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Again, I was only suggesting a possibility for the rumoured intergranular cracking/spalling that's alleged to occur on cams with very high ZDDP.
Agreed, and I was only directly addressing some of the issues raised in the link above, and in particular the part of the link that mentioned zinc.
The other issues such as lithium or mercury embrittlement don't matter, as we don't have it present in an engine. The issue of Halides (Cl, F, Br, I negative ions) which may occur in pens or cleaning chemicals has been addressed before. It only applies to high alloy steel like stainless steel or high temperature steel, often high in Cr / Ni / Mo, and often in a stressed (tensional forces) application. Again, not what we see in an engine.
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It's present in boiler tubes
I would assume a boiler tube isn't plain carbon steel, but rather a steel high in Cr and Ni and other alloy elements. This makes it a different material that has different issues.
What I'm trying to say, is talking to a number of failure engineers and metallurgists, they are all very familiar with the possible issues raised above, they consider them well known. But none of these issues apply to an engine component as far as they can see. The failure requires a particular combination of materials and events, none of which we see in an automotive engine.
I have raised all the issues above, and they all consider them true in their own right, but not applicable to our situation.
Again, I was only suggesting a possibility for the rumoured intergranular cracking/spalling that's alleged to occur on cams with very high ZDDP.
Agreed, and I was only directly addressing some of the issues raised in the link above, and in particular the part of the link that mentioned zinc.
The other issues such as lithium or mercury embrittlement don't matter, as we don't have it present in an engine. The issue of Halides (Cl, F, Br, I negative ions) which may occur in pens or cleaning chemicals has been addressed before. It only applies to high alloy steel like stainless steel or high temperature steel, often high in Cr / Ni / Mo, and often in a stressed (tensional forces) application. Again, not what we see in an engine.
Quote:
It's present in boiler tubes
I would assume a boiler tube isn't plain carbon steel, but rather a steel high in Cr and Ni and other alloy elements. This makes it a different material that has different issues.
What I'm trying to say, is talking to a number of failure engineers and metallurgists, they are all very familiar with the possible issues raised above, they consider them well known. But none of these issues apply to an engine component as far as they can see. The failure requires a particular combination of materials and events, none of which we see in an automotive engine.
I have raised all the issues above, and they all consider them true in their own right, but not applicable to our situation.
