stainless steel pipes after being bent prior to mig welding stainless steel exhaust pipes
A stainless steel welding machine can be used for mig stainless steel welding but before any welding process is undertaken it is beneficial to understand the metalurgical properties of the metal. There are 2 common grades of stainless: 304L (welded employing 308L filler), and 316L which is welded utilizing 316L filler.
Why is 308L filler used for 304L? Generally there are a quantity of grades that do comparable jobs, 302L, 303L and 304L (they are 17/7, 18/8 and 19/9 respectively). 308L is twenty/ten so can be used to weld all three grades.
Stainless is effortless to weld but very tough to keep flat, the coefficient of linear growth is one.7 times that of mild steel. There isn’t considerably you can do about that except to weld it rapidly and by performing so minimise the warmth input.
304 and 316 (as opposed to the L low carbon versions) endure from weld decay. When heated to welding temperatures the Chromium combines with the Carbon leaving the steel quick of Chromium and as a result unable to self restore itself.
This was almost eliminated by introducing stabilised stainless steels 347 and 321 which consist of Niobium or Titanium which sacrifices itself to conserve the Chromium, even so, when lower carbon versions 304L and 316L have been introduced the dilemma of weld decay was eliminated. These days the larger (in simple fact, standard) carbon versions are only employed for applications where heat resistance is required.
To make a steel “stainless” it’s requirements are to include a minimum of 12% Chromium (Cr). The Cr oxidises in the atmosphere forming a passive layer on the surface. This layer, as opposed to coated steels, is self repairing really should it be scratched.
The dilemma with 12% Cr is that it is pretty brittle and only offers the minimum corrosion resistance. Escalating the Chromium content to 17% improves corrosion resistance but raises brittleness. Including 8% Nickel tends to make the steel ductile once again. Thus 18/8 stainless was born (304). 316 / 316L has further Molybdenum and increased Nickel which provides higher corrosion resistance.
With stainless when you see two numbers they always refer to the Chromium and Nickel information – 18/8 is 18%Cr and eight%Ni. If you see three numbers like 19/12/3 they refer to the Chromium, Nickel and Molybdenum content material. 316L is 19%Cr, 12%Ni and 3%Mo. So now that you plan to mig weld stainless steel you are privy to it’s composition.