Alloy 400 can without much of a stretch be welded by the gas-tungsten arc, gas metal arc or shielded metal arc forms utilizing suitable filler metals. There is no requirement for post weld heat treatment; in any case, careful cleaning after welding is basic for ideal corrosion resistance and generally there is the risk of contamination and embrittlement. Completed fabrication can be delivered to an extensive variety of mechanical properties when legitimate control of the measure of hot or cold working and the determination of suitable thermal treatment is finished. Like most other nickel alloys, Monel 400 is usually difficult to machine and will work harden. Be that as it may, great results can be acquired on the off chance that you settle on the right decisions for tooling and machining. The usually utilized welding strategies work well with this alloy. The coordinating alloy filler metal should be utilized. In the event that coordinating alloy is not available, then the closest alloy richer in the essential chemistry (Ni, Co, Cr and Mo) should be utilized. All welds dots should be marginally curved. It is not important to utilize preheating. Surfaces to be welded must be perfect and free from oil, paint or crayon marking. The cleaned area should stretch out no less than 2" past either side of a welded joint.
Gas-Tungsten Arc Welding: DC straight polarity (electrode negative) is recommended. Keep as short an arc length as could be expected under the circumstances and use consideration to keep the hot end of filler metal dependably inside of the protected environment. Shielded Metal-Arc Welding: Electrodes should be kept in dry storage and if dampness has been grabbing the electrodes should be prepared at 600 F for one hour to safeguard dryness. Current settings shift from 50 amps for material (0.062" thick) up to 190 amps for material of 1/2" and thicker. It is best to weave the electrode marginally as this alloy weld metal does not tend to spread. Cleaning of slag is finished with a wire brush (Hand or powered). Complete evacuation of all slag is essential before progressive weld passes furthermore after final welding. Gas Metal-Arc Welding: Reverse-polarity DC should be utilized and best results are acquired with the welding weapon at 90 degrees to the joint. For Short-Circuiting-Transfer GMAW a typical voltage is 19-25 with a current of 100-175 amps and a wire feed of 225-400 inches per minute. For Spray-Transfer GMAW voltage of 26 to 33 and current in the scope of 200-350 amps with wire feed rate of 200-500 inches per minute, relying on filler wire diameter. Submerged-Arc Welding: Matching filler metal, the same concerning GMAW, should be utilized. DC current with either turn around or straight polarity might be utilized. Convex weld globules are favored.
Applications
Marine engineering
Chemical and hydrocarbon processing equipment
Gasoline and freshwater tanks
Crude petroleum stills
De-aerating heaters
Boiler feed water heaters and other heat exchangers
Environment
Safety
CSR