Original Posted By: rhartwig11(at)juno.com
Subject: Pietenpol-List: Stress relief of parts
Pietenpol-List: Stress relief of parts
RE: Pietenpol-List: Stress relief of parts
Original Posted By: rhartwig11(at)juno.com [mailto:rhartwig11(at)juno.com]
I took the statement to suggest that sandblasting might be a bit like shotpeening. Whether the impact carries enough energy to make a difference, Iwouldn't know, and sort of doubt.Gene-----Original Message-----
I took the statement to suggest that sandblasting might be a bit like shotpeening. Whether the impact carries enough energy to make a difference, Iwouldn't know, and sort of doubt.Gene-----Original Message-----
Re: Pietenpol-List: Stress relief of parts
Original Posted By: "Hubbard, Eugene"
Sand blasting and bead blasting will have the same effect yet will havedifferent cosmetic effect on the surface. This is based on my experienceusing both. if one wanted to have a polished surface then use walnutshells, but this will not effect the material. Blasting moves the metal,almost like burnishing yet its more aggressive. Either will stress relivethe outside surface of a material. this is where the cracks propagatefrom. You will find the connecting rods and other engine parts are beadblasted to stress relive, this is because sand has a tendency to impregnatein the metal, whereas bead are less likely to. If a part has internalstresses one would have to take another route. But we are talking aboutthin metal that will be bent, so blasting will stress relive the outsidesurface which went under tension and or compression from the bending. theinside is not effected, if and only a proper radius is made. If too small aradius is made then the inner will be over stressed and the part is ruined.welding will cause inner stresses, and stiffness closer to the weld, thisrequires different method to relive the stress, heating and cooling withvarious times and chemicals. Ever notice that when something welded isbroke the broke is at the weld???? I have heated parts and dipped them inburnt motor oil to carburize ( case Harding) the surface, a crude Bluingmethod.any questions?John C.----- Original Message -----
Sand blasting and bead blasting will have the same effect yet will havedifferent cosmetic effect on the surface. This is based on my experienceusing both. if one wanted to have a polished surface then use walnutshells, but this will not effect the material. Blasting moves the metal,almost like burnishing yet its more aggressive. Either will stress relivethe outside surface of a material. this is where the cracks propagatefrom. You will find the connecting rods and other engine parts are beadblasted to stress relive, this is because sand has a tendency to impregnatein the metal, whereas bead are less likely to. If a part has internalstresses one would have to take another route. But we are talking aboutthin metal that will be bent, so blasting will stress relive the outsidesurface which went under tension and or compression from the bending. theinside is not effected, if and only a proper radius is made. If too small aradius is made then the inner will be over stressed and the part is ruined.welding will cause inner stresses, and stiffness closer to the weld, thisrequires different method to relive the stress, heating and cooling withvarious times and chemicals. Ever notice that when something welded isbroke the broke is at the weld???? I have heated parts and dipped them inburnt motor oil to carburize ( case Harding) the surface, a crude Bluingmethod.any questions?John C.----- Original Message -----
Re: Pietenpol-List: Stress relief of parts
Original Posted By: "Les Schubert"
yes next to the weld. at the weld, NOT the weld itself.----- Original Message -----
yes next to the weld. at the weld, NOT the weld itself.----- Original Message -----