10-19-2018, 12:02 AM
So first of all sorry for the delayed answer time did not allow to write something.
No I am not a member over there but an avid reader for quite some time.
As for the Tempilaq experiments I remeber reading about some simmilar tests or reports thereof but cant find it at the moment (Will search for it).
Here is what I remeber on top of my head (may be completely off): The results where not pleasing to them as the material was ground away and the adjecent material was too far off to get a reading of the temperature on the grinding surface. This observation was then taken in relation to older research which I already linked where on page 19(17PDF) is a graph of a fast running disc (320FEPA @ 19m/s) with watercooling that shos peacs of temperature of up to 1200°C up to a depth of 59µm and that after ~1sec that temperature is already fallen as low as 450°C. Now this is an exptreme excample but shows how high and fast temperatures can become. The research also describes how the generated temperature heavily depends on how much material is removed (preassuer applied) in a given time Page 29(27PDF). Here different media wer used with diferent binders and grits: 320grit sic with ceramic binder, 50/320grit sic with magnesia binder and aio 280/320grit with magensia binder. The graph shows that the aio ground the coolest with temperature as low as ~450°C while taking away 20µm @ 19m/s uncooled grinding.
A Page further in the same was done with coolant (water) which shows a given the right media even fast grinding can be done below 200°C.
On the "detempering" it was argued that the most surface layer gets so hot that there is a rehardening effect going on which makes it harder but the layer directly below is softened up so that the hardened layer has not enough support to hold up and just dulls/crumples away quicker.
General consensus on the german board is that it is better to watercool while belt sharpeing but it is also acceptable to grind uncooled when the belt is run slow and only light passes get taken with cooling the knive off in between.
I hope this does not spread more confusion then it aleviates ...
No I am not a member over there but an avid reader for quite some time.
As for the Tempilaq experiments I remeber reading about some simmilar tests or reports thereof but cant find it at the moment (Will search for it).
Here is what I remeber on top of my head (may be completely off): The results where not pleasing to them as the material was ground away and the adjecent material was too far off to get a reading of the temperature on the grinding surface. This observation was then taken in relation to older research which I already linked where on page 19(17PDF) is a graph of a fast running disc (320FEPA @ 19m/s) with watercooling that shos peacs of temperature of up to 1200°C up to a depth of 59µm and that after ~1sec that temperature is already fallen as low as 450°C. Now this is an exptreme excample but shows how high and fast temperatures can become. The research also describes how the generated temperature heavily depends on how much material is removed (preassuer applied) in a given time Page 29(27PDF). Here different media wer used with diferent binders and grits: 320grit sic with ceramic binder, 50/320grit sic with magnesia binder and aio 280/320grit with magensia binder. The graph shows that the aio ground the coolest with temperature as low as ~450°C while taking away 20µm @ 19m/s uncooled grinding.
A Page further in the same was done with coolant (water) which shows a given the right media even fast grinding can be done below 200°C.
On the "detempering" it was argued that the most surface layer gets so hot that there is a rehardening effect going on which makes it harder but the layer directly below is softened up so that the hardened layer has not enough support to hold up and just dulls/crumples away quicker.
General consensus on the german board is that it is better to watercool while belt sharpeing but it is also acceptable to grind uncooled when the belt is run slow and only light passes get taken with cooling the knive off in between.
I hope this does not spread more confusion then it aleviates ...