Hot rolling production method for 400 series stainless steel coils

Abstract

The invention discloses a hot rolling production method for 400 series stainless steel coils, which comprises the following steps of: 1) hot rolling: rolling at low temperature of between 780 and 880DEG C; 2) coiling: coiling at high temperature of between 730 and 850DEG C; 3) heating: charging at a temperature higher than 300DEG C, and raising the temperature to 750-850DEG C at a high speed of 85DEG C / h; 4) keeping the temperature: starting to keep the temperature when the external temperature of the coils reaches the keeping temperature of between 750 and 850DEG C, and stopping heating whenthe temperature of the bottom centers of the coils reaches the keeping temperature for more than 2 hours; and 5) cooling: cooling with a heating hood, cooling by using a cooling hood, and naturally cooling respectively. By the method, the production efficiency of the finished hot-rolled coils is farther higher than that of the conventional hot rolling production process, and the batching annealing production efficiency is improved by over 50 percent; in addition, the hot rolled coils have good performance, and the performance of strip steel meets various standards such as national standard, Japanese standard and American standard, so the hot rolled coils and the strip steel have good application and promotion prospect.

Description

technical field [0001] The invention relates to a production method of hot-rolled stainless steel, in particular to a production method of hot-rolled 400 series stainless steel coils. Background technique [0002] Ferritic and martensitic stainless steel are collectively referred to as 400 series stainless steel. When 400 series stainless steel contains a certain amount of austenite forming elements such as carbon and nitrogen, even if there is a high Cr content, austenite will be partially formed at high temperature. , Martensitic transformation also occurs during cooling after hot rolling, hardening the steel. Usually in hot rolling production, the martensite is decomposed into spherical carbides evenly distributed on the ferrite matrix through long-term annealing treatment, eliminating work hardening and making the steel soft for subsequent processing such as cold rolling. [0003] The production of 400 series hot-rolled stainless steel includes two production processes ...

AI Technical Summary

Problems solved by technology

[0014] The rolling temperature of the existing 400 series hot rolling process is relatively high (above 900°C), the hot rolling deformation structure of the hot coil is coarse, and it is not easy to recrystallize during annealing, which affects the improvement of annealing mechanical properties

Heating from room temperature, and the decomposition of the martensitic structure in the steel coil takes a long time, so a long annealing treatment time is required, the annealing cycle is long, and the production efficiency is low