Filler material for welding 4330 to 4330

[Kulungi]

I would like to weld 4330 to 4330. What types of filler materails are avaiable that will give me the sames streight requirements as the base material or the best strenghts. I don't plan to preheat but I am going to post heat at 1000 deg F. It is the hot tearing in the material that has my in a bind. I thought if I added a filler material if might reduce the hot tearing and not really reduce the overall strenght on the material. Can someone offer some advise of a filler material that might help.

 

[metengr]

Kulungi:
You absolutely need to preheat for 43xx steels. What ype of joint configuration? What process? What is the heat treatment condition of the 4330?

One possible filler metal is

AWS SFA 5.5 E8018 C3 (SMAW process).

 

[stanweld]

I assume this is AISI/SAE 4330 alloy steel. Without preheat, you should anticipate cracking with or without filler metal additions. Since you have previously welded without filler metal additions, I assume that welding is by the EB process. If so, a defocused beam can be used to preheat and to provide a light tempering effect after welding as well.

 

[GRoberts]

To even begin to answer your question there is more information needed. What welding process? What thicknesses? What strength is the 4330 heat treated to? You would have to have very thin sections of 4330 in order to weld without cracking if you are not preheating.

 

[Kulungi]

The process is EB welding. The material thickness is .675 with backing materials to catch the beam. It is is a butt joint configuration. The materials condition from what I know is primarily tempered martensite, grain size is per astm E 112 6 or finer. The material is called 4330V to 4330V. No hot tearing is allowed in the welds and that is all we have gotten. I plan to narrow the beam to reduce the amount of silicon found in the hot tears under SEM. I thought a shim could be added maybe we would lose a little strenght but also the hot tears. Whats next and where to go?

 

[CoryPad]

To answer the final sentence:

You need to preheat to avoid high stresses during solidification and to avoid quenching the fusion zone which can produce high transformation stresses. These high stresses cause brittleness and cracking.

I don't see how reducing beam diameter will reduce silicon found in hot tears. I recommend adjusting beam diameter to obtain the proper penetration depth and to cover for any alignment variations from the parts and process.

You may need a filler, maybe even a highly ductile nickel-based one. We use one for similar welding of 4320 without preheat, but our metal has better weldability than yours (lower carbon concentration). I am not sure the huge expense on the wire is better than investing in a preheating station, but that is an economic decision.