heat treating 4130 steel
heat treating 4130 steel
(OP)
I tried to heat treat a piece of 4103 steel .125 thick 6 inches long shaped like a "u". I put the piece in the furnace at 1600 degrees for 2 hours (the oven was preheated), then oil quenched, and anealed at 700 degrees for 1 1/2 hours. The rockwell hardness I achevied was only 22 on the c scale. I would like to achive 45-50.
thank you
thank you





RE: heat treating 4130 steel
1. Where and how did you perform the hardness testing?
2. Did the furnace contain a protective (reducing) or inert atmosphere to prevent surface decarburization during heating and soaking at 1600 deg F?
RE: heat treating 4130 steel
Yes, it did. I meant 4130 not 4103
RE: heat treating 4130 steel
RE: heat treating 4130 steel
RE: heat treating 4130 steel
Place back in the furnace at your original tempering temperature of 700 deg F for 30 minutes (at temperature), remove from the furnace and cool to room temperature. I don't have immediate access to my reference material to confirm the 700 deg F tempering temperature, but off the top of my head it appears to be about right for your required hardness range.
RE: heat treating 4130 steel
RE: heat treating 4130 steel
RE: heat treating 4130 steel
RE: heat treating 4130 steel
This gives an austenitize recommended temperature of 1500 - 1600 F
Water Quench
Temper at 400F gives around 47 Rc
Temper at 500F gives around 45 Rc
RE: heat treating 4130 steel
Any bow or gap will produce a wildly soft reading. Testing hollow sections is tricky
RE: heat treating 4130 steel
RE: heat treating 4130 steel
I have a related question though. Austenitizing at the top of the reccommended temp range for over 4times the reccommended time seems like it would cause extensive grain growth. What is the effect of this grain growth on the as quenched hardness? Tempered hardness?
Nick
I love materials science!
RE: heat treating 4130 steel
RE: heat treating 4130 steel
Forgot to answer your question - no increase in hardness. The hardness of martensite is a function of carbon content not grain size.
RE: heat treating 4130 steel
RE: heat treating 4130 steel
eds026--can you give us the chemistry from your cert?
RE: heat treating 4130 steel
swall- oh I forgot to look at his geometry... [voice=HomerSimpson](DOH!)[/voice]
metman- ya know I keep forgetting that.
So the over temper reduced his hardness by 20some odd points?
RE: heat treating 4130 steel
RE: heat treating 4130 steel
As a side note, I was evaluating the temper cycle of 700 deg F for 30 minutes earlier today for this material after you guys had confirmed the 1 hour tempering temperature for this material.
My curiosity got the best of me because I had remembered that you could temper at higher temperatures with reduced time to achieve similar hardness results because tempering is a thermal activation process (time and temperature dependent). I was able to locate a H-J tempering parameter plot for AISI Type 4130 Q&T. To achieve a hardness of ~ 45 HRC, you can temper at 700 deg F for 18-20 minutes versus the standard temper of 1 hour @ 450 deg F.
RE: heat treating 4130 steel
RE: heat treating 4130 steel
Thank you everyone for the input.
RE: heat treating 4130 steel