Scale build up after induction 1

[zunom]

Hello People,

I have been seeing more than usual scale build up on axle shafts after induction heat treating. I have increased the quench concentration and the flow rate. But not much difference. What could be the reason. And can it be reduced/eliminated? Thanks

FYI: the axle material is SAE 1050 Mod.

 

[swall]

Do you really mean scale? Or are we talking heat treat discoloration?

 

[zunom]

Its scale I am talking about. I have a lot of scale build up with SAE 1541 material but not 1050. For information. Whats your definition of scale and discoloration. It may be discoloration but it comes off after I wipe it with Scotch brite. And also the build up can be felt with touch.

 

[dbooker630]

Once you wipe off the 'scale', is the surface hardness acceptable? Are the shafts machined the entire length or are you dealing with an as-rolled surface? Are the shafts blast cleaned sufficiently? These items are not particular to a steel grade necessarily, but in my own axle shaft experiences are things worth checking into for starters.

 

[TVP]

If this truly is scale, then the factors that affect oxide formation are temperature and time at temperature. This means that power and scan rate are the parameters that may have an effect: reduce the power, increase the scan rate or both in order to reduce scale formation.