High Chromium Casting Steel Cylpebs

Diameter tolerance and Length tolerance

Diameter（mm)	8×10	10×12	12×14	14×16	16×18	18×20	20×25
	25×30	30×35	35×40	40×45	45×50	50×55	55×60
Diameter tolerance(mm)	+1，-1
Length tolerance（mm）	+2，-2

Technical specification

Material Gr.	Diameter(mm)	Hardness(HRC)	Breakage rate	Impact value(J/cm²)	Drop times(times)	Micro structure
ZQCr26	17-150	>58	<1%	>7	≥12000	M+C
ZQCr20	17-150	>58	<1%	>6	≥12000	M+C
ZQCr15	17-150	>58	<1%	>5	≥12000	M+C
ZQCr12	17-150	>58	<1%	>3.5	≥12000	M+C
ZQCr8	17-150	>58	<1%	>3	≥12000	M+C

Chemical composition

Brand	Chemical composition（%）
	C	Si	Mn	Cr	Mo	Cu	Ni	P	S
ZQCr26	2.0-3.3	1.2max	0.3-1.5	>23.0-30.0	0-3.0	0-1.2	0-1.5	≤0.10	≤0.06
ZQCr20	2.0-3.3	1.2max	0.3-1.5	>18.0-23.0	0-3.0	0-1.2	0-1.5	≤0.10	≤0.06
ZQCr15	2.0-3.3	1.2max	0.3-1.5	>14.0-18.0	0-3.0	0-1.2	0-1.5	≤0.10	≤0.06
ZQCr12	2.0-3.3	1.2max	0.3-1.5	>10.0-14.0	0-3.0	0-1.2	0-1.5	≤0.10	≤0.06
ZQCr8	2.1-3.3	2.2max	0.3-1.5	7.0-10.0	0-1.0	0-0.8	－	≤0.10	≤0.06

1. Definition and Composition

• High Chrome Alloy: Typically contains 10-30% chromium, enhancing hardness and corrosion resistance. Additional elements like carbon (1.5-3.5%), molybdenum, and nickel may be included to improve wear resistance, strength, and toughness.
• Casting Steel: Manufactured via casting molten alloy into molds, followed by heat treatment (quenching and tempering) to achieve desired microstructure.
• Cylpebs: Cylindrical grinding media (25-100mm in length/diameter) with a slightly conical shape, offering increased surface area compared to spherical balls.

2. Key Properties

• Hardness: 58-68 HRC due to martensitic matrix and chromium carbides.
• Wear Resistance: Superior due to hard carbides (e.g., Cr7C3) embedded in the microstructure.
• Impact Toughness: Balanced through heat treatment to prevent brittleness.

3. Manufacturing Process

• Casting: Molten alloy poured into molds to form cylpebs.
• Heat Treatment: Quenching (oil/air) forms martensite; tempering reduces brittleness.
• Finishing: Surface grinding/polishing for dimensional accuracy.

4. Applications

• Industries: Mining (ore grinding), cement (clinker processing), coal pulverization, ceramics.
• Advantages: Extended lifespan (2-3x longer than low-chrome media), reduced downtime, higher grinding efficiency.

5. Performance Considerations

• Shape Efficiency: Cylindrical shape enhances grinding contact and material flow in mills.
• Size Distribution: Tailored to mill specifications for optimal performance.

6. Standards and Quality Control

• Standards: ASTM A532 (wear-resistant cast irons), ISO 9001 for quality management.
• Testing: Hardness (Rockwell), impact (Charpy), microstructure analysis, spectroscopic composition checks.

7. Environmental and Safety Aspects

• Sustainability: Longer lifespan reduces waste generation.
• Recycling: Spent cylpebs can be remelted to recover chromium.
• Safety: Handling requires precautions to avoid hexavalent chromium exposure during production.