forged from 60Mn, 65Mn, 70Mn and B2/B3 round bar, then quenched and tempered to HRC 58-62 with an impact toughness of 15 J/cm2 or more.
Balls are supplied from 90 mm to 150 mm. Use the single-ball weight table below for ball charge calculations: a 60 t charge of 100 mm balls is roughly 14,600 pieces, while the same tonnage in 150 mm balls is about 4,300 pieces.
SAG ball sizes and unit weight
Diameter (mm)
Unit weight (kg)
Hardness (HRC)
Impact (J/cm2)
Breakage
90
3.0
58-62
>=15
<=0.5%
100
4.1
58-62
>=15
<=0.5%
110
5.5
58-62
>=15
<=0.5%
120
7.1
58-62
>=15
<=0.5%
125
8.0
58-62
>=15
<=0.5%
130
9.0
58-62
>=15
<=0.5%
140
11.3
58-62
>=15
<=0.5%
150
13.9
58-62
>=15
<=0.5%
Chemical composition
Grade
C (%)
Si (%)
Mn (%)
Cr (%)
Mo (%)
60Mn
0.57-0.65
0.17-0.37
0.70-1.00
0-0.25
0-0.30
65Mn
0.62-0.70
0.17-0.37
0.90-1.00
0-0.25
0-0.30
70Mn
0.67-0.75
0.17-0.37
0.90-1.20
0-0.25
0-0.30
B2
0.70-0.80
0.17-0.37
0.70-0.80
0.50-0.60
0-0.30
B3
0.58-0.66
1.20-1.60
0.65-0.80
0.70-0.90
0-0.30
Where SAG balls are used
SAG mills in copper concentrators, 28-40 ft diameter
Gold and silver SAG circuits with high impact energy
Iron ore and platinum group metal primary grinding
AG mills that run a 6-12% ball charge as top-up media
Quality control
Forged from continuous-cast round bar – no casting shrinkage or sand inclusions
Through-hardened, not surface-hardened, so the ball keeps its hardness as it wears
Hardness checked on a cross section (surface, half radius and core) for every heat
8 m drop test and 12,000-cycle impact test on each production lot
Breakage rate below 1% guaranteed; typical result below 0.5% in SAG service
Packing and delivery
Packing
Net weight
20 ft container
40 ft container
Bulk bag
1,000 kg
25 t
27 t
Steel drum
850-900 kg
23-24 t
26 t
Plywood pallet + big bag
2,000 kg
22 t
24 t
Lead time is 20-30 days for a 20-100 t order, ex-works Shandong or FOB Qingdao. Send the mill size, ore type and current consumption (g/t) and we will recommend a ball size make-up and a quotation. Request a SAG ball quotation.
Start from the feed F80: 100 mm feed suits 80-90 mm balls, 150 mm feed suits 100-110 mm, and 200-250 mm feed suits 125-150 mm. Confirm with your power draw and ball charge after one lining cycle.
What is the unit weight of each size?
90 mm = 3.0 kg, 100 mm = 4.1 kg, 110 mm = 5.5 kg, 120 mm = 7.1 kg, 125 mm = 8.0 kg, 130 mm = 9.0 kg, 140 mm = 11.3 kg, 150 mm = 13.9 kg.
Which grade is used for SAG duty?
60Mn, 65Mn, 70Mn and B2/B3, quenched and tempered to HRC 58-62 with impact toughness of 15 J/cm2 or more.
What is the MOQ and lead time?
MOQ is 20 tonnes per size for a first order; a 5 tonne trial lot is available if you need to test the media in your mill. Lead time is 20-30 days for 20-100 tonnes and 30-40 days above that, ex-works Shandong or FOB Qingdao.
Can you recommend a make-up charge?
Yes - send the mill size, ore type, current consumption in g/t and the ball charge, and we will propose a size mix and top-up schedule.
