PSI - Issue 81

Viktor Kovalov et al. / Procedia Structural Integrity 81 (2026) 346–352

351

The results of accelerated laboratory tests using the destructive feed method are summarised in Table 1. Tool modification increased the destructive feed from 1.82 to 2.20 mm/rev, while the coefficient of variation decreased from 0.42 to 0.24, indicating an improvement in structural strength and operational stability. Table 1. Results of comparative accelerated laboratory tests of assembled carbide cutters after tool modification (D max = 1300 mm, 90KhF steel, continuous stock removal)

Destructive feed S p , mm/rev.

Coefficient of variation V Sp

Test conditions

Cutter design

t , mm

Insert material

v , m/min.

PSBNR/L SNMM

12

20

1.82

0.42

Т5К10

Т5К10 (modified)

12

20

2.20

0.24

The results of comparative operational tests are presented in Table 2. The data demonstrate a significant improvement in reliability indicators after PMFT: the mean tool life increased from 29 to 46 min, the coefficient of variation decreased from 0.7 to 0.3, and the γ - percent tool life (γ = 80%) increased from 10 to 35 min. The reduction in tool life scatter confirms a substantial decrease in variability and a marked improvement in the reliability of the cutting tool.

Table 2. Results of comparative operational tests of assembled carbide cutters with modified inserts

Tool life distribution characteristics

Mean tool life T , min.

№

Coefficient of variation Vτ

Percentage of insert failures, %

γ -percent tool life Tγ 0.8, min.

Tool life range, τ (min)

Distribution parameters

Weibull a =34.8, b =1.5

1

29

0.7

10

6 – 94

26

1,5



  

  



( )  P e 

34.8

Normal T =46, σ =12

2 (modified)

46

0.3

35

22 – 69

9

    12 46



  

( )  P



4. Conclusions This study experimentally demonstrated the effectiveness of pulsed magnetic field treatment (PMFT) as a bulk modification technique for improving the durability and reliability of WC – Co cemented carbide cutting inserts used in heavy-duty turning. The obtained results confirm that PMFT significantly enhances both the average operational performance and the statistical reliability characteristics of cutting tools operating under severe thermo-mechanical loading. The application of PMFT led to an increase in the mean tool life by a factor of approximately 1.5 – 1.7, indicating enhanced resistance to damage accumulation and premature failure. At the same time, a substantial improvement in reliability was achieved, as evidenced by the increase in the γ -percent too l life (γ = 80%) by approximately 3.0 – 3.5 times. This result demonstrates a strong reduction in early failures associated with critical microstructural defects and confirms that PMFT is particularly effective in stabilising the most failure-sensitive portion of the tool population. Statistical analysis showed that PMFT also leads to a pronounced reduction in the scatter of mechanical and operational properties. The coefficient of variation of tool life and mechanical strength decreased by more than twofold, reflecting a transition toward more stable and predictable tool behaviour. This stabilisation is of high practical importance for heavy machining operations, where large variability in tool life can cause unplanned downtime and reduced process reliability. Fractographic analysis (Figs. 1 – 3) revealed that PMFT modifies crack initiation and propagation mechanisms in cemented carbides. The treatment reduces the density of critical crack-initiating defects, promotes more tortuous crack paths, and extends the stable crack growth stage. These microstructural changes increase resistance to catastrophic brittle fracture and contribute directly to the observed improvements in tool life and reliability. The accelerated laboratory tests and industrial trials (Fig. 4, Tables 1 and 2) further confirmed the practical significance of PMFT. The treatment increased the destructive feed, mean tool life, and key reliability indicators under real heavy machining conditions, while significantly reducing the frequency of catastrophic tool failures. These results demonstrate that PMFT provides tangible benefits not only under controlled laboratory conditions but also in real industrial environments.