heat treat SAE 1095
heat treat SAE 1095
(OP)
I am having cracking issues after heat treat and draw. Heat treating at 1550°, quench oil is at 165°, 15 second dwell, draw on flattening fixtures at 720°to obtain a C47-52 hardness. Most all of our 1095 material is not heat treated so this is new to me.





RE: heat treat SAE 1095
RE: heat treat SAE 1095
RE: heat treat SAE 1095
You need to keep the temperature of the material above 300F (preferably 400F) before quenching. This is easy to check these days with a infrared non-contact thermometer (in the old days, you had to use tempil-sticks). Your actual maximum quench exit temperature will have to be determined by trial and error, but I'd guess around 450F. You may find that quench exit at 500F is fine as long as it cools below 350 before temper.
Which makes me think, your flattening fixtures are just heavy pattens, right? Maybe you need to preheat them to 350F to keep them from quenching your blanks to below 300 before the tempering furnace can get the temp high enough to prevent cracking.
rp
RE: heat treat SAE 1095
Should read
You need to keep the temperature of the material above 300F (preferably 400F) before tempering.
The point is not to let the material cool to too low a temperature before you temper it. Most quench cracking occurs below 300 F, so if you can keep the material above 300 F, you can prevent the cracking
rp
RE: heat treat SAE 1095
The part gets degreased after quench, which means at this point it is room temperature. I am going to put them in a pre-draw furnace at 350° before tempering on a fixture to maintain flatness in draw.
RE: heat treat SAE 1095
If the oil temperature is 165F, they cannot be below 165. With only a 15 second quench, I wouldn't be surprised if they were a bit higher. Check the temperature with a non-contact thermometer and see what it is.
By waffle plate, I am guessing you have a quench fixture. The fixture should be at oil temperature (165F). If the fixture is at room temperature, that could cause cracking.
rp