Straighting Heat Treated Inconnel 718

[slyym]

I have a part that I'm using the Dynamic Mill toolpath on and its bending about .05. Its about 80 inchs long about 3 inch dia with a 1 1/4 inch hole offset .4 thru the part. We have a 50 ton press and tried fixing it ourselves but it ended up breaking on us. Have any of you guys ever had to straighten parts after you rough them out? We roughed out 2 mill slots that almost run the entire lentgh of the part. We are thinking we will have to heat it up but are worried that we will mess up the heat treat properties. Thanks in advance for your help.

[jeff]

I worked with a guy that was totally old school and always knew which spot to use a torch so it would bend back almost totally flat every time.

If you do it right, you shouldn't lose the HT properties.

But the trick is to know how much heat and precisely where to apply it.

[slyym]

Wouldn't you apply the heat where you want the part to bend? Would you heat up the top, bottom or all around?

[jeff]

From what I've saw, you want concentrated heat at the point where you want it to bend.

Try using an Oxy/Acetylene torch with a small tip, I'm no master at this, but it might work... just don't get it red hot.

[slyym]

I have a temp gun available. I wonder what temperature I should get it up to for best results. I'm thinking maybe 400 to 500 degrees to start. What do you think?

[depasquale]

I have a part that I'm using the Dynamic Mill toolpath on and its bending about .05. Its about 80 inchs long about 3 inch dia with a 1 1/4 inch hole offset .4 thru the part. We have a 50 ton press and tried fixing it ourselves but it ended up breaking on us. Have any of you guys ever had to straighten parts after you rough them out? We roughed out 2 mill slots that almost run the entire lentgh of the part. We are thinking we will have to heat it up but are worried that we will mess up the heat treat properties. Thanks in advance for your help.

[depasquale]

Sometimes when I know a part is going to move during machining I rough leaving extra stock so I can machine the bow out of it.

[slyym]

Sometimes when I know a part is going to move during machining I rough leaving extra stock so I can machine the bow out of it.

 

Yea thats what we did but for some reason this batch of parts moved a little more than we had hoped for.

[LaszloK]

Well, you have already scraped one part and you have a 50/50 chance of applying the heat to the correct side. I am by no means an expert on this type of operation but if I could afford to test another piece, and possibly scrap that one, I would apply the heat to the concave side of the part. If it gets worse, then I was wrong.

[jeff]

I'm pretty sure that you apply the heat on the convex side of the part, at the center of the bend.

[petro7]

Heat the high side it will get worse then I quickly cool it with coolant and it will shrink and bend the opposite way. I do this with stainless all the time. sorry no experience with inconel. good luck.

[petro7]

start with a small amount of heat then cool it. just to see how much it moves. make sure it is completely cold when checking the straightness.