Susceptibility of iron castings to heat absorption from an electric arc and to hardened-layer shaping

Abstract

Surface fusions were performed by the gas tungsten arc welding (GTAW) surfacing process on plate castings of spheroidal graphite cast iron with a travel speed from 200 to 800 mm/min. Their geometry and hardness were measured. Calorimetric measurments of the net heat input for the GTAW process have been conducted. A stepwise regression method was used to develop the relationship between GTAW process parameters and those of fusion geometry, microhardness, arc efficiency, and melting efficiency for the obtained data set.

On arc efficiency in gas tungsten arc welding

“…In some cases the range was estimated from published values. The more plausible data range in [24] was selected. [7] are outliners or not?…”

“…The thermal response of spheroidal graphite cast iron (substrate) was studied in calorimetric experiments by Orlowicz & Trytek [24] in GTAW DCEN. Travel speeds ranged from 0.2 to 0.8 m/min and arc currents from 100 to 300 A.…”

“…The range 0.66 -0.77 is the more plausible arc efficiency range. Increased arc gap reduced the arc efficiency [24].…”

“…But there are conflicting results with respect to the influence of arc current and travel speed. There are some reports that there is no influence of arc current or travel speed [14,16,18,23,28], whereas some claim that there is [2,8,9,11,12,15,24].…”

Surface Remelting of Mold Inserts Made of NC11 Steel

“…Repair of damage or the regeneration of parts of machinery worn as a result of operation usually involves supplementing the damaged area using powder spraying techniques or 3D printing [14][15][16][17][18]. The present authors' experience in the area of the local hardening of alloys with the use of a concentrated heat stream enabled them to advance the conclusion that, with the use of a laser beam, it would be possible to locally alter the microstructure of NC11 steel, increasing its hardness in comparison to the initial material, and thus extending the service life of the mold inserts [19][20][21][22].…”