Development and application of Cr25 high chromium cast iron grinding ball (2)
2.Development and production of CR25 high chromium casting grinding ball
Cr25 high chromium cast iron grinding ball, the research is, by the customer China, Electrical Machinery, head office orders, according to, the United States FW proposed, high chromium, grinding ball, technology, conditions, see table 1
Mechanical Properties: Hardness HRC63- 68; crushing rate ≤1.5% (running 2000h).
To meet the requirements of the components and mechanical properties, according to the above theory and years of factory production experience, organized the development and production of CR25 high chromium casting grinding ball.
(1) Chemical composition
The main chemical composition of Cr25 high chromium casting grinding ball is shown in Table 2
(2) Melting and pouring
The furnace is GW 1.0 as a 500/j medium-frequency coreless induction furnace.
D1SA continuous production line in Denmark is used for casting, and the molding system is vertical parting in south and Slav
(3) Heat treatment
Computer-controlled quenching and tempering of continuous heat treatment furnace. This quenching and tempering process can make CR25 cast ball obtain better toughness to offset Brittleness’s increase due to the increase of carbide. For the heat treatment process, the curves are shown in fig.
This cast ball’s heat treatment process is different from that of the grinding ball of Cr 15 high chromium cast iron. Similarly, the martensitic matrix Cr 15 cast ball is cooled by air mist. The other Matrix Crl5 cast balls generally adopt the as-cast tempering process, more economical, but as-cast, temper group, Brittle, more.