Weaken Steel

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How does "overwelding" weaken metal that you are welding on?Miller Dialarc 250Miller Bobcat 225Hobart Oxy/FuelCouple of Dewalt and Milwaukee GrindersJET Bandsaw and Drill Press
Reply:Depends on what you mean by "overwelding". Google how time at high temperatures change the crystalline structure of steel and how that affects the strengths of the steel.Airco Ac/Dc 300 HeliwelderMillerMatic 200 (stolen)Miller Maxstar 150STLMiller AEAD200LE (welding and generating power) Hobart MIG
Reply:Excess heat causes grain growth. Time and temperature take their toll."USMCPOP" First-born son: KIA  Iraq 1/26/05Syncrowave 250 w/ Coolmate 3Dialarc 250, Idealarc 250SP-175 +Firepower TIG 160S (gave the TA 161 STL to the son)Lincwelder AC180C (1952)Victor & Smith O/A torchesMiller spot welder
Reply:overwelding adds heat to the metal which can change its metallurgical properties, and can add warpage or shrinkage stresses to the metalMiller Multimatic 255
Reply:something to do with the way the iron atoms arrange themselves around the carbon atoms that heat disrupts and the steel changes properties..i believe taint an issue with mild  steel cause there aint enough carbon..i believe for the same reason mild steel wont take a temper like higher carbon steel will,,in closing i'll say that anything i've ever read about metallurgy quickly made me realize i was not smart enough to read about metallurgy..Last edited by weldbead; 03-07-2015 at 06:29 PM.
Reply:cooling or rate of cooling can have as much of an effect as "overwelding", some materials have very specific rates/temperature/times IF what you want or want to keep in terms of properties is importanthttp://www.matweb.com/ is a good place to start
Reply:Originally Posted by farmwelderHow does "overwelding" weaken metal that you are welding on?
Reply:In what context do mean over welding?
Reply:@ farmwelder - recommend watching, listening, and availing yourself to first understand the iron-carbon phase diagram.  Before we talk about arc welding affecting the "strength" of steel, you need to understand its primary constituents and their behaviour through the heating/cooling cycles."Discovery is to see what everybody else has seen, and to think what nobody else has thought" - Albert Szent-Gyorgyi
Reply:The first couple of pages of this document (NBS Monograph 88) goes into more detail of the iron-carbon phase diagram and the phase diagram for carbon steels.   It's a good compliment to the above video.   http://digicoll.manoa.hawaii.edu/tec.../PDF/NBS88.pdf