Return to M ENU

General Welding Procedures
SMAW-GMAW-FCAW, Carbon & Low Alloy , Cylindrical Parts, Manganese Steel Submerged Arc, Overlay, Grooving/Anchoring, Backwashing, Hardfacing

Shielded Metal Arc Welding SMAW, Gas Metal Arc Welding GMAW,
Flux Cored Arc Welding  FCAW

A. Weld deposit porosity might be the result of long arc length, wide weld bead, overheating, dirty base material or, in semi-automatic gas welding, too much wire extension or lack of gas coverage.
B. Never make wide weld beads when welding steels that should not be overheated.  Remember that the wider the weld bead, the slower the welding travel speed.  The slower the travel speed, the higher the heat input into the base metal.
C. In manual welding the backhand welding technique is preferable.  Forehand welding might produce porous, unsound weld deposits and deeper penetration.

Carbon and Low Alloy Steels
A. For better results, preheat base metal according to recommended preheat temperature.
B. When welding heat-treatable carbon and low alloy steels, weld a stringer bead to outline the area to be hardfaced and/or rebuilt.  All welds should be within this area with the last weld bead to be 100% on the previous weld deposit.  This will temper the martensite formed when welding on the base metal, minimizing under bead cracking.
C. Do not weld magnetic steels with standard 14% manganese steel welding alloys.  Use a manganese-chromium, such as Postalloy 2865-FCO , or high manganese content alloy, Postalloy 286-FCO

Cylindrical Parts - Wheels, Rollers, Shafts, etc.
A. Weld outside extremes first, including the top of  flanges.  Next, weld any location where dimensions change significantly (i.e. shoulders, edges, etc.). Weld from outside dimensions towards the larger mass of material to minimize heat build-up.
B. If rebuilding with a martensitic overlay material over 40 Rc, keep the preheat and interpass temperature above 600ºF (315ºC) so that the individual weld beads do not harden until the welding is complete.  Hold part at temperature after welding until part is at uniform 600ºF (315ºC) before allowing it to slow cool.

 

Return to MENU


Welding Manganese Steel

Austenitic manganese steel is extremely tough and is characterized by excellent strength and ductility.  It is particularly useful for applications  involving impact and abrasion.  Prolonged or repeated welding of manganese steel is more critical than ordinary steel because overheating can result in embrittlement.  In the past, emphasis has been placed only on temperature as the main factor to consider during the weld operation.  However, embrittlement of manganese steel is influenced by both time and temperature.  Welding at high temperatures for short periods of time is no more detrimental than welding at low temperatures for a long period of time.  The effects of heat are cumulative and the number of times that a part is repaired should be factored in.  If repaired too many times, keeping in mind time and temperature reaction, embrittlement and subsequent failure could occur.

A. Consider using a smaller diameter wire.  It will deposit at a rate 10 to 20% greater than the next largest size wire at the same current setting.  A faster deposit means less heat input.
B. Skip weld on the surface to disperse heat uniformly throughout the part.
C. Use high travel speeds to distribute the heat.
D. Do not allow welded surfaces to reach temperatures above 500ºF (260ºC).
E. Submerge the part in water to reduce the heat build-up.
F. Spray water onto the part if it appears to be reaching 500ºF (260ºC).
If the manganese part is to be repaired repeatedly, such as hammers, cones, rolls, frogs and switches, putting two layers of Postalloy 2865-FCO can be very beneficial.  Besides not embrittling until 1000ºF(538ºC), this alloy will act as an insulator to the original base metal, helping it keep below 500ºF(260ºC).  It also provides a readily visible crack-free surface with the appearance of stainless steel that indicates when rebuilding is necessary.

Before rebuilding check the worn part with a magnet.  If the wearing surface is slightly magnetic, a good penetrating first layer will be sufficient.  If the wearing part is strongly magnetic, grind or arc to remove the magnetic material.  As when welding, keep the part cool when arc airing.
Further Considerations:
A. When welding austenitic manganese steel with manual stick electrode, the weld beads should not be wider than 3 to 4 times the diameter of the core wire and the depth should not be any more than 1.5 times the core wire diameter.  Always use good convex crown.  Flat deposits have a tendency to develop center bead cracks, while large, wide weld beads tend to increase heat build up and should be avoided.
B. With the use of modern composite manganese steel covered electrodes and flux-cored manganese steel wires, peening of the weld deposit is not necessary (as when using bare manganese filler metal rods).

Submerged Arc Welding
A. Submerged arc fluxes, especially fused fluxes, affect the deposit chemistry and Rockwell hardness.  Pick the correct flux/wire combination.
B. The bead shape and surface appearance are affected by flux characteristics/flux burden.
C. Use new or correctly screened flux to prevent contamination of weld metal.  Reused flux may affect deposit chemistry.
D. Excessive flux overburden and fines will result in trapped gas under the slag which in turn can cause porosity and affect surface finish.

E.

 Excessive interpass and preheat temperatures adversely affect the slag removal characteristics of many fluxes.