Evaluation of High Chromium Overlays to Protect Less Alloyed Substrates from Corrosion in a Coal Gasification Atmosphere. Quarterly Report,December 1, 1977--February 28, 1978.

摘要

One-half of the welding is complete and testing started on this program to produce overlays with corrosion resistance to coal gasification atmospheres at 1800exp 0 F. In the last quarter,single and double layer overlays were deposited with INCONEL Filler Metal 72 (44percent Cr) on 304L, 310and INCOLOY alloy 800H with the submerged-arc (SAW) and hot wire gas tungsten arc processes (GTAW-HW),and on 304L with the gas metal arc process. In addition,the experimental R139filler metal (31Cr-3Al) was overlaid on 304L with the SAW process. Percent dilution of the base plate was measured and percent recovery of the major alloying elements were calculated for the AWS-ER309overlays on 304L for all weld processes and for the R139overlaid on 304L by the SAW process. Pre-exposure testing of the AWS-ER309overlays on 304L was completed and stress rupture testing started. The tests consisted of hardness surveys,bend and tensile tests,bulk chemical analysis of the overlay and microprobe analysis for the distribution of the major alloying elements from the outside edge of the overlay through the thickness of the base plate. Inspection of the weldments was by dy-check and examination of cut slices. (ERA citation 04:001073)