2 Shock absorber parts induction heating 2.1. Introduction There are three operations where induction heating is commonly used for heating shock absorber parts: A) Hardening and/or tempering of shock absorber rods B) Chromed rod dehydrogenization C) Tube forming/closing
Closing of the outer tube The operation consists of induction heating one end of a tube, which is then sealed in a spinning operation. The great advantage of induction in this process is its heating speed and the control of the process.
Shock absorber rods hardening Shock absorber rods need to be hardened, generally with a hardening depth from 0,8 to 2 mm. This operation is performed on high production lines. This document shows three different solutions for rod hardening. Skew rollers installations (TSR class) This system is composed of two heads, each of one has rollers with different angle inclination related to the advance axle in order to transfer an turningadvance helicoidal movement. The inductor and the quench are placed between these two heads. This class of machine is the fastest and the one that produces less deflection on the rods.
Installations advanced by rollers conveyor (TCT class) This machine is a variation of the TCE one in which two roller trains transmit the linear movement to the rod. The part on which the movement is transmitted, push the precedent parts. This machine represents a good compromise between speed (it is faster than the TCE class) and the precision (it is more precise than the TSR class) with fast configuration for changing the kind of production.
TSR Type: Skew rollers Pages: 8-9 HARDENING AND/OR TEMPERING
Centerless with pusher installations (TCE class) In this kind of machine the turning movement is transferred by two parallel turning rollers. A servocontrolled pusher transmits the linear movement. This class of machine offers the best hardening precision and is the easiest to adjust in case of multiple rod kinds manufacturing.
CLASS OF MACHINE
4
Pages: 10-11
TCT
Pages: 12-13
TEMPERING OR DEHYDROGENISATION
TRE Type: Tunnel Pages: 14-15
FST FORMING MACHINES
Rod dehydrogenization After chroming the rods, they are usually heated in order to perform a dehydrogenization process. GH Group TRE induction heating tunnels are a compact and high production solution.
Type: centerless with pusher
Type: centerless with rollers conveyor
In all cases, typical speeds are between 2m/min and 8 m/min. Power installed is typically contained between 50 KW and 200 KW and the frequencies between 70 kHz to 160 kHz. . Induction tempering After the hardening it is usually performed a rod induction tempering, being possible to use any of the precedent solutions (TCE with a second pusher, TSR with a second double head, and TCT). Installed capacities are 25-50 KW using 4-10 kHz frequencies. There is also the possibility to use a TRE heating tunnel, a compact and high production solution.
TCE
Type: Tube locking Pages: 16-17
SHOCK ABSORBERS INDUCTION HEAT TREATMENT TRATAMIENTO TÉRMICO DE AMORTIGUADORES