Change from 316 SS to 410 SS

[AllenH59]

Gentlemen... I have to do good sized job on some SS, and it is one of those "polish to size" jobs on part of it. It was to be made from 316, so I took some scraps and proved to myself and the customer that I could work within the tolerances required. Then naturally the customer could not find the shafting he wanted in 316, and is purchasing the size he does want in 410. Is there a significant difference in the machining characteristics of the two materials? Do I have to go through the pursuit of good results again? Thanks..

[Harold_V]

Your customer would be so much better served to use 416 instead (assuming it meets the physical demands). 410 in the annealed condition does not machine well, while 416 is the easiest of all to machine. Both can be heat treated. My experience with 410 leads me to believe that it is similar to mild steel in that it likes to tear, so achieving a nice finish can be challenging, while 316 (or any of the 300 series alloys) offer nice cuts without tearing. A damaged cutting edge with pretty much any of the 300 series will yield a less than good finish, and they like to work harden easily when cut with dull tools.

If you are stuck with the 410, do some preliminary finish cuts so you can determine how it responds. I have machined very little of the material, but did not enjoy the limited experience I had. I have machined a great deal of 303S, 303Se and 416 and have never had what I'd call a bad experience. Those three stainless alloys are a pleasure to machine.

Sorry I'm not more help.

H

[AllenH59]

Thanks Harold.. Although the data pages for 410 say it is machinable in the annealed state, I thought when no one had used it, there must be a reason. I get good results on 316 with HSS tooling, and that will be my first approach on 410. I hope I do not have to buy a tool post grinder to make this stuff look good. I found a page that said to cut 316 with HSS, it wants 10 to 20 degrees of top rake. I ground them to 8 degrees, then cut a chip breaker to make a very sharp edge with a high angle, this cut very well. I hope a similar approach works on the 410.. I am stuck with it, and have to find a solution. Luckily this is by the hour. I have to turn and polish some bushing seats.. It will be an adventure. I will report back on progress, I do not get the material for 2 weeks. this will be the first time ever making something that is 40 inches long in my 19 year old 16x48 lathe... my lathe is new out there, it will be interesting to see how it cuts.




My favorite metal work advice was my dad's favorite also. The young blacksmith asked the old blacksmith how to make money. All he said was "never pound cold iron".

[Steggy]

Your customer would be so much better served to use 416 instead (assuming it meets the physical demands).

I'll second what Harold said. I consider 410 to be the low rent form of the martensitic stainless alloys. The relatively low chromium content (typically around 11 percent—compare that to the 18 percent of type 304 and the typical 12-14 percent for type 416) makes 410 cheap—that's the best thing it has going for it. 416 has superior properties, machines better and has better corrosion resistance.

That said, 316 is superior to both in terms of machining qualities and corrosion resistance. 316 seems to be readily available from steel houses in our area, so I don't know why your customer can't get it.

[AllenH59]

That said, 316 is superior to both in terms of machining qualities and corrosion resistance. 316 seems to be readily available from steel houses in our area, so I don't know why your customer can't get it.

There does not seem to be 316 available in 1.75" in western Canada.. he found the 410...He will not pay me to turn 316 down..

[John Evans]

Well seems to me your customer will have to live with tolerances and finish that you can obtain with the 410. If he doesn't like the results show him the door !

[AllenH59]

John Evans... I am not too worried. I am patient.. It is by the hour.. If what I have will not do it, I will look for something else.. My lathe is plenty stiff to use carbide.. I have 3 HP and .0015/turn... I will try deeper cuts and shallower cuts.. I will try with the coolant on and off.. I have lots of material to remove to find the speed/feed and other variables that will make it work. I have 4 different carbide systems.. , and will try the different inserts.. my lathe will go down to 50 rpm.. I would like to say I have a secret weapon, but I do not.. Patience and determination will have to do it. In a moment of weakness I bought a Tangential Tool holder years ago.. maybe it will save the day.

[Steggy]

I will try with the coolant on and off.

Years ago when I was first learning how to do this stuff, I was taught that any steel alloyed with chromium should never be machined dry. I also learned from experience that water-based coolants are not as good as petroleum-based cutting oil when it comes to getting a decent finish with stainless. I use a 90/10 mixture of petroleum-based cutting oil and mineral spirits when machining stainless and the chrome-moly alloys.

Incidentally, I use the opposite when working with aluminum: 10 percent cutting oil and 90 percent mineral spirits. It produces a nice finish and helps keep the chip out of the way.

[AllenH59]

So would the saw coolant I mix up with an oil based mixture count as water based or oil based?

[GlennW]

Water based.

I use Mobilmet 766 oil in my lathe flood system for stainless.

[Steggy]

Water based.

I use Mobilmet 766 oil in my lathe flood system for stainless.

From where do you obtain the Mobilmet oil?

[Steggy]

So would the saw coolant I mix up with an oil based mixture count as water based or oil based?

What Glenn said. Water-based coolants are what they are called: coolants. They help mitigate heat buildup at the point where the cutting is going on. They do not have the lubricating properties of petroleum-based products.

BTW, this stuff is what I use for stainless. As I said above, I cut it with 10 percent mineral spirits.