What is "stress relief" on an engine block?
What is "stress relief" on an engine block? I frequently look at websites that do Darton Sleeved LS blocks and dream (my wife says it's car ****), and I noticed that R.E.D. talks about stress reliving their blocks when they install sleeves. What is that? Is this like cryogenic treatment on transmission gears to eliminate weak spots?
I could be wrong...wouldn’t be the first time...but I think that Steve told me he uses vibratory stress relief, meaning the block is fastened to a vibrating table for a certain period of time, before sleeves are installed.
The stress relieving I'm familiar with involves smoothing or removing casting lines/sharp edges and generally cleaning up poor casting features like oil return holes.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
The stress relieving I'm familiar with involves smoothing or removing casting lines/sharp edges and generally cleaning up poor casting features like oil return holes.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
That's my understanding as well plus ideally vibration table.
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stress risers/ smoothing with a dremel. Vibration/Shaking and cryo affect the metal on a molecular level
designed to provide a harder and more thermally stable Block and Bore. Block prep by
removing casting flash and irregularities to prevent flash coming loose in the Oiling system
etc, and to prevent cracks from "stress risers.
Last edited by NAVYBLUE210; Oct 3, 2018 at 02:46 PM.
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The stress relieving I'm familiar with involves smoothing or removing casting lines/sharp edges and generally cleaning up poor casting features like oil return holes.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
The idea is to stop cracks before they get started and to remove material that could end up damaging the engine if it comes loose down the road and improve oil flow to the oil pan.
You know how you have to heat metal when you're shaping it or else it will break? That's a type of stress-relieving. When metal is shaped or when it solidifies after being cast, stresses build up inside it. These stresses can cause fractures. So, there are a bunch of different ways to relieve these stresses - cryogenics, heat treating, vibration, etc - but they all basically focus on the same thing - realigning the molecules in the metal. Now the metal can withstand a lot more force before it fails.
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What is "stress relief" on an engine block?
Seriously, the most common form I know of, is shot-peening; but you'd need to contact RED to see what they actually do.
I frequently look at websites that do Darton Sleeved LS blocks and dream (my wife says it's car ****), and I noticed that R.E.D. talks about stress reliving their blocks when they install sleeves. What is that? Is this like cryogenic treatment on transmission gears to eliminate weak spots?
In the aerospace world we use "stress relieve" for various reasons. It is most common when larger amounts of material are removed and the residual stresses are present in a lesser amount of material which will have a larger effect on dimensional conformance, stress fractures, etc. Another example is grinding, a "smearing" type of machining process and stress relieving is often used to remove the stresses that were introduced into the part as part of that process. Per the industry standard specification for thermal Stress Relief of Steel Parts - AMS-2759/11 the definition is as follows:
1.2 Application:
Stress Relief of parts is performed to reduce residual stresses and thereby improve dinensional stability, decrease warpage during machining, and facilitate subsequent forming operations. It is also performed prior to plating or other chemical processing to prevent cracking during processing.
Stress Relieve can be accomplished in many different ways. Heating is one of the most common. The material is heated to typically 50-100 degrees below the "aging or tempering" temperature so it does NOT alter the strength, or hardness.
1.2 Application:
Stress Relief of parts is performed to reduce residual stresses and thereby improve dinensional stability, decrease warpage during machining, and facilitate subsequent forming operations. It is also performed prior to plating or other chemical processing to prevent cracking during processing.
Stress Relieve can be accomplished in many different ways. Heating is one of the most common. The material is heated to typically 50-100 degrees below the "aging or tempering" temperature so it does NOT alter the strength, or hardness.
If anyone is interested.....
Metals have a crystaline atomic lattice. The easiest way to explain it is to think of a Rubik's cube. Aluminum and steel both tend to be cubic, and that's the easiest one to work with. The atoms will ultimately reach their lowest energy state when arranged in cubes. Misalignments of the atoms in the lattice cause increased hardness, but also increased brittleness. Similar to twisting one face of a rubik's cube slightly out of alignment -- it is harder to move the cube when the squares are not all properly aligned. Far enough misaligned and the cube just breaks. When they are realigned, the cube is easier to move
Whenever metals are first cast, forged, formed, rolled, etc, there are a lot of internal stresses due to random misalignment of the atoms from the freezing or forming processes. If you take a freshly made piece and let it sit long enough, eventually, the atoms will align themselves in their lowest energy state, which in steel and aluminum is cubic. This realignment is sometimes referred to as polygonization. Heating the metal, vibrating the metal, or both accelerate the aging either with thermal or kinetic energy. Heat expands the lattice, which makes it easier for the atoms to move around and reach their lowest energy state. Vibrating adds energy to the system, which helps atoms that need to slip do so more easily. Either way the result is the same. Reducing the chances of a catastrophic failure.
Metals have a crystaline atomic lattice. The easiest way to explain it is to think of a Rubik's cube. Aluminum and steel both tend to be cubic, and that's the easiest one to work with. The atoms will ultimately reach their lowest energy state when arranged in cubes. Misalignments of the atoms in the lattice cause increased hardness, but also increased brittleness. Similar to twisting one face of a rubik's cube slightly out of alignment -- it is harder to move the cube when the squares are not all properly aligned. Far enough misaligned and the cube just breaks. When they are realigned, the cube is easier to move
Whenever metals are first cast, forged, formed, rolled, etc, there are a lot of internal stresses due to random misalignment of the atoms from the freezing or forming processes. If you take a freshly made piece and let it sit long enough, eventually, the atoms will align themselves in their lowest energy state, which in steel and aluminum is cubic. This realignment is sometimes referred to as polygonization. Heating the metal, vibrating the metal, or both accelerate the aging either with thermal or kinetic energy. Heat expands the lattice, which makes it easier for the atoms to move around and reach their lowest energy state. Vibrating adds energy to the system, which helps atoms that need to slip do so more easily. Either way the result is the same. Reducing the chances of a catastrophic failure.
If anyone is interested.....
Metals have a crystaline atomic lattice. The easiest way to explain it is to think of a Rubik's cube. Aluminum and steel both tend to be cubic, and that's the easiest one to work with. The atoms will ultimately reach their lowest energy state when arranged in cubes. Misalignments of the atoms in the lattice cause increased hardness, but also increased brittleness. Similar to twisting one face of a rubik's cube slightly out of alignment -- it is harder to move the cube when the squares are not all properly aligned. Far enough misaligned and the cube just breaks. When they are realigned, the cube is easier to move
Whenever metals are first cast, forged, formed, rolled, etc, there are a lot of internal stresses due to random misalignment of the atoms from the freezing or forming processes. If you take a freshly made piece and let it sit long enough, eventually, the atoms will align themselves in their lowest energy state, which in steel and aluminum is cubic. This realignment is sometimes referred to as polygonization. Heating the metal, vibrating the metal, or both accelerate the aging either with thermal or kinetic energy. Heat expands the lattice, which makes it easier for the atoms to move around and reach their lowest energy state. Vibrating adds energy to the system, which helps atoms that need to slip do so more easily. Either way the result is the same. Reducing the chances of a catastrophic failure.
Metals have a crystaline atomic lattice. The easiest way to explain it is to think of a Rubik's cube. Aluminum and steel both tend to be cubic, and that's the easiest one to work with. The atoms will ultimately reach their lowest energy state when arranged in cubes. Misalignments of the atoms in the lattice cause increased hardness, but also increased brittleness. Similar to twisting one face of a rubik's cube slightly out of alignment -- it is harder to move the cube when the squares are not all properly aligned. Far enough misaligned and the cube just breaks. When they are realigned, the cube is easier to move
Whenever metals are first cast, forged, formed, rolled, etc, there are a lot of internal stresses due to random misalignment of the atoms from the freezing or forming processes. If you take a freshly made piece and let it sit long enough, eventually, the atoms will align themselves in their lowest energy state, which in steel and aluminum is cubic. This realignment is sometimes referred to as polygonization. Heating the metal, vibrating the metal, or both accelerate the aging either with thermal or kinetic energy. Heat expands the lattice, which makes it easier for the atoms to move around and reach their lowest energy state. Vibrating adds energy to the system, which helps atoms that need to slip do so more easily. Either way the result is the same. Reducing the chances of a catastrophic failure.
Metallurgy is pretty interesting to me. Not that I'm an expert, I've just learned enough to make decisions with what tiny bit of knowledge I have gained.
Very well said. And within that group you have "face centered" and "body centered" grains depending on the material type.
Metallurgy is pretty interesting to me. Not that I'm an expert, I've just learned enough to make decisions with what tiny bit of knowledge I have gained.
Metallurgy is pretty interesting to me. Not that I'm an expert, I've just learned enough to make decisions with what tiny bit of knowledge I have gained.
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Yeah, I had metallurgy in junior college; pretty interesting! It was from there that I knew stress-relieving was done with heat, among other things. The most extreme version of that is annealing which makes steel into putty, relatively speaking. It removes any previous hardening.
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So with this stress relief would we see any real world result with it or is that still not the weak link of the stock ls blocks, given had sleeves done. Curious if worth doing or not and if other companies besides just R.E.D do it. Btw I know this is a little old...
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My machine shop heats the block to 450 degrees F, right at tempering temperature for high high carbon steels if I remember correctly, to clean the baked on grease etc. then shot peens it. They say that it helps maintain stability when boring etc. Plus they look brand new when you get them back.
