Introduction

Shandong Bailin Mining Industry Co., Ltd has successfully completed comprehensive performance testing for 

our high‑chrome grinding balls through SGS‑Certified laboratory, following ASTM‑recommended test protocols

 (ASTM E112‑25, ASTM E23‑25 and ASTM E3‑11). The authoritative test outcomes prove our grinding media’s

 reliable physical properties to serve global mining operations, especially copper‑cobalt mineral projects across

 the DRC and Africa.

Detailed Analysis from SGS Test Report

1. Grain‑Size Examination (ASTM E112‑25)

The specimen was treated with 950℃ heating and water‑quenching, then inspected under a metallurgical microscope.

 The average austenite grain size achieved No.12 uniformly across three observation views. 

Fine and even grain structure is the fundamental guarantee for our steel balls.

 It improves the material’s overall density, reduces internal defects, 

minimizes break‑down risks and extends service time inside ball mills.

2. Impact‑Energy Test (ASTM E23‑25)

Two groups of impact tests were conducted at 23℃ ambient temperature.

• Average absorbed energy of un‑notched samples reached 4.6 J

• Average Charpy U‑notched impact energy is 1.2 J

Proper impact‑toughness prevents steel‑ball cracking caused by continuous heavy‑impact loads inside ball‑mills. Many high‑chrome products fail in actual mining work due to insufficient toughness. Our formula balances high hardness and anti‑fracture capability to fit harsh African mining environments.

3. Metallographic Structure Analysis (ASTM E3‑11 (Reapproved 2025))

After grinding, polishing and etching with 4% nitric‑alcoholic solution, 

microscope observation confirms that our material microstructure is composed of dense martensite and carbides. 

This typical high‑chrome structure supports our finished steel balls to hit surface hardness HRC60 and core‑hardness HRC58. 

This performance exactly fulfills the technical requirements raised by Congolese mining buyers for 70‑mm grinding balls with Cr13‑16% content.

Our Core Advantages for Global Mining Partners

1. Authoritative certification: Every batch of our grinding balls can be supplied with SGS test reports 

complying with ASTM standards for clients’ qualification review.

2. Optimized formula: We add Nb‑V micro‑alloy elements on the basis of 13‑16% chrome content,

 further optimize grain structure to keep breakage rate below 0.8%.

3. Customized service: We adjust chemical composition, 

diameter and hardness range according to clients’ mill‑model and ore‑type. We support trial‑order first before bulk‑purchase.

4. Mass‑production capacity: Our factory can undertake large‑volume orders up to

 500 tons and above with punctual delivery for global clients.

Closing Statement

Nowadays, more and more mine owners realize that qualified grinding balls can greatly cut down their later‑stage maintenance costs.

 With verified SGS‑approved performance, 

our high‑chrome grinding media will be your cost‑effective and trustworthy choice. 

We welcome mine‑owners, mining‑supply agents from USA, Africa and Middle‑East to contact us for samples and business negotiation.