PSI - Issue 17

Berta Igor et al. / Procedia Structural Integrity 17 (2019) 509–513 Berta, I., Pokusová, M./ Structural Integrity Procedia 00 (2019) 000 – 000

513

5

Alloying by Ni was slightly positive, but only when it was applied simultaneously with Mo . Additions B in an amount of about 0.01% or a combination of 0.05% Ti + 0.05% V , which are introduced into the melt just before casting, also have a beneficial effect. The effect of Mn on abrasion has not been demonstrated, but it was presented in the final composition, since it significantly improves the fluidity with contents above 1%. A further increase in fluidity was achieved after melt processing just before the end of melting with CaF 2 -based synthetic slag, CaO and Al 2 O 3 in an amount of about 0.1%. Surprisingly high melt penetration with the Mn content of about 2% allowed casting bars of additional material to be welded  5-6 mm long 400-500 mm.

4. Conclusion

For higher abrasion resistance, the chrome cast iron having a continuous closed carbide chain in microstructure with a predominantly austenitic matrix was designed. The hardness of this material reaches 65-68HRC, the carbides reach a hardness above 2000 HV30. The recommended composition is as follows:

C

Cr

Mn

Si

Ni

Mo

2,8-3,1

20-24

0,8-2

0,6-1,0

0,8-1,3

0,7-1,0

Abrasion resistance increases almost linearly with C and Cr rising. When the 3% C threshold is exceeded, the brittleness is intolerable increased and the increase in Cr content above 22% has no significant effect on abrasion resistance. Alloying by Mo has significant positive effect for abrasion and fracture resistance. Alloying by Ni was slightly positive, but only when it was applied simultaneously with Mo . Additions B in an amount of about 0.01% or a combination of 0.05% Ti + 0.05% V , which are introduced into the melt just before casting, also have a beneficial effect. The effect of Mn on abrasion has not been demonstrated, but it was presented in the final composition, since it significantly improves the fluidity with contents above 1%.

Acknowledgements

This work was supported by the Slovak Research and Development Agency under the contract No. APVV-17 0666.

References

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