PRODUCTION OF HIGH-ALLOY STEEL CLAD STEEL PIPE

摘要

PURPOSE:To prevent the deterioration in the characteristic near a weld zone by subjecting the groove part of a specific shape formed to the part of a carbon steel to butt welding with a carbon steel wire then subjecting the high alloy steel part near the preliminarily machined butt part to one-layer welding with a high alloy steel wire. CONSTITUTION:The groove 3 of which the depth is 40-70% of the thickness of the carbon steel 1 and the angle is 60-90 deg. is provided to the outside of the steel pipe. The high alloy steel 2 near the inside butt part 4 is machined away at 10-20mm width to expose the carbon steel and thereafter the groove 4 of which the depth is 20-50% of the thickness of the carbon steel 1 and the angle is 60-90 deg. is provided to the carbon steel 1. The outside groove 3 and inside groove 4 provided to the carbon steel 1 are subjected to one-layer welding respectively with the welding wire consisting of carbon steel and thereafter the inside butt part 5 is welded under the conditions of 400-600A welding current, 40-50V arc voltage and 30-50cm/min welding speed by using the high alloy steel cored wire having >=5mm outside diameter. The excellent weld zone is obtd. in the above-mentioned manner.