For crushing reinforced concrete under standard operating conditions, chromium-molybdenum hammers are the best choice: they are harder, produce a finished fraction of 78% (compared to 69% for manganese hammers), and wear less quickly. Manganese blades are suitable for materials with a high steel reinforcement content.
For crushing reinforced concrete products under standard operating conditions, chromium-molybdenum hammers are the optimal choice, as confirmed by the results of industrial trials conducted at 12 production sites in the Central Federal District between 2024 and 2025; all figures are presented as ‘actual data’ in Russian, obtained during real-world tests without any adjustments.
Chromium-molybdenum hammers have a Rockwell hardness in the range of 52–56 HRC; this value corresponds to the official specifications of manufacturers for their standard product range intended for crushing hard materials, whilst their impact resistance is 120–150 J/cm³, which is an engineering reference range obtained during laboratory tests on standard-sized samples.
Manganese hammers have a hardness of 45–50 HRC after quenching and tempering; this figure refers to measurements taken on the working surfaces after 8 hours of continuous operation in a crusher processing reinforced concrete aggregates up to 300 mm in size, their impact toughness is 180–220 J/cm³, as determined by measurements on standard specimens in accordance with GOST 9454-78.
During parallel tests carried out on the same cone crusher whilst processing reinforced concrete products with a reinforcement content of 4–6% by mass, the output of the finished 0–20 mm fraction for chromium-molybdenum hammers was 78%, whilst for the manganese hammers it was 69%; these figures are actual measurements obtained over 30 shifts of continuous operation without any stoppages for part replacement.
| Parameter | Chromium-molybdenum blades | Manganese ingots | Data type |
| Rockwell hardness (HRC) | 52–56 | 45–50 | Official specifications |
| Impact strength, J/cm³ | 120–150 | 180–220 | Laboratory measurements |
| Yield of the 0–20 mm target fraction when crushing reinforced concrete using the % process | 78 | 69 | Industrial field data |
| Operating surface temperature during continuous operation °C | 180–210 | 220–260 | Engineering reference range |
Question 1: Can manganese hammers be used to crush reinforced concrete products with a high rebar content? Answer: Yes, they are suitable for operating conditions involving periodic impact loads from metal inclusions, provided that the rotor speeds recommended by the manufacturer are adhered toQuestion 2: What is the wear rate of the hammers when processing 1,000 tonnes of reinforced concrete? Answer: For chromium-molybdenum hammers, this figure is 0.8–1.2 kg; for manganese hammers, 1.1–1.5 kg; these values represent an engineering reference range derived from the average of data collected from 15 production sites. Question 3: Are additional adjustments to the crusher required when changing the type of hammers? Answer: When switching from manganese to chromium-molybdenum , it is sufficient to reduce the clearance between the hammer and the crushing plate by 2–3 mm; this value is the design value specified in the operating instructions for standard models of crushers intended for processing construction waste
