Induction Hardening

hello guest.

There are several possible means of cracking this grade.

A prior existing seam is quite likely if insufficient/ no stock removal has been taken off the original steel bar.

Look for a layer of different 'texture' just under the OD of the failure surface. That will likely be decarb from rolling in the bar mill and is testimony that the seam prexisted the crack.

If no such visual evidence presents, then a quench crack is the likely explanation. Many factors including tool marks, severe change of section, improper quenchant makeup (too much Water/insufficient/improper polymer) as well as improper operating parameters for grade.

To Characterize the failure to solve the problem, look at the fracture surface

milo

There could be following reasons:- 1.Sharp corners at different diameters. 2.Incorrect quenching process. 3.Basic matterial may not suitable for induction hardening.Do the chemical tests for raw matterial. 4.Improper temperature in heating of shaft.

Not to put too fine a point on this, but ck45 is intended for quenching and tempering. If the comment is that this specific lot of material is not ck 45 and thus not able to be successfully induction treated, I agree; if the comment was that ck45 is not induction hardenable, my 30+ years in the steel business tells me to strongly disagree.

Here's the chemical analysis per din 1652-4:

Chemical Composition Grade Ck45 WNr. 1.1191 Standard DIN 1652-4 Country Germany Heat Analysis Element Symbol Min. Max. Carbon C 0.42 0.5 Manganese Mn 0.5 0.8 Phosphorus P 0.035 Silicon Si 0.4 Sulfur S 0.03

milo

It seems my comments are not properly understood.I am not questioning suitablity of ck45 (DIN Std) for induction hardening. I asked you to check confirmablity of material used by you to this standard. Also please take care of the other points I have raised.

pls check the various process parameters like gap between the induction coil and workpiece , current etc.