Grinding Ball National Standard Based On GB/T 17445-2019

Release time：2026-01-13

Grinding Ball National Standard Based On GB/T 17445-2019

The national standard for high-chromium balls is mainly based on GB/T 17445-2019 "Casting Grinding Balls". This standard stipulates the technical requirements, testing methods and inspection rules for high-chromium cast iron grinding balls, and is applicable to grinding equipment in industries such as mining, metallurgy, and cement. The core technical indicators of the high-chromium balls include chemical composition, hardness and impact toughness. The specific requirements are as follows: the chromium content should be ≥ 10.0%, the carbon content should be between 1.80% and 3.20%; the surface hardness should be HRC ≥ 58, and the impact value ak should be ≥ 3.0 J/cm²; the material matrix should be a martensitic structure, and there should be no defects such as shrinkage cavities or gas pores inside. The production process must strictly follow the heat treatment and inspection specifications. The high-chromium balls must undergo high-temperature quenching (such as oil quenching or air quenching) and tempering to ensure the hardness meets the standards. If the hardness is lower than 54 HRC, it is regarded as not having undergone compliant heat treatment. The inspection must be carried out in accordance with relevant standards, such as chemical composition analysis referring to GB/T 223, hardness testing following GB/T 231.1, and impact testing in accordance with GB/T 229. The classification criteria are based on chromium content, and different grades are defined accordingly. High-chromium balls have a chromium content of ≥10.0%, while low-chromium balls (with a chromium content of 1%-3%), multi-alloy balls (with a chromium content of 4%-6%), and medium-chromium alloy balls (with a chromium content of 7%-10%) have their own hardness requirements (such as medium-chromium balls with HRC ≥ 48). However, high-chromium balls are often used as a substitute for low-chromium balls to reduce unit consumption due to their superior wear resistance.