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Good insert for roughing 4340HT at 29rc/30rc?

M

ManualEd

Stainless
Joined
Oct 13, 2014
Location
Kelowna, Canada
I have 50 slugs of 4.750" diameter x 4"long 4340HT that are turned into 50% chips.

The last time I ran them out of 4340 annealed a Sandvik CNMG433 4015 at 600sfm lasted about 30 parts/edge. At 30rc I imagine I'll be closer to 350sfm and half as many parts.

I'll have claw jaws holding on to 18mm of stock, so I should be able to push it at .150"DOC, .014"/rev ish.

I'm a big fan of the Walter WPPxxS grades with an RP5 chipbreaker in the manual lathe. Nice low cutting pressure required compared to other inserts with a flat edge.

I lean towards process reliability rather than having to swap inserts every 10 minutes.
Anything magical grade out there that will last at 800sfm?

Thanks a lot!
 
For high-speed, pre-hardened steels, Seco TP0501, with M5 or M6 chipbreaker is going to be hard to beat. (There's a lot of overlap between those two chipbreakers, but for interruptions, I'd go M5 as it has a nice big ground flat area which to sit against the shim. M6 will be better for higher feeds.)

I don't know their chipbreakers as well as Seco, but Walter's WPP20S is a stellar grade for general-purpose steel turning.
 
30HRC really isnt that hard... you might find that it actually cuts like a dream. I am with you on the walter grades, I don't have it in front of me to quote the grade I generally use but the equivalent of iscars IC907 should last you. Since it's a generic CNMG I would definatly go the tiger-tec way because it has always been my go to for when i was a bit worried about a job and used either a cnmg or wnmg. I am the opposite of a sandvik fan boy so have no idea what you were originally using.

I always have to do some back calculations being metric and all especially sfm to M/min but your 600sfm should really not be a problem. You are taking healthy cuts and your feed seems good to me for roughing so hopefully you are getting nice chips that are clearing the insert nicely. You could probably even push it a bit more to say 650sfm-700 if my calcs are correct. 800 seems to be on the high side.

I am just guessing that your 10min insert change is an exaggeration because you should be getting way more time than that.

on edit I think the walter grade is Wpp20s with a MP5 chipbreaker
 
Last edited:
I run a lot of forged and heat treated 34CrNiMo6 which is basically 4340, at 300BHN, which is about 32Rc.

Tool life at 240m/min is asking a lot, really a lot, although I am running much higher DOC and feed than you, so the reduced thermal load on the insert may help you.

Currently using Tungaloy T9105 which is giving me a few minutes more in the cut than the Sandvik 4205/4305 I was using previously.

I am running 180m/min with 7mm DOC and 0.7mm/r with high(ish) pressure coolant. This gives me about 20 minutes in the cut before the edge is done by plastic deformation.
 
ManualEd said:
I have 50 slugs of 4.750" diameter x 4"long 4340HT that are turned into 50% chips.

The last time I ran them out of 4340 annealed a Sandvik CNMG433 4015 at 600sfm lasted about 30 parts/edge. At 30rc I imagine I'll be closer to 350sfm and half as many parts.

I'll have claw jaws holding on to 18mm of stock, so I should be able to push it at .150"DOC, .014"/rev ish.

I'm a big fan of the Walter WPPxxS grades with an RP5 chipbreaker in the manual lathe. Nice low cutting pressure required compared to other inserts with a flat edge.

I lean towards process reliability rather than having to swap inserts every 10 minutes.
Anything magical grade out there that will last at 800sfm?

Thanks a lot!
Click to expand...

Sandvik has really good insert grades.
30Rc isn't hard at all, just back off about 100-200 sfpm at most from non PHT 4340.
 
We cut a fair amount of that kind of stuff and +1 on the Walter M5 chipbreaker all day. As long as you can take a sizable depth of cut and have the HP to feed it, those inserts seem to last a ridiculous amount of time for us. We use the Seco, Sandvik, and some Mitsubishi's in this stuff too on occasion, but for us, the Walter's way outperform. They just make nice little chips and don't break down. Now, if you're trying to do something silly like take a light finishing cut, well, that creates the nastiest birds nest of razor sharp garbage you can imagine.
 
gregormarwick said:
I run a lot of forged and heat treated 34CrNiMo6 which is basically 4340, at 300BHN, which is about 32Rc.

Tool life at 240m/min is asking a lot, really a lot, although I am running much higher DOC and feed than you, so the reduced thermal load on the insert may help you.

Currently using Tungaloy T9105 which is giving me a few minutes more in the cut than the Sandvik 4205/4305 I was using previously.

I am running 180m/min with 7mm DOC and 0.7mm/r with high(ish) pressure coolant. This gives me about 20 minutes in the cut before the edge is done by plastic deformation.
Click to expand...

+1 for this ^^^
personally i would tend to keep it under 550sfm and bump up the DOC and feed. This will yield much more than those burning fast light .150" cuts.
say 450 sfm .600" off the diameter @ .018-.022"/rev. any old insert should work....if you have the HP
 
ManualEd I'm a big fan of the Walter WPPxxS grades with an RP5 chipbreaker in the manual lathe. Nice low cutting pressure required compared to other inserts with a flat edge. [/QUOTE said:
I'm confused. Looking in my Walter catalog,,I don't find any WPP grade inserts. I find WAP, WAM, WAK,WSC, WTA, WTL, WTP WXK, WXM, WXP, WQM, WQK WMG . What's what here?
Click to expand...
 
Alphonso, I saw the WPP grade in the 2012 general turning catalogue for sure. Near the back they have a grade/speed chart.

Mtndew said:
Have you ever used the Seco Duratomic inserts?
Click to expand...

I haven't yet, but the Seco technical guy got back to me today.
He/she recommended 700sfm and .022"/rev for a CNMG 432 M6 TP0501.

Walter and sandvik were both closer to 550sfm.

That's seems pretty impressive so I'm going to see what they recommend for DNMG 432 for finishing and get a pack of each to try.

Is that tech way out to lunch for speed or does that sound reasonable?




Sent from my iPhone using Tapatalk
 
ManualEd said:
Alphonso, I saw the WPP grade in the 2012 general turning catalogue for sure. Near the back they have a grade/speed chart.



I haven't yet, but the Seco technical guy got back to me today.
He/she recommended 700sfm and .022"/rev for a CNMG 432 M6 TP0501.

Walter and sandvik were both closer to 550sfm.

That's seems pretty impressive so I'm going to see what they recommend for DNMG 432 for finishing and get a pack of each to try.

Is that tech way out to lunch for speed or does that sound reasonable?




Sent from my iPhone using Tapatalk
Click to expand...

We got a test sample when they were handing them out. They performed as advertised in 4150PHT.
But we get such a good discount with Sandvik, that we stayed with Sandvik.
 
ManualEd said:
I haven't yet, but the Seco technical guy got back to me today.
He/she recommended 700sfm and .022"/rev for a CNMG 432 M6 TP0501.

Walter and sandvik were both closer to 550sfm.


Is that tech way out to lunch for speed or does that sound reasonable?




Sent from my iPhone using Tapatalk
Click to expand...
Since that is what i basically recommended in post #7, I'd say it's perfect. :D :D :D
 
ManualEd said:
Alphonso, I saw the WPP grade in the 2012 general turning catalogue for sure. Near the back they have a grade/speed chart.



I haven't yet, but the Seco technical guy got back to me today.
He/she recommended 700sfm and .022"/rev for a CNMG 432 M6 TP0501.

Walter and sandvik were both closer to 550sfm.

That's seems pretty impressive so I'm going to see what they recommend for DNMG 432 for finishing and get a pack of each to try.

Is that tech way out to lunch for speed or does that sound reasonable?
Click to expand...

That chipbreaker is certainly capable of .022"/rev, and in softer 4140"s you may need that much feed to break a chip sometimes. 700sfm & .022"/rev & .150" per side is going to be pretty aggressive. You might want to back off the feed like 25% starting out, and judge from there. Don't be afraid to turn the coolant off with that grade though. It'll take some heat.

For finishing with a DNMG432 - TP1501 MF2 would be my first choice, for chip-breaking & feedrate reasons. For a slightly tougher edge, or contour-roughing, go with M3 chipbreaker.
 
Here is my crash course on turning 4340.

At least 80% of my work is 4340. Some annealed, then heat treated, others heat treated first. Most of the heat treated is 30 HRC, occasionally 45 or a little harder.
Been doing it since the late 90's. 2005 to 2012, 4340 was probably closer to 95% of my total workload. Most of my production work (500 to 20,000 pcs) is small however (.1" - 1.25" ). I only normally do short runs with larger parts (1 to 100). My lathes max out at 6,000 rpm so my experience with super high surface footage is limited.

I agree that often heat treated is a blessing. Chips break easier and you don't have issues with tearing which can both be problematic in the annealed state. This is especially true when it is production work with finish requirements ranging from 32 to 63 micro inches. I notice no added tool wear or need to reduce cutting parameters until at least 40 HRC.

I used to get amazing life in iscar inserts but somewhere along the line in the early 2000's, they changed something. The reps swore nothing was different, but on a part i had been making for years, using the same programs, machines, coolant, suddenly tool life went from getting consistently over 2,000 pieces per insert with a CNMG (5,000 on occasion) to 500 max.
It took me years of recommendations, trial and error, etc to find inserts that did better than just ok.

I swear by sumitomo nowadays. CNMG432ENK grade AC820P for roughing. I use as much as 400 to 500 sfm, .100" D.O.C., .025" feed if the part and setup will permit. I only go through 2 to 3 edges in a 10 hour shift. For finishing, I use DNGG430.5ESU grade T2000Z. I occasionally had problems where the face finish would start tearing prematurely with the standard type tool (-3 degree lead). I switched to one that is offset back to negative 17.5 deg (equal clearance for both turning and facing). The added clearance consistently keeps the face nice without sacrificing the OD finish over a very long tool life. The downside is it strings and wraps chips easily. Obviously this tanks the tool life, usually shattering rather than wear. This is remedied by slowing the surface speed until you find the sweet spot for your desired D.O.C. This is only desirable if you can take it one cut.
If you are roughing, which you are, leave .020" ( .010" D. O.C.). The chip doesn't break, but it coils into a nice, neat, not sharp, very flexible, manageable spiral. I have used this approach with as high as 900 sfm.
As long as you keep chips from wrapping on the tool or work, this tool lasts forever, sometimes i can get a whole 10 hour shift and then some out of one edge.

Sent from my KFGIWI using Tapatalk
 
Unfortunately Sumitomo is a bit of an oddball brand in Canada. There's no local guys, only the main branch back East.

The Seco insets never showed up. Turns out they're stock Europe, not Canada like the salesman had thought. They might be here on Monday.

So I started roughing with a Sandvik CNMG 432 4315 PM. 450sfm, .150" doc, .014"/rev.

Insert lasted 12 pc until the tip melted off and it looked like this. (Probably should have been changed 3 parts earlier)
52c4fc65549026862828d0ba8e68b500.jpg


The job isn't really a rush so I'm tempted to leave it until next week to see how the Seco inserts perform.




Sent from my iPhone using Tapatalk
 
Hard to say exactly from a picture, but to me that looks like you could back off the speed and make up the time by feeding faster, if you have the horsepower to do it.
I would try 20 or 30% slower and try 20% feedrate increase. If it appears to have been a favorable change, increase feed and or slow down accordingly.

If you don't have the horsepower, a smaller depth of cut and maybe 50 or 60% more feed could be a workable strategy.


Sent from my KFGIWI using Tapatalk
 
Orange Vise said:
How much time in the cut does that amount to?
Click to expand...

Roughly 25 minutes in the cut, which is about what you can expect from it.

Its definitely not the right insert for the job. The chip breaker is too tight for how hard I'd like to feed it.
Sandvik calls for a max feed of .5mm at 4mm DOC.

I have an out of shop job to work on tomorrow, so I'll see how the Seco inserts do when they get here.
 
ManualEd said:
Roughly 25 minutes in the cut, which is about what you can expect from it.

Its definitely not the right insert for the job. The chip breaker is too tight for how hard I'd like to feed it.
Sandvik calls for a max feed of .5mm at 4mm DOC.

I have an out of shop job to work on tomorrow, so I'll see how the Seco inserts do when they get here.
Click to expand...

Yeah 25 minutes is a bit short.

Sandvik's PM chipbreaker is for "medium" feeds. The PR chipbreaker is for roughing and is probably what you want. Maybe the CNMG433-PR 4315 or 4325. Just make sure your workholding can keep up with the higher cutting forces. Feeding at 0.020+ IPR close to the max DOC is no joke.

I agree with mikespahn that your SFM might be a bit high.
 
Orange Vise said:
Yeah 25 minutes is a bit short.

Sandvik's PM chipbreaker is for "medium" feeds. The PR chipbreaker is for roughing and is probably what you want. Maybe the CNMG433-PR 4315 or 4325. Just make sure your workholding can keep up with the higher cutting forces. Feeding at 0.020+ IPR close to the max DOC is no joke.

I agree with mikespahn that your SFM might be a bit high.
Click to expand...


4305 is Sandvik's most wear resistant grade, it would be more suitable.
 
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