PURPOSE: To lower hydrogen brittleness sensitivity and to suppress peeling of high alloy steel at the interface with low alloy steel by forming the root pass of specific Ni equiv. of the high alloy steel under spraying of a specific BC value of a flux on the low alloy steel by the use of a high alloy steel belt-like electrode.
CONSTITUTION: In subjecting low alloy steel to build-up welding of a root pass consisting of high alloy steel, said steel is welded under spraying of a flux having ≥0.5 BC value expressed by the equationIby the use of a belt-like electrode of high Ni-Cr high alloy steel. The build-up weld metal of the root pass of high Ni-Cr high alloy steel having ≥30(%) Ni equiv. expressed by the sum of Ni(%)+ 0.5Cr(%) is formed. The reason for limiting the Ni equiv. lies in that if the Ni equiv. is below the limits, hydrogen embrittleness sensitivity increases. If the BC value is below the limits, high temp. cracking resistance is not provided at all.
ASAMI KIYOSHI
TANAKA OSAMU
SAIDA HIROSHI
MATSUSHITA YUKINOBU
| JP46015409A |