Normalising process 1

[aansssa]

hi,
dear all one i want discuss about normalising process.i know its so simple process but i want to discuss with ...
actually if we use 0.40%C and 0.72%Mn and grade C40,EN8 or EN8D raw material for any part and forge then normalise its raw material hardness max 179 BHN.
can u suggest how to achieve hardness min 180 bhn in normalise.
plz sugget ur valuble suggestion

 

[desertfox]

Hi

You cannot increase the hardness of a material by normalising.
Normalising is a process to bring a material back to its raw state.

“Do not worry about your problems with mathematics, I assure you mine are far greater.” Albert Einstein

 

[aansssa]

i agree with u but we can achieve 180 bhn sir with air cooling i think

 

[aansssa]

in EN8D material can i achieved plzgive the suggestion

 

[metman]

Gas quench or forced air quench should produce more hardness on this AISI 1040 steel based on the CCT and TTT curves linked here.

But of course this is no longer normalizing rather a modified normalize.

http://matsec.ustb.edu.cn/dbguide/element/steelpic.jsp?path=40.pdf

Now that I think about it, this subject -or a very similar one - was already discussed in another thread. After questioning, the OP said his customer or the end user wanted this hardness range to provide consistency for press fitting the parts. Hardness is irrelevant in this instance because it is an elasticity issue and heat treatment does not effectively change elasticity.

And in that thread, someone gave the cooling rate that would produce the desired hardness range.

Design for RELIABILITY, manufacturability, and maintainability

 

[Tmoose]

"Normalising is a process to bring a material back to its raw state."

But, with properties significantly better than annealed, and more uniform throughout than large quenched and tempered parts.

http://www.engineersedge.com/materials/carbon-steel-properties1.htm

FWIW the above table suggests 4140 Annealed ends up ~ 200 BHN.
Normalized, at least on small parts, would likely be much higher, ~ 300 BHN

 

[weldstan]

If you are only cooling in still air, use fans to accelerate the cooling rate. I assume that you are achieving hardness near the 180 BHN minimum requirement with standard normalizing conditions.

 

[aansssa]

thanks for reply....