Heat treatment klp 4

Heat Treatment

Induction Hardening

By :AfmardiIbnu Fajri

Induction Hardening

What is induction hardening?

Induction hardening is a process where steel is hardened by means of induction heating and subsequent quenching in water.

Basic of PrinciplesInduction hardening works by placing the part to be hardened inside an "applicator" coil of one or more turns, through which alternating current is passed. The coil, which in the case of gears and sprockets is round, is usually made of copper tubing which has water passing through it to prevent the coil from overheating. The piece to be hardened is rotated within the applicator coil. At JP Engineering multiple pieces are hardened at the same time by placing the sprockets or gears onto a rod and then rotating the rod, heating the parts and then feeding the rod downward into the quench water.

The Depth of Penetration

For T = 20°C

fd c

20

For For T = 800° CT = 800° C

fdh

500

Frequency distance

Power supply Frequency

(KHz)

Depth of Penetration

min (mm)

Diameter of material

min (mm)

Medium Rotary converter

0,5 - 10 1,5 15

High Valve generator

100 - 500 0,2 1,5

Change Of Materials

td t 2,0

Where d = The Depth of Penetration

t = time

Major uses of induction heat treatment

• Melting ferrous and non - ferrous metals with temperatures up to 1800 0c.

• Heating for forging up to 1250 0c. • Stress relieving and normalizing steels after

cold forming between 750 0c and 950 0c. • Surface hardening of steel or cast iron

workpieces at 850 0c to 950 0c. • Soft soldering and brazing up to 1100 0c. • Recrystallisation. • Tube and Pipe Welding.

Procedure of Work

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Factor of Influence to Induction Hardening

•Composition of Carbon •Temperature•Time Holding

Chart of Induction Hardening

Advantage of Induction Hardening

• Localised hardening of tooth surfaces where hardness is needed

• Hardened teeth are pre-work hardened. • Speed of hardening• Depth of hardness is easily controlled• Selected parts of the workpiece can be

heated. • Heating time and temperature can be

precisely controlled. • There is no smoke or soot pollution;

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• Heating operation can be integrated in semi - automatic production sequences;

• Induction equipment can usually be operated by unskilled personal

• Very fast partial hardening; • High production rates; • Significant reduction in pollution,

distortion, forging scale, energy and space requirements;

• High degree of reproduction and automation;

Example Product of Induction Hardening

Microstructure of AISI 1045

Structuremicro of AISI 4140

Structuremicro of AISI DF2

Hardening of AISI 4140

Hardening of Materials

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