| Popis: |
Bimetallic rolled plates with a base layer made of carbon or low-alloy structural steel and a cladding layer made of corrosion-resistant steel are used when it is necessary to combine corrosion resistance with high mechanical properties. Chemical and petrochemical plants traditionally use two-layer corrosion-resistant plates to make equipment that operates under pressure in contact with an aggressive medium. The dimensional and grade range of such plates and their quality characteristics must conform to GOST 10885-85. The continuity and cohesive strength of the joint between the layers of bimetallic plates are the main parameters that determine the quality of the plate, its workability, and the service properties of the products made from it. The continuity of the joint is determined by ultrasonic inspection, while its cohesive strength is characterized by the shear strength a s . These two parameters depend mainly on the technology used to obtain the bimetallic semifinished product. More precisely, they depend on the character of the processes that take place at the interface of the layers when they are joined together. There are four main methods used to produce bimetals [1-5]: packet rolling - the metals are joined together as they undergo simultaneous plastic deformation; casting - joining occurs as a result of interaction of molten metal with solid metal, i.e., during the crystallization of one metal on a substrate composed of the other metal, with the new bimetal then being subjected to hotrolling; explosive welding - joining occurs by means of a blast wave, with the high collision velocities and pressure in the contact region resulting in cleaning of the surfaces, their activation, and formation of the joint; eleetroslag hard-facing of the cladding layer onto a semifinished product (slab, ingot) comprising the base layer - joining of the cladding layer occurs mainly in the molten state and involves fusion of the base layer to a certain depth and mixing of the hard-facing metal with the molten base metal. The differences in the character of the processes that take place at the interface account for the differences in the quality |
