In maintenance and repair welding, situations often arise when it is difficult to identify the base metal and you know the repaired part will be subjected to extreme conditions. At other times, you have a general idea of what the base metal is but are not sure of what filler alloy to use to make the repair. To select the proper filler alloy in such situations, several factor must be considered, related to what the final use of the part will be:
1. High impact strength
2. Ductility
3. Corrosion resistance
4. High tensile strength
5. Non-contaminating to food
6. High heat service
7. Low temperature service
8. Tough but machinable
9. Dissimilar metals
10. Unknown metals
Heres a typical maintenance repair problem involving MG special alloys:
The broken part came from a furnace. The base metal looks like stainless
steel; however, the previous weld repair was done using stainless steel,
and the weld failed after a short period of use. What do you do now?
This situation calls for a special welding alloy. In this situation,
special consideration must be given to:
High heat service (part from a furnace)
Unknown base metal
High tensile strength (the last weld failed)
Tough but machinable
(after welding, the part must be machined)
The above information would lead to selecting MG 690 because this
product can be used on steel, stainless steel, Monel and Inconel. (The
metals the part could be possibly made from.) It has a high tensile
strength (up to 85,000 psi), and it will with stand high heat service.
MG 690 would be the alloy to use because even if the
part wasnt stainless steel it is compatible to a wide range of alloys
typically used for furnace or high heat applications. It is stronger
than most of the base metals the part may be made of. It is tough, yet
machinable. MG 690 is a special alloy that can be used on hundreds of
special maintenance applications.
Another example of a typical maintenance shop situation follows:
A part of a machine must be modified to conform to a new
manufacturing procedure. A high-strength alloy part was fabricated and
must now be welded to an existing machine part made of an unidentified
base metal. The existing machine part is probably made of a very strong
material because of the work it must do.
It could be one of many alloys.
Some consideration of the weld deposit to help select a filler alloy
are:
Must allow for F.D.A. System approval.
Must be compatible to a wide range of base metals because the base
metal is unidentified.
Must have a high tensile strength because of the work being done.
Must be ductile for the same reasoning.
The above considerations would lead to selecting MG 600 because it has
high tensile strength and good ductility. (Usually high tensile alloys
have low ductility. The magic of MG 600 is its very high tensile
strength along with good ductility.)
Universal Problem-SolverTM for Special Alloy Welding
One of the most versatile alloys for solving most problem situations is
MG 600. It can be used for the joining of all steels - low, medium and
high carbon steels, stainless steel, manganese steel, and tool steels-or
any combination. It is a build-up alloy as well as a padding alloy used
prior to wearfacing. It is exceptional because of its compatibility to
all steel and most iron alloys. It gives the welder capability to use
any surfacing electrode on almost any iron base alloy without fear of
the deposits spalling (breaking off). This is the ultimate cladding
alloy prior to hardfacing. MG 600 has also developed a reputation as the
Stud Removal Rod. It not only removes broken high tensile studs, but
also removes taps or drills that break below the surface of the hole.
