When I grind/sharpen my lawn mower blade with my electric grinder am I ruining it.
Michael E. Esh On Sep 6, 2011, at 4:25 PM, G Mann <[email protected]> wrote: > Color change in heated metal is strongly influenced by metal composition. > More of one component or another in the makeup of steel [a compound > substance] gives different "color points" at different temperatures, thus > without controlled conditions with known materials most of what's being > offered in this thread is pretty baseless. > > Temper, hardness and other strength factors are also influenced by quench > time, coolant temperature, and other factors. All which need be tightly > controlled. > > Sorry to rain on your individual parade. No disrespect intended. > > > On Tue, Sep 6, 2011 at 12:58 PM, Fmiser <[email protected]> wrote: > >>> Max Dillon wrote: >> >>> My friend the machinist tells me that to affect the temper, >>> the metal needs to be heated until the color is correct >>> (glowing red or hotter/lighter), then quickly cooled. I think >>> 400 degrees is not hot enough. >> >> By the time it just begins to glow is is _way_ past tempering. >> >> Temper is a decreasing of the hardening. >> >> 400 deg F can effect a hard-tempered steel. Often 350 >> deg F is considered the maximum safe temperature to avoid >> affecting temper. >> >> To fully harden, heat the metal to glowing red, then quench >> (cool very quickly . This is often too hard and so must be >> tempered. >> >> To temper, remove the scale and oxide so there is shiny metal. >> Then heat and watch for surface color - NOT glowing color. When >> the color is reached, quench. >> >> The first color is often called "straw" - a pale tan or yellow. >> This is the least tempered, or the most hard. >> >> The last color is blue. This is the most tempered, or the least >> hard. At this point the hardness is nearly entirely gone. >> >> Here's a website with colors and temperatures. Keeping in mind >> that the actual temperature can vary depending on the steel >> alloy. >> http://www.engineeringtoolbox.com/tempering-colors-steel-d_1530.html >> >> -- Philip >> >> _______________________________________ >> http://www.okiebenz.com >> For new and used parts go to www.okiebenz.com >> To search list archives http://www.okiebenz.com/archive/ >> >> To Unsubscribe or change delivery options go to: >> http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com >> > _______________________________________ > http://www.okiebenz.com > For new and used parts go to www.okiebenz.com > To search list archives http://www.okiebenz.com/archive/ > > To Unsubscribe or change delivery options go to: > http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com _______________________________________ http://www.okiebenz.com For new and used parts go to www.okiebenz.com To search list archives http://www.okiebenz.com/archive/ To Unsubscribe or change delivery options go to: http://mail.okiebenz.com/mailman/listinfo/mercedes_okiebenz.com
