208
- possibility of automation.
- lack of an decaburation and scale formation.
- minimum buckling of a detail.
Shortcoming is the high cost of the inductor, individual for each detail.
Surface hardening apply for carbonaceous steel, almost not containing about
0,4% of carbon, for alloyed steel almost don't apply.
To high-frequency
hardening subject necks of cranked shaft, sleeves of cylinders, piston fingers,
spring fingers, etc. Thickness of a strengthened layer makes 1,5-3MM if only
high wear resistance is required, and increases to the 5-10th
in case of high
contact loadings and possible regrinding.
Fig7.1. The scheme isothermal transformation of austenite eutectoid steel: І –
pearlite transformation; ІІ – between transformation: ІІІ – martensitic
transformation.
Fig 7.2. Influence of austenite carbon steel of temperature transformation: a —
the diagram of isothermal transformation; — temperature began transformation
in one cooler.
209
Speed of cooling of used environments in the process of chilling ,
table7.1.
№
Coolant medium
Speed of cooling, %
700-500
0
С
300-200
0
С
1
2
3
4
5
Water t=18ºС
t=28ºС
In water 10%
NaOH solution
t=18ºС
In water NaCl solution
t=18ºС
Mineral oil
Air
600
500
1200
1100
150
3
270
270
300
300
30
1
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