Flux-cored wire and method for welding hot-rolled back-up roll by same

Abstract

The invention discloses a flux-cored wire and a method for welding a hot-rolled back-up roll by the same, and relates to the welding technology. By using an iron-based steel strip as a sheath, the flux-cored wire comprises the following components in percentage by mass: 0.15 to 0.60 percent of carbon, 0.10 to 2.00 percent of silicon, 0.15 to 2.00 percent of manganese, 2.50 to 7.00 percent of chromium, 0.50 to 2.50 percent of molybdenum, 0.30 to 3.50 percent of tungsten, 0.20 to 1.00 percent of vanadium, 0.20 to 3.00 percent of nickel, 0 to 0.03 percent of sulfur, 0 to 0.03 percent of phosphorus, and the balance of iron. The flux-cored wire needs to keep the surfacing interpass temperature of the cold-rolled back-up roll between 300 and 350 DEG C during constant temperature surfacing work. The flux-cored wire well solves the problem that the intensity of a surfacing material is not matched with the toughness after surfacing of the cold-rolled work roll, so that the hot-rolled back-up roll has high intensity and excellent toughness. Therefore, the service life of the hot-rolled back-up roll is improved.

Description

technical field

[0001] The invention relates to the field of welding technology, in particular to a flux-cored wire for welding hot-rolled back-up rolls, and a method for welding hot-rolled back-up rolls with the above-mentioned flux-cored wire. Background technique

[0002] Hot-rolled backup rolls are large-scale metallurgical spare parts. The materials used at home and abroad mainly include 50CrMo, 60CrNiMo, 60CrMnMo, 70Cr3Mo, 45Cr4NiMoV, Cr5, etc. The main reason for failure is that when working under heavy loads and alternating cold and hot conditions, they are affected by the rolling The effect of steel-making changes (plus the segregation of some base metal components and defects in the manufacturing process) makes the roll surface very prone to local accumulation of residual stress at a certain depth. With the passage of time, layered tears gradually spread from point to local level, and even cracks occur, eventually leading to large-scale shedding. Therefore, the sur...