Abstract:
Industrial knives are widely used in paper, plastics, rubber, etc., they must have a high hardness and strength, wear resistance, resistance to mechanical and thermal shock. Use for the manufacture of industrial knives stainless steel 9XC (C $\approx$ 0.9 %, Cr $\approx$ 1 %, Si $\approx$ 1.2 %) ensures high hardenability tool. The paper considers the technology of cryogenic processing, the purpose of which is to transfer the residual austenite in martensite to increase the hardness and durability of hardened steel 9XC. Cryogenic hardening subjected to eight parties of industrial knives, various configuration ready for exploitation. Lot size from 15 up to 40 articles. Knives cooled to a temperature of minus 196 $^{\circ}$Ñ, were kept at it, return to room temperature and then dispensed with the goal of removing internal stresses. Evaluation of stability of the technological process of bulk thermal and cryogenic processing was spread hardness parties knives, and for controlling the level of internal stress of the material and structural State of metal after cryogenic impact-on coercive force. Noted that the change in the variability of coercive force and hardness are independent information parameters. As a result of cryogenic hardening products, made of steel 9XC there has been a slight increase in hardness, by an average of 0.3 units HRC (max 1.0-HRC). In this variation of hardness 50 % hardened knives from eight parties exceeds 4 units of HRC. As a result of cryogenic hardening in none of the eight parties not scatter gains recorded knives hardness. The toughened knives variation of hardness, resulting in cryogenic exposure does not exceed 2.8 units of HRC. Thus, cryogenic treatment, eliminated heterogeneous firmness of knifes after hardening. As a result of coercivity of cryogenic impact on hardened tool grows. The average gain of coercive force amounted to 2.5 a/cm (max 7.0 a/cm). After cryogenic hardening scatter coercive force declined from 49 to 10 %. Tribotechnical tests contained abrasive revealed that the wear resistance hardened steel influence Cryo 9XC increased by 31 %.
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