Boiler-steam-drum-use steel with thickness no lower than 80mm, and production method thereof

Abstract

The invention relates to boiler-steam-drum-use steel with thickness no lower than 80mm. The steel comprises the components of, by weight: 0.11-0.145% of C, 0.22-0.42% of Si, 1.24-1.49% of Mn, no more than 0.010% of P, no more than 0.010% of S, 0.22-0.38% of Cr, 0.68-0.90% of Ni, 0.22-0.38% of Mo, and 0.005-0.016% of Mb. It is controlled that [H] is no more than 0.0002%, [O] is no more than 0.001%, and [N] is no more than 0.005%. The production method comprises the steps of: electric furnace smelting; molten steel preheating; LF furnace processing; slag skimming; VD vacuum furnace processing; Si-Ca wire feeding; secondary argon blowing; continuous casting; heap-cooling to room temperature; electroslag re-melting and smelting; ingot drawing; mold cooling; pit cooling; slab heating; staged rolling; air cooling; and normalizing and tempering heat treatments. The obtained steel plate is ready for utilization. The purity of the steel in the steel plate provided by the invention is high. The surface of the ingot is smooth. The crystalline is uniform and compact. The thickness of the steel plate is 80-150mm. The process efficiency is higher. The steel has good tensile properties, impact resistance and high temperature tensile properties. The steel is safe and reliable in use.

Description

technical field [0001] The invention relates to pressure vessel steel and a production method thereof, in particular to steel for a boiler steam drum with a thickness ≥ 80 mm and a production method thereof. Background technique [0002] Boiler steam drum is a pressure vessel, and its working environment is under high temperature and high pressure. Therefore, a series of main technical indicators such as material purity, embrittlement resistance, and internal quality are extremely demanding. Currently, the steel used is 13MnNiMoR. [0003] More and more manufacturers use more than 1000t / h boiler drums, and the use of drum steel with a thickness of less than 80mm can no longer meet the requirements. Therefore, the demand for large single-weight and ultra-thick (more than 80mm) steel plates for manufacturing boiler drums It is getting bigger and bigger, and from the perspective of reducing manufacturing costs, it tends to be larger and more reliable. In terms of the current ...

AI Technical Summary

Problems solved by technology

[0005] The present invention aims to solve the problems that the existing boiler steam drum steel has many inclusions, low yield, and the process cannot satisfy the steel plate with a thickness of more than 80 mm, especially the steel plate with a thickness of more than 100 mm, and provides a steel with high cleanliness, that is, steel The non-metallic (A, B, C, D) inclusions in the steel should not be greater than grade 1.0, the sum of each category is ≤3.5, [H]≤0.0002%, [O]≤0.001%, [N]≤0.005% in steel Steel for boiler steam drum with stable mechanical properties, safe and reliable thickness ≥ 80 mm and production method thereof

Images