Sampling and shearing method for steel for pressure vessel

Abstract

The invention discloses a sampling and shearing method of steel for a pressure vessel, the steel for the pressure vessel is rolled and produced by adopting a TMCP + tempering process, and the sampling and shearing method is characterized by comprising the following steps that after a steel plate is rolled, only head and tail burrs are cut off, the steel plate is cut in sections without cutting the burrs, and heat treatment is carried out; after heat treatment tempering, the steel plate is cooled off line, sampling analysis is conducted on sub-plates obtained after segmented cutting by avoiding the shear stress end, and the influence of shear stress on the performance of the steel plate is avoided; after the performance is qualified, the steel plate is transferred to a shearing line for back shearing, and four edges of the steel plate are cut according to order sizes. According to the method, the production process is stable, the manual off-line flame cutting cost is reduced, the one-time qualification rate of the performance of the steel plate is improved, it can be guaranteed that products are delivered to customers well and quickly, efficient operation, controllable maintenance quality and controllable product quality are achieved, the production efficiency is improved, and economic benefits are remarkable.

Description

technical field [0001] The invention relates to the technical field of steel production, in particular to a production process of steel for pressure vessels. Background technique [0002] Among medium and heavy plate products, there are more and more demands for structural steel with high toughness and low yield ratio, and steel for pressure vessels. From the dual considerations of production cost and energy saving, quenching is cancelled, and TMCP+tempering is used to obtain hot rolling+quenching The same performance as + tempering, if the process technology is mature and stable, the performance of this TMCP + tempering is better than that of hot rolling + quenching + tempering production route, but the production difficulty is relatively greater. [0003] The TMCP process adopts the mode of "relaxation and low red return temperature after rolling", and controls the red return temperature range between 200-400 °C to maximize the phase transformation strengthening effect of ...

AI Technical Summary

Problems solved by technology

[0004] The steel plate produced by the TMCP process has high strength, high toughness, and low yield ratio. The production process is cumbersome and the steel plate has high strength. Taking Nangang’s key variety of hydropower steel (N610CF) as an example, the hot-rolled strength in TMCP state can reach 900MPa, and the thickness is 30mm-38mm It is difficult to cut the steel plate after rolling, and it is easy to damage the blade of the shearing machine when it is cut for a long time, and the end face of the cut steel plate is prone to cracks, which poses a major quality risk

In order to reduce the impact on the equipment, the steel plate with a thickness of 30-38mm was changed to the off-line manual fire cutting method. The residual stress at the shear end of the steel plate is large, and it is difficult to eliminate the tempering after heat treatment, which affects the sampling performance and detection.