Issue 49

D. Kumar et alii, Frattura ed Integrità Strutturale, 49 (2019) 507-514; DOI: 10.3221/IGF-ESIS.49.47 513 The test results are given in Tab. 2. The results show that the HCrCI grade, FB Cr26MoNi with 0.5wt% vanadium addition is comparatively a higher wear resistant alloy which is more suitable for wear resistance application. The wear resistance of the developed cast iron grade (FB Cr26MoNi +0.5V) was calculated as the ratio of volume loss of the reference material (FB Cr26MoNi) to the volume loss of that material. The average abrasive wear resistance of FB Cr26MoNi +0.5V material as compared to FB Cr26MoNi material is 2.33. This shows that FB Cr26MoNi +0.5V material has higher wear resistance and it is more suitable for liner applications in coal pulverizers. Therefore, the comparative wear study of prototype liners of these materials for 2,667 hours was made by installing them in a coal pulverizing tube mill. The average wear out thickness of the developed liner (FB Cr26MoNi +0.5V) and the normal liner (FB Cr26MoNi) were found to be 0.83mm and 2.08mm, respectively. The above data shows a higher wear life for the cast iron grade, FB Cr26MoNi +0.5V. Material: FB Cr26MoNi FB Cr26MoNi +0.5V Sample No: A11 A12 A13 A3H1 A3H2 A3H3 Test time, min: 45 45 45 45 45 45 Initial mass, g: 84.5123 84.7395 84.5744 86.8523 86.8457 81.5244 Final mass, g: 84.1666 84.3957 84.1764 86.7301 86.6998 81.3267 Mass loss, g: 0.3457 0.3438 0.3980 0.1222 0.1459 0.1977 Mass loss, mg/min: 7.7 7.6 8.8 2.7 3.2 4.4 Volume loss, mm 3 : 46.2784 46.0241 53.2798 16.3588 19.5315 26.4659 Volume loss per kg of erodent, mm 3 /Kg: 9.3492 9.2978 10.7636 3.3048 3.9457 5.3466 Average volume loss per kg of erodent, mm 3 /Kg: 9.8035 4.1991 Table 2: Abrasive wear test result of the base material and the developed material C ONCLUSIONS etailed study on the abrasion wear, mechanical behavior, microscopic examination and characterization of HCrCI and HCrVCI grades leads to the following major conclusions: 1. All grades of cast irons were cast using die casting method and chemical compositions were achieved successfully with homogeneous matrix in the respective casting blocks. 2. 0.5 wt. % vanadium addition to the base HCrCI grade (FB Cr26MoNi) has refined the microstructure to form globular VC type carbides and chunk like Cr 7 C 3 carbides distribution in the martensite matrix. This is quite favorable for improved life of liners in tube mills. 3. HCrVCI grade, FB Cr26MoNi+0.5V has higher abrasion wear resistance and higher combination of hardness and impact strength as compared to the reference HCrCI grade, FB Cr26MoNi. Hence, the HCrCI with 0.5 wt. % vanadium addition is more promising with enhanced properties of hardness, impact toughness and higher abrasion wear resistance for tube mill liner application. 4. The study of prototype liners of the developed cast iron shows a higher service life as compared to the existing base material liners. A CKNOWLEDGEMENT uthors express their gratitude to the managements of BHEL, Corporate R&D, Hyderabad for financially supporting this study. They acknowledge the officials at Surface Coating Department, BHEL, Corporate R&D, Hyderabad for their support in carrying out the wear test of cast iron samples. They acknowledge the concerned D A