Test on Corrugating Slitter Knife

To determine the advantages of cryogenic treatment on an item used in the Container Industry, tests were conducted on a Zenith G-63 corrugating slitter knife. This knife was circular, with a 9 1/8 inch OD (232 mm) and a thickness of 5/16 inch (7.9 mm). The blade was cut in half, and one half was tested in the as-received condition. The other half was cryogenically treated by soaking it at -310°F (-190°C) for 19 hours, followed by 1 ½ hours post tempering at +300°F (149°C).Hardness and wear tests were conducted on the two knife halves and the results are shown in the table below. As noted from the table, the hardness of the knife was relatively unaffected by the cryogenic treatment; however, the wear resistance was improved considerable.

The increase in wear resistance of more than 7 times, as determined from the laboratory test, was in agreement with field tests on similar slitter knives. The average life of an untreated slitter blade was 6 to 10 weeks between sharpenings; whereas, cryogenically treated knives lasted from 6 to 18 months between sharpenings.

QUANTITY UNTREATED SAMPLE TREATED SAMPLE
Initial Mass 459.9 g
1.014 lbm
454.0 g
1.001 lbm
Mass Loss 4.8 g
0.011 lbm
1.1 g
0.002 lbm
Volume Loss 645.3 mm³
0.0394 in³
147.8 mm³
0.0090 in³
Time of run 30 min. 30 min.
Wear Rate, W 0.3585 mm³/s
21.8 x 10e-6 in³/s
0.0821 mm³/s
5.0 x 10e-6 in³/s
Hardness, Hv 59.4 Rc
6700 MN/m²
58.9 Rc
6590 MN/m²
Force on sample, F 431 N
96.9 lbf
431 N
96.9 lbf
Surface velocity, V 412.5 mm/s
81.2 fpm
412.5 mm/s
81.2 fpm
Wear resistance, Rw = F V/W Hv 74.0 537.0