CLASSIFICATION

írod-CIB is an oxy-fuel (oxyacetylene) gas welding rod RCI-B (Nodular Cast Iron) Classification. These nodular (ductile) cast iron welding rods can produce sound weld metal when used to weld higher strength gray iron, malleable, and nodular iron castings with the oxyfuel gas process. Under optimum conditions, the welds produced have mechanical properties of 410 MPa minimum ultimate tensile strength; 310 MPa minimum yield strength; 5 to 15 percent elongation; and a maximum Brinell hardness of 200. These mechanical properties are because most of the graphite content in the weld metal is in nodular form, which results in good ductility and machining properties for the weld. Color match to the base metal generally is good.

Post weld Heat Treatment: PWHT may also be used to improve the machineability of the heat-affected zone adjacent to the weld metal. Tempering beads sometimes are employed to achieve the desired improvement. These beads, consisting entirely of filler metal and a previous bead, are made in such a manner that the heat input tempers any martensite present from a previous bead.

Recommendations

• • Pre-heat of 595-650°C generally required.
  • Post-heating varies with the size of the casting: slow cooling, complete stress relief 620°C or full annealing 900°C.
  • Gas welding produces less hardening in the HAZ than does arc welding.
  • Readily machinable.
  • Porosity can be minimized by using a slightly reducing flame.
  • The RCI-B rod contains enough Si and C to replace those elements lost through welding process.
  • Use METAFIL Cast Iron Flux.

CHEMICAL COMPOSITION OF UNDILUTED WELD METAL

Single values shown are maximum, unless otherwise noted. *Nickel plus incidental cobalt. #Copper plus incidental silver.

ALL-WELD-METAL MECHANICAL PROPERTIES

*Annealed

Welding Considerations

The casting skin should be removed from the weld area by machining, grinding, chipping or other suitable means. When repairing casting defects, care should be exercised to ensure removal of any defective metal to sound base metal before welding. Also, all oil grease, dirt, or other foreign material should be eliminated using suitable solvents. If oil, grease, or solvents have impregnated the casting, heat should be applied to the area to be welded until volatilization is no longer observed. A temperature of 400°C generally is sufficient for this operation. If the casting is too greasy, flash heating the welding surfaces to about 540°C should drive off the grease in a gaseous state.

Castings to be welded with a V-groove should have the edges beveled to form a 60 to 90 degree include angle. The groove should have a root face greater than zero, so that there is less difficulty in aligning the joint members and there is no melting through of the entire thickness.

The application of RCI-B welding rods is the same as that described for the other RCI filler metals. The weld zone can withstand higher residual stresses without cracking. However, it is advisable to apply slow cooling to prevent stress cracks in the base metal. It is recommended that residual stress be reduced by preheating castings uniformly to 1600°F (870°C), and providing slow furnace cooling by covering with, or immersion in, an insulating material such as dry sand. After such treatment, the castings will withstand exposure to considerable thermal expansion and will permit heavy machining.

ELECTRODE SIZE & WELDING CURRENT (OFW)

WARNING: Safety and health information is available from many sources, including, but not limited to Safety and Health Fact Sheets listed in A11.3, ANSI Z49.1 Safety in Welding, Cutting, and Allied Processes published by the American Welding Society, 8669 Doral Blvd., Suite 130, Doral, FL 33166., and applicable federal and state regulations. The Safety and Health Fact Sheets are revised, and additional sheets added periodically.