1075 Carbon Steel - grain size problem...

I have problem with buying W2 as well. It is not common in Poland. As other shallow hardening steels it is almost impossible to get in reasonable dimensions:)
What would happen if bainit forms.?
I was adviced to do hardening in air (you get perlite, bainite and martensite mixture) and then temper high (650C), repeat this process as many times as needed.
I've tried but the grain size was still the same. The same size as with or without normalizing...
Regards
PS couldn't find CCt for 1075 nowhere.
 
I can't really explain what the problem with bainite is, but I do know it is unnecessary to form it, austenite/pearlite transformation is sufficient for a grein refinement. I think the bainite thing has to do with grain uniformity, imagine entering the pearlite nose, forming pearlite, and a little later forming bainite, it might give other kind of grains?? Anyway, don't do it.

What is the purpose of this: "I was advised to do hardening in air (you get perlite, bainite and martensite mixture) and then temper high (650C), repeat this process as many times as needed.".

1075 in the thickness of a blade can't be air hardened to martensite. Tempering at 650 doesn't exist, that is more like a stress relieving aneal.

I haven't found a cct for 1075, but have found one of an eutectiod steel and I think it might be close regarding the carbon percentage.

Image5.gif


You have under 5 seconds to form martensite
 
Yes I have similar CCT but it will be different for 1075 with .4 -.8 % of Mn which improves hardenability. the process i described earlier was recommended by a person who knows a lot about steel and apparently he don't recommend usual normalization process for hypereutectoid steels (and i think cause of Mn content you can treat 1075 as hypereutectioid). Anyway it should also reduce the grain size. regardless what process is the best for this steel i had no good results with any of those. I keep trying and testing though, changing those variables i can effect. I will definitely share with results if i get somewhere and achieve satisfying results.:)
Regards.
 
Van Zanten said:
I can't really explain what the problem with bainite is, but I do know it is unnecessary to form it, austenite/pearlite transformation is sufficient for a grein refinement. I think the bainite thing has to do with grain uniformity, imagine entering the pearlite nose, forming pearlite, and a little later forming bainite, it might give other kind of grains?? Anyway, don't do it.

What is the purpose of this: "I was advised to do hardening in air (you get perlite, bainite and martensite mixture) and then temper high (650C), repeat this process as many times as needed.".

1075 in the thickness of a blade can't be air hardened to martensite. Tempering at 650 doesn't exist, that is more like a stress relieving aneal.

I haven't found a cct for 1075, but have found one of an eutectiod steel and I think it might be close regarding the carbon percentage.

Image5.gif


You have under 5 seconds to form martensite
Click to expand...

Very nice normalizing results. Have you tried to process steel more cycles?
 
You must log in or register to reply here.
Back
Top