hardening and tempering 8

[aansssa]

Hi sir ,
i want to ask that how to controlled ferrite % in hardening and quench tempered steel.
after hard and tempered structure observed tempered martensite with 25% ferrite plz tell how to control ferrite level

 

[aansssa]

that means if we done with 400-450°C than not much more effect in structure and structure not fully tempered martensite.only stress relief in this temperature for better structure should i go above 500°C tempered.and material is 35C8 grade

 

[CoryPad]

What strength/hardness do you need? If it is 241-295 HBW, then 500 °C to 550 °C should work.

 

[aansssa]

sir hardness required 180-220 BHN after tempering and observed after hardening max 255BHN

 

[CoryPad]

Why are you quench hardening to achieve 180 HBW? Other options seems better (as rolled, normalized).

 

[aansssa]

hi sir,

please suggest to me for reduce decarburization.
actually new development item i have hard n tempered.
but in final micro observed fully decarb.
its socket Wt. 800gm Spec hardness 201-255 BHN